Going to put a 12:1 piston in the ds, run alky, only want so spend 500 bucks, is there anything else I need to go with the 12:1 piston, will I notice much difference with the 12:1, don't have any other internal engine mods, thanks.

 

if you're going to alky anyway, might as well go with 14:1

 

the DS doesn't have enough ignition timing even on gas. when you go to alcohol you need more timing.

 

I am running 12:5:1 in mine and i could tell a whole lot of difference. I am not running alky though because it is to big of chor to take care of. U shouldnt have to do nuthing else to the motor when u but the piston in, but if u are going to be running alky and 12:1 piston i would go ahead and drop some 110grind webcams in that sucker. You will be putting about 60 to 65 HP if u go with cams, ported end take, carb, K&N filter and piston, on alky. Itshould rip, oh and also a rev limiter but u said only $500 bucks so yeah the piston on alky would be great. [img]i/expressions/face-icon-small-smile.gif[/img] Lance

 

Oh I'm sorry forgot to say it already has a rev box and tm45 carb and I think a graydon pipe. So the 14:1 piston would be a good improvement for 500 without doing the head porting or cams? The head gasket is leaking pretty good so we thought we would pull it down and put a piston in. Is there a better than stock headgasket to run on these, is this a common problem with the ds thanks.

 

are you sure your headgasket is leaking? no its not a common thing for stock bikes. the stock head gasket it totally cool for the stock bore, even with the 14:1 piston from what I understand. just make sure the surfaces of the cylinder and head are completely clean and install the gasket dry, oil and sealant free. I go so far as to clean the aluminum surfaces with alcohol.
what is very common is water pump seals going bad, often misinterpreted for a head gakset leak. but really, when head gaskets go, the more common symptom is combustion pressure getting into the cooling system forcing antifreeze out the expansion tank overflow, rather than coolant in the oil.

but you will need to replace the head gasket when replacing the piston anyway, and it costs $50, so if cams and porting are on your future agenda you're better off saving for a bit and doing it all at once. I would think you would want cams with that 14:1, ask Mr.HP what he recommends with it.