87 motor into an 88 chassis? Will it fit? What about pipes?

[RJacks258]

Just as the title says, will the '87 motor fit into the '88 chassis? I just picked up a decent, middle of the road as far as condition, '87 KX500. I have a chance at a clean '88 roller.  My '87 had a rigged YZ490 pipe on it. I am having a hard time finding a pipe, so which years will fit my '87. Every listing shows '88-'04, and I've only been able to find '86 and older.

[Goat]

I happen to have a newer frame 87. The engine will bolt right in to the 88-04 frame and the exhaust from 88-04 will work as well. Really the only thing different on the pipes between the years is the lower mounting point. The older ones didn't have it if I remember correctly. I'm sure the chamber girth and length changed slightly to accommodate for the updated engine mods. You running a pj or pwk carb? PJ's choke hit's the bottom of the tank by the petcock so you need to turn the carb towards the kick start so it doesn't break or bend the chock shaft. Everything else just fits. Any questions or issues feel free to message me.

[don46]

As goat says it will bolt right into the 88, it will almost bolt right into the 89-04 chassis, the head stay is not the same bolt pattern as the 89 up chassis. The 87 used the mikuni and the 88 used the Kehin pwk carb.

[Goat]

I'm running an 88 frame on my 93 engine and didn't notice anything different between the frames. The 87 engine is in a 92 frame with slightly modified head stay plates. When we got the 87 it had a junk pj carb (I really hate them for the record) I wasn't sure when they switched from Mikuni. My 85 had a mikuni but that was pre-kipps.

[sawakaki]

i have a dyno mort pipe that will fit ,made for 87kx500