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[Solved] FJR1300 Header Dent


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Dear Scotty,

I am a huge fan of you and your shows. Thanks for being you!

Your show(s) with the Yamaha FJR1300 got me thinking.

I watched the market for months and found a 2006 in good mechanical condition with low miles from a private party. However, it does need some cosmetic TLC. 

My question for you is about the exhaust system. One of the header down pipes is dented. I am wondering if it is worth the time and money to replace with a used exhaust and no dents. Personally, I would think it is probably no big deal since full flow is only really needed under high load, but the other side of me says this single pipe dent may change the balance between the cylinders. 

Your thoughts are appreciated. 


Mike Wilson

P.S. — I am a DIY retired engineer, live on a farm, and only owned used Toyota, Lexus, Honda and Japanese bikes. My tractors are older than me (and you) restored John Deere Model-A's, Ford 8N, and Farmall 460. Looking forward to many safe miles on my beautiful budget FJR...Thanks to you. 


2 Answers

Anything that compromises the exhaust flow has to be considered a negative.  Even a small dent in the header decreases the flow the system was designed for.  I could not live with myself if I could not repair this defect, but that's a personal semi-OCD thing.  To what extent it affects the performance of the engine is a matter of opinion and for seriously educated engineers.   


The big question is whether it's a cosmetic dent or a constrictive dent. Up to 3/8" probably not a big deal. There are quite a few motorcycle salvage places out there, and the FJ1300 is an understandably popular bike, should you wan to replace your header.