I have taken it back to the dealer many times because of the back firing and yes it does blow the carb. out of the rubber boot . The manifold and clamps have been replaced under warranty.The back firing can occur off idle or under wide open throttle,cold or warm. you just never know when it will happen.Stock air filter with the lid on and this weekend I installed a big gun exhaust, but I havent ridden it yet.I have owned it 5 months and every time I have ridden it the carb has blown off.There is less than ten hours on it because it lives at the shop.Im at a loss
Thanks bearman

 

I wonder if it could be a fuel starvation problem?

Have you checked your gas tank overflow line to be sure it is venting properly?

The fuel valve in the gas tank contains a fuel filter. I wonder if it is getting clogged. I've already cleaned mine once.

Have you taken the carb off and used carb cleaner to clean it out?

If it were my bike, I would want to confirm which jets were installed. My DS came with a #40 pilot and a #165 main jet.

I'm not sure about the float bowl, but that ought to be checked as well.

I also heard that the throttle valve spring tension/length can cause problems if it is not in spec.

What do your plugs look like?

 

Scooby my plugs look a nice tan color.The spring you mentioned has been modified and replaced by my dealer.The carb has been apart and cleaned many times and the fuel petcock has been replaced with a new one.We have replaced the entire fuel cap assembly .numerious new spark plugs and a new coil.I have tried many diffrent brands of gas with no luck.The dealer said to take it home because he is out of ideas.I am hoping a jet kit will be available soon
Bearman

 

Did the dealer make sure the coils were getting a good ground connection to the frame through the thick paint? Sounds maybe like an interrmitent/loose/weak electrical connection where the continuity is affected by temperature.

Are you saying that the DS will run fine/normal prior to the backfiring or does it run crappy all the time whether is it backfiring or not?

Like I said, I would want to remove the jets and make sure they are not getting clogged and confirm what sizes are installed.

Has the dealer been in contact with the Bombardier Headquarters Service Manager for help on this? The dealer should not just give up! I would expect the dealer to continue debugging the problem with help from Bombardier, possibly swapping out carbs, CDI boxes, etc until the issue is resolved once and for all. I'm not saying replace every componet at will until the problem goes away, but continue to try an isolate the problem by swapping components.

Does the backfiring occur when the dealer has been working on the DS in the shop, or has it only happened when you take the DS home and go out riding?

 

I think the mud sharks are way to soft for non-mud riding. After just a few hours of riding last weekend on grass, stones, hard pack, the tires are showing wear/rounding on the deep tread. I'll see how they hold up after another weekend.

 

It has happend once at the dealers, a witness said a 2 to 3 foot flame shot out the carb boot and an extremely large bang startled customers in the show room 50 feet away and through a wall.I am taking youre advise and checking all grounds and cleaning the carb myself this weekend.I am concerned that it is firing through an open valve on the compression stroke.I dont know for sure just a guess.
Bearman

 

I forgot to say that it runs fine, very strong ,and idles good until it backfires.
Bearman

 

Bearman, The type of backfiring you have described is not the type I had in mind. I was thinking of an air release or gasping sound or popping sound, not flames & explosion!! I don't have a fix for you on this one. Good luck.