[bbowles]

OK so, I have both coastered AND marbled the 750. I still get popping and some backfiring. I'll have to double check the gaskets! But I digress...
I havent really torn into it yet, but I think the air injection system is causing the bike to whistle, like the Jetson's space-mobile... Anyone else have this? I hadn't seen any posts about this before.
It seems loudest at about 45 to 50 mph. My pipes are drilled out so it's a little louder than normal, but that these speeds the whistling sounds to me, to be louder than the exhaust.
Any one have ANY ideas about this???? Sounds crazy I know.
Thanks,
Bill

 

[Tater bug]

whistle or whine

I have a 92 750 that has a whine or whistle,I cant hear well enough to determine if it comes from the transmission or would it be the stator?

 

[VN750Rider/Jerry]

On CA bikes, the gas cap will whistle, but only after you park the bike. IMO, both the CA evap system and the air injection system should be COMPLETELY removed, and all holes plugged or capped, except for the gas tank vent, which should be open to the atmosphere. If that doesn't stop it, it is something completely different. You have a mechanical problem of some kind. Jerry.

 

[vulcanjoe]

not meaning to sound like you didnt do it properly. but did you remember to cap off the vacuum line on the right carb when you coastered. i forgot mine and it caused a whistle sound on accelleration. hope this helps

 

[bbowles]

Actually, I did that today, and I didn't notice it as much on a test run. but before I plugged the line the motorcycle had a hard time running, so I wasn't that worried about that. I removed the whole vaccuum system, up to the intake hose and I plugged that, then noticed that there was a lot less popping on deceleration... I thought I had it all blocked off.... who knows! Oh, well...! thank you all!
Peace,
Bill

 

[vulcanjoe]

glad to help