stock or 440??

[pigpin]

anybody from NC running a 440 kit??? I already have a ton of problems out of the 426 kit, and instead of rebuilding it, i was thinking of goin all the way to the 440 with little lower compression to run it on pump gas. are these set ups good for the trail, i never race it, just ride it. or for the little bit of power advantage i gain should i just go back stock bore and higher compression piston. i just want my 400 turn key reliable and fun, not turn wrench aggervating and broke 70% of the time.

thanks for any and all input

[honda6490]

If you dont want to wrench, dont put anything in it. Your best bet for reliability is to keep the engine stock. You can get way more horsepower out of a full exhaust kit, air intake, and some other mods than a 440 kit will put out. I have the 440 kit so no Im not being biased, but IMO a stock engine just feels much more reliable and I would trust it a lot more on the trails.

Hope this helps.

[pigpin]

thanks, this isnt my only qaud, and im one to have the "fast" quad, but the "fast" quad usualy leaves me sitting..... idk, i think imma do it just becouse I already have the full exhuast and all kinda crap, the bore is just wore out and instead of keeping the 13:1 i figured Id just go up a bore and lower the compression some to run pump gas.

thanks though, any others running 440s on trails in mild weather?? over heating is my main concern!!

[Chin_Chilla]

I'm a trail rider in the Texas heat (80-90 degrees) with a 12.5:1 440EX. Never had any problems out of it for the 7 yrs. It's a 02' model but it's been a 440 for about 2 years.

What is happening that is giving you trouble? Cam chain snapping? valves bending/breaking? Any info. would be helpful!

[400exrider707]

Yes tell us your current problems, what mods you have currently, and then we can assess it better.

[pigpin]

well all the mods are in my sig... as far as problems, a real b**** to crank sometimes, actualy most times (stock CDI), ESPECIALY after warmed up, and most times it want idle, and if it does for just seconds at the time... i know the bore is whore slam out.... i had it apart to replace two valves and install HD chain and i could literaly wiggle the piston in the cylinder. so i believe its something with the bore issue and junk "mutt" carb on it. i wanna go to the 440 with a 450r carb with about 11:5:1 so i can run pump gas.

thanks

[400exrider707]

Well a piston should move a little in the cylinder, the rings are what needs to be tight against the cylinder walls. Im surprised you dont have more problems with 13:1 on a stock rod and stock head studs. Your hard starting problems and bad idle are things you can fix, its either bad valve issues or jetting issues, Im willing to bet jetting. I dont think boring it out is going to fix your problems, you still have problems. Masking it up is not the way to fix it. Try getting this one to run decent first.

[GPracer2500]

Barring unusual circumstances, 11.5:1 on a 400EX is not a pump gasser. Most will tell you 11.0:1 is the limit for pump gas with a 400EX.

That can vary. I built my 400EX around a 10.8:1 JE and it would not tolerate AZ pump gas. It deto'd badly in the dunes and deto'd some everywhere else.

[Ruby Soho]

i usually run 93 in mine. when im out of that i put in pump (not often...) and it does fine but i still put in the 93

[pigpin]

i just want turn key reliability... what a 4 stroke is supposed to be about, and ive tried about everything, jets, new valves when two were bent due to timing chain breaking. adjusted the valves to hotcams specs..... im just sick of it and want a pump gas qaud, the power advantage isnt worth it on a trail.

[GPracer2500]

Originally posted by Ruby Soho
i usually run 93 in mine. when im out of that i put in pump (not often...) and it does fine but i still put in the 93

87, 89, 91, 93....if it comes out of the pump at the gas station it's pump gas.

[honda6490]

I just buy cheap 87 or w/e it is and throw some octane booster in. Now adays its a lot cheaper to put octane booster in than to buy the premium or race fuel.

[Dill]

octane booster is a waste of money and is basically doing nothing for you.