I recently installed a big gun slip on with a jet kit. Got everything together and it started and ran like a bear, at least for a minute or so. Then it started sputtering and coughing and wouldn't start without the choke and wouldn't stay idling at all. I figured it was the jetting (which I am not an expert) so I pulled the carb apart and checked the jets and floats. I also checked the slide, no probs. I even installed a 40 pilot to aid in starting as this thing has always been a pig to start cold. Put it back together and nothing. Same problem. I even checked my air filter for over oiling and dirt and it looked great. Checked the plug, which looked ok, but I put a new one in anyways. WTF?

Then I noticed that where the slip on met the header pipe there was a small opening. I had noticed when I put the pipe on that it was bigger than the stock header and I thought I had it sealed and clamped good. Guess not. I took it off, put some more high temp exhaust silicone on it, and put it back on making sure I clamped it tight. I then hit the starter without the choke, not expecting anything different but to my surprise it started and idled like a champ. I warmed it up and took it for a quick spin and no problems. I had no idea that a small exhaust leak could cause a lot of troubleshooting problems. I am glad I put a bigger pilot on though as it starts easier than before. Anyone else had this problem when putting on a slip-on? Seems like since it is bigger than the stock header that you really have to make sure it is sealed good.

 

I used to have to re-silicone all the time on a full Big Gun system.
From what you describe,,,,an exhaust leak doesnt sound like the problem.

 

I didn't think it would cause that big of a problem either but that was the only thing I fixed before the last time I started it. Somewhat puzzling, but nonetheless it starts and runs great now. [img]i/expressions/face-icon-small-smile.gif[/img]

 

Im having a problem with my exhaust leaking too. I just installed a Megamax II on my 250ex and it seems to fit good, but there is a small leak where the header and slip on meet. Ive tightened it as much as i could, but it wont help. Its sputtering a little bit too, and wont start good at all. Ive messed with the idle and everything, but nothing will work. So where could i get high temp exhaust silicone?