Big singles work good. Got the torque down low. Our group has my KLX650, a 660 Raptor, and a 500 Sportsman. 2 shifters and the sportsman runs a CVT. Mine is the only Odyssey, but the other buggies are similar in size, and both of them are heavier.

Yamaha 660 Raptor. If I build another buggy, it will have this Engine. Works awesome, has built in reverse, and dry sump oiling.


Farr was working on a Sportsman 500 swap. Haven't seen any updates though.


I did a lot of research when I was looking for a good 4 stroke to swap in. My concern with a multi cylinder street bike Engine is the torque is way up in the RPM's. You would be screaming in revs all the time. Not really conducive to the type of ridding we do. But I would be happy to be proven wrong if someone successfully does it.

Also packaging a 4 cylinder Engine in an Oddy frame with exhaust air intake will be tight.
A big single leaves lots of room.
My KLX650( bored to 678cc). 6900 rpm tops.

Stock FL350 Engine is about what, 27hp? Is that with the orignal head, or the lower compression ones?

That's partly why you need 700cc in a 4 stroke. Bigger bang per stroke, but half the strokes. Hoser I know you will defend your passion for 2 strokes to the death, and that is ok by me. If someone makes the decision to put a stock 350 Engine in, fine by me,a small sled Engine, a big sled Engine, or a twin turbo 1300cc monster, who am I to tell them different. I can only share my experiences with the intent to get them to their goal, out riding. I only responded because the twin chain drive on 760rider's machine is pretty similar to what I have.
I'm not saying that an Engine like I have is better idea, nor a worse idea than a sled or a stock or modified 350 Engine. It is just the option that I chose and I am very happy with it. And to me building stuff is half the fun.
And don't get hung up on rated horsepower numbers as a deciding factor. It's all about using the power efficiently for the type of riding you do. Where the Engine makes it's power is as important. I dropped 50 hp (rated) going from the Rotax 670 to the KLX 650, but I have almost the same usable power. I gave up the ability to throw rocks at the people behind me when I'm taking off, but overall it does not show that I have half the power I had before. For the riding I do. Will it stay with a stock FL350 ripping full song across the dunes? I don't know, maybe I should drag this thing down to Silver Lake MI and we can meet up and try each others machine out. I bet we both come back with smiles on our faces because these things are a blast no matter what Engine is pushing them around.
Here's teaser vid from the back of my Oddy with the 670 being followed by the 660 Raptor powered buggy which is about 60lbs heavier than mine. I'm not getting away much.


And with the 650 4 stroke.

I won't load up 760rider's thread with my stuff, so go here.

viewtopic.php?f=5&t=8463" .".." ."..