removing head gasket layers?

I'm surprised I never hear this with DR's but on the SV650's its common practice to remove one or even two of the head gasket layers to bump compression a bit. The gaskets appear to be the same type and my SV has been running around fine that way for a long time.

The DR has three layers about .010 each and the base gasket is two layers. removing one layer on each would be like milling the head .020. It would throw off your cam timing by a tiny amount but that would retard it and give you more top end,.. probably a miniscule amount?

Cars also use multi-layer metal gaskets and tuners peel layers to adjust compression. If you have the head off this is a free mod,.. has anyone done it??

It has been discussed here. Procycle has posted about it several times, I think. I don't know anything about it, but I remember him talking about squish, whatever that is.

I build M/C motors for a living, not Suzuki DRs, but Harleys and I've also built high performance Japanese 4 cylinder roadracing motors for several years, so I'll give you my take.

Moving the head .010" or .020" closer to the cylinder will result in a very slight increase to compression. It will also retard valve timing, both the intake and exhaust on a SOHC motor. This could be self defeating, as a slight increase in compression could benefit from a slight advance in intake cam timing and possibly a bit delayed exhaust timing. Tuning is usually acheived to deliver maximun power and torque for a specific application.

Normally you would first decide what type of power characteristics you are looking for, then do several things to make the motor more suited to your specific goals. Often, people just do a couple of things and actually make the driveability worse instead of better. Low compression, mild cams, small valves, small carbs, long pipes are all good for low rpm torque, whereas the opposites favor high rpm horsepower.

I would leave the layered gasket as is, if you want more power, look for better carb, pipe, higher compression piston, larger bore piston, precision valve job, porting.

Taking .020" out of the head gasket will raise compression by about 1/4 of a point on the DR650. If that .020" is what it takes to get the squish clearance right splitting the gasket is easier than milling the head. You'll get more benefit of a proper squish band than a little bit of compression.

Taking .020" out of the head gasket will raise compression by about 1/4 of a point on the DR650. If that .020" is what it takes to get the squish clearance right splitting the gasket is easier than milling the head. You'll get more benefit of a proper squish band than a little bit of compression.

I agree that getting the squish right can be a big benefit but milling the head will not change the squish whereas a thinner gasket (base or head) or milling the cylinder block itself will.

Create an account or sign in to comment

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

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now