Questions on 1015 cc big bore kit for Z1

I have a 1975 Z1B that has scuffed cylinder walls and needs a rebuild. It's a street bike, not a drag bike.I'm considering a 1015cc 10.25:1 compression big bore kit, mainly because I can get the kit for $200 less than a OEM stock .020" over piston and ring set. I'm a little worried about the jump from 8.5:1 stock compression to 10.25:1 compression from the big bore kit. I've heard of problems such as engine overheating, blown base and head gaskets and pinging that requires mixing fuel to get rid of. The increased power would be fun but don't want a high maintenance bike. Anybody got any experience with this? Thanks for the help in advance.

northwestZ1,

First off, Welcome!

I've heard of problems such as engine overheating, blown base and head gaskets and pinging that requires mixing fuel to get rid of.

Your concerns are the same as many of us have gone through with the 900 series bike upgrades but since your only going to approximately the same displacement as a KZ1000, not a problem.

As for the base gaskets, you may want to upgrade,
APE 12 piece Heavy Duty Cylinder studs and head nuts... You can get these at the following.

NOTE: Some have replied to this question where the original studs are fine at 1015cc...

Z!: Excellent Source for Z's...
www.z1enterprises.com/detail.aspx?ID=175

APE:
kzzone.com/studs.html

No mixing of fuel is required...

OMR

Almost forgot, there is another thing you may want to do...

Here in Phoenix Az, they wanted $80 per cylinder hole for Bore & Hone! Ouch! I also had some busted fins I wanted repaired for an additional $200-$300 :pinch: :pinch:

The I came across this...
www.overstockpartsgalore.com/engine1007.html

$600 for newly refurbished cylinder with Wiseco piston kit. I went with the 1015cc for I didn't want to open the upper case nor was I requiring anything more than this displacement... Even so, a 1075 for $600!!!!

Anyhoot, I had some issues with their machining service provider at first on another issue but finally got it taken care of.

Just a thought for you for these cylinders are already bored and honed and is cheaper than having it done elsewhere... Check the web, Wiseco piston kits normally run $500 so your getting a completed and clean cylinder for $100, how can you go wrong...

OMR

just do it you will love it it makes good usable power all the way from bottom to top and with some head work a set of 29's and a decent set of cams you will make an easy 100+horsepower,i've have one of those kits in a bike right now it's always been one of my favorite combos if you use good quality oil you won't have any cooling problems some guy's run coolers but i hate the look and dont have one,and i've never had a problem by the way the gaskets that come in the wiseco kit work fine if the surfaces are prepped right you should not have any problems sealing