TRX Crank question - need answer

[atctim]

After looking up some part numbers - I see the 1986 TRX250R crank has one part number - and the 1987 - 1989 has a different but common part number.

What I need to know is - what is the difference.

Please help me.

Thanks,
Tim

[tecat-z]

86 short rod. 87-89 long rod. 86 trx is the same as 85-86 atc.

[atctim]

OK guys - so you could put an 86 crank in an 87 bottom end - and vice-a-versa - 87 crank in a 86 bottom end???????

Basically has nothing to do with crank length.

[jason85atc250r]

you just need the piston to match the style crank your using or use a 87-89 crank with a 86 piston and a spacer plate

[3leggeddog]

tim,my motor is a 86 bottom end,with a 89 hotrods crank,with a esr 5mm spacer plate.Makes her a lil stroker motor of sorts.You have to use the 89 piston,with the 89 crank/rod.

[tecat-z]

Two different piston styles. 85-86 atc trx short rod. 87-89 long rod. Pin to crown height is the difference. Which is the difference in rod length between years.

[atctim]

thanks guys - all cleared up now!

Very informative thread

[KASEY]

tim,my motor is a 86 bottom end,with a 89 hotrods crank,with a esr 5mm spacer plate.Makes her a lil stroker motor of sorts.You have to use the 89 piston,with the 89 crank/rod.

with a long rod and a short rod piston,, you don't have a stroker motor,,, the only way is if the pin location in the crank has been moved,,, so you still have a stock stroke motor,,,,,,,,,,,,,