KZ 650 begining engine build- Pic

Here is a pic of the bike at the begining of the project.

Thanks for all the info so far

Tweasl

Post edited by: Tweasl, at: 2006/08/11 19:40

Hey Tweasl. Looks like you have some other toys that you have bike wrenching experience with. If you have any questions post 'em here or send me a U2U. I've done the 650 rebuild twice in the past 18 months, first the Wiseco 700 then the 810 kit.

Cheers-Colin Firth-Ontario Canada.
1977 Kz 650 Custom, now with 810 kit and lottsa go fast goodies.
Here's a pic of my ride from last season.

Post edited by: reborn650, at: 2006/08/11 19:48

Plenty of toys: 1970 CB 750, RG 500, Guzzi Lemans and a ton of RD stuff etc. Anyway, I appreciate the help. I'm not sure if I'll do the big bore thing yet $$$, but my goal is to have a streetable old school looking miniature superbike. How bout that for a new motorcyle category.

Later Tweasl

What is involved with the 810 kit? Case boring and oversize sleeves I'm sure. Good Street cam? I could go on and on, but I'll stop with these questions reliability? Gasket sealing problems? You have a good looking bike. Probably a good show for some of the smaller modern sportbikes

Later Tweasl

Looks like a good progect. I built my 650 back in the early 80's and it would still be going strong if a young girl didn't werck me. No sealing problems and always ran great. It has Yoshimura pistons, cams pipe and 29 smoothbores.
Mark





Post edited by: steell, at: 2006/08/13 11:31

Hey Mark

Thanks for the encouragement. Lots of good parts in your bike. I just have to know something though, isn't the weather always good in Ca.

later Tweasl

Hey Tweasl. From the pic, your 650 looks like a '76 or '77 B Model. If this is correct you will need to do the following for the 810.

You will need to get your hands on Kz or Gpz 750 cylinders for boring for the 810 Wiseco pistons. If you are going to use the '77 motor's bottom end, then the crankase cases will have to be opened up to accept the larger sleeves of the Kz750/4. Later model 650 bottom ends are large enough to handle the 750 jugs without modification. These later 650's also had the Hy-Vo camchain set up.

With the motor out of the frame and the cases split, it took me about 2 hours to carefully open up the top of the cases' bore openings using a variable speed drill with an aluminum cutting bit. A little bit of grinding, test fitting, marking, then more grinding. Go slow and it should be a piece of cake. It is pretty much a waste of time to try to open the cases without having them split as you have to manouver around all of the studs to get deep down into the nooks and crannies.

I stuck with my stock roller cam chain and adjusters but fitted in cams from a 1980 Kz 750/4. I swapped over the cam gears from the 650 onto the 750 cams.

I had the 650 head milled about 8 thou, just to clean up the fire ring on the combustion chamber. I also ported and polished the head. The final step was to install Gpz intake valves and springs. I avoided the GPz cams as I wanted to retain the stock tach gear set up. My goal was to make a true sleeper that looked bone stock except for the pipe, velocity stacks and a few sublte body mods.

Everything was pretty much a drop in except with having to go with larger diameter bolts through the front and rear of the 650 head to mate with the 750 jugs. Leaking has not been an issue anywhere on the motor. I also went with Mikuni 28's from Wired George, Dyna electronic ignition, green 4.0 ohm coils and new wires.

If you run a similar set-up to mine, you will be very impressed with the performance of the engine in the mid-size 650 frame. This package will give you performance that will match much bigger displacement bikes. It is considerably stronger than the Wiseco 700 with Mikuni 24's I had on the bike last year and the 14 tooth sprocket makes this thing launch hard off the line and pull strong all the way up to 11,000 rpm.

Cheers-Colin Firth - Ontario Canada

Post edited by: reborn650, at: 2006/08/12 14:16