Is milling the head advisable or do you in up with other problems?

How much can you mill?

 

I think it depends on how much you plan to mill. If you want to mill the head to get rid of any warp, the amount of material removed will hopefully be very little and the correct height can be regained by thicker or additional base gaskets.

If you want to mill the head for performance reasons, you would be better off going with a different piston to increase compression. Its not as easy as it is with 2 strokes. I believe if you mill the head too much you will start messing up the cam timing.

 

you can also look into a thinner headgasket rather than milling the head, but your best bet would be just going with a higher compression piston on any 4stroke quad ...JMO

 

Like Sandaholic said, timing can be a issue with milling on a DS650. If you want hi-compression then go with a piston in lieu of milling. JMO.

 

While cam timing is on hand, will thicker/thinner head gaskets throw it out like milling would? I would assume so.
I think it would be easier to buy a piston matched to the compression you would use at most, and then just use gaskets to lower it for normal riding then switch back if you need the high compression for an event or something. Would save money on buying 2 pistons.

 

I am sure cam timing is affected by thicker or thinner base/head gaskets, but the amount is very minimal.

I couldn't imagine someone going through all the work to change base/head gaskets to alter the compression ratio on a regular basis. The amount of work and cost of gaskets would not make it worthwhile.

 

If you desired 2 different compressions maybe? It would be the same amount of work to change the piston, but cheaper due to not having to buy the second piston. However like you say if you did this often, then yes the price of gaskets would outweigh that of the second piston.
How bout if you want to try a different compression than stock, buy the highest you would be willing to go, then if you don't like it use gaskets until you achieve the desired comp instead of trying different pistons. I have been told these special gaskeys seal better than the OEM ones so leak issues wouldn't be a concern. Just a thought.

 

i have a 12.5:1 piston in my predator, and got a special "thinner" head gasket to put my compression in the 13's and it did seal easy and good!! just make sure to use 'copper coat' on your head gasket atleast ...i use it on ALL my critical gaskets

 

Copper coat is usualy bad news on alluminium, I could be wrong but you might be better off using nickel or alloy never sieze if you have to grease the head gadket ?

Also why do you grease it ?

 

copper coat is a gasket sealer...you spray 2 LIGHT coats on the gasket and it helps it seal right!!! basically an almost indestructible seal!!!!