Motorcycles, Snowmobiles, Go-Carts, ATV's and Golf Carts - Suzuki 160 atv

My nephew has a late model Suzuki 160 ATV. About a month & a 1/2 ago he started having carb problems, gas coming from overflow, we tore the carb down cleaned it up & sealed the winterizing screw, thats where the leak seamed to be. No more leak & it ran great for about two weeks. Turns out that we also sealed the overflow and had not stopped the leak just diverted it into the crank case. We have since torn the carb back down & adjusted the float that was out (broke down & bought the book), cleaned & reseated the valves, adjusted the rocker arm clearances, checked & tightened the chain, and of course changed the gas filled oil. We seem to have good fire & have the carbs jet set at factory 2 turns out from seated. It won't run. Backfires through both the carb & tail pipe. Thought maybe the timing was 180 out, no, doesn't seem tobe possible on this bike, piston TDC, cam lined up on comp, coil seems to pick up on every stroke. HELP! We've done everything we can think of & everything the limited multi-model book says. Just call me butt kicked...

The basic principles never change, fuel, compression, and ignition. It sounds like you have compression, If you did not take the timing chain off I doubt that it is timing, or ignition, To field test compression, pull plug and put finger in hole and bump her over one time you should feel the pressure without any doubt. The ignition can be partially proved by sticking a screwdriver in the plug boot and laying it so that there is about a 1/4 inch gap to the frame and again bump her over and look for a blue/white spark. That does not prove that the spark is in time with the rest of the engine, just that it is there. Check your main jet again very carefully, it is possible that the fuel is not atomising and just dribbiling in to the engine, causing the backfiring.I have loosened an intake manifold just to let some air in once before when I suspected a similar situation was happening on a dirt bike and she did fire up runnning really rough, and at least I knew where to go after that. I'm believing that you are still having carburator problems rething everything that you did there and see if that doesn't cure your problems.
STIMPY21

Is it a lt 160?? I had one of those about 12 years ago single cyl little brother to the lt 185, and both of them are on the manual cover. I never did go into the carb except dropping the bowl to clear bad gas more quickly. there is something wrong with the carb if you are having overflow problems, the needle and seat that are on the bussiness end of the float is supposed to regulate the fuel level in that bowl so that the propper amt can be sucked up the main circuit in to the engine. Pull the throttle needle and look for trash, matter of fact it wouldn't hurt to drain the gas into a glass container to check for contaminants, which is probable what started the problems to begin with.
STIMPY21

Thanks Stimpy, We've been through that carb several times & everything looks okay. I had to readjust the float to stop the fuel leak but that was the only thing I found out of specs. We did pull the chain to clean & seat the valves, but unless it is 180 out it is on time. We have fire & can smell fuel in the cylinder, seem to have good compression. Its got us cry'n, any other ideas?:confused:

Maybe 180 out I did not catch that you had the chain out the first time. I believe that could be the problem Check it you've got the book, if not then think about this Gas out the over flow means that the float, float tang(correct distance, freely moving) and neeedle/seat(almost always trash or the tip of needle worn not seating) are suspect items. keep at you will get it fixed. Check your valve timing again and then the carb stuff, post back so others can learn.
STIMPY21