Oversize Piston Kits...

ive got the 1197 from my z1 sitting in the corner waiting a new home! :laugh:

I guess I've been curious mainly becuase I see good deals occasionally on cylinders and pistons and turbos. :woohoo: I always wondered if, for example, I could slap on a 1075 or an 1197 turbo piston kit with a turbo or supercharger some day without having to swap cases too.

No immediate plans for going smaller....you're right plum, why would I want to do that? :laugh:

Sorry DoubleDub, no extra sets lying around... :laugh:

It seems that the only issue would be the extra base gasket material that would overhang where the cases had been bored. The knock pins should keep the cylinders aligned.

I'm assuming I would use a smaller base gasket to match the OD of the cylinder sleeves and not the larger one I'm using now that matches the bored cases, correct?

yep

You only need the base gasket that matches the case, unless you are running a block with stock sleeve where you are using the o'rings on the bottom. In that case the smaller base gasket would help keep the o'rings from falling into the motor.

However, if you had a set of cases bored for a 1425 and you were to install a 1200 block, either base gasket is fine.

Well, I think it's OK to hijack my own thread, isn't it? :laugh:

While on the topic of base gaskets...what is the best material to use for leak prevention? I've had luck with copper and fiber but I think the fiber seems like it seals better. I even had one made of head gasket material (CFM20) at the local gasket place (Cometic) and it's weaping just a little. Might be my own fault...long story...

So anyway, my motor will probably be coming apart to correct a leaky valve seal, so what's the best base gasket material? I've been very happy with the Cometic CFM20 head gaskets.

Just jumping in because I have the same questions

Any opinions on base gasket materials? I'm ready to order but I'm not sure if I want a fiber base gasket, a copper base gasket, or if I should try the custom CFM20 base gasket again. I'm running a stock block bored and sleeved to 1260cc.

Anyone have an opinion? There's not usually a shortage of those around here! :laugh:

Thanks

kawsakiman wrote:

leave the pistons alone.
buy some cams like .429 and it will be a different beast.
for what you all ready have with the 1075 kit and flatslides you undercammed for the power you want.
there is a member here who had a 1200 with .410 cams and 36's and a 1075 with .429's and 34's walked away from him most times.
these motors are all about the cams, not piston size.

Steve you are the smartest in the bunch! Don't tell anybody, let them keep buying them big pistons looking for power.....Bigger cams are not always needed on racers, the trick is dual pattern cams(Horsepower). Everyone is stuck on single pattern cams(torque).

79MKII wrote:

OK - just a quick note from my very recent personal experience (today!). After moving up from a 1075cc to a 1229c and finally this year to a 1260cc (stock block btw), I have been a little disappointed in my bike because it seems to heat up a lot more than even the 1229 did last year with the same block.

This had me thinking earlier today that maybe the way to go would be around 1200cc or smaller but with HIGH compression. Sure sounds like I was on the right track.

My favorite set up yet was the 1075 kit (high compression) with an old Denco pipe. I have never ridden a bike that ran so perfectly and crispy. I guess I've learned the hard way that bigger isn't always better. Both the 1229 kit and the 1260 kit are 10.5 to 1 compression (street). I'm guessing that the 1260 still probably puts out more HP than the 1075, but that smaller engine sure felt faster.

I'll bet that 1075 was faster! Nothing like a small bore motor, with a small tube pipe. Most people won't understand that, until they had one. The best thing about a large bore motor is, you get to brag about how much money you spent.

What size cams did you have in it? What size carbs,?

That's why most pro stocker are less than 1100cc.

APE Jay wrote:

That's why most pro stocker are less than 1100cc.

There's no replacement for displacement

How about base gasket material recommendations? Anyone?

79MKII wrote:

APE Jay wrote:

That's why most pro stocker are less than 1100cc.

There's no replacement for displacement

How about base gasket material recommendations? Anyone?

Right. My post was a joke to the bigger motors don't make anymore power crowd.