poor gas milage w/ motor work???

[Glamis400ex]

Hi all,

Ok, here's the deal. I want to get a 10.5:1 stock bore, and a cam(hot cam, Web,..etc..) Will the added compression and hotter cam decrease my milage significantly on the 400ex? I'm running a 160 main now w/ mods listed below. I figure I'll have to bump up to like a 170 or so. I thought about getting a IMS desert tank, but frankly, I think they are hideous looking. I would also need to get a +1 stem to clear the tank. I can ride about 60 miles or so now with no motor work. We take LONG rides occasionally and I don't bring extra gas with me.

Here's the other thing...How do I know that a hi-comp. stock bore is going to be ok with a 99 quad, that's never been apart? Meaning...My 400 runs excellent now, doesn't eat oil or smoke. I do not know the condition of the cylinder walls. I don't want to bore to a 416 until it's necessary. I want to run the hi-comp stock bore untill the walls are shot....Does that make sense?

Any help is gladly accepted, let me know what you think,

Thanks,

Glamis

[nakomis0]

I don't go on many long rides, but I didn't notice a huge fuel consumsion difference. My buddys Banshee still runs out of gas before I will.

When you get your high comp piston, just 'hone' the walls. You won't have to bore it or anything. You can get away with a few hones unless the wall has big scratches which I'm sure yours doesn't. GL

[Tommy 17]

my gas mileage is about the same i think... i didn't notice a differnce...

[Ex'r Marlin]

I recently did a 416 10.8 to 1 compression piston on my '99. After reviewing the cylinder wall, my friend (an experienced motorcyle engine mechanic) and I noticed the walls were looking very good! But since I already had the 416 piston, I was commited to do the bore. Note: I feel I have ridin the 400 a lot since I have owned it since April of 99.

As for fuel consumption.... Due to my pilot being too rich, I noticed after a hard day of riding with my other 3 friends with stock 400 engines, they had just a little more gas by the end of the ride. We did not hit reserve, but we were all close.... With me definetly being the first to hit reserve if it came to that. I can't wait to get the right pilot in, and my "Hot Cam" in for more testing!!!! (Maybe by the end of July I will be healed and ready to ride):macho

I think mine drinks more but I'm on the gas alot harder too now..:eek:

[Glamis400ex]

ok, well, that certainly sounds promising, I'll probably bite the bullet and do it.

Thanks for your input guys....

Glamis

[Leo]

my mileage didn't seem to suffer to badly, but that's not exactly sientific data!

if I remember next time I'll check and see how many miles I get out of a tank..

Leo

[Glamis400ex]

Thanks Leo, that would be awesome,

Glamis