Pinging/Rattle under load

[KDXohio]

I'm probably posting this too soon as I haven't had time to investigate much but here it goes.

The end of the season last year my bike did not have these symptoms and the only engine change to the bike has been the addition of a boyesen rad valve bc I noticed some dry rot starting on my intake boot.

So riding around the neighborhood, nothing crazy, I noticed putting the bike in 4th or 5th gear and pulling 1/2 throttle at low rpm the engine started pinging/rattling pretty bad. All opinions welcome! I'm going to dump the gas and put in another batch in case I mixed up low octane when I got it out and put in fresh. Also I'm sure the Rad Valve has thrown off my jetting but I didn't expect it to make it Lean enough for the pinging? Thoughts?

THANKS!!!!!!!!!!!!

[Julien D]

You should certainly rejet after any change to the intake/exhaust or engine. That said, I would see what happens with fresh fuel before jumping to any conclusions.

[royadams]

Id lean towards fuel or dirty carb. Usually reads will make is rich not lean.

[KDXohio]

Thats what i was thinking too Ill know more this weekend hopefully

[90kdx200]

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