My 86 VFR after carb rebuild - engine knock

Posted for my mechanic buds online so they can hear the tapping coming from the top end #4. Not extremely noticeable in this vid, but in order to duplicate it 100% I'd have to drop the idle to 1000 rpms and with the carbs being so far out of sync it'll stall more than you'll hear the tapping. If I did that, you'd hear the starter more than the tapping is what I'm getting at, so this is what you have to work with :(

Category:

Autos & Vehicles

Tags:

• 1986
• VFR750f
• Interceptor
• troubleshoot
• tapping
• rebuild
• carb
• sync
• timing
• adjustment
• valve

[igetemailherenow]

@333edr - it turned out to be completely carb related. One of the sync balance springs had popped itself out of the plate and the other two had lost so much of their rate that they were pretty much useless. I replaced all 6 sync springs and did a bench sync, which solved all idle issues and there is now no knocking noises at all. My instructor informed me that when the carbs are out of sync that it can and will cause the engine to rattle inside, including at the clutch/trans and cams.

[333edr]

sounds like dry at the top like no oil getting to your cams.If no oil to top check oil pump,or just check if oil light is on,if the oil sender still works,and get rid of the blowing exhaust first,and dont run the bike to long like that or you will do more internal damage.You also need to check valve clearances and do a compression check on that cylinder and compare it to the others and specs on the manual