[engine size help?] - ATV Riders Forums - Honda, Yamaha, Suzuki, Kawasaki, Polaris, CanAm, Arctic Cat, Kymco ATVs

Pages:1

engine size help?
(Click here to view the original thread with full colors/images)

Posted by: darkstar

ok, I want to bore my 400 to something buy dont know a good size and boring really cheap and with this bore i am going to put in a stage two cam and high com piston. but i dont know what size to bore to to get a 516 or 426 or what ever other size people have.

I have all so benn looking at this big bore kits on ebay for $280 and the come with:440 PISTON,TOP END GASKET KIT AND CYLINDER SLEEVE.W/STAGE 2 HOTCAM. THIS IS A 11:1 BIG BORE KIT

Which is the best thing to do?

Posted by: 2004exrider

jmo, go with the 416 11:1 w/ port n polish, hotcams stage 1 cam, good exhaust (your choice), and k&n. a well built 416 will keep up with a 440. its also good because its still very dependable and runs on pump gas. There wont be problems with it like a 440 SOMETIMES has, like pulling head studs (if you dont replace them), runs pretty cool, and still uses stock sleeve, n if u dont like the 416 u still have another bore on it. Its all up to your preference though.
just remember its only gonna be as reliable as you make it and maintain it. Good luck with the choice you make though!

Posted by: jak1389

2004exrider: thats the exact build im doing! but i want to get a full hmf exhuast instead of my e-series slip-on but it might have to do for now until i get more cash flow.

Posted by: darkstar

Do i just take it some where and ask for a 416 bore and they know what to do. And what is a good piston for that

Posted by: EXer #33

i run a JE with mine and i love the power

Posted by: jak1389

the 416 bore is 87mm. a je 10.8:1 compression piston would be good. a port and polish with the bore would also increase the power.

Posted by: yzfmxer

did you already buy the white bros there exhaust is one of the worst to use one bored out motors

Posted by: 2004exrider

quote:
2004exrider: thats the exact build im doing! but i want to get a full hmf exhuast instead of my e-series slip-on but it might have to do for now until i get more cash flow.

Good luck with the build, i bet youll still have some good power with the e series.

Posted by: darkstar

this is what i have come up with on my build.

Engine:
11:1 comp JE piston 416 $120
cometic steel flex gasket kit $40
stage 2 hotcam $114
port and polish $175
valve seals $5
3 angle valve job $65
cylinder bore $60
exhaust gaskets $2.10 each
oil filter free

it's going to be bad *** so what do you guy think.

Posted by: jak1389

as long as its built good and strong you will have a beast!

Posted by: 2004exrider

sounds good, but with the old stage 2 (which is the stage 3 now) you are gonna loose a little bottom end but gain more midrange and topend. Hotcams reccomends the stage 1 for stock bore-426cc, that ways theres no possibility of loosing bottom end. Also might be cheaper just to get xr400 head gaskets (thats what they test the kits on with) because they are thinner than your stock ones and probly the same size as the ones that will cost you $40.
Sounds good though!

Posted by: bwamos

Look into heavier valve springs. like $30 and will reduce your valve bounce with the agressive cam.