Mid range noise

Im not sure if anyone has experienced this, but I have this strange sound at 5000-6000 rpms. If I hold steady throttle in that range, this noise is very evident. Performance is not affected. If I snap the throttle from there and go above 6000, it goes away or if I let off and go below 5000 it goes away.

The only way I can describe the sound is like a tractor type sound or maybe a little like a 4 stroke sounds. I had a bmp Y pipe on it and took it off and put the oem back on. The noise got much quieter but is still there. It is more pronounced the hotter the engine is. In fact, it doesn’t do it if the engine is cool.

Any thoughts?


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I’m pretty confident it is exhaust or intake related, just by the type of sound I’m hearing.
I would agree the primary is sort of noisy on mine as well but I had it gone through about 350 miles ago.

Isn’t this about the range the power valves open up?


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I think I’ve found the cause. I have a lot of play between the pipe/flange and Y pipe. That rpm range must be the beginning of some bigger pressure. I’ll try a new flange, new springs and a better seat into the Y pipe. Anything else I’m missing?


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I had a look at the springs this morning and they look a bit stretched. I’ve ordered new and will take that advice on the silicone. Thanks.


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