Exhaust Issue/Question(s)

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101stpathfinder

Trading miles for memories
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So I may have waited too long to service my suspension. I do not know if the term "Sagging Suspension" is literal or not, but

I felt like my cycle was getting lower or my legs were growing longer. I am in my 50's so the legs growing longer theory was shot.

My bike was nearing 60k though and it seemed as the the ground was getting closer. To make a long story short:

I was riding over a speed bump that I am forced to ride over quite often when I bottomed out. The contact was made on the bottom

of the exhaust pipe assembly. When It happened a 2nd time I made my Traxxion appt. and had my Penske and AK20 cartridges transferred

over from my '05. The bike now had more clearance and a much stiffer suspension, but the damage was already done. At first the "fluttering"

noise was intermittent and very seldom. Now however the noise is much more constant and much louder. Its not getting better, its getting worse.

I think I am starting to feel a loss of power with a loss of compression (?) So I now feel the need to take care of this before YFO.

Before I start taking things apart, I would like some opinions from the riders who would know much more about this than I. Has anyone had

an experience comparable to this? I mean there are very few possibilities with so few parts involved here. Is it most likely the gaskets need

replacing? Perhaps there is a hairline crack that I cannot see without disassembly? The sounds are very high (Like near the connection area)

Could I have bent the seating area? Are the gasket like crush washer type material? If there is a crack, could JB weld be used? I really think

the problem is the seating near the gasket area, but I am hoping someone here can give me some advice. This bike is my main transportation

as I am trying to keep the mileage down on the Dakar (For resale) thus I would like to disassemble and repair in one quick action.

I have my '05 sitting here waiting to donate parts. Is there any difference in the Gen 1 and 2 pipe assemblies?

Thanks, Tony

 
Muffler gasket is a metal mesh impregnated graphite material. I assume you are speaking about the join between the muffler and the exhaust?? (Or between the engine and the headers? That is copper, I think.)

JB Weld will last about 3 minutes before it cooks off - in either location.

Is the pipe dented significantly?

Do a compression and leakdown test on the engine to make sure you are dealing with a simple exhaust problem.

 
If the pipe is dented to the point of reducing flow, your headed in a bad direction. As in burning an exhaust valve and needing a new head. It's concerning that you can feel a power loss.

1st, inspect your pipes and be sure there are no major dents. A small detent shouldn't cause any issues. If those are acceptable, I'd suspect the header connection before the exhaust pipe, so I'd start there and replace gaskets. JB Weld will NOT work. It's too hot there, but Ross already said that.

Be sure there is no separation between the headers and the Cats. If you find a crack or tear, take it to a muffler shop. Welding is cheap.

 
Muffler gasket is a metal mesh impregnated graphite material. I assume you are speaking about the join between the muffler and the exhaust?? (Or between the engine and the headers? That is copper, I think.)JB Weld will last about 3 minutes before it cooks off - in either location.

Is the pipe dented significantly?

Do a compression and leakdown test on the engine to make sure you are dealing with a simple exhaust problem.
The engine and headers - If it is indeed copper, it could have just caused a unseating caused by the up and out force caused by the ground strike.

if there is a thickness to the gasket, it could now be thinned on the top edge witch would cause a bad seat. Or is this not

logical thinking?

 
HRZ

No dents or cracks are visible on the pipes or any of the assembly involved. I need to disassemble plastics to fully inspect.

I really suspect the engine and header connection area because the sound is frontal of engine and high up near that area.

The loss of compression could be in my head (Or I am just remembering the power of my Gen1 '05 compared to this POS Gen2 '08)

 
You could try just tightening the connections. If nothing is broken, that could work. You might have to anneal or replace the gaskets. If header is cracked, it might be weldable.

If you have a perceived loss of power, I still think compression and leakdown should be checked.

 
You could try just tightening the connections. If nothing is broken, that could work. You might have to anneal or replace the gaskets. If header is cracked, it might be weldable. If you have a perceived loss of power, I still think compression and leakdown should be checked.
I think that is gonna be my approach NEXT weekend maybe…
rolleyes.gif
(Not that I hold off for tomorrow what I should do today )

 
T, bring it to Mims if you can. As far as Gen 1 vs 2 exhaust, I don't think there's a difference. When I ran over the Harley part on I95 that time and ruptured a couple of the pipes, I replaced the assembly with a used Gen 1 unit.

Give me a call, or I can come down there. Let me know............

 
If you have enough of an exhaust leak that you can hear it then you might be able to feel the air flow through the leak. Have someone hold a rag over the ends of the mufflers to create a lot of back pressure and force the exhaust air out the leak to increase flow at the leak and it may become obvious where the problem is.

 
I have replaced the exhaust in my Gen 1 with a Gen 2 exhaust when it dented badly when i tried to get down her of a high pavement.

Gen 1 & Gen 2 exhausts looks similar outside.I don't know if inside there are some differences,but i didn't noticed any difference in the power.

 
The Gen2 exhaust pipes have a second set of catalytic converters in the pipe section. I replaced my stock exhaust with Gen1 exhaust cans without the catalyst. They are a bit lighter also. I did the trooper mod on the Gen1 set and the Gen2 cans are hanging down cellar all pretty like new.

Dave

 
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A couple of thought for Tony:

When you went over the speed bump you would have dented the underside of the header pipes. This changes their inside area of the crushed pipe(s) and reduces the exhaust flow, and will cause a noticeable reduction in torque (power).

You do not want to do a lot of riding in that condition as the back pressure can cause issues with the exhaust valves, as HRZ noted.

It is highly unlikely you unseated the connection of the header to the head. The gaskets at that joint are solid copper rings, and the ends of the pipes are seated in deep holes in the head. To cause a leak up there would require breaking the bolts that hold the header connected to the head, or worse, cracking the head. Bumping the underside of the header would tend force the header up and back, which would force the header further into the recess in the head.

If you are hearing an exhaust leak it's more likely that you jarred the connection loose between the header pipe and the muffler pipe. The gaskets at those joints is a soft mesh backed material which is easily damaged even when trying to take the joint apart, and might have crumbled a bit when jarred by the speed bump. You should be able to detect the leak by feeling around those joints while revving the engine.

Or you may have torn / cracked the metal header at the support point where the pipe hangs from the centerstand.

When you find a replacement header you'll want to use new gaskets at that joint anyway, while the four copper rings can be reused at the head.

 
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Related to this topic, I have a small dent on the right header pipe caused by an accident ride over a curb. Is that a danger to the valve health? If yes, are GenII and III headers interchangeable? Thanks!!

 
Depends how big the dent is. Big enough yes. Minor? roll the dice I guess?

Header pipe was the same from 2003 - 2012. New part number in 2013 on.

 
Converters have small passages lined up to flow of gases. If damaged, broken they can rotate and block exhaust flow. Might rattle?

Chunk of converter stuck at back of pipe causes a major restriction.

I've seen it happen to AUTO converters. OR just a leak at muffler as others stated.

 
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