High compression piston.....Need advice

[Glamis400ex]

Hi folks,

I'm toying with idea of getting a 416 kit for the ol' 400ex. High comp. piston, all around cam and new carb.

I know that the 11:1 piston is race fuel only, but what is the highest compression I can go and not need race gas? I will maybe be o.k. with running a 50:50 mix of race/pump if needed.

I don't want to be in the middle of the desert and run out of race fuel and not be able to find any or have to cut the trip short. If I do run out of 50:50, I still wanna be able to run pump only also........that make sense?

I wanna here from you guys who have the 416 kit and what you think about it. I'm not crazy about the 440 simply because I believe it's a time bomb, and the 416 supposedly runs like a 2-stroke...and I want the higher rev's.

Thanks a bunch,

Glamis400ex

[kat400ex]

I just had the JE 10-8 to 1 piston xr 400cam and some other stuff ..........its awesome terry did it in like 3 days......this piston runs off pump gas and thats why i got it thats about as high as you go on pump gas he sells a kit and its really reasonable and he is extemely GOOD at what he does. He also sells a rev box that advances timing 5 degrees and has no rev limit at all.....he wont tell anyone what it is i just call it the marcums special cdi he takes care of the serial numbers too i mean its his little secret and its the best money i have spent on my bike......he is the sponsor of this website MARCUMS tell him a girl told you about him he will know me........the Je piston has awesome oil rings puts any other piston to shame.......10-8 to1 pump gas.....get with him he will hook you up right......he rides and works on them its his life and he is good at it.......my 416 is unbeleivable i am totally impressed.

[Leo]

If you get the 10.8:1 JE piston, and use the 400EX headgasket it works out to around 10.6:1 (the 10.8 rating is in a XR400) so you should be well within the safe zone on pump gas assuming the quad is jetted correctly..

Leo

[Glamis400ex]

Leo, Kat...thanks for your replys.

If I wanted to, would I be able to run race fuel in the 10:8-1? Just to see if the difference in price is justified for me? Either straight or 50:50?

So, is it true that it rev's fast like a 2-stroke? I wanna be able to FLY up those dunes and turn some heads with my "stock" looking 400. Does it vibrate anymore than normal?

Will I be able to still put around and not have it load up on me?

I already have a full DMC exhaust and K&N , so I think those will definately be big factors in getting a properly built 416?

Thx,

Glamis400ex

[kat400ex]

I havent broke mine in yet but what i felt here in the yard was awesome and i have had two strokes i mean theres nothing like a two stroke but its got some grunt and the sound of mine totally changed if i was you i would email terry and ask him all these questions cause i havent broke mine in yet....we just put motor on sunday....good luck... go to his website and any of the emails will send you to the right spot he is a personal friend of ours his shop is only 15 mints from our house.....we go racing with him too.. and he climbs hills with his we havent been to hernando yet only on two strokes we both had them and now we both have 400's and i wont go back but yes you can run race gas if you want i know that much cause my husband does at the races we usually mix it 50/50 but thats all i know

[papaw]

add a liitle port work and it will really rev!!!!!!!!!!!!!!!!!1

[Colby@C&DRacing]

Glamis the 416 with the 10.8 to 1 piston runs really well on good pump gas. I run a 50:50 mix when racing and like the difference, it seems to run a little cooler with the higher octane fuel. I would recommend the new stage two cam from hot cam's it is a really nice billet cam that is a direct drop in ( no springs needed) and has no core charge. As someone already said flow porting is just that much better with these mods. Give me a call sometime we haven't heard from you in away.

[VegasEx'r]

The specs on the hot cam are just about the same as the HRC cam, which I hear is an excellent mid & top cam. It costs less than the HRC cam (by quite a bit). Does anyone have a Hot Cam yet, and is Dennis Kirk the only place that you can buy them from?