I was thinking of getting a hi-comp piston for my ds, but i want to keep stock reliabilty will this effect the reliability. Thats all i want to do to the motor no cams or bore. What kinda gains can i expect. I have cdi, exhaust and jetting

 

The compression ratio you choose will determine the amount of gain you will see & where in the rpm range. You can go with a 11.5:1 piston , run pump gas, see (feel) agood dose of low/mid rpm pull. If you choose to run paeformance cams you can choose where the power comes on. I recomend a set of all around cams if you are going to do a piston, depending on what type of riding you do, trails,dunes,drags.Anyone else agree? Hope this helps.

 

I really didnt want to go to deep. I did on my warrior and i had alot of trouble with it. Can i just run the piston

 

A large part of reliability is doing things right and not being afraid to spend a few more $$ to get the high quality.

So, first thing I suggest is heavy duty clutch springs. Great to have a reliable engine but, if your clutch is slipping I don't think that is true reliability!
I did the piston the same time I did head work so, not really sure what the piston itself will do.
With the 11:1 piston you can run pump gas. Are you looking to run pump gas?
I would also suggest heavy duty head stud bolts. My stock head was leaking before I did my original work. It was a little over a year old (which I think is rather soon to see that kind of thing.) The aftermarket head studs can be torqued down a little further.
I would suggest (hey, you asked for our opinion [img]i/expressions/face-icon-small-wink.gif[/img] ) port work, race 1 cams and heavy duty valve springs. Higher compression gets you overall power, the cams give you overall but, more gains on the top end. Overall you will have more power and your top end will be endless! The difference between a piped bike and one with piston and cams is night and day!

If you just go with the piston I'm sure you will see very good gains. If ou are mostly riding trails and you are mostly in the meat of your powerband the piston should help quite a bit. You may want to get the port work done and put in heavy duty valve springs though, that way if you want to add cams later you won't have to pull the head. The cams can easily be changed without pulling the head in the future!

 

Sure you can run just a higher comp piston. The reliability of your motor will not change. You can always change your cams later if you decide to. [img]i/expressions/face-icon-small-smile.gif[/img]