Would small exhaust leak cause this?
 

Hello, I posted about a bit back about issue with 89XT sputtering and quitting when hot only. I found a connection in the exhaust (near the engine) that is leaking a fair amount of air. Could that cause the stalling/sputtering/backfiring when it got fully warmed up, but run fine when you first start it and for the first 10-15 minutes? I'm a newb when it comes to exhausts, is there seals you can replace on the connection that's kind of near the air intake/crankcase area?

Thanks for your help.

Yes I believe you tracked the problem. Go to your Yam dealer and get the metal gasket (get a pair, just in case also the other is in bad condition) between cylinder and exhaust. Think that with max 10 euro you are ok.
The fact that the problem appear only when hot can be easily caused by the increased tolerances due to temperature.

If the problem does not disappear, second check are intake collectors, try to move carburetor with engine running and see, if they start to crack. If you need to buy a new pair, you will get cheap in ebay (search for ansaugstuttzen XT in Germany) 35 euro against the 100 euro of the originals.

cheers

I'm wondering if I could wrap some muffler tape or something around it and clamp it down till I can get there for the part. The leak is at the middle connection in the exhaust (near crankcase), not the connection coming from the engine, so I think I could get something wrapped around the leak pretty good to hold it for a bit maybe?

Thanks for your help. I really hope this is what is causing it, I was worried could be something big.

Not convinced..........
 

........I 'm not convinced that is causing the problem that you describe, now you have clearly identified where the leak in the exhaust is located.
Quite a few things can cause those symptoms.

As for the leak, there is usually a gasket type of material in there - it looks a bit like a piece of pan-scrub material and it is squeezed in between the pipe sections that overlap.

As for the bike running problem: there are already quite a few posts in here about similar engine running problems - it would be worth your time to do a search of these and get the information that already exists (you may have done this already, so apologies if you have!).
After that, if you can describe the symptoms fully, including the age of the bike, mileage etc etc, then someone will be reminded of when they experienced much the same thing -- so, the more information, the better.

I can only hope it's that... I did tape it up good yesterday and took it for a pretty long drive and it didn't sputter out. It was pretty cool out though so that might have hidden the issue. I'm going to replace the gasket and keep my fingers crossed. It came on so suddenly and there is quite a bit of air coming out of the connection so I don't know. Thanks

Problems like this are generally caused by the intake not the exhaust.
I would have checked the intake rubber boot and air filter. If the bike was a 2 stroke then maybe the exhaust.

Tom