Crank Swap...Newer '89+ into older '86/'87 cases...???

[Speedway73]

Hey all....Does anyone know if a newer '89+ crank will swap into the older '86/'87 cases??

[kwakman]

the primary drive gear location is achieved differently, but I dont think there are any other differences.get a few more opinions first....

[hughes]

I used the 89-04 crank shaft main bearings and rod kit with zero issues in my 87 KX500. I just rebuilt my old crank with newer parts. I also used the 89-04 piston/ring set in my 87 500. The 87 piston is only one ring where the newer ones where two rings.

[dave916]

I used the 89-04 crank shaft main bearings and rod kit with zero issues in my 87 KX500. I just rebuilt my old crank with newer parts. I also used the 89-04 piston/ring set in my 87 500. The 87 piston is only one ring where the newer ones where two rings.

i think he i talking about a complete swap
what i wrong with the orginal crankshaft?
the primary gear is going to be different  fit ,  keyway /nut  86/7 ,splined /cirlip 88on   
the clutch looks like it has different gear [ in the Clymer manual]83/86 and 87on   so the later primary gear will not match
it may fit the 87 if it has the later clutch gear but not 100%on this

[Speedway73]

Yes...a complete swap. The '86 crank is toast and I have a really nice '90 crank sitting here collecting dust.

By the looks of it....the total widths of each crank are the same. Other than the primary gear to cluch gear issue...which I've yet to verify...it looks as though it could be a sucessful swap.

I'll have to do a mock up this weekend.

[kwakman]

pull it out and have a gander...

[Roostmad1]

I used the 89-04 crank shaft main bearings and rod kit with zero issues in my 87 KX500. I just rebuilt my old crank with newer parts. I also used the 89-04 piston/ring set in my 87 500. The 87 piston is only one ring where the newer ones where two rings.

Hi,i got told from the guy at kawasaki shop who also owned and raced a 86 KX500 back in the day said you can use a later piston in a 86 87 that had a flat top piston but the head had to be recut to suit!!