Rebuild of my English CB175K6, 1972

Thank you for the surprise post!
I'm finding it a bit hard to keep enthusiasm.
Hope to strip the front wheel tomorrow and try to measure any ovality.
If there is some there are 2 companies who specialise in refacing the drums on old bikes, neither are close, but a wheel can be posted easily enough.

I have too many interests going on at the moment, and the Honda is at the bottom of the pile at the moment.
 
Didn't realise there was a competition!

I have a thread about my hill climb race car elsewhere with 731,000 hits and about 3K posts!
People like to read about my troubles!
Wish i could dissapoint them.

I was contemplating selling this CB to fund a fresh race engine for the hillclimber, Permission given to do the engine today, AND keep the bike!
 
911hillclimber said:
People like to read about my troubles!
Wish i could dissapoint them.
Click to expand...

If you weren't as entertaining as you are, your troubles wouldn't be as interesting! And if you could disappoint them we'd have 25,000 less views of threads here, we can't rely on James alone. :)

911hillclimber said:
I was contemplating selling this CB to fund a fresh race engine for the hillclimber, Permission given to do the engine today, AND keep the bike!
Click to expand...

Now that's a SWMBO to hold onto! (y)
 
Ha!
Back to the 'issues'!
Took the front wheel off the bike and mounted the wheel on the bench to try to check the ovality of the drum.
Using my apprenticeship calipers, I found the minor diameter of the oval and turned 90 degrees and found a 4 though/0.1mm difference. I just about got a 0.1mm feeler between the one leg of the internal caliper and the gap.
The drum is a true oval rather than an egg shape, so at least simple for me to understand.
The drum surface is poor tbh, and should have been machined ages ago, me being lazy for once has caught me out...

I hope the pics show the predicament.

I think i know a local engineer (a one-man-band) with a Bridgport miller with a throat deep enough to take the radius of the wheel, maybe the tyre too, but he is racing this wekend in the north of England (Harewood House) so will have a tele call with him Tuesday and discuss.
There is a great video of the drum being hand machined using a miller on Youtube,

https://youtu.be/qvLvoNMhbG8?t=4

If Terry can do it this can be a while I wait/assist job.

The drum itself is not tapered (conical) so I hope a 5 thou cut will clean everything up.



 
I know I'm chiming in a bit late but just a thought about your forks not working well. I know you've fixed it now but I found out to fit the forks and tighten just the top nuts then fit the wheel, brakes etc but do up the bolts/nuts gently. Then get over the top of the handlebars and bounce a few times with the centre stand off, then tighten the lower yolk bolts, bounce again and tighten the mudguard bolts etc. working your way down until you are done. I know this works because I re-fitted the forks to my CX500 once and tightened all the bolts up willy-nilly and rode off and the bike crabbed first one way, then the other and threatened to throw me off. Once tightened like above it was as smooth as anything.

Just a thought Graham . . . . . . .
 
One of my fork lower castings is porous...I have a whetting of fork oil on one side coming out of somewhere in the casting.
Always something to do.
however, the forks now plunge down with comparative ease using my weight on the bars and rebound well too.
just need to fix this oval drum and things look good.
 
Hi 911hillclimber, I've frantically been searching for information to see if CB200 guides will fit a 175 head and it seems you may be able to answer all of my questions and I've read all of this thread with much interest. I was referred over to here from the 'other' not so active forum by Richard Pitman which was absolutely great :)

Now, I've recently restored a 1973 CD175A4 and stupidly decided to take a chance with the engine parts I had. I managed to re-cut the valve seats, replace all bearings and seals and it looked as if it was going to be a good engine. On first start up though it smoked terribly, particularly from the right hand cylinder so I immediately knew then engine was going to require more attention! So, all in bits again I decided to take the head and barrel to see Steve Riley at Piston Broke in Bristol who is a well respected time served engineer in the Bristol biking world and beyond.

Within in minutes he condemned the surface finish of my bores and noticed a score in the right hand one which would account for the excessive oil burning. (My eyes aren't brilliant so I didn't spot quite how bad it was....once he brought it to my attention even I could see daylight past one of the rings!!) Idiot!

Anyway, no harm done, another gasket set, re-bore pistons and rings and that part is all good. Lesson learnt....

However, he has also suggested that my valve guides are less than ideal and require replacement. I'm having real difficulty finding the original guides other that NOS items through eBay from the states at great expense... besides this I'm not keen to refit OEM guides as the exhaust stem seals are a pretty rubbish design by modern standards and the inlets don't have any at all! This got me wondering about CB200 guides as the engine is very similar and they are fitted with what I would call 'proper' stem seals.

I've discussed this possibility with Steve at Piston Broke but he seems to think the o/d of the guides is different (from his records) and they won't fit the head; your post however would suggest otherwise.

The 200 guides seem to be available from DSS and CMSNL which is a good sign, so just wondering what else I would need?

Am I right in saying you just replaced your inlet guides and stuck with the original exhaust ones?

I'd ideally like to replace all four with the 200 ones.

I also have a lathe so spacer washers to correct the spring heights won't be an issue.

I assume I would need the following if you could clarify?

- 4x CB200 valve guides
- 4x CB200 stem seals
- 4x CB200 inner valve springs (to clear the larger diameter stem seals)
- Various spacer washers to raise the outer spring seating to the same level as the shoulder on the CB200 guide and make the springs all sit level; or fit CB200 outer valve springs too which I would assume are longer?

Anyway, sorry for the lengthy post and all the questions; I'm getting nowhere with this at the moment and the bike has been back in bits since June and I'm itching to get it going again!

Thanks in advance and all the best.

Steve
 

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Hello Steve, as you have read in this very long thread I simply put CB175 exhaust guides from a spare head to the inlet side and used CB175 ex seals on them so sealing all valves.
I used no new parts except the seals which iirc came from CMSL. A lot of DS parts have to come to the UK from their USA warehouse, so adding cost and around a week at least. You don't find this out until your order is placed!

Basically you just end up with exhaust guides (heat the head to a good temp and drift the ones to use out/in. Turn a stepped drift up as i did to hit things square. No real brute force required or get you engine machinist to do them.
All parts transfer across.
I have repeatedly run my engine smoke free since. Seems strange the engine was designed with no inlet seals so oil would burn 'by design' and the CB200 has seals all round.
As you know, you will need to get new springs for a 200 if you use 200 guides, hence me using some 175 exhaust guides from a dead head i had, in fact the original head off the engine which was damaged/corroded to bad to use. The valve seats were too far gone.
Hope this helps, but do not hesitate to contact me again if you feel the need to.
Richard and everyone on this great Site has helped me so much, happy to pass a bit of that on.
Graham.
 
Apologies, my mistake, I thought that Graham had indeed fitted CB200 guides to a 175 head.

I'm sure it should be possible, the answer is probably buried deep in young Jakes thread about doing the ton with a CB200. Chap named Teazer would certainly know.

I notice that Otto Classic Bikes does replacement valve sets for a very reasonable price, same valves fit both heads, also, with changes to the camshaft sprocket and oilways 175 and 200 cams are interchangeable, so can't be that much difference.

Honda CB175 SL175 CD175 CA175 CL175 CB200 CL200 Valve Inlet + Exhaust 4pcs Japan | eBay

I have got a CB200 engine on the bench here, often wondered about swapping the complete head, as again in Jakes thread they found CB200 ports were better flowing. Dome on 175 piston is larger than 200 piston, so combustion chamber volume possibly same on both heads.
 
Taken the wheel to a hill climb friend in Cheltenham who has a nice machine shop. He can get the tyre'd wheel in the Bridgeport miller to skim the drum face.
Should be done for 25 Sept or before when I have my last race of 2021.
Ordered a set of '72 forks, "bent" but good cast lower halves, then, of course, I managed to get the RH fork to seal! At least they were cheap (!)

Soon have enough rough parts to build a rough cb.

Tempted to swop the original carb jets over from the Chinese ones.
Starting is a struggle no matter the technique I try, but the engine as it is still runs even temperature both side, a real bonus.
 
Interesting about the Chinese carbs.

I have the Wincycles ones on my CL175, and that starts easily, runs and idles well. I have swapped to original Keihin jets now, but it was acceptable straight from the box.

I have the Chinese carbs, which appear identical to the Wincycles ones, on my 'SL175'. This has a known good engine, but is also a pig to get started, and doesn't run that well even when warm. This may be due to other non standard factors, but I am beginning to suspect the cloned clone carbs. A change to Keihin pilot and main jet / emulsion tube is next thing on my list.
 
Little update:
Collected my front wheel from the machine shop yesterday, all ground smooth and just the right surface finish. Mounted horizontally as per the video above and was 4 thou out of round.
Now round!
Back on the bike and the front action is super smooth. Just needs bedding in.

Well, for that to happen the bike needs to engage a gear. How hard can that be?

Of course, no action on this one. Must be the adjustment of the new clutch as you can pull the lever in, clunk nicely into gear and let the lever out and not move forward....

Little job for tomorrow.
 
Sounds as though you could put it in gear without bothering to pull the clutch then... clearly not engaging, start with checking the adjustment.
 
Sadly I'm back!
Last 8 months have been a real mix, but I still have the blue CB 175.
I also never got to ride it in 2021 for various reasons, BUT it has to go.

I want to sell the bike in the very best condition I can, so charged the battery (for 5 mins, no more needed after 6 months) , choke on, fuel on, and nothing fired.

Plugs dry.
Fuel in tank but nothing flowing from the petcock. Worked in September!
Tank off, drained fuel, petcock off and apart. Found nothing wrong (new DS part a few years ago). So, lots of brake cleaner and 100 psi air line and back together. No fuel running through with about 1" of fuel in both sides tried all 3 positions of the tap.
The petcock has a tall tube and a stub cast in the body, no shorter tube for the reserve level.

Rather than fill the tank with 2 gallons and maybe struggle to drain it again I'm thinking of cutting the 3" tall tube down to 1" and filling to get above that tube.

All a puzzle because it ran last year!

Changed the chinese jets to the originals to try to improve things, but last year it certainly was hard to start from cold, yet all the CB's on You Tube start instantly!

As to the gear prob, I changed the clutch for new, but can sometimes get a 'neutral' between gears as you click up and down the box. Really do not want to strip the engine unit to go through the box...

Massive and difficult engine rebuild/uprating on the hillclimb Lola Porsche engine has drained all the time and money, awful experience, and I promised the wife i would sell the Honda to balance the books just a little, bt values for the se classics continue to sink (£3000 for one fully restored, that is less than the cost of the parts!)

Any ideas on the petcock mystery and the action of the box please?
 
Just been through something similar with the fuel tap on my CL175, no fuel at reserve position. This was with the hoses disconnected from the tap. I suspected debris in the tank had found its way into the reserve 'hole', for want of a better word. Cleared this by attaching a length of fuel hose to one spigot on fuel tap, blocking the other by reconnecting fuel line to other carb, then blowing hard through the length of hose.

In your case, doing the above would show one way or another if your tap is indeed blocked.

( I then compounded my issues by fitting inline filters, one of which turned out to be effectively blocked, despite being a new part.)
 
Thanks Richard, noticed your comments in your thread after posting mine..
Cleaned 3 times now so will try again, but before stripping the Petcock would pass nothing at any position.
Irritating it worked well last year, so contamination can be the only reason.
 
As you'll see from my latest post in my CL175 thread, I'm still struggling with fuel supply issues. Did wonder about ethanol fuel swelling the rubber in the fuel tap, but that would not explain my latest episode.
 
My tap is just 18 months old, and I've only had Shell 99 octane in the bike.
On fully stripping it the other day, the rubber disc with the 4 holes was fine, supple etc.
All the fuel hoses to the carbs were rock hard, and will be replacing with nitrile.

RH rotated cuff in my shoulder and something else in my left hand stopping all tinkering ATM...
 
A few hours tinkering in the garage on the pesky CB 175.
Put the petcock back together all blown/washed through with a 100 psi air line.
Tank and pipes back on, and fuel flows from one outlet!
Block that off (pinch tube on the petcock with pliers) and fuel flows from the other outlet...

Nothing is easy on these bikes!

Linked up to carbs. Tap to ON and gave the bowls a minute to fill. Fresh 99 octane fuel.
Fired on one side only

Dropped the bowl off the LHS carb, empty.

Turned tap to reserve and both sides fired, BUT talk about running rich even with choke off.
LHS started to leak fuel so re-seated the bowl gasket, and the bowl filled to a point of leaking again.

Pulled the carb off so I could seat the gasket properly.

In messing about to fit the original needle to the Chinese carbs the throttle wire pushed back and the LHS cable has come out to the 'Y' junction in the throttle cables under the tank.

Had enough of the bloody thing, so came in to type this!

Sooner I get it to run the sooner I can sell it.
 
After a wet/dry/cloudy/sunny/wet morning in Shrewsbury and my left hand suddenly largely painless, I set to on the CB this afternoon.

Zen must have been with me as everything went to plan.

Petcock on Reserve, choke on, bike fired almost within 3 crank turns.(!)

No leaks, needed choke for a minute then weened -off over 3 more, about right ?

After 6 mins running on a steady 1700 rpm good throttle response.
Job done i think, but will see how it fires tomorrow morning.

Such a good looking bike, but has to go.

 
Header pipe color suggests the bike is running very lean, which might also require the high tick-over of 1700 you mentioned.....
The 175's generally will idle at 1200 to 1300 (or lower) if the carb settings and jets are correct....
 
Indeed, not it will run I'll have a go at fine tuning the carbs.
Forgot to say that each side is as hot as each other and warm-up at the same rate.
The pipes blued over early last year when i had the Chinese carbs on. They now have the original jets and needles in them.
The needles are on their weakest setting, clip in the uppermost groove, so will go mid-way tomorrow and start from scratch again.

I slightly reset the tickover to 1700 to get a steady and long lasting tick over, might have got to 1500 but it would hesitate a few times at that speed just ticking over.

What is the best method to remove the blue oxide off the chrome pipes?
 
Worth reminding folks that those are the single skinned David Silvers header pipes, which do colour up very easily. Solvol Autosol and a lot of elbow grease.

My bike was actually running quite rich when this photo was taken, if the plugs were anything to go by.

N5jPpEh.jpg
 
Pleased to say I've done 3 cold starts, and each has seen the bike fire and run in 2 to 3 seconds, and a few mins to run steady at 1700 with choke off.
Sad to say now on ebay UK.

Heavy heart taking some pics in the bright English sunshine of this afternoon.....



 
While I realize this bike has taxed your patience for a while, you don't really have to sell it... especially now that it's working the way it's supposed to. And it looks so lovely too.
 
There's one just like this on Ebay at the moment …..

As the typical nitpicking person I am, the stripes on the tank let down an otherwise outstanding restoration.
 
Yes, a reasonable comment, too much DIY!
My gold CB was pro painted, cost £450, paint on this bike was £80.

I've just turned 70. If I was to take up riding again it would have been last year, but it did not happen, so i feel the moment has past.
To get the room in the garage back would be good, having to move the bike around all the time to access bench etc is a pain.

I have had some good responses to the Honda and the Peugeot BIMA moped on ebay, so my fingers are crossed.

The gold CB sold instantly for £4000 in 2017.

Here is the pro painted tank detail. I think the gold CB was a far better restoration than the Blue one.



 
It was a beauty. Hopefully it still looks as good, though sometimes we sell bikes and don't enjoy seeing them again based on the purchaser. The guy that bought my first CBX (which I should never have sold, but that's another story) did not take good care of it and when I saw it a few months later it made me sick.
 
The gold CB went to a keen biker in London.
His first bike was a gold CB 175, and wanted to re-live those days.
Went to a good home I think.
 
Sadly, the CB 175 sold today to a bike man to join his 29 other bikes today.
Have spoken to him and exchanged a further 20 pictures and both parties are happy. Sometimes you get the feeling it is 'right', and so it is here.

He is in Cornwall, deep south of England, so is arranging a specialist carrier to collect it soon.

I can't see me doing another bike again now I've reached 70 and have some age related joint injuries, done my bit so to speak.

Been a roller-coaster this blue one, the gold one was much the same, but overall they have been great.

I thank everyone on here for their kind help and words, lovely forum, but great people!
Graham.

 
Well it's been fun and I think you should keep up with the forum, your experiences may help others in the future. I'll be 72 this year and have 4 SL350's to go thru with my youngest son when he gets moved up here. I understand the joints aching and other broken parts talking to you, I have a list if you want to compare. Been dealing with vertigo the last couple of weeks but that seems to have cleared, at least for now.
 
Well done, that sold very quickly, for a good price.

As for the aches and pains, I turned 68 last week, and have my share of aching knees, dodgy right shoulder and collar bone, aching foot which I have self diagnosed as plantar fasciitis, GP appointments being virtually impossible, unless you want a 'virtual' one. Nightly sessions on a circulation booster gadget, interesting to see if actually does any good.

First longish run this year on the CB175 yesterday, felt distinctly stiff when I got off, need to get 'bike fit' again. As for giving up, to paraphrase a certain bunch of nutcases, 'they'll have to prise the twistgrip from my cold dead hands' ...
 
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