I've just recently obtained a 2013 sher Co 2.9. The bike had wear and tear on it but since I've gotten it I've done a few wheelies that ended up with the rear end of the bike (exhaust and gas tank) being smashed into the ground. With that being said the exhaust pipe, where it connects to the frame, is now separating at the weld. The separation is about 2 inches long and isn't quite large enough to stick my little finger in, but it's close. The bike ran fine, not much sputtering and popping, but now it is and no matter what I do to the carb the sputtering and popping is still there. My question is should I replace the exhaust or would it be fine to keep running it with a hole in the exhaust? The rear plastic fender won't even bolt up because of how bent the exhaust and tank are. I'm just learning and am going to break things I know. I just need to know if I could cause damage to the motor running it like this. Thanks in advance.

Some things can be straightened and welded, yet that does not sound the case here. Best to replace the parts, as the bike will tell you it does not like them!

I understand that and thank you for the reply. But if I richen the mixture up and only run it an hour a day will it cause damage to the motor. If I'm going to tip it back more learning rear brake control I don't want to replace it yet if I don't have to.

I doubt it would damage the motor, yet I would avoid high revs.

You might attempt a temp repair on the split by cleaning the area and roughing it up with sand paper, then apply an thick epoxy like JB Weld, back it up with gorilla tape!

Just a thought?

On 2 stoke engines it is important to think of the combination of intake, engine and exhaust as a "system." Change one part and other parts are affected. The crack in the exhaust is highly suspect in this case. Also look for a carb boot that is kinked or deformed from the airbox damage.

A good metal worker might be able to heat, bend and weld the pipe.

While it is likely that the running issues are related to the damage, don't overlook normal causes of poor running. One of my riding buddies has a 2.9 and recently when warming up for an event, it would not rev cleanly and was popping and sputtering. He was about to give up on riding when I asked if he had a spare plug. Quick plug change - problem solved. He took first in his class that day.

Would the deformation in the carb boot be easily seen without taking anything on the bike apart? Or would I need to take the carb off to fully inspect it. Also, the spark plug I change is something that I will be doing in the next tank of gas.

Oops, I forgot that the airbox and fuel tank in opposite locations to most bikes. Boot may not be any problem but I would check to see that both ends are still properly connected and clamped.

A disturbed carb boot is not so likely to cause the running problems, although remember intake, exhaust and engine are a "system." I was thinking more of the possibility of the boot being off, allowing dirt to get into the engine.

On 2 stokes, spark plugs should be considered as disposable items. Sure, if everything is jetted and adjusted perfectly plugs should last a very long time. When my 2 strokes don't run right, the first thing I do is change the plug. Three bucks and 5 minutes often solves the problem.