difference between cranks on an 86 and 87-89 250rs

[quadracer440ex]

ok i recently have gotten a crank off of my buddy not knowing what year it was and everything i put it in my 86 250r motor put everything together and put the cylinder on now it hits the top of my head.....so i looked into it and saw that the 86 cranks are different then the 87-89 cranks.....so now what do i do to fix this problem i heard about spacer plates but i dont know what size spacer plate i would need can you help me out? and also could i just switch out to an 87-89 piston i recently have the 86 style piston that i had on before....thanks alot let me know what you guys think i just got this bike ..........thank you so much please respond asap

[Honda 250r 001]

the 86 cranks have a shorter rod, not increasing stroke but changing the side push on the piston twords the skirts. the 87-89 rods were longer making the push less causeing the piston to last longer. there is nothing wrong with the 86 crank infact some people perfer them. but with the 87-89 crank and a 86 piston you need to run a spacer plate.

if you wanted to, you could buy a 87-89 piston and you would NOT have to run the spacer plate.

I have an extra spacer plate i would sell you if you want. With the spacer plate, you also have to back the base studs out about 3 turns so you can get the nuts on.

Tell me what you want to do i will help ya.

[Honda 250r 001]

Hey man your welcome anytime. I would do 20 shipped for the spacer. I believe its a duncan racing spacer plate. When you back the studs out you are going to need to use a good set of vice grips and squeeze below just below the threads so you dont booger them up. It can be a real chore to get them out but i have been successful 2 out 2 times getting them loose. My paypal is stevejirak@yahoo.com

If there is anything else you need give me a holler.

your pm box is full i would suggest cleaning it.

[quadracer440ex]

money was sent thank you keep me updated