Yamaha Tri Moto 175-No 5th gear.

[mdeckeradpro]

I recently got my old Tri Moto 175 running from high school that has been sitting in the back of our farm shop for 27 years. I am slowly getting it restored, but I did encounter one problem. I am pre-mixing fuel. Should I just pull the oil injector pump and remove the drive gear so the pump doesn't lock up and cause problems? How is the best way to handle this?


Also, my tranny is working fine. The clutches were stuck when I first got it running, but I got it really hot and was able to free them up. All the gears work fine, but when I shift into 5th, I have nothing. It is like going into neutral. Is there an adjustment that I can make or is my 5th gear just fried?

Please let me know.

Thanks, Marc

[Highhorse78]

Personally, I would do as you suggested and remove the oil pump and plastic gear on the inside of the clutch housing. You can either remove gear and leave pump in place or remove all together and make a block off plate.

You might get lucky with the trans if you run it through a few heat cycles with a couple fresh fluid changes, but chances are you're going to have to split the cases and inspect. I would look for bent or worn shift forks, cam followers, ect. Discoloration and galling shouldn't be present. Make sure everything moves smoothly. Also don't be intimidated by splitting the cases... Its very simple once you open it up. Just lay the motor on its magneto side and pull the top half off. The trans internals will stay in the lower part of the case. Now would be a good time to do crank seals. Also if your rod is loose it would be a good time to do crank bearings and a new rod kit as well.

Hope this help, and let me know if you have any other questions.