My SL175 look alike project.

I think it's just case of too low and rpm with the drill and not enough time to build pressure. Fire it up and give it 30 seconds to a minute before checking.
 
I wonder how well the oil pump works at 350 rpm. I wouldn't be surprised to learn that it could still deliver oil to the head at that speed, but I have no idea. I know it only takes a few kicks on my CB750 to temporarily douse the low oil pressure light, whether or not I've managed to start it.

I'll look forward to positive developments in the next installment.
 
Agree with Jim to start the engine.
Did you use a CB175 oil pump or maybe a CB200. Don't think the 200 would have pumped up at 350rpm, just curious.
 
This one is using a CB175 pump.

On reflection, if it can get oil up to the right side top of the engine at just 350 rpm, think how much oil must be being pumped at 10,000 rpm! Hence the need for the spring loaded relief valve assembly in the side cover.

Yesterday afternoon I refitted the battery, checked for a spark at the plugs, and put some fuel in the tank. Set tap to Res, and checked float bowls were full. Chinese carbs fitted, these have nice drain screws, easy to check if carbs have fuel.

Ignition on, full choke. Kicked and kicked, no sign of it starting. Clutch is dragging too much for a bump start - it's adjusted correctly, just needs to run a bit to fully free off. I really hate kick starting this bike, no center stand, awkward after market kick start lever, grrr …..

Gave up, after it occurred to me that I'd not set the ignition timing when I rebuilt the engine. Using Charlies ignition, needed the battery etc connected before I could set the timing, unlike points which can be set on the bench. So, that's my next task ..
 
Something not right in the ignition department. Trying to check the ignition timing of my Charlies Place ignition. Plugged my timing light into the circuit, in parallel, so when 'points' open, light comes on, goes off again when crank is rotated further. Except today, light stayed on permanently, impossible to check the timing. Bit worried now, in case it's fried.

Removed Charlie, fitted my Dynatech ( modified GL100 ) ignition. Same wiring as Charlie, but in this case timing light ( instrument bulb holder and crocodile clip ) failed to illuminate at all.

So I'm going to revert to mechanical points, once I've located the parts, start from first principles, in case fault lies elsewhere, perhaps the ancient coil has shuffled off ..
 
Funny things sometimes happen when parts sit idle for a while... I'm quite sure you'll get it figured out.
 
Hi Richard,
Just finished reading up to this point in your build - very impressive - congratulations getting to this point - your bike looks really great!
I have 2 SL175 projects (one is mine, the other is a friends) so it's been very interesting and informative reading through your progress. Thank you for sharing :)
Scott
 
A few parts arriving over the next few days. Condenser and advance retard mech came yesterday, I had lost the points cam off original ATU. coil on the way, then I can rebuild the ignition system.

Air filter bodies arrived yesterday, via the Ebay global shipping programme. Bit rusty, but a dip in phosphoric acid brought them up nicely. Units are smaller than I expected. RamAir foam on order now. I already have some silicon hose of the correct size to make the connecting boots.

Kf9H8ia.jpg


LLYc9uw.jpg
 
The rather crude angle brackets that I've added to the filters is a (hopefully) temporary fix. My battery box didn't come with the bolt on bracket highlighted in my picture below, so I'll make a replacement part sooner or later. I've already made an ignition switch bracket to match the SL part. Previously, I had fitted a CB/CL bracket, which made the switch hang down much lower, didn't look right.

cs7uR00.jpg
 
The air filter bodies did clean up nicely. Does one need to do anything to prevent flash rusting after soaking in phosphoric acid? Based on one product description I just read, it sounds like the answer is no, which goes against my intuition.
 
stl360+450 said:
The air filter bodies did clean up nicely. Does one need to do anything to prevent flash rusting after soaking in phosphoric acid? Based on one product description I just read, it sounds like the answer is no, which goes against my intuition.
Click to expand...

Having never used it, I wondered about that myself.
 
I've derusted things using toilet cleaner containing 10% Hydrochloric acid, washed off with water and seen it flash rust almost instantly.

Phosphoric acid apparently leaves some sort of phosphate coating which inhibits rust. Certainly, those parts in my photo had a couple of hours in 40% phosphoric acid, fizzed nicely as the rust dissolved, followed by a wash in water, no flash rusting. I have since given them a wipe over with ACF50, not planning to paint them.
 
Richard Pitman said:
I've derusted things using toilet cleaner containing 10% Hydrochloric acid, washed off with water and seen it flash rust almost instantly.

Phosphoric acid apparently leaves some sort of phosphate coating which inhibits rust. Certainly, those parts in my photo had a couple of hours in 40% phosphoric acid, fizzed nicely as the rust dissolved, followed by a wash in water, no flash rusting. I have since given them a wipe over with ACF50, not planning to paint them.
Click to expand...

Duly noted. Thank you! The product description I read said something about phosphoric acid inhibiting rust, but I'm more prepared to believe you than a product description.
 
Left side air filter fitted, also refitted points and replacement coil and condenser. Home made ignition switch bracket.

zDeAUxb.jpg


Coil and condenser mounted on home brewed aluminium plate, ground lead from this to engine top mount.

mPWWkot.jpg
 
A nice left hand side panel arrived from the US a couple of days ago. Soon got it painted to match the rest of the paint, Honda Modena Red car paint.

Still haven't got the engine running, this bike will end up as yard art if I'm not careful ….

KONFJo6.jpg
 
Discovered this afternoon why the SL has a longer shaft on the kick start lever.

If you fit a shorter CB/CL lever, you stub your toes on the foot peg every swing of the kick start, even with my dainty UK size 7s. SL lever ordered.

Think I'm getting closer to why it still won't start. Valve and ignition timing correct, compression feels similar to my other two 175s. Took a plug out to check spark, squirted some GT85 ( similar to WD40 ) down the plug hole while plug was out, got a couple of pops from that cylinder when I kicked it over again. So it looks like another fuelling issue, despite there being fuel at the float bowl drains. Jet check next, I suppose.
 
I never compared them, but assumedly the rider pegs on the SL were moved back a bit which would explain the need for the longer kickstart lever. It sure isn't because the 175 engine is hard to turn over.
 
Still can't get it to start. Float bowls full of fuel, jets are clean, got a spark, ignition and valve timing correct, feels to have reasonable compression, freshly charged battery.

Although, when I take the plugs out, there isn't any evidence of fuel on them, clean and dry. Two thoughts - my freshly rebuilt top end doesn't 'suck' hard enough to pull fuel through, or I was a bit hasty replacing the pilot jets in these Chinese carbs with the shorter Keihin parts, maybe it's a fuel level issue.

I'm away for a while now, won't have time to investigate. I think one option is to see if the engine will run on Easystart sprayed directly into the intakes, this would perhaps confirm that the actual engine build was OK (or not ).

Or maybe I simply need to practice my kick starting technique. I always use the electric start on the other two, and these often need to churned quite hard on the starter if they haven't been run for a while.

Chinese pilot jet compared with Keihin, Chinese parts on left of shot.

9KaGRsI.jpg
 
Using the starter fluid in the intakes sounds like the next best step.

Curious about the pilot jets. Are you replacing them because of problem or maybe a bit of prevention.
 
From this earlier picture (post #34), it seems that it could be possible for the pilot (in either carb) to sit above the fuel level in the bowl, depending on the float height.

Screenshot_20220318-072405.png

I believe there are original Keihin pilot jets (and replicas); that have the longer body like the Wincycle pilot, in case you end up determining it is a critical factor. They remind me of the pilot jets found in the early round top carbs on the CB750s - not sure if they are compatible.

In looking back at those earlier posts, 911hillclimber brought up the question of the internal passages. Did you blow air or carb cleaner through to verify the passages were open prior to assembly?

Since you already got a couple of pops on the GT85, I'd be inclined to swap out the pilot jets with the Wincycle jets, verify that all passages are open, and maybe lower the float height temporarily to ensure access to fuel.

How many kicks did you give it? Choke on? When one of mine has been sitting a while I sometimes need to churn quite hard on my right calf! (10+ kicks before evidence of combustion)
 
I've got Wincycles carbs on the CL175. On that one, I swapped the fitted main and pilot jets for ones out of the original Keihin carbs, and that bike starts, runs and idles OK.

The carbs fitted the SL175 are brand new unbranded ones, appear to be copies of the Wincycles (OEMSTD) carbs. Unmarked mains and pilots, same as the Wincycles ones, which is why I swapped these out as well. Pretty sure that I had the previous engine running on these carbs set as above, really ought to keep a log of these changes.

I'm assuming ( dangerous, I know ) that as new carbs the passages are clear, and float levels correct.

DHL have just delivered a correct SL175 kick start lever, maybe I'll be able kick it through a bit more vigorously, now that my toes miss the foot peg. And yet there's a vid on Utube, guy starts his 175 using his hand.

Away for a few days now, try again on my return ….
 
Back from a lovely week in sunny Devon, tried again to start the SL175.

Fresh can of EasyStart, air filters removed, choke open, slides pulled up, sprayed in some starter spray. Ignition on, kicked and kicked, no sign of the engine firing. Even took the plugs out, sprayed directly into the cylinders, still no sign of life (plugs back in and ignition on, of course )

This is a freshly built engine with new pistons and rings. I checked the compression with my car type tester, long hose etc, saw 128psi on both cylinders. Low, but engine obviously stone cold. Same gauge shows 155psi on a hot healthy 175 engine.

So, I'm stumped. I do have another known good 175 top end that I could fit to the SL bottom end, but I'd kick myself if I did this and it still won't run.
 
I've been caught out by kill switches in the past, once pushed my Lifan monkey bike 2 miles home because the kill switch was on ( or should that be 'off'), on that bike the starter motor still operated in the no spark position.

No kill switch on my SL175 alike, I'm using CB175 switch gear. Spark does look pretty weak, but that is also true for my other two working 175s.
 
It's really strange, since you had gotten a few pops out of it before. After spraying starter fluid into the plug holes, did you try opening the throttle at all while kicking it over? Did you try both open and closed choke?

Would it be difficult to swap the coil and condenser with known good units? No grounding issue from that homemade aluminum mounting plate?
 
Thanks, yes, I tried all permutations of open and closed throttle and choke, and I've replaced the coil and condenser. I will check the grounds again, but I have had this bike running before with all these same peripherals on another 175 engine. I only swapped this out for registration purposes, as that was a CB175 engine.

It seems that it must be lack of compression and my feeble kick starting technique. So, I will see about getting a UK registration with this non running SL engine, then put the electric start CB engine back in, sort the SL engine out at my leisure.

As an aside, I was following a young kid on a Chinese 125 through traffic yesterday, obviously a new rider, on L plates. He stalled his engine, but restarted straight away on his electric start. Just made me think of the chaos if he'd had to kick start his bike, surrounded by impatient car drivers, same environment my SL alike will get used in.
 
If you added a wee bit of oil to each cylinder, it would probably only help seal the rings for one or two kicks. I wonder if that would make any difference in terms of it firing, even if momentarily. It's hard to believe that 128psi is too low for combustion, especially since your gauge probably reads a little low on those small cylinders.

What makes you doubt your kick starting technique? Know any good substitute kickers?

I can relate to your observation about kick starting in traffic. It does inspire an uncomfortable sense of urgency, so the swap back to the CB motor sounds prudent. Nice that you have that option, assuming you can register it as is first. I'm still rooting for this motor firing up before you make that swap!
 
Still won't start, so I've made a start on getting the known good spare engine ready. I'd robbed the clutch and oil pump from this motor when I rebuilt the SL175 unit, so I got a second hand clutch assembly on Ebay. Other parts are being taken from my CB200 engine, oil pump, oil spinner and retaining nut, gear change shaft etc. I already had some 175 duplex crank gears in my box of bits.
 
This is a really odd situation Richard, I know you stay on top of your maintenance and it's strange that just sitting over the winter would create this issue.
 
It's my freshly rebuilt engine that won't start / has never run. I'm thinking that it must simply not have enough compression to start and run. I'm using new standard size pistons and rings in a used, but apparently good, standard size cylinder. Valves passed the solvent leakage test. I'll probably have to bite the bullet and get a rebore.
 
Ah, I lost track of which engine we were talking about. Shame it's weak enough that it won't fire and has to be disassembled again (I know you're not fond of the term "torn down" :) )
 
Date of Manufacture letter arrived from the VJMC this morning, so next step is to get all the paperwork off to the DVLA. In the past, I've had an age based registration back almost by return of post, but since Covid the DVLA has come in for a lot of criticism over slow service, staff working from home or simply off sick. We'll see …

Electric start motor now built up ready to fit. Now fantasising about fitting flat bars, CL low front mudguard / fender and CB final gearing, to go with the road tyres and 2LS front brake, make a little light weight road bike.
 
Just back from another week in sunny N.Devon, hoping to find registration document from DVLA on the doormat. No such luck.

Bit of a national scandal in the UK, passport office in particular, huge backlog of applications and renewals, caused by staff 'working' from home.

And yet the general public seem to think that the epidemic is over, very little evidence of any precautions being taken anymore.
 
Richard Pitman said:
And yet the general public seem to think that the epidemic is over, very little evidence of any precautions being taken anymore.
Click to expand...

Very much like that here as well Richard, particularly in the more conservative regions. Few masks, if any, on people in stores. We still mask up for long-term public activity inside a building like grocery shopping, etc. We sit outside on those rare occasions we eat out.
 
DVLA returned my application today, rejected it because of a discrepancy in the NOVA ( Notification of Vehicle Arrival ) database, which is maintained by HMRC ( Her Majesties Revenue and Customs ). DVLA gave me a telephone extension number at the HMRC, and a nice chap there looked up the details. They had it down as an SL175 but with a completely different frame number. Sounded as though he was quite happy to amend this, on receipt of an emailed photo of the real frame number. ( Unlike DVLA, who wanted actual hard copy printed photos )

So I've done this, told to wait up to 5 working days for a reply. Fingers crossed this will satisfy the DVLA chap.
 
Well, the chap at HMRC corrected the NOVA entry for my bike on the database, and sent me an email confirming this. So I wrote a covering letter to the DVLA and sent my application off again, this time in an envelope which they'd addressed, so that it would get to the right person at the DVLA.

That was over a week ago, not heard anything yet, postman's visit eagerly anticipated each day.

Meanwhile, I've been tidying up the air filter installation. Made a new bracket it for it, basically a copy of the missing OEM part, except that I've fitted a stud to the bracket rather than a captive nut as original, makes fitting the filter body easier. Stainless domed nut retains it.

Also found that the inlet hose from a CB174K4 air filter fits nicely with just a little bit of trimming.

3MitOnS.jpg

i
In this pic, you can see the domed nut mentioned above, also the starter motor solenoid, ready for the CB motor. Aftermarket reg rec also fitted on other side of solenoid mounting bracket.

dtvJq7l.jpg
 
LongDistanceRider said:
Nice work, good luck on the paperwork.
Click to expand...

Just had an email from the DVLA. Apparently they've been trying to contact me by phone, need to know what the engine capacity is, so that they can continue with the registration process. And if I don't respond to this email by the 30th May, they'll assume email address is invalid and return my paperwork.

Overall, this is encouraging, just need to be patient. Emailed them back, answer is '174cc', resisted being sarcastic and saying that the clue was in the name SL175.

Which would have been unfair, as some bike makers have model numbers that bear no relation to actual capacity.
 
Richard Pitman said:
Just had an email from the DVLA. Apparently they've been trying to contact me by phone, need to know what the engine capacity is, so that they can continue with the registration process. And if I don't respond to this email by the 30th May, they'll assume email address is invalid and return my paperwork.

Overall, this is encouraging, just need to be patient. Emailed them back, answer is '174cc', resisted being sarcastic and saying that the clue was in the name SL175.

Which would have been unfair, as some bike makers have model numbers that bear no relation to actual capacity.
Click to expand...

Ah, working with the government employees who generally have little knowledge of the things they oversee. Patience is always required, and on occasion a sore tongue from biting it.
 
I've just had this lovely email from a nice person at the DVLA, happy days !

Hello again Mr. Pitman,

I will be out of office from now until Monday but I’ve managed to find your application and can see it was entered onto our systems on Monday 30th, and a letter will have been sent at that time confirming the registration and the vehicle registration number that was allocated to the vehicle. You should receive this within the next few days, with your V5C to follow. Have a lovely afternoon
Click to expand...
 
He/She was as good as their word, UK V5 reg document has just arrived in todays post (mail).

Age related reg number, ends in 'K' ie UK 1971. Ordered a licence plate online straight away !

So, I must get my finger out and get this bike running. Yesterday, I got the fuel tank cleaned out (again) and lined it. I've used POR15 products successfully in the past, but this time I decided to try a UK product from RustBusters.

I cleaned the tank out with their Tank Clean, which I guess is similar to the POR Marine Clean. Followed by a soak in phosphoric acid to remove a few light areas of rust, washed with water, drained then dehydrated using methylated (denatured ) spirit ( ethanol with a dash of methanol and blue colouring ), then dried out using heat gun, followed by a spell in the sunshine.

Next day, once bone dry, lined tank using their 'Slosh' product, which cured overnight. All very much like the POR15 kit, but a bit cheaper.

SLOSH FUEL TANK SEALER (rust.co.uk)
 
Glad that went well, and I'm sure it's a relief to know you can make it legal and ride it like your other bikes.

"So, I must get my finger out..." LMAO
 
Finger duly taken out. BTW, that's not rude, it's a British saying meaning that one should stop prevaricating and get on with some work. I assumed finger in mouth, like sucking a thumb, I guess it could have been stuck somewhere else ....

Anyway, this morning has been spent pulling out one engine and getting ready to fit the known good CB engine, with electric starter. The SL frame is a joy to work with, engine slips out easily, none of the CB/CL finger trapping origami stuff. Had a good workout, lifting engine off and back onto work bench in the shed, then transport to and from my lock up.

bikgrId.jpg


vJ9h36w.jpg
 
Richard Pitman said:
Finger duly taken out. BTW, that's not rude, it's a British saying meaning that one should stop prevaricating and get on with some work. I assumed finger in mouth, like sucking a thumb, I guess it could have been stuck somewhere else ....
Click to expand...

Of course the first thought would always be off-color... but finger out of ear came to mind. I like the prevaricating reference though, hadn't seen that used in some time.
 
Got the SL175 running today. Tyres pumped up, chain lubed. Checked for oil at both rear headnuts, took a little while for the left rear but oil positively gushed out once it got there. Checked that battery was charging OK, went for a short ride around the parking space, all seemed OK. Fairly obvious that this is just the beginning, will need a proper shakedown, get the carbs dialled in etc.

Then back to the house, 20 minute phone conversation with my insurer, Carole Nash. Cost me a whole 5 quid to add the SL to my multi bike policy, plus a 30 quid admin charge, grrr.

Same carbs and ignition as before, so that last engine I built must have been at fault, lack of compression seems most likely.

Jury is out on that oversized Honda seat logo, just stick on vinyl so easily removed. Aftermarket seat cover would not take the vinyl dye that I've used successfully in the past, with a stencil.

xuQIxu8.jpg


And a video

(602) SL175 startup2 - YouTube
 
Looks great, sounds great! That other motor makes for a real head scratcher, I will be curious to know what you find when you check into it.

I'm not so familiar with the 175s, but the oversize Honda logo doesn't stand out to me. It looks good. The license plate looks huge, though!
 
Thanks !

That licence plate is technically illegal, smaller than the standard size, but large enough ( 8 x 6 ) that it won't upset the traffic police, not that I often see many around here. I would just use the historic bike excuse, it came like that officer ..
 
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