MV Agusta Forum banner

2nd gear noise/vibration

2K views 13 replies 7 participants last post by  MORT 
#1 ·
Hi guys.
My F4 312R makes a strange noise/vibration in second gear at low rpms.
It's hard to describe the noise but it only comes up in second gear and at low rpms (below 5.000 rpms). the noise/vibration seems to come out of the engine or the gearbox and besides the noise itself it never gave me any problems.
The last time i sent the bike to the MV dealer i told them to check that out and they said their mechanic who tested the bike easly detected the noise/vibration but says it's normal and they all do this....
I have had an F4S who never did that, my friend's 312R doesn't do that and even my 312R only started to make that noise/vibration some 4 to 6 months ago.

Any of you have had the same issue? What can it be?
 
#2 ·
I know nothing about the 312R, but it's an MV, and I assume similar to 1000's in there. Some thoughts. I believe it isn't normal and as none of the other 312's you mentioned aren't doing it nor has anyone ever mentioned it in a 1000 then it's worth looking at. Vibrations are a bitch to track down with all that stuff going around in there. But it only happens in 2nd gear and only at 5000 rpm. So probably not engine related. I don't know if MV gears ride on bearings or the shafts or if 2nd gear is a slider or is fixed. But, were it me I would start by taking a look at the actual 2nd gear itself and the connections between it and the ones to either side which it may be engaging as you shift from one to the other. Somewhere in there is a little too much clearance between something causing it to generate a vib. At least I think so and it's where i'd look. I'd also find another dealer.
 
#10 ·
It may be a tolerance stack issue, which would justify the comment "some do some don't." If you can, try running it on a dyno with a fairings removed to see if you can pinpoint the origin of the noise. Also, what variables cause the noise (full throttle, light throttle, no throttle, does it happen under acceleration and/or deceleration, does it happen in a corner, does the noise change when you lean left/right, does it make noise only when shifting up from first, does the noise change if you take off in 2nd gear, did you observe the proper break-in methodology, etc)?
 
#12 ·
If it is specific to operation in one gear and one gear only then it is time to disassemble the transmission and inspect.
 
#13 ·
Something in the transmission my be loose, out of balance and/or misaligned. It is interesting that the noise stops when the real power come on around 5K. I would examine the parts associated with moving and positioning the gears (gears them selves, shiftdrum, etc ). Take it to a dealer or cycle transmission specialist and skip 2nd gear while you are riding there. If they can't diagnose anything, you many need to start swapping parts until you find the culprit.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top