Has anyone out there installed a 11.5 to 1 compression piston in there ds 650? Would I need to change anything else? I have a 2007 that is all stock. I have a hmf pipe on the way, but I haven't touched anything on it yet. I am also wanting to know what kind of power increase to expect.

 

Alot better power increases would had by OMR carb mods (do search) which is mostly free. Porting your intake, a good pipe such as a top gun, big gun, HPR open end cap. K&N or no-toil filter, rev box, gearing change, 520 chain conversion. You might only see a couple of hp by just replaceing the piston you need to do the head work ie cams porting, shim underbucket set up to take full advantage of the higher compression. You might as well do the head stuff while you have it apart to do the piston. Just my .02

 

Thanks for the quick reply I will look into those things. Do you know of a way to stop it from sputtering out when I ride a wheelie? It seems to run out of gas when I am nose high.

 

Yea.........shift! J/k what gear are you riding your wheelie in 1st? It will rev out pretty fast and hit the limiter.

 

Aftermarket CDI will solve that problem

 

Could possible be a float bowl issues....

 

It does this in any gear when the nose is high enough and no it is not the rev limiter. I think it just cant pump the fuel at that angle.
Today I installed my hmf pipe and changed the jet only to find out the jet they sent me was the same as the stock. Does anyone have any experience with these pipes and what is the best jet for them?