Bent exhaust header flange on KLR650 / FMF Powerbomb Header | GTAMotorcycle.com

Bent exhaust header flange on KLR650 / FMF Powerbomb Header

M

MaksTO

Well-known member
So I finally got my bike together with the new piston and freshly worked head, and noticed that the flange on my FMF Powerbomb Header (KLR650) is now bent. It still goes on to the studs, but takes some force.

I torqued the acorn nuts to factory spec (15ft/lb), and the flange is even more bent now. I don't think its replaceable without cutting the header since the "Powerbomb" bulge at the back end prevents the flange from coming off. Worse case I guess I can get a shop to cut and re-weld it with a new flange?

Is this a normal thing to happen? I imagine my exhaust isn't very well sealed as a result. Though no noticeable difference from last year as far as popping goes. Still happens on deceleration, but not enough to bother me.

Has this happened to anyone else, or does anyone know of any possible solutions? I emailed FMF but It's been a few days with no response.
 
Likely from overtightening one nut before the other, no biggy.
If it really bugs you, yes have the header pipe cut apart then smack the exhaust flange flat and reweld.
 
TK4 said:
Likely from overtightening one nut before the other, no biggy.
If it really bugs you, yes have the header pipe cut apart then smack the exhaust flange flat and reweld.
Click to expand...
Good to know its not a huge issue!

I think I will leave it as is in that case unless it becomes a bigger problem. After finishing the top end I've honestly had enough of working on the bike for a good long wile :rolleyes:
 
Did you install a big bore kit?
 
Is it visibly bent, or is it possible that one of the studs is bent/misaligned? You could take two measurements to confirm (one at the base and one at the stud ends).

Also, put a straight edge on the flange while you have the pipe off to see if it lays flat.

One more thing…double-check that the mating surfaces of the pipe and cylinder face are clean and they line up properly.


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Robbo said:
Is it visibly bent, or is it possible that one of the studs is bent/misaligned? You could take two measurements to confirm (one at the base and one at the stud ends).

Also, put a straight edge on the flange while you have the pipe off to see if it lays flat.

One more thing…double-check that the mating surfaces of the pipe and cylinder face are clean and they line up properly.


Sent from my iPhone using Tapatalk
Click to expand...
Very very visibly bent. Studs are straight. Supposed to be a 5-7mm gap from the flange to the manifold, and its almost touching (2-3mm space left).

Cylinder mating surface was clean as it was straight from the machine shop. I might pull it to see if its aligned, but might not since I dont wanna risk damaging the studs by constantly taking it on and off. Might leave it until I can either afford a new header, or cut this one to bend it back.
 
soo trip 026.JPGWith that extra power on tap you could upgrade to Action Packers ( the Givi's of the KLR world) and as you can see it keeps stuff dryish.
 
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