Ok I started my bike up today to head off to get some bits n pieces from the auto shop, it had been sitting for a couple days but the bike started fine on choke first crank and went to 3000 rpm like normal, I went to close the gate when I came back (less then a minute later) I could hear a high pitched whistle noticeable mainly from the back sounding like it was through the exhaust but  as I rounded the front it sounded like it was coming from the head or the header pipes I worked the choke off as the RPM increased and the noise went away, I gave the throttle a blip and no noise just the usual clatter. Got to the shop ok, I didn't ring the neck off the thing started the bike back up to leave and no whistle, went a long way with a straight road to give it a blast and nothing unusual.

Now I would've thought it was an air leak but it should be constant if that was the case shouldn't it? I sprayed some wd40 over the carb boots to check and there was no change in idle and a hole in the exhaust or a loose header would just make the clatter louder but not whistle right?

Im at a loss as to where it came from and why it didn't hang around, I received the last of my parts today so tomorrow were cleaning, rebuilding and synching the carbs, valve shims, new chain and sprockets and the K&N air filter ill give the exhaust a good once over and check the header bolts to make sure nothings loose......

Has anyone seen this before??? or is it just another quirky noise?

Think if it was header bolts it would be weee weee weee weee .... Not weeeeeeeeeeeeeeeeee

Something that tightened up with heat? ... Air sucking in through the K&N restrictor funny? ... Blocked or part blocked breather in tank? 

Quote from: Janx101 on October 31, 2013, 04:08:08 AM
Think if it was header bolts it would be weee weee weee weee .... Not weeeeeeeeeeeeeeeeee

Something that tightened up with heat? ... Air sucking in through the K&N restrictor funny? ... Blocked or part blocked breather in tank? 

I haven't put the k&n on yet but ill check the tank breather didn't think of that one