My CL175K7

Looks like Red Hermatite to me, my Dad introduced me to it back in the day, but he was brought up on British bikes.

I got the cam out in the end, but it fought me all the way. Lots of heat, gentle tapping and WD40 had absolutely no effect, so I got the angle grinder out with a thin cutting disk and started nibbling away at the advance retard mechanism central shaft. Still wouldn't release, so I ended up angle grinding through the lot, destroying the advance mechanism and the cam journal. The cam came out relatively unscathed, apart from a flat on one side of the very part that I was trying to preserve. Looks like it will be OK though, spare advance mechanism still fits and no damage to the area that bears on the oil seal. Both cam bearing surfaces on the ends of the cam are very good. Cam lobes have cleaned up quite well, just a few blemishes that I think will polish out.

The 'tree museum' was of course a Joni Mitchell reference. We visited Westonbirt Arboretum, on the sunniest day of last week, to see the autumn (Fall) leaf colour. Not as good this year as others, apparently due to the generally poor weather throughout the seasons. Just down the road from Charles and Camillas gaff, Highgrove.

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Our dogs had a great time though, running loose with loads of other visiting pooches.

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I got bored with treating the engine gently and worrying about things breaking down in the back of beyond, so once the engine was fully warmed up this afternoon I treated it to a sound thrashing. Full throttle and 9500 rpm through the gears, saw 70 on the speedo at one point, holds 60 on the flat. No smoke, leaks or nasty noises, 120 miles on this rebuilt engine when I got back home. Plugs are a nice tan colour, although the single skinned DS header pipes are taking on a golden tinge at their upper few inches..

My reasoning for this rough treatment - if something is going to break, better it happens now, within a few miles of home.

I'll give it another change of Castrol GTX 20/50 mineral bike oil and run that for another few hundred miles before fully synthetic. Also check the timing with the strobe light, check valve clearances etc.
 
Richard Pitman said:
I got bored with treating the engine gently and worrying about things breaking down in the back of beyond, so once the engine was fully warmed up this afternoon I treated it to a sound thrashing. Full throttle and 9500 rpm through the gears, saw 70 on the speedo at one point, holds 60 on the flat. No smoke, leaks or nasty noises, 120 miles on this rebuilt engine when I got back home. Plugs are a nice tan colour, although the single skinned DS header pipes are taking on a golden tinge at their upper few inches..

My reasoning for this rough treatment - if something is going to break, better it happens now, within a few miles of home.

I'll give it another change of Castrol GTX 20/50 mineral bike oil and run that for another few hundred miles before fully synthetic. Also check the timing with the strobe light, check valve clearances etc.
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My concern is always for a fresh bore, but just new rings with a light hone will bed in pretty quickly. After 100 miles they should be fine, probably sooner really. It's always good for it to pass the first thrash test though.
 
As described in the carburetion thread in the small twins section, I've been out on several runs on this bike in the last few weeks, while playing with various permutations of PE22 carbs and jets. With the float level now set correctly it seems to be running quite well, so time to get the CL175 pipes refitted. It's been running on my spare set of DS pattern CB175 pipes whilst I've been fiddling with things, much easier access with those pipes.

This turned up in the post today ( Well, actually thrown over the back garden gate by a Yodel driver :mad: ) It's the correct CD / GL 175 carb to air filter hose, one of those unobtanium parts. I thought it would be a five minute job to fit this, instead it's taken all afternoon. Although it's lovely and flexible still, it could do with being 20mm longer. When fitted to the carb it barely reaches to the air filter stub. It's on now, just barely making an air tight seal at the filter end. I'm thinking about making a thin metal sleeve to extend the air filter stub.

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CL pipes fitted yesterday afternoon. I'm getting quite practised at this now. The trick is to remove one of the left side exhaust head studs. Ideally the outer one, but that refused to come out easily, so I removed the inner one, and the exhaust went on with just the minimum of brute force. Need to have one or the other stud in place so that the retainers all line up correctly.

Hoping for test ride later today.
 
It seemed to be running a bit rich, with a #40 idle jet and 105 main, so I changed these to a 38# idle and 95 main. Test ride today seemed OK, still starts and idles well, runs along at a sustained 60mph indicated. Much easier to make these adjustments with just one carb !

Also sorted out the permanently 'on' front brake light switch, and a front LED turn signal bulb that had worked loose in its socket. Fixed a rattling pillion rest on the CB175, then got the SL175 out to pump up the tyres and oil the chain, generally check it over. Might ride that one this weekend.

And the Hornet sits neglected in the corner ......
 
Oil change yesterday. Drain plug seemed a bit tight, 6 point socket and breaker bar sorted that out. Noticed that oil started to seep out as soon as the plug was just loosened. Turned out that I'd been running without the O ring on the drain plug, it had dropped off at the previous oil change and I'd put the plug back without noticing this. Says a lot for Honda precision manufacture that even without the O ring the bottom of the engine was bone dry, no oil seepage at all. Found the old O ring in my oil drain container, but I fitted a new one this time.

Oil that came out was filthy after only a couple of hundred miles, second change of 20/50 mineral oil since new rings in honed bores. Now reverted back to 15/50 Mobil One fully synth, same oil as in the other 175 engines.

Temporary fix to front brake light switch ( cable tie and gorilla glue :oops: ) failed, new switch on the way ....
 
Back to this thread after a brief diversion to a carb settings thread. In summary, set the float level correctly ( I hope !) to 28mm, dropped the needle one notch, still on 38 pilot and 95 main. Bike starts, idles and runs well up to 6 or 7k, After that, it will run up to 9k without much enthusiasm. Plug check now looks as though it really does need a bigger main jet, symptoms previously masked by incorrect float level. Took a test ride around the local lanes, followed by a visit to local Tesco, for red wine and petrol, a lovely cocktail o_O

Whole point of the single carb conversion was to make a reliable bike that I could pop around on locally, go to the store on etc. To that end, I refitted my home made rack and attached the top case. This takes a full face helmet, or tools and shopping. One side effect I'd not noticed before is that this bike shakes its head quite violently if I try to ride hands off. My other bikes don't do this. The Hornet in particular is completely stable hands off, and that's a bike that can get into a tank slapper if provoked under acceleration.

The engine is currently the SL175 bottom end with CD head. Winters project will be to rebuild the bikes original CL175 engine with the single carb head, so that the frame and engine numbers in this bike will match the V5 document again.

Latest pics. Really wish I could find a proper old school chrome rack like I had in the olden days.

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Windmill John said:
Transalp 650, Transalps 700, certain Bandits….. bikes I’ve had that acted normally, but as soon as I fitted the top box!!! Could never let go of the bars then.
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I was actually thinking that earlier but didn't say anything because I've often seen boxes on bikes that didn't affect them unless they were heavily loaded. Generally speaking, weight above and/or behind the rear axle is never good.
 
Common suggestions were stiffening up the rear shocks and/or dropping forks slightly… Wasn’t going to any of this because of a top box!
I think the sail analogy could be correct because even with an empty top box adding no weight, the issue appeared.
 
The high bars on the CL don't help. On my other bikes with low bars there's more weight over the front. When I had my tank slapper scare on the Hornet it still had the original raised handlebars, I fitted Renthal Ultralow bars after that fright.
 
The Hornet one was vicious. Accelerated hard, downhill, poor road surface, just outside Upton Snodsbury, heading towards Wyre Piddle. ( Don't you love our Brit village names;) ) both hands gripping the bars. Felt like it was going to snap my wrists, I really thought something on the bike had broken. I pulled over to inspect the bike and a following rider also stopped, he'd seen what had happened. This was in my early Hornet days when I rode like a t*at, bike still had high(ish) standard bars, soft suspension and 16" front wheel. Since fixed with low bars, 17" wheel and Ohlins.
 
I think that I've finally got the carb settings right. Changed the 95 main for a 100 main, as per CD175 original spec. Retained the #38 pilot. Slide needle dropped one notch from central position. Bike now starts and idles, pulls to 9.5k without flat spots or hesitation. Just had a very pleasant 25 mile local ride. Indicated 70mph at one point.

However, there is an odd whining noise from the engine. It's got a new cam chain and tensioner assembly, otherwise I'd be suspecting that. Anyway, this engine has to come out soon, to swap this single carb head onto the bikes original engine, which is currently sitting in the shed. Engine in the bike is the SL175 bottom end, which really ought to go back into the SL175, so that numbers in the registration documents match up again.
 
Was the whining noise there before you changed the carb settings?
How are the camshaft end caps? Not related to above 🙄
I fitted new cam chain and tensioner to my CD175. Tried new end caps etc due to a weird rattling.
When I sold the bike to Charlie at Oxford classic Honda… oops, Classic Motorcycles, he changed carbs and let me know the sound had gone!
 
Yes, it's had that noise for a while. I'm possibly worrying about nothing, but it's a different noise to my other 175 engines. Varies according to which helmet I'm wearing, my open face actually deadens sound more than my full face. I don't use ear plugs. Sound is definitely engine rather than cycle gear related, goes away when I pull the clutch in and coast. Just ordered another gasket set, so I'll have a look inside in due course.
 
It frustrated me! Good cam chain, good tensioner, good cam end caps, honed barrels with good ring gap, good valve clearances… good everything… .i thought!
 
Inside my very untidy shed. On the floor is my original CL175 engine, now fitted with a CD175 single carb head, CD cam notched to take the CB/CL cam drive. This is going into the CL175, swapping out the SL175 engine that is currently in there. Once out, that engine will receive the CB200 head that is sitting on the workmate bench. That head also has a notched CD175 cam, along with CB/CL cam journals. CB200 head drilled for oil feed to points side bearing.

With me so far ? All means that the CL and SL will once more have engines that numerically match their respective V5 registration documents. The SL is currently running a CB175 engine that I rebuilt a while back. My CB175 still has its original untouched engine and carbs.

There's a CD175 engine in the background, behind the CL unit on the floor, along with the remains of a CB200 engine behind me, along with boxes of bits of engine. And then there's my loft in the house :rolleyes:

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I'd never be able to find anything then ! Anyway, it's always fun when I find some tool or part that I'd completely forgotten about ......

To be fair, my garage, where the bikes live, is much tidier, relatively speaking.
 
Down the rabbit hole yesterday. I was fiddling about with the static vs advanced ignition timing, as described elsewhere, when it occurred to me that the CD engine might have different ignition timing to the CB, CL and SL 175 engines. Short answer is that they are all the same, despite having different part numbers for the rotors. This part number matches the spark advancer, which physically all look the same, but might have different springs and advance curves, although full advance on the rotor is in the same place on all the 175 rotors I have here. One difference that I did notice is on (what I think is) a rotor from an SL175 engine, static timing advanced ( bigger gap between F and T marks ) to the other engines.

Anyway, I've ended up with matching 307 rotor and advance mech in this engine that is fitted with a CD single carb head, have to see how it goes.

While rooting around in the parts boxes, I found the carb insulator that came with the CA77 PW20 carb. It's much thicker than the one currently on the engine in the bike, to the point that I had to make up some longer mounting studs. This might explain why the nice OEM carb to air filter hose barely reaches between the carb and air box, thicker insulator might make all the difference.

And that's how to spend ( not waste ! ) several afternoons in the shed ...
 
A rather trying afternoon. Engine all buttoned up, ready to fit. Valve clearances set, static timing etc. Just thought that I'd better check the top end oiling, so I added enough oil to cover the oil pump pickup, then spun the engine using the cordless drill. Plenty of oil at the tacho drive side, but dry at the points side, even after a prolonged spin on the starter.

So I pulled it all down to check the oil ways were clear, including checking the points side gasket for oil hole alignment. All clear all the way down, including the tiny hole in the crankcase top. I did run a 1mm tiny drill through this, just to be sure. Removed the alternator side cover to check the oil gallery, and that the tiny hole communicates OK with this.

All I can conclude is that when the engine is running, once the tacho side, which feeds the camshaft lobes as well as the cam bearing, is full of oil, the points side will then get some oil. Just not spinning it fast enough on the drill. And this engine has a CB200 oil pump. Will also check the O rings on the filter cover, although I cleaned the filter out this time by removing the entire case, CB200 style.

Nagging thought that the dowel that is present in the CB cam, but not in the CD cam, actually has some influence on the oil distribution. Can't see how though, once that side is full of oil the other side should fill. I'll build it all back up and see how it goes. :(
 
The 450 engine is similar in that it has both orifices for oil flow to the top end on the right side of the cylinder base and fills each camshaft before the oil travels over to the left side, which is why the most failures and excess wear happen to the left exhaust cam lobe and follower. Hopefully longer duration with the starter motor, or actual engine idling speed, will be the difference for you.
 
All back together again. Those pistons and bores have done 8000 miles since a +1.00mm overbore, looking good to my eyes, honing marks still visible, just a bit of carbon buildup on the crowns. I noticed that I'd fitted the cam chain tensioner axle upside down, it's now right way up in the photo below, those notches feed oil dropping from above into the CCT pivot. Starter cable needs a bit of insulation adding to it.

I'm getting to the point where I could strip and rebuild one of these in my sleep, maybe that's a 'Honda Dream'. :sneaky:

( And we are not alcoholics, those Bristol blue bottles are just too nice to throw away )

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Getting on well with swapping engines over, all went very easy, even the CL175 exhaust, removing a left side exhaust stud makes like simple. I've got myself a little sack truck for moving engines from shed to garage, also use my cordless impact driver for whizzing fixings off and back on. Nice bit of exercise lifting the old engine up onto the workmate in the shed.

I've just got to put the exhaust, fuel tank and seat back on, along with the drive chain and gear box sprockets., foot bar etc. Turned the engine over on the starter to check for a spark and was startled to hear the engine start and idle instantly. Can't imagine what it was finding to run on, WD40 fumes perhaps ? More likely a drop of fuel left in the carb. Shut it off straight away, but very promising sign for the future.
 
Yesterdays bit of mechanical idiocy.

Nearly finished engine swap. Hooked up the clutch cable. Far too much free play at lever. So it was 'obvious' what had happened, I'd lost the ball bearing out of the release cam. No problem, I've got a bag of spare ones. Removed the alternator cover, tearing the new gasket in the process, and of course, the bearing was still present, sat in the grease. So it all went back together, complete waste of time and effort.

What I should have done was check the adjustment on the case, the round thing that you rotate with a coin ( or tyre lever in my case ). Just a tiny movement on this took out all the free play. Grrr ...
 
Richard Pitman said:
Yesterdays bit of mechanical idiocy.

Nearly finished engine swap. Hooked up the clutch cable. Far too much free play at lever. So it was 'obvious' what had happened, I'd lost the ball bearing out of the release cam. No problem, I've got a bag of spare ones. Removed the alternator cover, tearing the new gasket in the process, and of course, the bearing was still present, sat in the grease. So it all went back together, complete waste of time and effort.

What I should have done was check the adjustment on the case, the round thing that you rotate with a coin ( or tyre lever in my case ). Just a tiny movement on this took out all the free play. Grrr ...
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Another 'forest for the trees' event, I just had a couple of them myself over the last few days. Staring at a scratch on the sealing surface of the countershaft in the 450/500T transmission I'm assembling and failed to notice the extreme spline wear, literally only a few millimeters away.... :rolleyes:
 
All back together and running again, relieved to find oil at that left hand rear cylinder stud, so that cam bearing WILL get some oil. Usual battle getting the CL exhaust back on, but removing the two left side exhaust studs did make things much easier. Lock nutted them back into position once the exhaust collets etc in place and lined up correctly.

Middle exhaust mount through the side panel was the usual faff, made worse because I'd got the frame bracket on the inside rather than the outside of the side panel. UK monsoon season has arrived here, so no idea when it'll get a test ride.
 
Sun came out today, so I had a brief test ride to the filling station and back. Used my toolkit ( in the top box ) to adjust the clutch whilst I was at the petrol station. Seems to run OK. I can actually start it from cold by hand on the kick start, first go. When I got back with a fully hot engine, no leaks, but a rather noisy top end. Hopefully just valve clearances, and nothing to do with that dowel that I left out from the tacho drive end of the camshaft. Other thing of note is the exhaust, which seems to have become louder than before. It's not leaking anywhere, a hand over the tail pipe silences it. More compression in the rebuilt motor, retarded ignition ???

Here it is back after that ride, proudly displaying its new VHT stickers !

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Richard Pitman said:
Sun came out today, so I had a brief test ride to the filling station and back. Used my toolkit ( in the top box ) to adjust the clutch whilst I was at the petrol station. Seems to run OK. I can actually start it from cold by hand on the kick start, first go. When I got back with a fully hot engine, no leaks, but a rather noisy top end. Hopefully just valve clearances, and nothing to do with that dowel that I left out from the tacho drive end of the camshaft. Other thing of note is the exhaust, which seems to have become louder than before. It's not leaking anywhere, a hand over the tail pipe silences it. More compression in the rebuilt motor, retarded ignition ???
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Hopefully just a little excess valve noise. Hard to understand the louder exhaust though.
Richard Pitman said:
Here it is back after that ride, proudly displaying its new VHT stickers !
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Beauty! That's full coverage right there, very nice.
 
Rediscovered this thread last week and just finished re-reading it from the start. Great read and great pictures!

Fascinating to see you mixing-and-matching bits from different bikes. Makes me wonder how many pieces of my disassembled 1975 cb200 might come in handy on my current cl175k4 project..
 
Just had to re read this thread to remind myself what I've done to this bike :geek:

Gave it a quick clean and polish, to get rid of some rust spots that had developed during winter storage. Pumped the tyres, oiled the chain and refitted the battery. Started right up, on fuel that had been treated with Stabil in the autumn.

Went for a ride, taking it easy at first, still thinking about last years breakdown and recovery epic. It cruises easily at 50 mph, but will hold 70mph on the flat, even with the CL bars making me sit upright like a sail. Revs to 10k, presumably the single carb limits the revs, the extra 3bhp from the twin carb motor must live up there at the red line. Lower down the rev range this bike performs same as the twin carb bikes. Tacho drive works fine on this engine, despite having the same modified CD cam that has been worrying me in my SL175 engine.

The exhaust note is very loud, as mentioned before. It is a NOS system, I think from the earliest of the upright CL series. Maybe Honda didn't bother so much about the exhaust noise on the earlier bikes ? It certainly wouldn't qualify as the 'Quiet Pastoral Bike' in their GL175 advert.

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Last day of the UK heatwave, first day of summer tomorrow, so expect it will rain. I had a decent 45 mile ride around the local lanes. Since my mechanical breakdown last year I've been wary of straying too far from base, but I'm starting to build some confidence in this current engine build. The single carb setup certainly lives up to my expectations, easy starting and reliable idle. Probably improves fuel consumption as well, although I've not really measured this. Certainly, 90+ miles since last fill up, tank still at least a third full.

So many interesting back lanes all around this area. Google maps and Street view clear up a lot of 'wonder where that lane goes' puzzles when I get home.

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One thing I omitted to mention is that after 45 miles I was still very comfortable, no knee or back pain, could have easily done another 45 miles. Honda really sorted the ergonomics on these bikes. My Hornet is a literal pain in the arse by comparison, at 45 miles my knees would be aching, as would my back and backside.

Also that I forgot to put my ear plugs in, which instantly reduced the CL175 top speed by at least 10 mph ..
 
Richard Pitman said:
One thing I omitted to mention is that after 45 miles I was still very comfortable, no knee or back pain, could have easily done another 45 miles. Honda really sorted the ergonomics on these bikes. My Hornet is a literal pain in the arse by comparison, at 45 miles my knees would be aching, as would my back and backside.

Also that I forgot to put my ear plugs in, which instantly reduced the CL175 top speed by at least 10 mph ..
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Concerning Hornet, in my CBF600 I was reducing gear one down to increace vibration frequencies to keep my legs out of sore state.
 
Richard Pitman said:
Inside my very untidy shed. On the floor is my original CL175 engine, now fitted with a CD175 single carb head, CD cam notched to take the CB/CL cam drive. This is going into the CL175, swapping out the SL175 engine that is currently in there. Once out, that engine will receive the CB200 head that is sitting on the workmate bench. That head also has a notched CD175 cam, along with CB/CL cam journals. CB200 head drilled for oil feed to points side bearing.

With me so far ? All means that the CL and SL will once more have engines that numerically match their respective V5 registration documents. The SL is currently running a CB175 engine that I rebuilt a while back. My CB175 still has its original untouched engine and carbs.

There's a CD175 engine in the background, behind the CL unit on the floor, along with the remains of a CB200 engine behind me, along with boxes of bits of engine. And then there's my loft in the house :rolleyes:
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This excellent thread reminded me of the slippery slope I seem to have stepped upon. Having just intended to get it going, I’m still buying bits for the CB360… and I should receive a replacement cylinder head for the CB200 soon so I’ll be pulling the motor out for a third time to see if I can identify what is making that irritating noise.

The problem gets worse - I’ve just seen a CL175 I quite like advertised for sale. I’m struggling to keep my wallet in my pocket :)

Alan
 
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