FMF Fatty Exhaust Leaks

[Muggzy]

Hey gang, I just replaced my DG exhaust with a full FMF system. With the very short ride I was able to give it, i'm happy with the swap. Trouble is the mounting flange that is bolted to the cylinder leaks btwn the pipe and flange so exhaust residue is getting all over the place.

Anybody got a fix for this?

 

[Braaaptor]

High-temp sealant usually does the job; its hard to get an FMF pipe to seal well at the flange. Do you have a spring holding the pipe in place? You can attach a spring from the bung on the pipe to the engine's cylinder to help hold it tight against the flange.

If you've got lots of goo oozing out around the exhaust, you may be running the engine extra-rich. Check your jetting and fuel mix ratio.

 

[YFS101]

I use high temp sealant and o-rings on my customers bikes

 

[99LRDblaster]

Hey gang, I just replaced my DG exhaust with a full FMF system. With the very short ride I was able to give it, i'm happy with the swap. Trouble is the mounting flange that is bolted to the cylinder leaks btwn the pipe and flange so exhaust residue is getting all over the place.

Anybody got a fix for this?

Pack it in with high temp RVT sealer. Always has worked for me. You can pick it up at your local shops like Autozone or Napa. It's usually just labeled as exhaust sealant. A high temp O-ring and RVT together also works like YFS said.

 

[Muggzy]

If you've got lots of goo oozing out around the exhaust, you may be running the engine extra-rich. Check your jetting and fuel mix ratio.

Yeah, my mix is 32:1 and it's jetted intentionally rich right now until the snow melts off enough for me to get out and jet it properly.

I use high temp sealant and o-rings on my customers bikes

YFS101, where do you get high temp o-rings? I tried a few local autoshops and came up empty. I figured if I could get a thin o-ring with a 2" ID, it would probably solve the problem but they all looked at me like I was crazy for even thinking an o-ring wouldn't melt on an exhaust port.

Pack it in with high temp RVT sealer. Always has worked for me. You can pick it up at your local shops like Autozone or Napa. It's usually just labeled as exhaust sealant. A high temp O-ring and RVT together also works like YFS said.

Thanks all, I'll pick up some RTV as soon as I get the chance. Would love to get an o-ring the right size for the job though.

 

[piezzi]

I used the copper RTV and it sealed up nicely for me.

I put a very small bead between the flange and the head, and another very thick bead between where the top of the flange and the inside of the pipe come together.

Good luck!

 

[YFS101]

I get the universal FMF spring/oring kits from Parts unlimited.
even if they do melt off eventually they will prevent the hightemp silicone from blowing out at the fisrt start up, but the orings held up well on my YZ and RM with no issues. I have used them on Blasters before as well.

 

[biggercb]

I get the universal FMF spring/oring kits from Parts unlimited.
even if they do melt off eventually they will prevent the hightemp silicone from blowing out at the fisrt start up, but the orings held up well on my YZ and RM with no issues. I have used them on Blasters before as well.

Do you have a link to the universal kit? I can't find one...

 

[fitblaster]

i have this leaking problem too except mine is a trinity exhaust

 

[FaH-S.A]

yeah its no biggy! Had the same problem. Its just really messy. You can seal it up wif some RTV if you like! I did the same thing. The thing with the fmf pipe is that it doesnt fit perfect right into the flange and there is a gap, thats just the way it is. Thought i was losing compression in my case, but no. Hit me up if you need any more help on this.