1977 kz 650

I'm redoing the top end on my kz and thought now is a good time to bump it up to a 700cc. Anyone know where to get a kit that doesnt cost more than 300 dollars?

how bout a 750 topend?

how 'bout some more details on your Kaw. Can you send picture? I've sorta been thinking along the same lines as you. I'm pretty sure the next 1/4 mil oversize is unavailable (kaw oem). The guys at Z1enterprise are very helpful with this. I decided I would measure first and weigh the costs. The one I'm working on reads 30K on the clock, so it shouldn't be totally worn out. Rings alone were nearly $200, with knew wrist pin clips. As for piston kits, I wonder how far oversize you can go in the stock 652cc block. I saw 2mil overs (aftermarket) for a pretty good price, but that seemed it would thin out the cylinder wall considerably. This must change the dynamics of the original design noticeably, I would think. It might change its wear pattern. I think the advice on a 750-4cyl top end is a good one, since I believe they both used idientical bottom end motor cases and everything. The cam chain train looks different, so I'm not posative. Also there was some top end emission control crap (cafe compliance) on the 750(4cyl 1980 or 1981 I think) which you might have to deal with.

I don't know about price, but my 1977 KZ650b has been rebored to run stock GPZ750 pistons. This setup works great at least to me as this is the fastest KZ650 I've ever ridden. You can also get the Wisco kits ect, but any more than stock compression ratio won't work on the steet. You can take it from me, or believe the other guys that run 11-1 pistons on regular pump gas without a problem. I have problems even on stock compression on pump premium in hot weather, but your mileage may vary.

I thought the 650 liners were thick enough to bore to 750, it's good to hear that someone has actually done it.

With 83-85 GPz750 pistons and a 650 cylinder head, I think that would put it real close to 10:1 compression.

Sounds like it's time to list my GPz750 standard size pistons with new rings in the Classifieds again

Post edited by: steell, at: 2007/02/20 23:58

I may consider the 750, but I think i may need new carbs as well with that set up. I unfortunetly have a budget. The wiesco kit that is 2 mm over bore making it 700cc cost 520 for everything. I have a spare motor with 7k on it that i might just swap over if i cant bore it for cheap.

atp wrote:

I may consider the 750, but I think i may need new carbs as well with that set up. I unfortunetly have a budget. The wiesco kit that is 2 mm over bore making it 700cc cost 520 for everything. I have a spare motor with 7k on it that i might just swap over if i cant bore it for cheap.

Last time I checked (just last year), the Wiseco 718cc kit was only $440 through a local Mega-bike "stealership". They couldn't have gone up that much? :huh:
I'd suggest shopping around if you really have your heart set on one.

FWIW, I picked up a complete, brand-spanking new Wiseco 718cc kit on eBay for $220 two years ago.
The deals are out there, ya just gotta be patient and look around.