I was LEAN?!?!?!

[plkmonster2]

?? I would have never guessed this... I recently got a newer style carb from Juggalo, Thanks buddy! And I stuck the bottom end on my carb for my 99. I gave it a test run, for the first time in a month. I noticed a heavy bog when you get on it from idle. The motor would just sit at the same rpm, and then go, and hit hard. I cleaned the carb atleast 3 times. No luck. So I got pissed, and I plugged up my filter on my lid. Ran much better, but didn't have as much snap. So I figured it was lean. I go back to the shop, and put a 165 I had laying around, in my 400. It only has a hmf pipe, and vented lid. I gave it a run, wow!! The bog was gone, even off from idling in 3rd. I haven't tried this before, so I never noticed it. Also, I was riding in some weeds, which gave it more drag than a gravel road. I would never have thought that my 155 was lean, but it was. I'll have to see if the plug changes color. I doubt the temperature difference would make that much of a difference, Since it did the same thing in 85 degrees as it did in 70. The motor seems to run cooler too. I'm going to the dealer to get a few jets. I'm going to try to go up until it starts to sputter lightly, and go down a size or two.

[plkmonster2]

Another thought, could crappy gas cause this? The plug looked perfectly tan when I did a test... I am using 87 octane gas that we get from our Ranch, which is refilled each month, but this stuff was taken from the tank... a week and a half or better ago. Also, it was yellow when I put some in a clear bottle?? LOL, I know I should get some better stuff, but 3.30 for premium really hits me hard.....

[ALLUWANT]

man if u read in the owners manual you will see that it says no lower than 91 octane. i only ran 93 in mine and u really need to while putting aftermarket parts in it. i can t believe u havent heard any loud pinging

[meanyellow03ex]

I run a 170 keihin main in mine with the HMF slip on and a vented airbox lid with filter. It was dyno tuned to find this jet. It runs great with no bogs or sputters at all.

[400exrider707]

Originally posted by ALLUWANT
man if u read in the owners manual you will see that it says no lower than 91 octane. i only ran 93 in mine and u really need to while putting aftermarket parts in it. i can t believe u havent heard any loud pinging

87 is fine on a stock EX, you shouldn't notice any pinging. "aftermarket parts" in general aren't going to require the use of higher octane. Only when you mess with your compression and timing will the higher octane be necessary. I've run 87 in my EX with 11:1 and have heard no pinging although I typically run 91 at least.

[ALLUWANT]

and no the octane doesnt just mean compression it also has to do with timing. there is a reason that the owners manual says to run 91 at least. and why not run the better gas.

[WheelerBob]

The reason is because it's air cooled, the higher the octane rating the faster the fuel burn's Which generates less heat. higher octane = cooler running.

[ALLUWANT]

yes higher octane does mean cooler running but it doesnt burn faster it burns slower. and cooler. the slower it burns the less valve pinging u will have cause it make sure it pushes them closed.

[AnthonyWhite]

I only run 110 race gas and my machine runs cool as could be. My frinds has a 450R and also runs race gas. His cooling fan has yet to come on.