Everyones bikes are getting faster and I usually have been able to beat everyone up the hill, with this problem, but now that they are getting quicker I my need to find a fix.
Okay here's my problem, my lt500 runs great all the time, the only thing that causes this problem is hitting the whoops hard and racing up the hill.
Right after pulling out of the whoops 1/2 way up the hill the motor dies out for a second or two which causes me to loose momentum and really fight to win the rest of the way up. I am still able to pull out in front. Its almost like hitting the whoops causes an air bubble in the fuel line and I just cut out for a second or two until it passes. The main reason I want to figure this out is cause my dad just got a 450 and it hauls and I don't want to lose. Those extra 2 seconds will need to be there to help me pull out front.
So what do you think?

 

I would check your float height is correct and make sure none of the carb vent hoses are plugged at all. Cleaning the carb with caRB cleaner and compressed air wouldnt be a bad idea while your checking the float level.

 

Ill check the float level and clean the whole carb. I haven't done that for awhile now.

One more question, I just replaced my head gasket, my water pump went out 2 trips ago and I over heated the motor pretty good. Fixed everything and the end of last trip my head gasket went out in the middle of glamis I tried to get as close to camp as I could so I over heated it again pretty good. One dune from camp the radiator hose going to the head blew off and sprayed the rest of my radiator fluid onto my leg. Took it hope drained the oil and replaced drained the coolant, none was left and refilled it replaced the head gasket and removed some carbon deposits from the head and put it all back together. I could kick it to start tied it behind the truck and after a block it fired up, ran it for awhile turned it off kicked it and started, did this a few more times then packed it into the trailer. A week later I pull it out to kick it and I can't get it again, hook it to the teuck and a block later its running. Now I used to be able to kick it in one or two tries what do you think I should do?

 

Have you tried a new spark plug? Usually that fixes mine when it gets hard to start.

It may have gotten hot enough to cook the rings. I've seen it happen before.

I also have the same problem as you on a hard uphill acceleration. I am about to decide that when going uphill, the gas doesn't gravity feed quick enough due to it running to the back of the tank, and it sucks the carberator bowl dry. I haven't figured out how to fix it. If I do, I'll let you know.

 

What's compression suppose to be on the lt500?

 

The LT500 has a Kiehn carb on it, correct? I think I've heard of that problem with certain models , they make a different bowl to correct the fuel starvation from hitting whoops and sloshing the fuel around, causing leaning out of the motor. Check Dennis Kirk or Rocky Mt ATV catalogs to see if you can find the bowl. As far as the starting problem, I have to agree with the other guys, the overheat probably cooked the rings, or possibly scored the cylinder, lowering compression and making it hard to start.

 

the fuel **** is on the back of the tank so i don't believe thats the problem. this definitely sounds like an issue with the carb and carb only. thats at least the best place to start. i dont have a stock carb so i dont know how they act but i know my 44 mikuni and 38 keihin dont have problems like that

 

Well if I can check the compression what should it be at, and any info on a new carb would be great, I have no idea what a new carb would to performance wish with a stock motor.

 

For my 87 i run a Keihin pwk39 carb, i dont know if it has any power over the mikuni that comes stock. but for me it made it way easier to start and its alot simpler to jet and get it dialed in.

 

<div class="FTQUOTE"><begin quote>Originally posted by: gogoquadzilla

the fuel **** is on the back of the tank so i don't believe thats the problem. </end quote></div>

It's about 4 inches from the back of the tank