1977 CB200

[Othen]

I have become somewhat addicted to older project cars and motorcycles, in recent years there have been quite a few Volvos (several 240s and the Amazon I still use most days) and motorcycles from Triumph, Suzuki, CCM and Honda. I tend to buy unfinished projects that someone has given up on, like this 1984 Goldwing that was a non-runner the PO had given up on, but 5 months later is a nice bike that I’ll keep:



Having more or less ‘finished’ (projects are rarely ever completely finished) the Goldwing I started looking for something else interesting. This 1977 Honda CB200 was advertised on eBay as a runner but needing ‘a few jobs to finish’:



The seller and I agreed a price of £1,500 over the telephone, then Bob (the dog) and I hitched up the bike trailer early this morning to collect it in Surrey (2 hours drive away). The PO seemed a genuine chap, he was new to motorcycle projects and having spent a fortune on the bike and new parts had realised he had bitten off more than he could chew. This was exactly what I was looking for: a complete bike in need of some work (but I hope not much money) to get it to a good standard. I never attempt to get vehicles to a show standard, but always to make good useable and reliable cars and motorcycles.

It looks like the CB200 had been off the road for at least 20 years until reassembled by the penultimate PO. Being more than 40 years old it is registered as an historic vehicle and so doesn’t need a MoT test and is tax exempt. The bike looks lovely, and seems to consist of more or less original parts, except the horrible silencers (mufflers for North Americans):



The silencers are far too noisy, don’t fit properly (the kick start would hit the right hand one) and not correct at all. I have found a supplier of new copies of the originals at £300/pair; I’ll order some tomorrow.

The motorcycle came with a printed copy of the Honda workshop manual, a Haynes manual, a folder of receipts and box of useful spares. The issues that foxed the PO were a very noisy top end (sounds like a bag of nails) and poor running. If I’m fortunate the noisy top end will be fixed by adjusting the tappets and tensioning the cam chain, I’ll do those jobs tomorrow. The PO had the carburettors cleaned, but they obviously need setting up properly, once I’ve sorted out the mechanical issues with the top end that should be easy enough to fix.

I noticed a few electrical jobs that need sorting, such as the horn button doesn’t work. There will probably be a myriad of other jobs once I have a better look at the motorcycle.

So, that is episode one. I’ll have a better look at the Honda in the light of day tomorrow and make a better estimate. I hope the noisy top end will be fixed by a bit of adjustment, but if it ends up needing something more then so be it - I bought this as a project. I’ll post an update after a proper reconnaissance - and almost certainly ask for some advice on fixing the issues I find.

More to follow…

Alan

 

[J-T]

Pretty bike.

 

[2wheel]

Nice looking bike. If the front brake caliper has not been serviced by the PO take it apart and clean it up and relube it. I, like you just like to clean a bike up the best I can and Leave it with its patina. Probably because I’m cheap and it saves some money.

 

[Othen]

Nice looking bike. If the front brake caliper has not been serviced by the PO take it apart and clean it up and relube it. I, like you just like to clean a bike up the best I can and Leave it with its patina. Probably because I’m cheap and it saves some money.

Thank you for that, cosmetically the motorcycle is very good.

The cable operated front brake seems to work fine, and looks like it has been refurbished. What lubrication does it use (I'm guessing copper grease)?

I strongly agree about not trying to achieve a show bike - I would have no interest in trailering it to a farmer's field in Lincolnshire to have a group of other middle-aged chaps with beards judge it (I'm also a tightwad). I'm not renovating this motorcycle - just winding back the clock about 4 decades so my 47 year old machine runs and rides like it did in about 1984.

I'll have a look at the tappets and cam chain adjustment. The Honda workshop manual is very clear except for one ambiguity regarding tensioning the cam chain. In the maintenance section (pp 5) it advises making a static adjustment with the timing mark at TDC, whereas in the rebuild part (pp 30) it says this says this should be a dynamic adjustment with the engine ticking over. It is a really simple system, so both methods will probably work just as well, but I think I'll stick with the static procedure today. Is there a preferred way?

I'll give the motorcycle a good check over in the light today, fix anything obviously wrong and come up with a plan for anything requiring more thinking about or work. I'll report back on anything I might need help with.

Alan

 

[Othen]

I’ve started investigating the lumpy motor - some good news and some bad.

The PO had spent quite a lot on bling bits like these Allen bolts for the engine covers:



… very nice. I was a little surprised to have so much oil drain from the generator cover - half a litre came out. Is that normal or do I have a leaky oil seal on the left side of the crank? I’m guessing some oil there is normal because Mr Honda bothered to fit a gasket under the generator cover.

I’d intended to adjust all the tappets and the cam chain tensioner, two of the tappet covers came off easily but the other two (right side exhaust and left side inlet) just would not move. Someone has obviously tried to hammer them off in the past:


… and also on the right side:



It looks like someone has used some sort of sealant instead of O rings, which has set hard. The covers will have to come off one day, but I decided not to pursue that today. It is likely that the two mashed up covers will be destroyed getting them off, so I’d better get some replacements ready before I attempt that one.

The two tappets I could access both needed tightening. i adjusted the cam chain tensioner using the static method and that seems a bit quieter.

It would seem that the carburettors are a long way from where they should be. The left hand plug was sooty and that cylinder is clearly running much hotter than the right one. I think I need to take a step back and set up the carburettors from scratch - so I’ll have a read of the service manual before trying that.

I‘ve ordered the correct (reproduction) silencers (mufflers), and I’d better start looking for some tappet covers.

As always with 50 year old machines: one pace forward… one step back

 

[Othen]

I've found a set (of 4) used tappet covers that look (from the photos) to be in good condition for £20. They should be here about the same time as the new silencers, so I'll shelve work on the CB200 for a few days.

I was looking through the box of spares that came with the CB200 whilst putting the tools away. The PO told me he had re-built the carburettors, but I found one complete and unopened carburettor reconditioning kit - I'm just wondering whether the PO only got round to rebuilding one of them, which might explain why one cylinder is running far richer than the other? I think the only answer is for me to strip both carburettors down, check them out and replace any parts required, then set them up from scratch as per the workshop manual.

I also found in the spares box a complete and unopened engine gasket set - I'm wondering whether the PO knew something was amiss inside the motor/

Perhaps I'm just being a bit cynical? Time will tell - if I end up doing more work to sort mechanical issues then that will be okay (and perhaps to be expected on a nearly 50 year old machine).

Alan

 

[Othen]

Sometimes thinking is better than doing - I had a think about the issues that have emerged so far whilst pumping some iron in the gym:

a. The tappet covers: I think I'll need some heat (try the hot air gun first, if that doesn't work then the butane torch) to melt the black sealant, then perhaps hammer on a slightly smaller socket to twist the covers off. It needs doing so I may check the tappets, but there is no rush. I'll do it whilst I have the carburettors out of the way (see below).

b. Oil in the generator case: I can't see any seal outside of the main bearing on the left side (in the diagram on pp 31 of the manual), so I conclude there is nothing to stop the engine oil ending up there.

c. The rough running: this can't be an ignition problem because it is a wasted spark system; the most likely cause is the two carburettors being set up very differently: the left so rich it will start with no choke, and the right providing almost no petrol (gas) at all. We are in the middle of a cold snap at the moment so I'll pull the two carburettors off the motor, bring them inside and check them on the desk in my study.

If I'm right about all the above then there isn't much wrong and I should have the CB200 running sweetly quite soon. I'll do a compression test whilst the carburettors are off the motorcycle just to be sure, but I don't think that is the issue.

 

[ancientdad]

If you're not aware, most carb rebuild kits are sold with incorrectly-sized jets and float needles so the advice is to always clean and re-use your brass parts (jets never wear out of course, only get clogged). Yes, oil is present in all the late '60s and '70s twins, though half a litre sounds as if it might have been a little bit overfull. As with all Honda twins, check the oil with the bike upright (on centerstand or held there manually) and without screwing in the dipstick.

 

[Othen]

If you're not aware, most carb rebuild kits are sold with incorrectly-sized jets and float needles so the advice is to always clean and re-use your brass parts (jets never wear out of course, only get clogged). Yes, oil is present in all the late '60s and '70s twins, though half a litre sounds as if it might have been a little bit overfull. As with all Honda twins, check the oil with the bike upright (on centerstand or held there manually) and without screwing in the dipstick.

Thank you for that - it is very useful indeed.

I didn't know about the incorrectly sized jets in rebuild kits - which may be a problem if the PO has used new parts in just one of the carburettors in that I won't have the originals. I'll find out when I get the carburettors apart on the bench (maybe tomorrow if I get time).

Alan

Addendum: I've just checked the spare carburettor rebuild kit that came with the motorcycle and can see that the replacement jets would be the correct size for the CB200 (#88 main and #38 slow running), so that has turned out to be a blind alley.

 

[Cycleranger]

Decent looking little 200!
I always wondered about the unique tank design on that model.
It's unlike any other model from that era.

 

[ancientdad]

Addendum: I've just checked the spare carburettor rebuild kit that came with the motorcycle and can see that the replacement jets would be the correct size for the CB200 (#88 main and #38 slow running), so that has turned out to be a blind alley.

Even if they show the same numerically (stamped on the jet) they can still be incorrect. Read this article by former American Honda service executive and our resident carb guru Mike Nixon about carb kits, it's damning for the industry and he points out many things most aren't aware of.

Carb Kits www.motorcycleproject.com

 

[Richard Pitman]

Regarding the valve adjustment covers, I've just won a similar battle on a recently purchased butchered 175 motor.

I resorted to filing the hex on the cover to the next size down, then hammering on a six point impact socket, then using my Clarke mains electric impact gun on it. I had previously tried usual approaches of heat and cold, penetrating oil etc.

Regarding the noisy top end, don't want to be a Jeremiah, but the CB200 camshaft and nearside cam journal have a bit of a reputation for lubrication failures and subsequent damage. Fingers crossed yours will be OK, spare parts availability is a bit of an issue.

 

[ballbearian]

Pull out a magnifier. the Keihin jets have a tiny K on them.

 

[2wheel]

Decent looking little 200!
I always wondered about the unique tank design on that model.
It's unlike any other model from that era.

I read that it was Hondas shot at a cafe style bike with the tank design. I think it’s a love it or hate it thing. I bought mine just because I thought it was different. Maybe not better but different. Plus the yellow looks blazing fast..

 

[Othen]

I read that it was Hondas shot at a cafe style bike with the tank design. I think it’s a love it or hate it thing. I bought mine just because I thought it was different. Maybe not better but different. Plus the yellow looks blazing fast..

Super duper.

Talking of café racer style, here is a photo on my motorcycle in a previous life: when the PO first bought it;



... he returned it to the original style and colour; I'm rather pleased he did.

 

[Othen]

Regarding the valve adjustment covers, I've just won a similar battle on a recently purchased butchered 175 motor.

I resorted to filing the hex on the cover to the next size down, then hammering on a six point impact socket, then using my Clarke mains electric impact gun on it. I had previously tried usual approaches of heat and cold, penetrating oil etc.

Regarding the noisy top end, don't want to be a Jeremiah, but the CB200 camshaft and nearside cam journal have a bit of a reputation for lubrication failures and subsequent damage. Fingers crossed yours will be OK, spare parts availability is a bit of an issue.

Thank you, that is helpful. I suspect getting the tappet covers off will be a mission!

I'll get the carburettor issue (which is a very real one that I know about and needs fixing) sorted first, if it still noisy I'll go looking inside after that. Other folk have suggested the CB200 motor is prone to snapping piston rings or the cam chain tensioner failing... so I don't want to jump to any conclusions.

If I do end up stripping down the motor to fix something inside then that will just be part of the project, and a reasonable thing to expect for a nearly 50 year old machine. The really good thing about the CB200 is it is so simple.

Yours aye,

Alan

 

[NeverEverJamToday]

I bought mine just because I thought it was different. Maybe not better but different. Plus the yellow looks blazing fast..

You got the Parakeet Yellow tank. I am peanut butter AND Jelly. Rarely see that og scheme come up.

 

[Othen]

Houston, we have a problem!

I took the carburettors off so I could bring them inside the house to clean and check them over this morning (we have a bit of a cold snap here so the dining room table will be a lot more comfortable than the garage for that job).

The carburettors being off the motor was an ideal opportunity to conduct a compression test, which was bad news: 75 PSI in both cylinders - and taking a while to get there. If I'm fortunate it might be just a head gasket, otherwise rings or valves, but either way we are now into at least a top end rebuild. No matter, this is just part of 50 year old car/bike ownership. I'll do the carburettors first, then get the head off for a look around.

It was a bit ominous that I found a complete and unopened gasket set in the spares box that came with the motorcycle. Perhaps this is why the PO gave up with the project (having spent a fortune on bling)?

The good news in the shiny new reproduction CB200 silencers arrived by courier this morning .

Time for a nice cup of tea, then have a look at those carburettors. If I have time I might take the head off this afternoon .

Alan

 

[Othen]

It was a nice, sunny afternoon, so I sat outside on the deck and have cleaned and reassembled the carburettors. Apart from a few nitrile O rings I didn't change any parts. There was nothing noticeably wrong with either: the jets and needle settings were all correct - and it looked like they had been cleaned fairly recently (last couple of years).

The carburettors are ready to go back on the motor - but there would be no point doing that as the head is going to have to come off in order to find the missing compression. I'll have a read of the workshop manual this evening and take the head off for a look tomorrow. I rather suspect the head gasket has failed because the low compression readings were about the same both sides. The question is why did it fail and has anything else failed? Perhaps we will find the answer tomorrow .

My purchase on a whim has turned out to have many more problems than met the eye; if it had been a £40,000 motorcar I'd be pursuing the seller (and would have checked more thoroughly in the first place). I'm not that fussed though, this was a project motorcycle, bought cheaply and with a bit of risk. It is a really simple motor and it will be fun to sort out its little problems.

More (possibly much more!) to follow .

Alan

Addendum: I still need to get those other two tappet covers off - but I'm thinking that might be easier with the head on the bench.

 

[ancientdad]

I rather suspect the head gasket has failed because the low compression readings were about the same both sides. The question is why did it fail and has anything else failed?

Head gaskets actually leaking compression are rare on these Honda twins, typically the problem is rings or valves and yes, to find the low compression numbers that equal is fairly rare too. Makes you wonder if the bike had sat for a very long time prior to the PO buying it and he dressed it up before trying to get it running with what may well have been an engine that was lightly stuck previously, and now has stuck rings on both sides.

I'm going to say the obvious here because I want to be sure that you know, but that engine has to be removed from the frame to do any top end work.

 

[2wheel]

More (possibly much more!) to follow .

Alan

Addendum: I still need to get those other two tappet covers off - but I'm thinking that might be easier with the head off.

I would be tempted to try to get those caps off while the engine is in the frame unless you have a good way to hold the engine secure while working on it. I would think you might have to use a good bit of torque to get those loose and if there is room to work in frame I would give it a go.

 

[Othen]

Head gaskets actually leaking compression are rare on these Honda twins, typically the problem is rings or valves and yes, to find the low compression numbers that equal is fairly rare too. Makes you wonder if the bike had sat for a very long time prior to the PO buying it and he dressed it up before trying to get it running with what may well have been an engine that was lightly stuck previously, and now has stuck rings on both sides.

I'm going to say the obvious here because I want to be sure that you know, but that engine has to be removed from the frame to do any top end work.

Thank you for that. I had not realised the motor would have to come out of the frame to remove the head (but I suppose I'd have found out after reading the workshop manual this evening), so thank you - it wasn't obvious at all.

In that case I may have to reorganise my garage/gym a bit before starting work as I'll need a bit more space. Perhaps it wouldn't be a bad idea for me to have a bit of a tidy up first anyway. I'm not in a particular rush to do this work, but I might as well get on with it.

The PO did tell me the motorcycle had sat for a long time before the penultimate PO undertook the café racer project pictured above. That is corroborated by the lack of MoT history on the DVLA website - that normally records tests for about the past 20 years but there is nothing logged. One might assume it had been off the road for all that time (although it would not have needed a MoT test for about the past 8 years).

The PO had no mechanical aptitude, he bought the CB200 in its café racer incarnation about a year ago and outsourced all the mechanical and electrical work to a mechanic (hence a bill so large he could not tell his wife). If head gasket failures between the cylinders are rare, then I think it quite likely that the rings are stuck on both pistons. If that is the case and I am fortunate I may get away with some new rings and honing the bores - but that is jumping to conclusions.

Alan

 

[Othen]

I would be tempted to try to get those caps off while the engine is in the frame unless you have a good way to hold the engine secure while working on it. I would think you might have to use a good bit of torque to get those loose and if there is room to work in frame I would give it a go.

Thank you for that.

I'm still thinking about this problem. There isn't much room around the head whilst it is in the frame - and I understand the whole motor will have to come out in order to remove the head and barrels. Someone suggested in the discussion above that I might file the damaged hexagons to a smaller size, hammer on a smaller socket and then use an impact driver (plus a bit of heat I think) to get the caps off. That might be easier with the lump on the bench (but before I take the head off)?

Alan

 

[Cycleranger]

The state of those tappet covers makes me wonder if the tappets are adjusted correctly.
If they're too tight that could contribute to lower compression.

 

[ancientdad]

The state of those tappet covers makes me wonder if the tappets are adjusted correctly.
If they're too tight that could contribute to lower compression.

That's a good point and certainly a possibility, and I agree that the frame holding the engine still would help with the removal of those stuck valve covers. Might be worth doing that to check the valve clearances beforehand, though I suspect it will still need to come apart.

 

[ballbearian]

When all else has failed a large plumber's pipe wrench will get those tappet covers cracked loose. I try to loosen all side cover screws and whatever while the engine is still mounted. Work smarter not harder.

 

[Othen]

When all else has failed a large plumber's pipe wrench will get those tappet covers cracked loose. I try to loosen all side cover screws and whatever while the engine is still mounted. Work smarter not harder.

Thank you.
I was thinking of that, but there isn't much room around the head with the motor in the frame. I'd like to get the covers off before pulling the engine out so I'll concentrate on that and creating enough room in my garage/gym to undertake an engine-out repair today.

 

[Othen]

If you're not aware, most carb rebuild kits are sold with incorrectly-sized jets and float needles so the advice is to always clean and re-use your brass parts (jets never wear out of course, only get clogged). Yes, oil is present in all the late '60s and '70s twins, though half a litre sounds as if it might have been a little bit overfull. As with all Honda twins, check the oil with the bike upright (on centerstand or held there manually) and without screwing in the dipstick.

I was just thinking about the amount of oil that came out of the generator cover (0.5 litre) - that was rather more than I'd expected. Having now discovered that the motor has very low compression both sides I'm wondering whether the oil level was high because of fuel blow-by past the rings? That would be an entirely plausible explanation for both issues.

I have found a supplier here in the UK (Steve Carthy Motorcycles - appears to be genuine) selling +0.5mm piston kits (including rings, gudgeon pins etc) for only £36 per side delivered. That seems very reasonable to me - in the light of the above I'm wondering whether I would be wise to order two sets and have them on the shelf for when I get the motor apart, that way I could get the barrels off to the machine shop with the pistons straight away for a rebore. Would this be a reasonable thing to do under the circumstances?

It is possible of course that the pistons and barrels are just fine and the leak is coming from the valves, but that seems somewhat unlikely given the oil level and equal (but very low) compression on both cylinders. If I can fix this issue for £72 plus the cost of a rebore I'd think that a win.

Views would be appreciated.

Alan

 

[ballbearian]

I was just thinking about the amount of oil that came out of the generator cover (0.5 litre) - that was rather more than I'd expected. Having now discovered that the motor has very low compression both sides I'm wondering whether the oil level was high because of fuel blow-by past the rings? That would be an entirely plausible explanation for both issues.

I have found a supplier here in the UK (Steve Carthy Motorcycles - appears to be genuine) selling +0.5mm piston kits (including rings, gudgeon pins etc) for only £36 per side delivered. That seems very reasonable to me - in the light of the above I'm wondering whether I would be wise to order two sets and have them on the shelf for when I get the motor apart, that way I could get the barrels off to the machine shop with the pistons straight away for a rebore. Would this be a reasonable thing to do under the circumstances?

It is possible of course that the pistons and barrels are just fine and the leak is coming from the valves, but that seems somewhat unlikely given the oil level and equal (but very low) compression on both cylinders. If I can fix this issue for £72 plus the cost of a rebore I'd think that a win.

Views would be appreciated.

Alan

Blow by as a cause for increased sump level? Not likely. Probably just overfilled. Angle of the bike as parked makes a huge difference. Even when the small cover is off for a timing check, I lean the bike away from the stator side for reduced mess.
I'd hold off getting pistons till either you or the machinist checks the bores. I've had low comp and the cylinders had some deep scratches that called for 1.00mm over (4th OS).
Read Mike Nixon's excellent write up on the 'Leakdown Test' in our Mike's Garage section. It can show if the cause is valves or rings. Even if you don't want to get a cheap tester, it is still very informative. Knowledge is power and good for saving your wallet.

 

[Richard Pitman]

Unless you have a very large engineers vice, securely bolted down, it'll be easier to get those tappet covers off while the engine is still in the frame, if using a breaker bar or pipe wrench. I had my engine sat on the bench, hence the use of a powerful impact driver.

I'd certainly go for those piston sets ( when you say 'two sets' I assume you mean a pair, not two sets of two ), that's a reasonable price.

You'll find this info in the workshop manual, but worth pointing out that CB200 has an endless cam chain, not a split link in the earlier 175 engine. Getting the head off is consequently a bit more involved than removing the 175 head, unless of course you intend to replace the cam chain, in which case you can simply break the chain, head then lifts straight off.

EDIT To save me some typing, this is from my CD175 thread, that engine also uses an endless cam chain

Removed all four tappet adjustment screws, to unload the cam shaft. Took the eight screws out of the two cam journals, using the battery impact, came out easily. Undid the two cam sprocket bolts next, then pulled the cam journals off the head, followed by the rocker spindles and rockers, bagged up and labelled according to position in head.

Then a fun few minutes waggling the endless cam chain and loose sprocket about, until it all aligned and I was able to lift the cam out.

As said earlier, head gasket failure as a cause of loss of compression is unlikely.

 

[Richard Pitman]

Good point about bore damage. On the engines I've had rebored I've gone for 1.00mm oversize straight off, on the basis that bigger is better, and that engine is unlikely to need another rebore whilst in my ownership. Extra 7 cc's !

 

[Othen]

Good point about bore damage. On the engines I've had rebored I've gone for 1.00mm oversize straight off, on the basis that bigger is better, and that engine is unlikely to need another rebore whilst in my ownership. Extra 7 cc's !

Blow by as a cause for increased sump level? Not likely. Probably just overfilled. Angle of the bike as parked makes a huge difference. Even when the small cover is off for a timing check, I lean the bike away from the stator side for reduced mess.
I'd hold off getting pistons till either you or the machinist checks the bores. I've had low comp and the cylinders had some deep scratches that called for 1.00mm over (4th OS).
Read Mike Nixon's excellent write up on the 'Leakdown Test' in our Mike's Garage section. It can show if the cause is valves or rings. Even if you don't want to get a cheap tester, it is still very informative. Knowledge is power and good for saving your wallet.

Unless you have a very large engineers vice, securely bolted down, it'll be easier to get those tappet covers off while the engine is still in the frame, if using a breaker bar or pipe wrench. I had my engine sat on the bench, hence the use of a powerful impact driver.

I'd certainly go for those piston sets ( when you say 'two sets' I assume you mean a pair, not two sets of two ), that's a reasonable price.

You'll find this info in the workshop manual, but worth pointing out that CB200 has an endless cam chain, not a split link in the earlier 175 engine. Getting the head off is consequently a bit more involved than removing the 175 head, unless of course you intend to replace the cam chain, in which case you can simply break the chain, head then lifts straight off.

As said earlier, head gasket failure as a cause of loss of compression is unlikely.

Thank you chaps, that is all very helpful.

First some good news: the two tappet caps gave up the struggle against the hammer and chisel quite easily this morn:



… as you may see, the centre of the first one failed (when I tried forcing on a slightly smaller impact socket). The technique that worked was using a chisel to make several shallow starts around the outer rim (carefully avoiding the head). Both lids started moving quite easily - I suppose the extra torque from being a larger distance from the centre, plus the jarring motion did the trick. It is just as well that I‘d ordered some replacements (that should arrive today).

Now I need to make a bit more room for an engine out job:



… my son and I may have to forego the gym for a few days.

The leak down test is not a bad idea - indeed I think I have the test equipment somewhere in the garage. If I can find everything I may do that today, but with respect there is a bit of ‘so what’ - the top end has to come off anyway, and unlike a car engine taking the barrels off will only take a minute or two once the head is detached.

I did indeed mean one pair of pistons for £72 in the above Richard. That was rather less than I expected and may be something of an opportunity price.

Somewhat perversely I’m quite enjoying this project. It would have been nice if I’d sorted the rough running issue with a bit of fettling of the carburettors, but it will be fun to become more intimate with the inside of the CB200’s engine.

Alan



Addendum: I've just read Oldfart's article (I'm guessing that is Mike Nixon) on leak down testing. That is all good stuff. I've done a leak down test once previously on a Volvo 244 and the article was exactly as my understanding. That was a decade ago though, so I may have trouble finding the test equipment - but if I can I'll run the test today. As I said in the above though: it hardly matters, the head is coming off anyway, at least for inspection but probably for pressure testing as well. Once the head is off it would be madness not to remove the barrels and inspect the pistons and bores as that will take a moment.
I read about the continuous cam chain in the manual last evening. I would not plan to change it unless there are obvious signs of a problem.

 

[NeverEverJamToday]

+1 to leakdown test. made my adapter from hardware store parts for about 17USD.
-100 to chisels!!!!

Do you have any extra info on the .50 over parts to which you have access? Aside from nos, only know of one supplier (cruzinimage), in Japan.

What rec/reg is installed on yourbike btw?

 

[Othen]

+1 to leakdown test. made my adapter from hardware store parts for about 17USD.
-100 to chisels!!!!

Do you have any extra info on the .50 over parts to which you have access? Aside from nos, only know of one supplier (cruzinimage), in Japan.

What rec/reg is installed on yourbike btw?

Many thanks.
No apology for the chisel technique - it is a last resort I've had to use a few times when I'd run out of options. There is no damage to the head (I have a steady hand) and the cap was being replaced anyway.
I've just called the piston supplier to ask of the manufacturer, the receptionist thinks they are NOS, but will check and call back.
I have not checked out the R-R yet - why is that important?
Alan

Addendum: the supplier has just called back to confirm they are NOS.

 

[Richard Pitman]

Some others on Ebay UK

EDIT Actually, ignore this, wasn't the one I was looking at earlier .....

HONDA PISTON SET 56.00 mm + 0.50 mm OVER, CB200 T CB200 B CL200 SCRAMBLER 1974 - | eBay

CL200 SCRAMBLER 1974 USA. CB200 ENGLAND. CB200 GENERAL EXPORT. HONDA PISTON SET. PISTON 56.00 mm. CB200B 1974 USA. +.50 mm OVER STANDARD SIZE. 15 mm PIN SIZE.

www.ebay.co.uk

 

[Othen]

The replacement tappet covers arrived by courier today - all good used original parts. I have no idea why a PO used silicone sealant instead of O rings costing pence.

 

[ancientdad]

POs are the bane of our vintage bike existence... and as popular as these bikes have become again in recent years, the list of POs are no smarter than they were a couple decades ago when these bikes were newer and there were more of them around in better condition. It's as if they ignore all the information available out there despite there being so much more with the internet today, and so much more easily attained. Yet another good example I came across on a running engine when I bought my 450 in late 2016.

 

[Othen]

POs are the bane of our vintage bike existence... and as popular as these bikes have become again in recent years, the list of POs are no smarter than they were a couple decades ago when these bikes were newer and there were more of them around in better condition. It's as if they ignore all the information available out there despite there being so much more with the internet today, and so much more easily attained. Yet another good example I came across on a running engine when I bought my 450 in late 2016.

View attachment 28493

You are so right. My interest is in 40-60 year old motorcars and motorcycles (that is just an era I like: young enough to have disc brakes and electric starters - old enough not to have any computers). The thing about vehicles of that era is that they have all gone through a period (normally when they were 20-30 years old) when they were almost worthless. The owner at that point (normally the 3rd or 4th keeper) has bought the vehicle for a few hundred pounds, throws away the service history, parks it under an apple tree in the garden and bodges everything just well enough to keep it going with Harry Black (cloth tape), bathroom sealant and bailing twine. When the car or bike starts to gain some value due to its rarity at about the 40 year point an owner like us has to unpick all those bodges. I think this is what we all like about classic vehicles so much.

Alan

 

[ancientdad]

...has bought the vehicle for a few hundred pounds, throws away the service history, parks it under an apple tree in the garden and bodges everything just well enough to keep it going with Harry Black (cloth tape), bathroom sealant and bailing twine.

A more polite version of what we Yanks might say

 

[Othen]

A more polite version of what we Yanks might say

... I lived in Virginia for 3 years so I'm pretty fluent in both languages .

 

[2wheel]

POs are the bane of our vintage bike existence... and as popular as these bikes have become again in recent years, the list of POs are no smarter than they were a couple decades ago when these bikes were newer and there were more of them around in better condition. It's as if they ignore all the information available out there despite there being so much more with the internet today, and so much more easily attained. Yet another good example I came across on a running engine when I bought my 450 in late 2016.

View attachment 28493

I got my first motorcycle Yamaha JT2 60 when I was 9. When it broke I had to figure out how to fix it on the fly. The closest dealer/ parts was a 45 minute drive one way and my parents didn’t have the money to buy parts every time I needed a repair so I was probably guilty of some of these type hacks. Just the reality of a country kid with a shed of parts not meant for motorcycles. lol.

 

[EzPete]

POs are the bane of our vintage bike existence... and as popular as these bikes have become again in recent years, the list of POs are no smarter than they were a couple decades ago when these bikes were newer and there were more of them around in better condition. It's as if they ignore all the information available out there despite there being so much more with the internet today, and so much more easily attained. Yet another good example I came across on a running engine when I bought my 450 in late 2016.

View attachment 28493

Why would someone have even used sealant on that gasket? Although, by the looks of it, their 3yo was the one that did it.

I do like the tank line on that 200 - that's one fun clean looking bike - although crazy that he put all that money into it without sorting the engine first. Generally, the only time to do engine last is on a complete frame-off where you know you're going back in with a complete rebuild/swap. From the sound of it, the PO may have just been in over his head and been taken advantage of. I'd wager the gasket kit may have been a failed idea to correct the issues himself, before he realized he couldn't.

 

[Richard Pitman]

Most aftermarket full gasket sets for the 175/200 engines usually include a new set of those O inspection cover rings.

 

[Othen]

Why would someone have even used sealant on that gasket? Although, by the looks of it, their 3yo was the one that did it.

I do like the tank line on that 200 - that's one fun clean looking bike - although crazy that he put all that money into it without sorting the engine first. Generally, the only time to do engine last is on a complete frame-off where you know you're going back in with a complete rebuild/swap. From the sound of it, the PO may have just been in over his head and been taken advantage of. I'd wager the gasket kit may have been a failed idea to correct the issues himself, before he realized he couldn't.

Reading between the lines - I think you have hit the nail on the head. The PO was a genuinely nice chap who bought the cafe racer project with the intention of making it an original show bike. He probably thought the aim would be achieved by bolting on some (very expensive) parts. He had no mechanical aptitude and so outsourced mechanical and electrical jobs to expensive professionals. As the costs spiralled he realised he was in over his head. The PO had no idea how to get it running properly (but it looked nice).

This is where I came in. I didn't know what was wrong with it, but it was worth a punt and I knew I’d be able to fix it - just a question of how much it would cost.

Projects like this suit me well - much like the Goldwing - and a around dozen other bikes and Volvos and Mazdas I’ve had in the past decade. On the whole they turn out well, don’t cost much and are quite satisfying.

Alan

 

[Othen]

Most aftermarket full gasket sets for the 175/200 engines usually include a new set of those O inspection cover rings.

Yes indeed. I thought it might so I checked this morning - and you are right.
Alan

 

[ancientdad]

Why would someone have even used sealant on that gasket? Although, by the looks of it, their 3yo was the one that did it.

Don't watch too many YT videos on things like starter clutch repairs then, because the operative words are often "let's goop up the cover...". Yep, that's about a 3 yo level of application and other than the grommet around the alternator wiring that gasket survives quite well with clean dry surfaces alone.

 

[Richard Pitman]

I happened upon a video this morning, chap rebuilding an SL175 engine, doing quite a decent job, but applying a thin layer of sealant to ALL FOUR surfaces ie both sides of the gasket as well as the two mating surfaces. Good luck getting that engine apart and cleaned up in the future. Complete contrast to the Chinese lady I've been watching rather obsessively, she only uses sealant in the proper places.

 

[Othen]

I happened upon a video this morning, chap rebuilding an SL175 engine, doing quite a decent job, but applying a thin layer of sealant to ALL FOUR surfaces ie both sides of the gasket as well as the two mating surfaces. Good luck getting that engine apart and cleaned up in the future. Complete contrast to the Chinese lady I've been watching rather obsessively, she only uses sealant in the proper places.

Unless the manufacturer recommends otherwise, I mostly use a smear of machine grease on paper gaskets, that seems to work fine.

I've created enough room for engine-out work in the garage, so I'll start work on the CB200 today

 

[Othen]

It has taken about 2 hours to get this far, but then I’ve been plodding along and bagging everything carefully.



I‘ve stopped for a cuppa and to take Bob (the dog) for his lunchtime walk. I’ll get the head and barrels off this afternoon.



Addendum: the oil I drained did smell of petrol, so my bet is the rings are at issue and there has been considerable blow by occurring.

 

[Othen]

So, the top end is apart, there is some quite good news, some less good (but as expected) news and some bad news.

The best news is that everything came apart easily, no stripped threads, nothing was stuck or rusted together. The bad news became apparent as I was removing the camshaft:



... the sprocket carrier has failed - fortunately the bolt was holding on to the broken bit so it didn't fall into the bottom of the engine. I've found a second hand replacement on eBay for £200 (ouch!). I don't have any real options here, but perhaps I'll see if the seller will take an offer and save a few bob?

The rest of the head seems to be in quite good order - I've turned the head upside down and filled the combustion chambers with paraffin (kerosene), after half an hour there had been no leakage at all - I'll check again in the morning.



There are no broken piston rings, which is good news:



... but there are clear striations at the back of the skirts where they always wear. The bores feel smooth, but have clear marks:



... and:



It clearly needs a re-bore - so I've ordered the 0.5mm (2nd O/S) replacements and found a place in Nuneaton (40 miles away) that can do the work for £45 (which sounds fine to me).

So, some good news, some bad. It looks like the costs will be something around £300 to get the CB200 back on the road - which is more than I'd hoped for but it is too good a bike not to fix.

Alan