Where do i start!?

It runs and rides.

1.  The previous owner has the throttle cable going into the case but mixes fuel.  I was told replace rhe whole control with a domino and run the cable directly to the carb.  What cable do i buy?

2.  What ratio and premix type?  I run motule 800 80:1 on my modern bikes.

3.  What fluid do i put in the transmission?

4.  Forks seals leak.  Should i order oem stuff or is there a better alternative?

5.  Bearings!  Do i use oem or is there better?

6.  Sprockets and chain.  Where do i get these?

These are my "initial" questions.  I plan to use thia bike for sime vintage competitions.  I would like to make the bike better.  Not restore it to original.

Thanks!

If the po was running premix the oil injection is probably not hooked up. The stock throttle cable is a split cable with one end going to the carb and the other going to the oil injection pump. If you take the oil pump cover off(right side front of the engine) you can determine if the oil injection pump is still connected.

I believe Yamaha calls for 10w 30 engine oil for the tranny and allot of people use ATF. I would use a good quality motorcycle oil 10w30 like Yamalube.

Matt at Speed and Sport can help you with all your other questions and probably has the parts in stock. He is a good source for all vintage Yamaha stuff and has a good web site. I think he has manuals also for your bike. www.speedandsport.com He has done allot of the Domino/ throttle cable conversions for the TYs  and may be able to send you what you need from memory or tell you what he needs for measurements.

Thanks for the quick reply!  I was put in contact with B&J racing.  They had a answer and part for everything i could think of for the TY.  

Going to do this upgrade/maintenance in 2 or 3 steps.  Cant wait to start tearing her down.

 

I'm not much of a ty250 expert, but before even thinking about replacing fork seals, make sure to give them a good clean with a Sealmate..  I've had many a weaping seal clean right up with a few careful swipes of a Sealmate..   

 

Hi

We use 2 stroke gear oil for my dad's 250 TY (434, as yours) wich appears to be 10w40 grade, it works perfectly. Any motorcycle oil (with wet clutch) 10w30 or 10w40 will fit in the gearbox. As Yamaha doesn't make bearings or seals themselve, I would go on with any big brand like SKF, Timken, FAG, Koyo, SNR-NTN, SNK, etc. from an official distributor. I think that one or both of them should meet C4 specification.
Motorcycle fork seals are particulars, don't fit standard seals as they will leak, use fork seals. Here in Europe we have brands like Athena Seals, i guess that you have the same kind of company is the US.

The brand Talon makes sprockets for the TY

Thanks for the feedback.

Ive ordered from a few vendors now.  Wish i could find a new gas tank.

What are some additional vendors who sell ty250 parts?

1 hour ago, lolosuzuki said:

Thanks for the feedback.

Ive ordered from a few vendors now.  Wish i could find a new gas tank.

What are some additional vendors who sell ty250 parts?

Shedworks (UK) for a new fuel tank

On 5/27/2019 at 7:56 PM, lolosuzuki said:

Thanks for the feedback.

Ive ordered from a few vendors now.  Wish i could find a new gas tank.

What are some additional vendors who sell ty250 parts?

On ty if you replace main bearings save the o ring on the outside of right main.If you use a aftermarket kit the replacement is often smaller and does not keep the transfer of gear oil out of crankcase.When you put on the crank drive gear it squashes that o ring to seal the tranny from the crankcase completely as some can creep thrue the splines.