high compression head gasket

[mendomotox]

hey guys i ia curently hot roding an XR200R motor for a conversion i'm doing. i have an atc cylinder (bigger fins), a megacycle bearing midrange cam with springs and am getting a wiesco piston kit. i was wondering if anyone knows of a high comp. head gasket (so i can work with zero dech hight and still retain the squish band). so if anyone knows of a copany that makes them please let me know. thanks.?

[Chuck.]

Why do you want to use "zero" deck height?

I know of no "high compression" head gaskets for this engine, compression ratios are determined by the piston used. High compression pistons are available from several suppliers but they require race gas which can become a PITA. If you want a reliable engine use parts from Honda, Weseco, Powroll, XR Only, etc. The Weseco piston, or any other piston for this engine, will be designed to provide the proper squish area with the stock head and base gaskets.

[zbnutcase]

And I would use the stock Honda multi-layer-steel gasket, just ask parts guy for one for a 2002 model. 'nutcase

[mendomotox]

ive got the honda gasket, but the motor builder who is advising me said that it is better to get a thinner gasket which equals smaller combustion chamber volume which equals higher compression. it is a minimal factor but im just trying to do it the best possible.

Why do you want to use "zero" deck height?

my motor man just said it was better. i think it has to do with wear, possibly. i still want it to be reliable notice im not doing big bore or stroker or anything. oh and i forgot to mention before it is getting ported too.

[Chuck.]

I strongly suggest that you not attempt a R&D program on your engine but use modification processes that are proven to work on the XR200 engine; that is why in my previous post I suggested using certain suppliers for parts. Using "zero" deck height and/or a thinner head gasket may reuduce the combustion chamber volume but it also changes the squish band size/shape and that doesn't mean a better running motor; the motor may produce less power than stock.

In regards to porting: Someone with a grinder is not the person to do your porting; it needs to be done using a flow bench or you will lose power. Only polish the exhaust port, and DO NOT remove the rough texture on the inlet port. The polish reduces soot build up in the exhaust port and the factory finish on the inlet port improves air flow by disrupting boundary layer attachment to the port walls.

If you want the straight scoop on what works and doesn't work on a XR200 engine call Powroll, they've been modding XR200 motors for twenty five years.

[mendomotox]

the porting is being done by a local expert. his work has been proven at many local tracks and even on a semi pro motoGP bike.

about the squish band area being as small as possoble we are aming for .030 - .035" the thinking behind it is that all the fuel mixture in the area of the squish band is isolated from the spark and will not burn in time to be effecient.

PS after all im going with a stock head gasket and piston with a milled cylinder. only going to take off about .040". acording to my calculations this puts the comp. at 10.0056:1 so 10:1 and the squish band at .030". im aming for 20+ horses and i think this will do it.

PPS im running a 29mm mikuni VM round slide with K&N (Strait, no air box) and a custom flowed intake manifold. and a 28mm custom supertrapp exaust (steel 3").