How do you fix the exhaust leak where the exhaust mounts to the engine?

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KCvale

Well-Known Member
Feb 28, 2010
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Phoenix,AZ
You have enough pipe for the high temp silicone hose, your auto parts store should have it and it does wonders even if you have to put a couple hose clamps on it.
 

gera229

New Member
Sep 4, 2011
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USA
Would the spring fit over? Would the pipe bend over since it wouldn't be firmly mounted, but only held by the hose itself which flexes?
The only thing that holds that pipe for me is a clamp to the frame near the end of the pipe where the chamber is.
 
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gera229

New Member
Sep 4, 2011
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Using 2 layers of shims was a failed attempted. Maybe 3 layers next?

But then again, I noticed that if I try to wobble the exhaust, it moves alot at the pipe area before the expansion chamber. That area leads to the head pipe and probably causes alot of play there! This might be the problem too, I don't know. So maybe I can make an exhaust pipe mount to hold that area in place? Thing is I don't know exactly how or what to do to make the mount that will hold it.

I want to get the silicone from SBP, but it cost too much for me to be interested in purchasing it. Does anyone here have any spares that I can buy from? How long? I probably need only 3" length tops.
One reason I don't want to buy it for as much as it costs is I'm unsure if it will work since I only have 1/2" of space for it on the head pipe. So it's a tricky decision.
 

KCvale

Well-Known Member
Feb 28, 2010
3,966
57
48
Phoenix,AZ
Just go to Autozone and buy 4" of 1" heater hose.
It won't last long but you'll know if it works for ~$1.
 

goofyfoot2001

New Member
Aug 16, 2012
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South Carolina
The exhaust port out of my engine is basically square and my exhaust pipe is round with a round gasket, no wonder it leaks duh. I just used some "Ultra Copper" by permatex and so far seems ok. I dabbed it on the engine port, then put on the gasket that came with the bike and then some more before putting on the pipe. The bike isn't spitting hot stingers at me anymore but it hasn't been all that long.
 

gera229

New Member
Sep 4, 2011
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Goofyfoot I used that too on the base on the crank case where the cylinder mounts to.
But what you explained is not my problem.

I think the only reason soda can shims did not work is because my exhaust wobbles easily and is only held by a single clamp at the end of the expansion chamber. It wobbles in the part just before the expansion chamber which leads to the head pipe, thus distorting at the head pipe and causing the shims to fail.

Also the exhaust "falls" downward because that clamp cannot hold it upright, causing it to tilt and not be perfectly aligned at the head pipe.

I want to try shims one more time as the cheaper solution and use 3 layers if possible, but I just don't know how to make a second mount for the exhaust. Possible a hanger mount so it does not "fall" and tilt. I can use very flexible stainless steel as a hanger mount, but it's so flexible it just might not hold it sturdy enough, although it will prevent it from falling downward which might be the only fix I need.

Any other ideas?
 
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gera229

New Member
Sep 4, 2011
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USA
This post will be full of pictures with everything I have done to try to eliminate the leak.
This is the last time I will try the shim method before going a different route. I used 2 layers of shims because 3 was too much and the shims ended up getting damaged. Shims are from a green tea can, but should be the same material and thickness as a coke/soda can shim.

This problem is becoming increasingly annoying, so I might either try to use a high temp rubbery type tube if someone can give me a source for a good fuel resistant one, or I can try to make my own exhaust using a flex pipe and cut the expansion chamber off and attach it to the flex pipe. That will give me more adjustability and hopefully no loss of performance or not more than very minimal loss, but I will still have to figure out how to seal that.

Lowracer, I'd really like to know what you used to seal that place up. If I remember correctly, you used a flexpipe and somehow managed to attach it on there and seal it up.

I want to seal it up once and for all to stop smelling like gasoline with all this burnt fuel spitting on my clothes.

So here is what I did:
First layer of seal: 2 wraps of shims around the head pipe or 2 layers of shims.
Second layer of seal: teflon tape to hold the shim in place while I put the exhaust on and to possibly seal it up even more aside from shims.
Third layer of seal: Fiber glass rope to soak any fuel that spits to prevent that from getting on my pants.

To make the shims, I cut off the top and bottom of the can and bent it in half. Then I measured the size I need, marked it with a sharpie and cut it with scissors. They cut very easily with scissors.
It took me 4 attempts before finally getting the shims in the pipe without breaking. The other 3 attempts they just broke the shims probably due to the tight fit and me trying to push the exhaust on them.



See post below for more images since I was limited to 5 images.

To do:
Make a 2nd exhaust mount to hold the exhaust firmly so as to eliminate the massive play there that occurs when I ride. This play seems to be breaking the seal thus failing it.

Before I ride it again I will add another exhaust mount. I'm thinking of using 2 strips of flexible stainless steel and wrapping them around the bottom of the exhaust to act as exhaust hangers. To holds them in place I will drill 2 holes just below the engine mounts, and then bolt those strips of stainless steel in there. Here is a picture of the bottom of the exhaust that is loose, and that's the part that might have been the cause of the seals breaking all along:

 
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gera229

New Member
Sep 4, 2011
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So today I made exhaust mounts using very flexible steel. I had an entire roll of that steel sitting in the shop and when I looked at it I realized that I can use it and cut it to size.

Before drilling the holes I tight to push it tight together. When bolted on, the results turned out great. The exhaust does not drop as much as it used to anymore and does not move side to side when moved easily by hand like it used to.
Overall, it became almost wobble free and I can barely move it by hand now.

Now I know the exhaust port will not have much play there anymore so things should not move around as much. I will ride and see how well this solves the leaking problems I had.
Maybe it solves it, but still leaks just not as bad as it used to. Time will tell.

Painting it black might make it look better, I just don't have the paint.

 

NewbieOnAScootie

New Member
Jul 26, 2015
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Michigan
Thanks. I wrote the question wrong and you answer it right anyhow. Its leaking from the end of the exhaust onto my crank. Crank is white so it really shows and it makes my pants smell like gas. I get about 38 MPH and wonder if that exhaust extension will hinder my speed.

Doesn't matter if it takes me down a notch. The fact that I can't wear anything but work pants when I ride my bike is enough.