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Exhaust Header Question

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I have been upgrading my new to me 06' X and therefore I bought a new torque wrench. I installed the new exhaust for my bike and then I broke two bolts off in the motorcycle (mounting the rad shroud on the right side, just using the wrench at 3.7 lb-ft) I realized that I had just installed the new exhaust header and had only stopped tightening because I did not hear an audible click (or feel).

I tested the torque wrench after I broke the two bolts on the rad shroud and found out the wrench is defective and was basically a large ratchet wrench. The wrench is a Craftsman and I returned it and got another one that works perfectly. I tested the torque of the exhaust header bolts with the new wrench and it was over the recommended 15 lb-ft.

My question is: Can you over tighten the bolts for the exhaust header? I used a new copper gasket and tightened the *%$# out of the bolts with the defective wrench. I tested the bike and there are no leaks from the header.

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I have been upgrading my new to me 06' X and therefore I bought a new torque wrench. I installed the new exhaust for my bike and then I broke two bolts off in the motorcycle (mounting the rad shroud on the right side, just using the wrench at 3.7 lb-ft) I realized that I had just installed the new exhaust header and had only stopped tightening because I did not hear an audible click (or feel).

I tested the torque wrench after I broke the two bolts on the rad shroud and found out the wrench is defective and was basically a large ratchet wrench. The wrench is a Craftsman and I returned it and got another one that works perfectly. I tested the torque of the exhaust header bolts with the new wrench and it was over the recommended 15 lb-ft.

My question is: Can you over tighten the bolts for the exhaust header? I used a new copper gasket and tightened the *%$# out of the bolts with the defective wrench. I tested the bike and there are no leaks from the header.

In my experience, 50% of all Torque wrenches sold are useless. Even if you find one that works today, in 6 months it may go waaay out of calibration. Snap-on, MAC, etc are the only one's I trust.

Yes you can overtighten the nuts on the exhaust header studs, and stretch the studs....which then usually break.

Not to worry, they are probably fine.

Dont' get obsessed with tighten non-structural bolts to spec....learn bolt tensions by feel, and just be careful. Most ametuers with torque wrenches break a few bolts until they realize the bolt torque spec is for a lubricated bolt and thread, not a 4 year old dry, corroded fastener.

It's good practice when removing bolts to wipe them with anti-seize (or lock tite, if appropriate) before re-installing. ESPECIALLY mixed metal fasteners like tank inserts, swingarm adjusters, carb fasteners, etc.

Edited by Krannie

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For the 3.7 foot pound torque spec you should be using an inch pound torque wrench however that spec is near the lowest setting of most inch pound torque wreches (aprox 45 in/lb ), best to just go wrist tight IMO.

Unless otherwise specified torque specs are for clean dry threads. Antisieze, thread locking compounds do not effect the spec however lubricating the fastener with oil does and you need to reduce the torque spec accordingly to keep from damaging the fastener ( elongating it) or breaking the fastener. Once you exceed the yield strenght of a fastener its clamping force will diminish which is why you never reuse a 'torque to yield' fastener.

If it were me i would replace the overtorqued bolts/studs. If you exceeded the yield strenght they will loose clamping force or possibly break in use or next time you try to remove them. Bolts/studs in an exhaust system see a rough service life because the components are heatin up, cooling off, expanding and contracting. Replace the overtorqued fasteners now to prevent a possible broken fastener later.

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Thanks for the responses. I normally hand tighten everything, but I wanted to torque wrench the new exhaust header with the copper gasket. I only used the wrench on the tank shroud because it was a new toy, and they gave me torque specs in the manual (the wrench is in inch pounds, not foot pounds). I hope I did not damage the bolts coming out of the engine. I don't think I did because both nuts are just over flush with the bolts coming out from the engine. Not sure if I should loosen and re torque. My gut tells me to leave it alone, no leaks and the nuts are flush with the top of the bolts. I only did about three 1/4 turns on each nut before I realized the wrench was not clicking.

Krannie where do your nuts sit on the exhaust header bolts (that question does not sound right). But seriously, I also have the DrD exhaust. Are they flush with the top of the bolt? Thanks.

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