So I rode my bike to work this morning - after installing the "new" exhaust system... and I noticed that the exhaust pipe was MUCH hotter than it would get before with the stock pipe. Anyone know why this is... I understand that the gases that get ejected from the engine into the exhaust are really hot, but what would make them hotter?
Thanks.
Rolly
Nobody else is, so I'll take a shot at it.
When you say New exhaust, Im assuming you mean aftermarket, right?
I also will assume you havent rejetted. I dont know your setup so I may be way off, but . . .
Aftermarket exhaust will make the bike run leaner.
Leaner = hotter.
If you jet richer, it should cool down closer to stock.
Just a guess. :dunno:
You are correct, and I will agree with you.
Actually, the exhaust is homemade. I used an 18" auto exhaust pipe, had it bent into an s shape (of sorts...) and mounted a straight-though old-style exhaust. It's mounted along the bottom rail of the seat, so the pipe is a lot longer than stock, I'm wondering if this may be making the big difference.
Lean, huh? I've actually been thinking it may be lean. I also rejetted using a dynojet kit - stage III. Il took a look at the plugs and they also looked like it was running lean (one was whitish, but the other was pretty black/gray... like carbon, not oil or fuel), so I'll go back to the jetting and try to richen it up. Would the mixture screw at the bottom help any or should I stick with adjusting my carb needle. The dynojet needle has a little c-clip that attatches to grooves in the needle. I'm at the 2nd groove from the top right now, so maybe I'll move it down one at a time until it's working out right.
Thanks for the reply...
If you're interested, the pic is in the members gallery on poage 13.
Rolly
It can also feel hotter because the pipe you used is made of thinner metal.
if the plugs are black, it's already too rich.
I had thought black and wet means rich, but if it was dry, just sutty, then it was lean?
One plug is leanish looking, but the other has a bit of black sut on it... hmmm... is any black an indication of a rich mix?
Wonder why one carb would be rich and the other lean...
Rolly
dark and wet generaly means way rich posibly oil mixed in
(valve guides,rings worn ect)
dark soot is rich (may also show as clumpy deposits)
light soot and dry is ok - tad rich
light tan and dry is ok
whitish ashy is lean
dark brown dry is oily lean
OK aftermarket exhausts make the exhaust cooler to touch after a ride.... compare apples to apples guys... if you are riding say 10 miles running identical rpms on bikes that have been jetted right and one is with stock pipe and another is with a aftermarket one... the aftermarket pipe will get less hot... hot exhaust runs through faster, and transfers less heat to the pipe, and since rest of the parameters are identical... Now your bending swooping pipe going under the seat is a whole other story... cant see how it wont be much hotter than anything cos you have so much pipe length sucking heat off the exhaust gasses.
Cool.
Srinath.
I guess I'll just need to figure out the correct jetting.
I know that the bike seems to be running hotter... I'm just trying to figure out why... running lean makes sense... running rich doesn't... :dunno:
Then again, if one cylinder is running rich and the other lean, then maybe that's what's causing all the heat... not sure how that could happen...
Rolly
Quote from: seshadri_srinathOK aftermarket exhausts make the exhaust cooler to touch after a ride.... compare apples to apples guys... if you are riding say 10 miles running identical rpms on bikes that have been jetted right and one is with stock pipe and another is with a aftermarket one... the aftermarket pipe will get less hot... hot exhaust runs through faster, and transfers less heat to the pipe, and since rest of the parameters are identical... Now your bending swooping pipe going under the seat is a whole other story... cant see how it wont be much hotter than anything cos you have so much pipe length sucking heat off the exhaust gasses.
Cool.
Srinath.
A stock exhaust feels warmer than an aftermarket exhaust because the stock exhaust is made out of thick walled steel headers, and a steel can. The thicker the steel, the better it retains heat. It takes longer for the heat to disipate (sp?) after you shut the bike down when using your stock system then on an aftermarket. Most aftermarket exhausts are made from thin walled tubing and have alum. cans which heat up quick but also lose the heat quick.
Yes very true. The stock also retains the gasses longer, making them go through various crooked paths making contact with metallic walls and giving them heat... of course lean jetting form the factory and the ton of metal in the can exacerbate the heat too...
Cool.
Srinath.
Quoteso I'll go back to the jetting and try to richen it up. Would the mixture screw at the bottom help any or should I stick with adjusting my carb needle.
First check your mixture screws, and set them equal to each other.
Then check your float level. Make sure they are even, and also even with the seam.
See if those fix it before moving inside and adjusting needles.