I have an 07 nightster and i just put on V&H straight shots and once in a while when i ride i will here a whistl ecoming from what i think is the exhaust. It only does it when the bike is not warmed up from what i can tell and only when riding not at idle. When the bike warms up it goes away any thoughts? Thanks

 

did you replace the gaskets? possibly the gasket is not seated correctly and eventually the heat forces it ****.

 

Have you considered it comming from the brakes? Your brake pads warm up with time also which can relate to you thinking that it goes away with engine warm up. Next time you hear it, try giving your brakes a fairly hard squeze, and see if it stops the whistling, and maybe try each brake seperately to isolate which one it may be. Being the brakes would also explain why it only happens while riding too. I often get a good whistle from my rear brakes if i'm accelerating with the bike leaned to the left in a long turn.

 

Crossover gaskets

 

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