Progress - motor work - Project 73 CL175

dcmspikes

Over 1,000 Posts
well, i guess i started my project today. i have a 1973 CL175 and CL350. i think ill make different posts for each bike. at this point ill be working simultaneously on them. well here is what i started with. missing forks and rear brake lever.
cl175startl.jpg



and after a few hours in the garage today i took off the tank, lights, fender, and carbs, drained the oil, and cleaned the engine a little. ill be ordering carb rebuild kits and figuring out a front end. once i rebuild the carbs ill see if i cant get this thing to start. this is where im at with the tear down
IMG_8263.jpg

started cleaning one carb
IMG_8262.jpg

i should have taken a picture of the wiring in the headlight, but here is my wiring diagram so far
175wiringdiagram.jpg


if anyone has or knows where a manual for this little cl175 i could sure use one. thanks
 
Re: NEW - Project Little Brother 73 CL175

Do you think that the wiring is much different from the CL350? I would think the color codes would be pretty constant. After all.. UJM. ???
If so, I think I saw some links to the wiring schematics/diagrams for these bikes. I will see if I can turn it up.

BTW, I like it. Looks like a fun little bike. I think we could use one of these too. Oh no, I already swore I would only have one vintage bike. Right... next one is more modern. Gotta have one for going to retrieve parts for the other.
 
Re: NEW - Project Little Brother 73 CL175

Here we go. Got it from Oldmanhonda.com. A really terrific site.

CL175(after_1970).jpg
 
Re: NEW - Project Little Brother 73 CL175

What a killer bike! Do you have the triple trees? If so, I'd measure the ID and see what forks are available. Of course, the easy thing to do would be to just buy some stock ones (it's the route I'd take).

The wiring on that bike looks dead simple. If you aren't going to use turn signals and just need a basic wiring system, the wiring diagram I used on the CL350 will work fine.

I suggest keeping that little guy as light as possible. It will be fun.

--Chris
 
Re: NEW - Project Little Brother 73 CL175

yeah im fine with the wiring. those were just notes so i could get it straight when i put it back together. all the wires are color matched so it should be easy. the forks i need are 31mm. so im just trying to find some. the only ones i have come across on ebay are trashed. im going to a salvage yard on fri to see what i can find. today since i have no parts and i am waiting for carb rebuild kits i did a first mock-up for a rear cowl

cowlmockup.jpg


i want to get the forks and bars set up before i start making the actual seat. i think im going to have to go with rear sets because this thing is so small.
 
Re: NEW - Project Little Brother 73 CL175

So you have the stock upper trees? It might be simply a matter of having a couple mm's machined out so you can go with 350 forks.

Since you have a 350 right there, have you tried the 350 trees and forks?

--Chris
 
Re: NEW - Project Little Brother 73 CL175

holy shit. my brother is a machinist. why didnt i think of that? i can find 33mm on almost any small cc CB. it would only have to come out where the trees attach. that would take a few minutes on a lathe. looks like im going to go take off a front end right now
thanks chris. these forums are invaluable
 
Re: NEW - Project Little Brother 73 CL175

The cb175 uses 31mm forks as well. as far as rear sets go you can use the passenger peg mounts on these no worries. just flip the gear change lever around and change GP style then all you have to worry about is the brake side. ohio cafe racers and clever dog racing have some really good info on 175 racers that you can apply to this project. here are the links.
http://www.jrbranson.com/HondaRacer/mainpage.htm
http://ohiocaferacers.com/
 
Re: NEW - Project Little Brother 73 CL175

dcmspikes said:
holy shit. my brother is a machinist. why didnt i think of that? i can find 33mm on almost any small cc CB. it would only have to come out where the trees attach. that would take a few minutes on a lathe. looks like im going to go take off a front end right now
thanks chris. these forums are invaluable

No prblem buddy.

So did the 350 trees and forks bolt right up? If not, your brother should help you out nicely. Keep us posted on the progress.

--Chris
 
Re: NEW - Project Little Brother 73 CL175

didnt get that far. when i walked out there i saw a black widow under the rear fender. the 35o is filthy and covered in spiders. it definitely just got its name and paint scheme though. after looking at all the cables and wires connected to the front end i got a little discouraged. you have a standard approach at taking a front end off. ie: disconnect cables then unplug this then unscrew that??
i need to take a crack at it.
 
Re: NEW - Project Little Brother 73 CL175

dentedvw said:
Do you think that the wiring is much different from the CL350? I would think the color codes would be pretty constant. After all.. UJM. ???
If so, I think I saw some links to the wiring schematics/diagrams for these bikes. I will see if I can turn it up.

BTW, I like it. Looks like a fun little bike. I think we could use one of these too. Oh no, I already swore I would only have one vintage bike. Right... next one is more modern. Gotta have one for going to retrieve parts for the other.

i just used masking tape and an ink pen to mark the wires with matching numbers.
 
Re: NEW - Project Little Brother 73 CL175

progress. i got the 350 front end off and tried it on the 175. so close. i also picked up some dial calipers. it turns out that i need to lose 2mm somewhere. if i cant find 31mm forks i can try to machine down some forks or get an entire front end and machine down the inner part that bolts through the frame. the bearings seem to be identical. i wouldnt mind having a beefier looking front end. see what i can find at salvage yard tomorrow.
 
NEW - Project Little Brother 73 CL175

well i got some time and motivation and a little space to continue this project.
i was going to cafe this little bike and get it running, but ive now decided to just tear it down first. i got it to run for about ten sec and that is good enough for me. so here it is with the seat im making
IMG_8770.jpg

and here is what is left after a few hours
IMG_8799.jpg

IMG_8800.jpg


i have a few questions. first i have got the cylinders off, but how do i get to the pistons?
IMG_8812.jpg


second) does anyone know if i can bore these 175 cylinders to fit 200 pistons??

third) is this frame twisted? the down tubes are not symmetrical. is this normal?
IMG_8796.jpg



ill start a thread for my seat making soon
thanks for any help
 
Re: NEW - Project Little Brother 73 CL175

Hi Josh great to see you at it again. I've been a bit unmotivated myself after getting my tank and seat finished and then accidently knocking it over and dinging both of them...argh.
I don't think the frame is symmetrical, I'm pretty sure mine isn't. No idea how to get to the pistons as i've not torn down my motor. I think a 1mm oversize is the way to go for the rebore, that is according to clever dog that link i sent you before. He used a modified cb200 head for his bike and his own designed pistons.
Anyway good luck with it
Dean
 
Re: NEW - Project Little Brother 73 CL175

i stopped by my brothers shop today to talk about my plans for the bike. im thinking clean up the engine, bore cylinders and clean and lap valves. loose everything unnecessary(starter, airboxes....). replace as much as possible with Aluminum(triples, motor mounts...) anyway. im excited.

i looked through my manual and figured out how to get the pistons off. next time read first. so tomorrow is measuring cylinder tolerances and maybe starting on tearing down the wheels for polishing and drilling.

more pics soon
 
Re: NEW - Project Little Brother 73 CL175

yeah im excited. that job thing kind of got in the way for a bit, but things are slowing down so i have some time for fun stuff. sounds like youre almost finished.
 
progress

ok. updates from this weekend.
this is where having a brother with a machine shop comes in real handy.
392.jpg

so i tore down the motor

396.jpg

and my brother fabbed a plate for the Pertronix electronic ignition

400.jpg

we made a spring compressor for the valves

403.jpg

and i took the valves out for cleaning

407.jpg

i think i might try some mild porting


i am also hoping to win some cb200 pistons for a rebore
 
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