My SL175 look alike project.

The next piece of work which I did today didn't go so well.

I really don't like those Mitas block pattern tyres. I'm sure they would be fine on gravel roads, but on tarmac, the only place I'd ever ride it, I have no confidence in them. Leaning into turn it feels as if the tyre is on an edge, about to let go. Tyre carcass is very stiff and the rubber feels hard.

So I decided to fit these Michelin Pilot Street tyres that I found for sale quite cheaply at Demon Tweeks. Going for the 'super moto' look, if a 175 ever could be …

Had a real struggle to get the Mitas front off, then a battle with the Michelin, finally literally let down, as I pinched the inner tube. Should have dug out my tyre soap instead of assuming new tyres would just slip on easily without.

2.75 18 front and 90/90 18 rear. If anything, I could probably have gone up a size, these tyres look really quite skinny.

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Luckily for me, Amazon Prime had a 2.50/2.75 18 inner tube in stock, and with me by lunchtime today.

Using tyre soap this time, the 2.75 18 front Michelin Street Pilot slipped on. Still looks skinny though, more like a bicycle tyre compared with a 2.75 K82 or even with a ribbed CST, again a 2.75 18.

It'll be interesting to see how the 90/90 rear compares with a 3.25 tyre.
 
The lack of consistency in tire sizing is discouraging, since no matter what it's advertised as it may or may not be what you plan for when you get it. I'm looking at replacing both tires on the 450 and the 900F and I'm agonizing over the same possible issue
 
Got the rear 90/90 tyre fitted this afternoon. Hardest part was getting the valve stem through the rim, almost made me wonder if was doing something wrong. I always get the first bead over the rim, then fit and partially inflate the inner tube, then get the second bead mounted. Ended using needle nosed pliers to pull the valve stem through, not enough room to get my hands in to push it through.

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And back to my SL175.

As in another thread, I've fitted it with some of those pattern Chinese carbs, same as Wincycles but without the OEMstd logo. Engine fired up and ran straight away, carbs just as they came out of the box.

So this afternoon I went for a test ride, after wasting a morning driving around Worcester looking for a new fuel can, most places sold out, guess it's all the lawn mowers emerging from hibernation. Eventually found a 10 litre can, went and filled it with the Esso petrol that is supposedly ethanol free, back home and filled the bike.

Test ride went quite well. Engine is a known quantity, being the one originally fitted and rebuilt for my CL175, now fitted with my 'spare' 175 engine. This engine, in the SL175, has a 1.00mm overbore, CB200 oil pump, CB350 stator, new cam chain, NOS tensioner assembly, CL175 K7 chain and sprockets, on a CB200 rear hub, 1.85 rear rim.

Bike goes very well, good acceleration, revs easily to red line in gears. Brakes and handles well, new Michelin Street tyres feel lovely, roll into the corners, unlike the previous nasty Mitas trials type tyres.

Problems. Once riding, fairly clear that forks are slightly twisted in the yokes, bike is crabbing a little. Worst problem is the throttle, once hot the bike idles at 4K rpm. My fault, I built the bike up using spares from my parts stash, and this is obviously a throttle cable assembly that I'd rejected in the past. Basically, the two secondary cable inners are too short, stops slides dropping back, cause of my mystery hanging idle.

Also, my 2-1 exhaust is rather loud, embarrassing rather than outright offensive. Does sound good going up and down the gears, but a bit of a pain at cruising speed. 60 mph = 7k rpm in fifth, and is loud. Dropping back to 40mph on a part closed throttle and it's quite acceptable. I did remove my home made baffle for this first ride, as in the garage it did seem to be stifling the engine a bit.

A photo and a very short video.

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David Silvers has the SL 175 throttle cables in stock, same part number as his (pattern) CL 175 cables, order placed. I'm hopeful that they'll be correct, as his CB175 and CB200 throttle cables have a different part number. Also ordered an SL 175 front sprocket cover while I was at it, this is coming from his US warehouse, but no premium on shipping, which is nice. For some reason, upright 175 front sprocket covers are like hens teeth at the moment, I've been looking for a UK located one for ages now.

New fuel hose also on order, the hoses that I only fitted less than 12 months back are already cracking up, so I'm going for ethanol resistant yellow Tygon this time, sod OEM appearance.

I got the Mig out this morning ( welder, not aircraft ) and made up another tail pipe mute, from the Triumph end can that my home made 2-1 breathes through. Usual terrible weld filed down and painted black.

JLUh4sg.jpg
 
It's a shame that orders from 4into1.com cost so much more for you, they have the OEM 5.5mm fuel line that stays soft. I've bought a bunch of it, perfect fit and no clamps needed though I bought the OEM spring wire "clamps" from them as well for the factory look.
 
Well, that might be a bit much for the 175... is that a personalized license tag on your Hornet? Or just coincidental that it says "Bee" on a Hornet...
 
The Hornet was six months old when I bought it, I was the second owner, a lady had it before me, and it came with that registration. I think it was just luck on her part that that reg was available at the time, 'T' is the letter code for the year of registration. In fact, the salesman had to point out the registration to me, it's grown on me since then. I'm personally not a fan of personalised plates, I just think it makes it easier for witnesses if you ride or drive in an inappropriate manner !?!

That said, my Mini 1000 came with the registration RNP 654P ( P = 1976 ), and I did think about changing my middle name to Norman, as my initials are RWP ....
 
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Interesting difference between Florida and the UK (as well as some states here) in that the registration stays with the vehicle. In Florida we keep our tags and move them to the next vehicle. I've only had a couple personalized tags in my life but the most memorable one was on my City auction-purchased former Tampa Police Detective car, a 1977 Dodge Royal Monaco. It was a big old boat (4400 lb 4 door), and being a former cop car caused some friends and I to think about it while out together in it one evening (the car would seat 6) and the conclusion we came to was it was huge like a big "sled", and a former cop car as in "fed" so I got the tag Fed Sled. Say many a person pointing and laughing about it in my rear view mirror at stop lights, and many thinking it was a real cop car while I was following them.
 
Clutch Cargo said:
BTW - Great job on imitating the SL175 look. I don't think I would give it a doubtful eye, other than the blinkers, which US models didn't have.
Click to expand...

Thanks. They got fitted because I'm using CB/CL switch gear, and it seemed a shame to have a switch that didn't do anything, same as the button for the electric start. Also has a CB/CL 2LS front brake.

I did actually fit mirrors as well, but they just looked TOO weird, just have to get used to turning my head more often ..
 
My new throttle cable arrived, and straight away I could see what was wrong with the old one, the inner cable from the twist grip to the 2-1 part was too short, meaning there was not enough free play, hence the 4k idle when hot. Cable swapped, and off for a test ride. I had also untwisted the fork tubes, by slackening the top and bottom yoke pinch bolts, tweaking the steering then retightening, seems to have done the trick.

Anyway, on the test ride it still idled at 4k, despite excess free play in throttle cable. Sorted by adjusting throttle stops on carbs, then adjusting out the excess cable free play.

Tygon fuel tube arrived, far too small, 5.5 OD rather then ID ! Correct black stuff now ordered from Wemoto, 5.5mm ID, 10mm OD.

Here's a short video clip, camera still mounted on helmet in sound proof box, pointed downwards too far. Must sort out the chest rig which is still sitting on my bench.

Lots of wind whistle from my part opened visor on my Arai, worn instead of usual open face lid because of camera mount, another reason for getting the chest mount sorted.

 
Nice quiet road!
All seems good now with the bike I think?
Good luck with it all Richard.
Graham
 
Honda Grom exhaust can (eventually * ) arrived today. Too late in the day to offer it up to the bike, to see if fitting is feasible. Various mandrel bends also on the way, to make new link pipe.

( * I now know what the DH in DHL stands for. Since the pandemic started, couriers just leave packages in our front porch, ring the bell and stand back / walk away, all very convenient, no need to sign anything, a photo on the couriers phone suffices.

But todays genius managed to find our house, and as I later saw from the tracking data, put the package in the porch, uploaded a photo to prove this, then took the package back to his truck. Left a 'sorry you were out' note, informing me that he'd left the package at a drop of point at the filling station 1/4 mile away.

Well, of course, he hadn't. Instead, he took it for a ride around the county, not taking it to the drop off until late afternoon, by which time I'd already walked to the filling station twice, to be met with blank responses from the staff there. Third time lucky, although that involved the third degree, proof of ID etc, bloomin waste of time. DHL website unhelpful, DHL phone line fully automated, no way to actually speak to a human.)
 
My God, it's everywhere... (the DH part) and here I thought this type of idiot was only in the US.

Richard Pitman said:
DHL phone line fully automated, no way to actually speak to a human.)
Click to expand...

As for the automated phone line, it's how they continue to get our money while fully insulating themselves from any complaints. In order to watch our local NHL team this season (and they are one win away from a second consecutive Stanley Cup) we had to sign up with AT&T TV as they are the only company that carries all of the regional sports broadcasts sold off by Fox Sports last year. What a massive and very expensive fiasco, $93 a month for the middle-tier package (lowest priced package that carries the regional channels) and the menus are horrible, wrong listings of what is showing when more often than not, and their "customer service" line is just the same and is the worst I've ever had to deal with (and I thought Dell was the worst before these idiots). Called the first week of the season to ask why the team's games weren't listed and they (outsourced, of course) couldn't even understand what I was talking about, or at least acted that way... there ought to be laws against that level of "service" and detachment from the customer but big corporations pretty much do as they please.
 
RichardPitman said:
Cable swapped, and off for a test ride. I had also untwisted the fork tubes, by slackening the top and bottom yoke pinch bolts, tweaking the steering then retightening, seems to have done the trick.
Here's a short video clip
Click to expand...

Sure sounds good, Richard. And yeah, what a great test ride loop.


Tom - 1982 CM450E
 
Exhaust is a bit too noisy for my taste. Often meet horse riders in the local lanes, and I don't want to upset them.

So I'm going to try fitting a silencer from a Honda MSX 125 Grom.

Progress so far. Grom exhaust mounted on right side of bike, SL on left. So I've cut off all of the brackets, and last couple of inches of link pipe, then welded on a new link pipe, which aligns with my 2-1 header pipes. Next job is to weld on some mounting brackets, then realign the tail pipe and make up some sort of heat shield.

2LmGH9j.jpg


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Photos to follow later.

Had an afternoon of angle grinding and mig welding, got a mounting bracket sorted, also brackets to mount a heatshield.

Test fitted to the bike, still disappointingly loud.

I'd assumed that it would be whisper quiet on an unmolested standard Honda 80db silencer. Maybe I'm looking at this the wrong way. Exhaust intended for a 125 single ought to work on a 175 twin ? But maybe the supposed 20 bhp makes more exhaust gas / noise than 12 bhp Honda Grom ?
 
I have to agree, my thought was it would be quieter just based on the size engine it came from, possibly even too restrictive.
 
Same here. Can you add a baffle, or baffle material without adding too much restriction? What about those S/S scrunchies (cleaning pads)?
On a brighter note… you’re becoming a master fabricator! Or you are a master fine tuning your craft.

Tom - 1982 CM450E
 
It's a proper Honda silencer, with internal chambers connected by a labyrinth of tubes, not a straight through absorbtion type muffler, so adding more baffles shouldn't be necessary. Only thing I can think of is that the Grom has a separate catalyst upstream from the silencer which may also take out some of the noise.

I was working on the principle that a silencer for a 125 single should work on an engine whose individual cylinder capacity is 90cc ( 1mm overbore = 180cc ). Same as later Honda 4's, with a factory 4-1 system, silencer on those similar size to just one of the four individual silencers on earlier models.

Some years ago, I had a road legal Scorpion can on my Hornet. I didn't like it much, and it eventually got the angle grinder therapy. Here's what I found inside, typical I think of most original equipment silencers.

UzKvenw.jpg
 
Weather has cooled off a bit now, so I got motivated to get out of my comfy chair in the shade, and do a bit of cutting and welding. I cut some brackets off another exhaust system that I had in the shed, and attached them to the Grom can. I've decided to persevere with this for a bit longer, get the engine running properly on the new Chinese carbs, see it if really is as loud as I first thought. Next job is a coat of black exhaust paint, then refit to the bike, sealing the pipe joints with Holts exhaust assembly paste this time.

saTRijz.jpg


Heat shield is a piece of brushed stainless steel from another exhaust project some years in the past.

wmwH3Ni.jpg


NiNbV03.jpg
 
Modified Grom exhaust fitted to the SL alike, plenty of exhaust assembly paste used on the joint to the 2-1 bit. Actually doesn't sound too bad now, just looks a bit meh. I'll have a go at posting a video clip from my phone in a bit. Mega fuel leak on start up, one of the aftermarket inline filters had broken. Then took ages to start, very sensitive to fouled plugs, black and sooty. Put some cleaner ones in and it fire up. Wonder if I'd ge better results if I changed the 50 year old coil taken from my left over parts stash.

BpSgZ1E.jpg
 
It does look much larger and more bulky than I thought it would before seeing it mounted on the bike. I suppose your older coil could be down on output a bit, aftermarket replacement is fairly cheap so it would be worth giving a try I'd guess.

Did you happen to see member Scotthonda's question about a kickstart lever appropriate for his CD175?
 
Richard Pitman said:
Modified Grom exhaust fitted to the SL alike, plenty of exhaust assembly paste used on the joint to the 2-1 bit. Actually doesn't sound too bad now, just looks a bit meh.
Click to expand...

I think it looks pretty good, the silver heat shield helps a lot, much better than if you’d left it black.


Tom - 1982 CM450E
 
Hi,
Could you tell me what type (brand etc would be good) of the front guard you have on the bike - apologies if this info is already in the thread - if it is, I missed it).
I think your front guard looks good and is well proportioned for the bike (and front wheel).
Cheers
Mike
 
So, it's time for some more spanner time, after 'wasting' the summer months actually riding my bikes, along with all the other little tasks that we get sidelined with.

My CL175 currently has a CB175 engine that I rebuilt from what the seller described as a 'ceased' engine. Prior to that, I'd rebuilt the original CL175 engine and ran this for a while before fitting the CB engine.

The CL engine now sits in my SL project bike. I plan to put it back into the CL, so that serial numbers match the registration document.

I've just purchased an SL175 bottom end, and I hope to rebuild this using parts from my stash of parts.

oHvmKfz.jpg

tyd4Bbi.jpg

95CXPSI.jpg
 
I find it odd that Honda chose to remove the entire starter section of the upper case on the SL350K1 while totally revamping it from the K0 version, but simply left a closed hole and starter delete on the SL175. I suppose they figured the weight savings (vs. cost, of course) wasn't as dramatic on the 175 as it was on the more behemoth 350.

That engine looks pretty good.
 
All the clutch side parts appear to be missing, along with the clutch pushrod, and obviously the top end is not there.

I have a good standard size used 175 cylinder block, along with new standard size pistons and rings. I also have a good used 175 cam and cam bushings.

And this is where Simo's input would be invaluable. I have a rebuilt but never run CB200 engine. I hope to use the cylinder head off that, oil feed mod to left hand cam bush, so that the 175 cam can be used. Fingers crossed that combustion chamber volume is similar to 175 head, to preserve the 175 compression ratio. 175 pistons have a higher crown than the 200 ones.

I'm also thinking that I can fit the entire CB200 oil pump, primary drive gears and clutch, along with the CB200 right hand engine case and clutch lifter. Just hoping ( pretty sure that they do ) the oil passages in the 200 cover line up with the 175 crankcase. Blank off the clutch push rod seal on the left hand crankcase, as on CB200 engine.

Alternatively, I could take these parts from my spare CB175 engine, but it seems a shame to dismantle a nicely running engine.
 
I'm sure a PM to Simo would get his attention to your thread about it, he might even weigh in anyway though he hasn't been around much (not since our first month).
 
One gotcha already. CB200 crankshaft primary gear end is not same as 175, so I can't use the CB200 primary gear on the 175 crank. I do have a spare duplex 175 primary gear, but that doesn't work with the CB200 simplex gear clutch basket. I need to find a late CD175 primary gear, as this is a simplex gear like the CB200, but is cut to fit the 175 crank. Grrr.

EDIT - looks like using a CB175 clutch basket filled with CB200 plates etc would work, and easier to find than
13611-315-000, one left in Thailand !​

CB200 crank end

7V12NMt.jpg
 
You can NOT use a 200 crank and a 175 cam......

Mismatching numbers of teeth will negate the 2/1 turn ratio, effectively mistiming the cam further with every rotation of the crank......

CB/CL 200 have 16 teeth on crank, 32 on cam gear.......CB/CL/SL 175 have 15 teeth on crank, 30 on cam gear
 
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With respect, I think you have misunderstood my ramblings. I was pondering whether I could use a CB200 clutch and primary drive with a 175 crank, my photo of a CB200 crank was to illustrate the different machining on the end of the 200 crankshaft, meaning that I could not use my CB200 primary gear on the end of my 175 crank.

Later CD175 engines use a simplex primary drive, and the pinion from one of those would work with the 175 crank and 200 clutch basket.

After further thought, I think I will stick to using 175 clutch mechanism, otherwise my engine would look a bit daft with a clutch release mechanism on both sides, albeit nonfunctional on the left side.

I still plan on trying a CB200 head on a 175 bottom end, with a 175 cam and journals, 200 left hand oilway opened up to lube left hand journal.

Thanks,

Richard
 
Another thing I'll be interested to look at is the SL175 kick start mechanism, a ratchet type, unlike the CB/CD/CL mechanism.

I wonder if this has a different ratio to the others, one stroke of the kick start rotating the engine more revolutions than other type ?

Accounting for the longer kick start lever on the SL engine ?
 
Richard Pitman said:
Accounting for the longer kick start lever on the SL engine ?
Click to expand...

While I did not know the mechanism was different, I did always wonder about the length of the SL kickstart lever. I always figured it was because that 175 was the only model with out electric start so they built in extra leverage in case many kicks were required.
 
Just looked on CNMSL and the SL and the CB/CD/CL kick start pinions both have 18 teeth ie same ratio, so that scotches my theory that the SL kick turns the engine over more turns per stroke.

So I wonder why a different mechanism is used, more robust perhaps ?
 
Ancientdad and I were recently discussing changes in the basic designs of several (mostly) engine internal parts (on this and other Hondas) and came to the conclusion that many changes were simply so the assemblies were simpler (fewer or less complex parts) and required less machining (cost less and took less time to manufacture).....These changes all meant greater profits for Honda.....The kick-shaft differences are a prime example.....Much easier/less expensive to produce a ratchet mechanism than to broach matching spiral splining on the shaft and inside the gear (which already requires separate broaching for its toothing).....
If you also consider that the bikes were partially disassembled for shipping, not so that the crates would be smaller, but rather because they could then be shipped as "motorcycle parts" rather than as complete vehicles (vehicles were taxed at a much higher rate) you'll gain insight into how shrewdly and diligently Honda controlled every aspect that could increase their profit margin.....
 
Thanks, that's interesting, certainly makes sense.

But in the specific case of the 175s, the SL175 range only ran from 70 to 71, whilst the CB/CL range continued until at least 74, if you include the 200 range which also used the spiral type of kick start mechanism.

I think the SL uses the ratchet mechanism because the other mechanism is so relatively fragile, operate it with the engine running at high rpm and the pinion grenades itself. On an off road bike, rider standing on the pegs, inadvertent operation of the kick start might be more of a possibility. And in the absence of the electric start you'd be reduced to bump starting the bike, difficult on some types of terrain.

Not that I've ever ridden a proper off road bike. My teenage Yam YL1 and Suzuki B100P field bikes don't really count ..
 
I took the engine out of the SL frame this afternoon. With its removeable front engine mounting plates, and the removeable plate on the top rear right engine mount, the engine just lifts straight out, easier than shoe horning it in and out of the CL/CB frame. No foot rest bar to remove either. With the engine out, the bike now weighs about as much as a bicycle, all the weight is in the engine.

Managed to spill fuel all over my boots, which provoked some grumbles when I return to the house. Boots now made to stay outside.

Next task is to swap this engine back where it came from, into my CL 175.
 
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