Hey All,.  I  just rescued what I thought was a 74 ish ty 250 to clean up and resale.  The more I looked at it I thought the wheel base was a little long  it measures 50  inches from the lower front shock mount to the lower rear shock mount. That is 2 inches longer than my other 74 ty 250 I bought new. Everything else on the bike is exactly like my ty 250 except the angle of the front steering tower. I'm curious if the vin number might tell me something if anyone can help it is 434-008998. THanks for any info.   Jbird  

434 -00*** is A model (1973/74)

The frame geometry on twinshock TY250s was unchanged through all the models.

I would measure one of mine that I know is completely standard except I can't work out what you are calling the lower front shock mount

Probably better to measure the distance between the axle centres with the steering straight, because some people move the mounting points for the rear shocks

G Morning Feetupfun,.  The distance from the front axle to the rear axle is 50.5". The swing arm is the same as my other 250.  I've done no mod to the swing arm.  Another measurement is the front axle to the front motor mount is 20.5".  Also the motor and frame serial numbers match and the motor is clearly a trials.  I can see a difference in the steering angle.  I was curious if Yamaha starred building their trials with a steering angle similar to the enduro then changed to what we see on all others. GDay. 

Well I know that they didn't change the steering angle from go to whoa and will go and measure soon

Standard TY250A frame swingarm and forks. 340mm shocks fully extended. Forks extended to where the anti-topping springs engage

Axle centre to axle centre 51 inches with rear axle about halfway along the slot

Front axle centre to front motor mount bolt centre 21.75 inches (1' 9 3/4")