kz440 motor swap? Please read

quick question, I have an 81 kz650 frame with an 82 kz750 engine on it. I have built myself a bobber out of it and nearing completion I have seen some people with the 440's turn them into bobbers and it looks more period correct. I found a guy with a complete newer 440 engine and trans with complete wiring harness that is in great shape and he only wants $100 for it. my question is will it fit on my frame or is the 440 frame way different than the 650 frame?

Not sure on the swappability (I doubt it's a simple bolt-in), but if you want a 440, you should just get a whole bike. They are pretty cheap.

Your 650/750 looks way too good to dismantle. Not sure if the power matters to you, but obviously the 440 will be a lot slower.

The 440 frame (most of them in the U.S., but not all) are cruiser type frames. Turning one into a bobber is an afternoon project. But it will have mags. It should be easy to get kz400 spoke wheels on it, but they are both 18".

There was a phenomenon, in the 1970's, of converting inline-four bikes (from Japan) into choppers. They used frames like the ones from Amen. So inline-fours are not totally wrong for that period. In my opinion, they were some of the best looking choppers. They looked to have more muscle.

Sorry, I know, quick question, but long answer.

Ya, I dont know what I want to do. I am so close to finishing mine and I like it alot. I just think having the 2 cylinders would be easier to work on.

Well, the valve adjustment is easier for sure on the 400/440 twins. Also it only has one ignition circuit, the ignition is a little simpler. Other than that, though, the electrical is about the same (charging, lightling etc).

But the 400/440 twins have a complicated set of balancing shafts and chains inside to offset the vibration from the 360-degree crank. It usually doesn't have any maintenance issue, but if it does, it's a little more complicated than the fours.

One problem on the 650/750 fours is the starter clutch. It's relatively dificult to get too. On the 400/440, the starter clutch is easier to get to.

Your 650 frame is quite a bit larger than the 440. I wouldn't stop the build your doing already.
Maybe grab up that 440 stuff while you can, toss it under the bench, and keep your eyes open for an old beat up 440, or 400 if you want spoke wheels, the motor will drop right into the 400 frame.

Thanks, the biggest thing that worries me with the 440 is the power difference. Im affraid it would be too slow.

The highest I was able to top out on a stock Kz400 was right about 100mph. That was probably with a tail wind. It wan't scary though, because the 400 is pretty big for a 400, and the handling was very mild and steady. Probably get a little more on a 440, but not much more without some mods.

Hey Guys,
So just confirming that to our knowledge there aren't any engine swap options without frame modification? I've thought the other way in wondering about a different engine in a 440 frame.

Better off with a different bike.
Steve
orangecounty.craigslist.org/mcy/5560008029.html

Jbosh wrote: Hey Guys,
So just confirming that to our knowledge there aren't any engine swap options without frame modification? I've thought the other way in wondering about a different engine in a 440 frame.

Never heard of another option for a 440 frame besides a Kz400 motor.

It would be interesting to see if an EX500 (ninja) engine would fit, but I wouldn't hold my breath on that.

swest wrote: Better off with a different bike.
Steve
orangecounty.craigslist.org/mcy/5560008029.html

I'd have to ride half of North America to get it home though! Thanks though haha. I hear ya.

www.kzrider.com/forum/2-engine/593525-ex...ine-in-a-kz400-frame

A few have been talking about this already I guess. Still haven't found much. Interesting discussion here grassrootsmotorsports.com/forum/sprocket...rn-kick/18782/page1/ where one guy makes the comment that a "KZ440 with an EX500 engine is going to be 3/4 as fast as the EX500 and handle 1/4 as well." Valid point. Still haven't found an example for curiosity sake. They don't understand the love I have for my 440 :P.