TY 175 engine noise resolved

[Takhli44]

I had a noise in my 1980 (one of the 76's they kept making for Europe)TY 175 that sounded like a slack or floating gear coming in contact with another gear and bouncing off only to come in contact again. Ding. ding,ding. while under deceleration. The sound could be duplicated to a quieter degree with the bike in gear, clutch pulled in and revving then decelerating the engine leaving me to think it was in the primary gear or kick start area. I replaced the clutch and clutch baskets with an old 76? one from a parts engine and checked everything for proper fit and assembly. Problem solved.

The large primary gear has loose free play where it is mounted to the clutch basket while the parts engine primary gear has about the same amount of play but seems more cushioned and not as loose. I also notice that the 1980 basket has longer spring bolts and the splines on the internal basket are a steel insert while on the older one they are machined into the casting.

Anyone else run into this issue? I assume this play is there from new?

[David Lahey]

I noticed what I thought was too much free play in the clutch cush drive in a TY175B motor that had high hours and decided to remove the play, thinking it might make the bike nicer to ride in sections. I replaced the rubber discs inside the clutch basket and while it did remove the free play, I could not notice any difference in the way the motor felt riding in sections.
It had not been making any noise, but I imagine if the discs become worn enough that it would eventually make a noise.
Which splines are you talking about that are a cast-in insert? On the motors I've worked on, the clutch inner hub has steel splines where they drives the gearbox shaft, and aluminium splines where the steel clutch plates fit.

[Takhli44]

Thanks for the reply David. The splines where the internal clutch basket mates with the transmission input shaft are what I was referring to, both being in good shape with nearly zero play. The newer one has a steel insert molded right into the basket while the older one is made entirely from aluminum, splines and all. No apparent issues in this area, just describing the differences in the clutches. The old one could be any year as it was in a box of parts.

I have another one in the shed that is VERY worn and from an older bike that has the steel splines also. Never looked at that before. The plate that covers the rubber disks is round on the newer one and star shaped on both older ones. I'm wondering if there were issues with the aluminium splines and they were replaced with steel or perhaps that basket came from something other than a TY175?

I am not completely convinced that the loose primary gear was the noise as it still has cushioning but everything seemed to be in alignment and properly assembled and with the replacement of the clutch components all is quiet. The only thing I may have missed was checking where the kickstart gear spring (not return spring) was anchored on disassembly. There is a deep squared hole and a rounded shallow hole. I anchored it in the deep hole, not sure if it could be put together in the other hole.

[Takhli44]

That all aluminum clutch basket came from an engine with 525-002*** which is an early B. It had a 525 something inside it so I assume a TY175. Have a few hours on it now and all is quiet and shifts the best of any TY175 I have ridden.