whats the problem?

[jay]

was riding the r the other day. it started to miss. like someone was turning the kill switch on and off .i stopped and took the seat off while holding the throttle wide open to keep it going. it was blowing back through the carb instead of just drawing. i placed my hand over the carb to see if there was a piece of dirt messing with the carb and nothing happened. it quit on me so i let it sit a few minutes. after kicking it a few times it fired up. took it down the trail and it ran perfectly for about 5 seconds then started the same crap. it has been running a little rough lately. do you think it need new reeds. the carb is clean, new plug, good gas. the bike sat a little while before i bought it. ran good the first ride or so but has been going down hill since then. i am open for suggestions. thanks, sorry for the long post but don't want to leave out any details.

[Live4today]

A similar problem to this happened to my Honda ATC200. It would run alright, and then start cutting out on me. I would let it sit for a little while and then it would fire up, I would continue down the road, and then it would do it again. It turned out it was the fuel filter. I took it out of the tank and put an inline one on. You could probably just buy a new fuel filter and put it back in the tank if you want, but an inline fuel filter works as well.

[schuhboy]

which machine was giving you fits? if it is a two stroke, you might want to look at possible crank seals leaking, piston skirt broken, or junk reeds. a four stroke engine with that symptom could have a valve train or cam problem.

good luck
steve

[chuck]

My neighbor was having the same problem and it ended up being a dirty petcock.

[TimSr]

If it suddenly just cuts off, or quickly cuts in and out, and you get backfiring, its usually electrical in nature. If it bogs, and you get RPM variations and drifting its more likely to be fuel delivery. Blowing back out the carb is a normal result of backfiring.

Try another plug. If its been used for 5 minutes, its no longer a new plug. It only takes minutes to foul a perfectly good plug.

With the machine running, spray isolated water streams on the coil, plug wire, plug boot. If you have weaknesses in insulation, youll see the results immediately. You may also have to disconnect kill switchs to isolate possible problems.

Fuel flow is easy to check. Pull the line off the carb, and turn on the gas. If thats good, shut the gas off and open the carb bowl drain screw. Turn the gas on, and make sure it immediatly comes out the bowl drain. If this shows good flow from tank to carb bowl, your not likely to have any sudden cut offs due to carb problems.