The only real difference between the 650 and 800 motors is the cylinders and pistons. Of course if your converting you'd need a fuel tuner to compensate for the added displacement.

 

That's what I figured the problem with my engine is a cracked cylinder head and I just knew of this 800 engine would it also be the same if I just bolted on the top end of the 800 to my 650? Or only used the cylinder head off it?

 

No, not quite. 650 has different gearing if remember corretly, different helix, and for sure the ecm is different. Yes, it should bolt right up.
You could do the swap, but you would have to clutch it for the extra power. All very doable.

 

Yeah but that's all outside of the actual motor PFDK3, the motors themselves are the same.

But yeah, you can pull the top end off the 800 and put it on the 650 bottom end for sure. Or just swap cylinder heads. It's up to you. They are the same.

 

He asked if he could just drop in the motor, I answered that specific question,

 

Same motor part for part only it has a bigger bore. 500 is the same motor as well but it has a slightly shorter stroke and smaller bore again. Heads are the same on all of them I do believe.

As mentioned to change over you'd have to reclutch it and then either take it in and have the ecm reprogrammed by your dealer or buy a tuner.

 

I fully expected to need to reprogram or get a tuner that's not a big deal and my 650 currently has a dalton clutch kit in it not really sure if it would be good enough or not.

 

You would likely have to make a few adjustments to the kit but worth it

 

Easiest way is to slap a new head on it. No other fooling around.

 

So here's a bit of a different question. I just compression tested my quad and the front head was 180 the back 160 and leaks about 5 psi the back head has a brand new head gasket. It overheats and shoots antifreeze out of the overflow would this be my head?

 

So I picked up the 800 it's actually out of an 07 renegade and wired it all in and I have strong spark and looks like gas is going in but it will not run would I need to use the original computer and wiring for that engine?

 

Dealer will have to reprogram your computer for two reasons. 1) You went from 650-800. Yes you can compensate on your controller but having the base from BRP will serve you better. 2) The engine is actually coded like your key to prevent theft. People would steal a quad then put the computer from there own old quad they trashed in it to use it.

 

Ok so can am told me that the 800 engine will not work at all on my computer not even start I would need to put in an 800 computer. so would it work with just the 800 top end?