Bonneville America Forums Forums Technical Forums Exhaust Can slip -on's be "too tight"

Official Disclaimer: I'm NOT.....repeat NOT!!! mechanically inclined.

That being said, I have a set of Thunderbike's on my '03 BA. There was always a bit of play in the pipes laterally. I could move them an inch or so side to side while mounted. Is this how they are supposed to be? I tightened them up so they are now solid. My bike now gets terrible gas mileage ever since this. Just wondering if the pipes are restricting exhaust flow since I tightened things up (I do tend to over-torque things), or something else? I have already changed plugs and the air filter but that is where my mechanical knowledge ends. I also really don't notice any gross change in performance. HELP!!!

That is odd, the gas mileage. I have a set of Thunderbike pipes, they are great and non-restrictive. And yes, they should be tight and have no play, in or out or side to side. Use the hi-temp red silicone. If they were loose, you would have heard that tickety exhaust leak noise and you would have some backfiring and tell tale ashy marks.

Have the carbs been re jetted or screws turned lately ?

Nope. I have had this bike for 10 years with those pipes on the whole time. Never messed with the carbs.

I've got staintune pipes on my 07 america and I can wriggle them around the same as yours until I tighten them up, even then I can move them if I push hard enough on them, your change in fuel consumption has nothing to do with this.

Seems to be they should be tight. Id start looking at other probabile causes. Maby somethign wrong with the carb or are you just riding it harder?

Barry, what kind of mpg are you getting now? And what was the previous mpg?

Mike. I was pushing close to 50 mpg before. Getting mid-30's now. Very frustrating.

Rather bizarre. I assume it's running fine? Does it smell rich, exhaust tips real sooty? Has the bike been in winter storage and you just got her out? Recheck the exhaust to make sure no critter nests are in there causing a restriction. Same with the air filter, recheck it for blockage. Brake dragging? Tire pressure? Low compression would effect mileage as well but I doubt that's an issue.
I would recheck the plug and coil wires.
Could it be additives to the fuel in your area?

The exhaust tips are a bit sooty. Too rich possibly??

Could be. Can you access the mix screws on the bottom side of the carbs? Turn them in clockwise until they just bottom out. Easy does it.Count the turns for reference. Now back them out one and three quarters of a turn. Go for a ride and see how she does. If you get excessive popping turn them out another quarter turn.