89 cr250 with a 90 jug needs top end

[mxcrazed]

Hey all, Ive got as the title says an 89 cr250 with a 90 cylinder jug. The bike needs a top end as I heard some dieseling noises from it Wednesday and upon inspection I found the wrist pin and lower end which I replaced three seasons ago were still intact. What I found upon further inspection of some slight galling on the piston skirt was a small crack so it must've been piston slap i was hearing. The only problem I have is that there are two wiseco top end kits available PK1243 and PK1248, 1243 is for 86-89 and 1248 is for the 90-91 bikes does anyone know the difference I cant remember if I took this into account when building the engine
the piston in there was 614M06640 same part for both bikes on wiseco's page

thanks any help is greatly appreciated

 

[julien_d]

Well, if you think about it...

The piston kit part number is the same for both bikes? So then it follows that the piston in both those top end kits will be the same. Piston kit being the same, the rings, wrist pin, and circlip will also be the wame. The remainder of the "top end kit" is comprised of the top end gasket kit and the wrist pin bearing. If you have a 90 top end, then logically you want to get the 90 top end gasket kit, should there be a difference between those gaskets and the 89 gaskets. If there is no difference, you still get the right stuff.

Right? That would be my best assumption going off only the information you provided, and not researching it for ya. ;)