what to do?

[livealatimmy]

I was thinking about doing some major motor mods to the ol 400. What do you guys think is the best motor size to go with. I was thinking about the 475 kit w/ 10:5:1 comp. Is that not a good idea. I ride trails mainly

[xc400ex]

Get a good slip on pipe, JE 416 or 426 10.8:1 comp piston for pump gas, a stage 1 or 2 hotcam your choice..i run a stage 2 for the woods...use stock 400 gaskets and you'll have a great motor.

[xc400ex]

Well now I see you already have exhaust and cam...what grind of cam are you running?

[RAPTORAZ]

Originally posted by livealatimmy
I was thinking about doing some major motor mods to the ol 400. What do you guys think is the best motor size to go with. I was thinking about the 475 kit w/ 10:5:1 comp. Is that not a good idea. I ride trails mainly


Without an alcohol conversion, you'd probably have a hard time keeping that motor cool.

[skemp]

The big bores are really hot-headed, but you can keep them at a relatively safe level with a larger cooler and oil tank, which you already know. The key is to get cool oil to the cam. The thing with this is that he rides trails, so lugging around a big air-cooled thumper in the woods makes a potential timebomb. Not to say it can't be done, but for the weekend warrior, it may not be feesible. Stick with a stock-bore high comp. piston or a 416 if your jug is out of spec. The difference between the two is minimal.

[livealatimmy]

XC400, all i know is that its the biggest drop in cam that Sparks has.

With the 416 and 426 kits i can still use the stock rod and not be worried......... right

[RAPTORAZ]

Originally posted by livealatimmy
XC400, all i know is that its the biggest drop in cam that Sparks has.

With the 416 and 426 kits i can still use the stock rod and not be worried......... right


As long as you stay around 11:1, the stock rod will be fine. My 10.8:1 416 has been fine for over a year now. Also, my buddy's 11:1 440 ran for over year with no problems as well. He's now running an alky 465 stroker.