Jump to content
Sign in to follow this  

oversize or double head gaskets for reduced compression?

Recommended Posts

Are there any views on the merits of fitting an oversize head gasket to an XR4 to reduce compression? I've had a trawl through the archives, but no mention of this topic. I'm about to fit a Wiseco/Advanced Sleeves 440 kit with a 12.5:1 piston and want to preserve the reliability and reduce the likelihood of overheating. (Yeah yeah, I should have bought the correct piston in the first place....)

Any help is appreciated.

Share this post


Link to post
Share on other sites

Get the correct piston. I recomment the 11.5:1 piston from THUMPER RACING. It too is made by Wiseco but to their specs.

Otherwise you will be running Race gas or at least a 50/50 blend. A aftermarket cam will lower the compression some due to longer duration.

Cher'o,

Dwight

Share this post


Link to post
Share on other sites

Get the correct piston. I recomment the 11.5:1 piston from THUMPER RACING. It too is made by Wiseco but to their specs.

Otherwise you will be running Race gas or at least a 50/50 blend. A aftermarket cam will lower the compression some due to longer duration.

Cher'o,

Dwight

Yes, sell your piston on Ebay and go with the right one. I run 10:1, but they only make that up to 426cc. Comet does have 2 different gaskets, a steel shim type and a composite type that is thicker, but the difference in compression is minimal.

Share this post


Link to post
Share on other sites

Dwight And Dale

Thanks for your replies. I know the answers in my head, but am too stubborn to admit that I made a mistake!

Look for an 89mm 12.5:1 piston on ebay shortly.

Share this post


Link to post
Share on other sites

Use 2 base (cylinder)gaskets or cut your own out of gasket sheet(thicker than stock)...Normaly I raise the compression (on XR600's)by cutting a thinner one.Cheap extra power :cry:

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×