Hey guys just bought a 400 scrambler with a couple mods done. Bike has HPD Trail Pipe, HPD Silencer, HPD aggressive clutch kit, V-Force Reeds, Reed Spacers. The bike had the piston broke in half when I bought it, and I just got it all fixed. The mechanic bored the cylinder .040 to clean up any damaged and ported the cylinder.

First question is, mechanic wants to know factory squish clearance so he can mill the head a little, anyone know the factory squish for a 2000 400 scrambler.

Second question is, anyone know the suggested jetting for this bike with the HPD pipe on it. It has the stock 34 mm mikuni carb still on it.


Thirdly, what kind of injector oil do you guys reccommend. I have some Amsoil left from my snowmachine this winter and was thinking about using it.

thanks

kyle

 

If im not mistaken, HPD and RCR mill the factory head .020 If your going to do this mod, you should really consider a cylinder girdle. I had my head milled on my 4x4 and I didnt like it. It always seemed like it was detonating (pinging)
And after two blown head gaskets, I put a stock head back on.
Amsoil is great oil. my 2c.
As for the jetting... post this in the polaris forum. Youll get an answer.
Good luck

 

i wouldn't put interceptor oil into any 2 stroke,that fat stuff is just too much for a cast iron cylinder,
take regular polaris or you're regular favorite brand,those engines need to run clean as much you can
in order to maintain them for longer period of time wihtout rebuild.
start main jet at 280-290,after 1 tank of gas,start checking for spark plug reading to properly
lean it out (if it need so).
with those mods you should be close to 46-50 hp.

 

girdle kit for that is over kill

 

Overkill???? Ok if you say so. I know Ive seen a trail modded 400 break the front studs, Clean.
In my book theres no such thing as overkill when it comes to having a strong motor.

 

as for your pinging white dog I'd say you should have machined the factory squish back in it but left the smaller dome should have done the trick anyway

 

Well, I had the first one milled .020 and had trouble. then I swapped it in on one from RcR. And still had trouble. But that was on a stock port. Since then Iv had porting done on the cyl, just havent put it back together. Ill probably try the shaved head again.