1986 WR400 engine swap to a 510 4 stroke

[1986WR400]

Does anyone know if the 510 can be swapped into the 1986 WR400 frame? I've looked at the 510 and it sure looks like it would bolt right up with the exception of dimpling the front down tube for the twin exhaust and swapping out the air box plastic, tank plastic and seat.

 

[Michel Dufayard]

It works with a 84 wrlc frame, so I think it could be possible with a 86 2stroke frame.
Look at the front frame if a 84 looks like a 86 frame.

 

[ruwfo]

Looks pretty close

Michel,
Yes it sure looks like it would fit, here's a few pictures of my old
86 400wr.
Here's my thoughts
1) you may have to make new motor mounts, the 510 motor mounts
are different then 2 stroke ones.
2) I don't think you need to worry about the flat on the frame
for pipe clearance. Mine fit in a 81 250CR frame .
3) I doubt the 510 original air box will fit on the 400wr frame without
making some new brackets.
4) There's a 86 510 frame on Ebay though? which may just make
you life easier

I'm still working on my 86 510 project, almost at the point where i'm
going to she if she runs this weekend

Husky John

 

[Michel Dufayard]

Yes you need to put 2 stroke motor mounts in your 2 stroke frame for your 510 motor.
I think it is OK like that !

 

[1986WR400]

Thank you gentlemen for your timely response. I love my old reliable 400 engine, but I've always been a 4 stroke rider and I'm ready to get back to thumping. gentlemen, have a great day!

 

[fran...k.]

I think you will find the four stroke radiators are longer. Are you sure the exhaust pipes won't end up interfering with the branching twin down tubes which straddle the two stroke pipe?

Fran

 

[Hwy]

Is it air or water cooled 510?
You may have problems with the pipes and frame clearance. Here is a reference photo of the pipes.