So i recently acquired a 1970 ct175 to get running for a friend got the issue sorted with the carb from the last rebuilder and now the bike runs amazing I installed a new clutch cable and new clutch friction discs but did not replace the steel plates or springs and I left the rubber rings in . Got everything buttoned up and took it for a spin the clutch acted as a normal one would when shifting at a normal rate with out revving it out and just gradually going higher in the rpm range.....but once you get on it and rev it out and go to shift let the clutch lever go it slips till you let off the gas and then it engages and you can get to hammering on it again with absolutely no issues..... you can put the bike in 3rd gear and lug it up a moderate hill with no slippage or dragging of the clutch I changed the oil and added the proper 10w30 oil designated for wet clutches after the install of the new clutch. I'm at a complete loss and definitely puzzled as I've owned a couple ct1/2/3's throught out the years and wrenched on more bikes then a little

Did you use OEM discs from Yamaha?  If not, did you measure the thickness?



 

Did you measure the length of the springs, too? If the springs are shorter than spec, that means they are not squeezing the plates and discs together as tight as they might be were they brand new.

Yes as with all my older bike I prefer to use oem discs it's always worked great so I never saw the need Togo aftermarket

Unfortunately I did not and at this point I'm starting to think shame on me for not doing so while it was all apart.

If 4mm discs were used my first guess is the rubbers weren't installed right or are bad.  But then I don't care for them and always leave them out.

 

Is it a nice free cable. Does the actuator in pic two have clearance & is it binding in the case as that one runs in the alloy unlike CT3's with a nylon outer to run in. There's a small spring to help the actuator arm go right back. Sometimes--had it on my DT1--where the helical clutch & crank gears under load try to force the mainshaft sideways taking up any free play so maybe give it an extra clearance on lever & actuator to prove a point. That's clutching at straws as unlikely, but!!. Old steels still work good & Orings left out so even better. New plates "even pirate ones" should still grip good so umm, i'm no use at all lol.--& my AT1--175 top end slips so better get too it & fix.
I'll just add that if you give extra clearance & the worm, sorry actuator is dry & binding & return spring on the arm is uselless then you'll gain nothing in testing as will still likely sit against the rod rather than clear it. Same goes for a binding cable.

Took the clutch apart and to my finding the springs are shorter then spec smh so I went and picked up a set of heavy duty ones from Barnett and now I'm simply waiting for the case gasket to button it up, it looks like itll be arriving monday so the end is near. The springs I took out were about 1mm shorter then the bottom area of spec i now know to check for this next time

When installing the discs are you going by the parts diagram?

Don't.  Stack needs to start with a friction and end with a steel.

That's exactly what I did started with a friction and ended with a steel