i am going to start racing next year but i do alot of woods riding and ice riding. i am thinking of either going with a IMS 440 kit with either the 11:1 or the 10:8 compression or getting a 426 kit and either going the same compressions can't deside yet on compression . i would really like to run high octan pumped gas. and i do not want to over heat all the time or have to worry much about reliability that often but i do want alof of poer becasue i ride with raptor and i owuld lie to beat them. my buddy has a 440ex but he has to run race gas i thinkg it is 11:1 with a web cam but wow that thing huals a**. i was thinkg either a hot cam stage 1 or 2 . can you point me in the right drection.

 

From my knowledge on car engines, I'll say this. The stage 2 cam has almost the same lift but more duration than the stage 1 cam. The more duration will let you build more power on top end. I just installed a stage 1 cam in my 416 yesterday. A good port and polish will complement the cam too. On compression, I don't think that you'll notice any difference from 10:8 to 11:1. This is just my opinion.

 

It would be nice to be able to run pump gas but I would go with the higher compression. I usually run race gas on mine but when I can't afford it or its just not convinient I use nos octane boost. If you add a half bottle to a 5 gallon gas can and mix it with 91 cotane you should have just over 100 which should work fine with your high compression piston.

 

i would go with the bigger bore and lower compression, otherwise you will be facing reliability problems with high compression....and as far as raptors, youll need some good head porting and a few other doodads to hang.

 

also, regearing would help out alot, putting a different sprocket on it will have a noticable change, whether you want topend, or low end......

 

Wouldn't the Stage 2 make a 416 "chug" on the bottom end?

 

what compression piston are you running?? when going really slow it will chug a bit. if you have the rpms up a tad, you will be just fine. i wouldn't get the stage 1 unless you like tight trails or putt around a lot.

 

i have the 10.8-1...

 

sanman66 do you run pumed gas or race gas?

 

i prefer the stage 2 with that 10.8 compression piston because i like the power in mid to top. if you are wanting more low to mid, the stage 1 will be better. for drag racing, the stage 2 will perform better for yourself.

i run a 10.8 compression piston (406) with thinner head gaskets which will bump the compression up around 11:1 or so. i also use pump fuel and i don't have any knocking or pinging. it runs great. the fuel additive or octane boosts many times make your bike run hotter from what i read. i was told they may leave more deposits in the bike and won't help performance. i personally stay away.