125cc Cygnus scooter stuttering or juddering when slow riding.

 

I am in the UK and I have just bought a used, one owner 2005 Yamaha NXC
125 Cygnus scooter with 5,000k on the clock. When I start off slowly, or
ride very slowly, I am getting a stuttering or juddering which then
seems to give a knocking noise, this appears to be coming from the drive
belt, or rollers, and it only does it at very low speeds, (walking
speed), it then quickly disappears as the revs increase. The scooter is
still under warranty and before I take it to the dealer, I would like to
have some idea what the problem might be so that I can explain it
exactly to make sure it is not overlooked. I have searched the web and
cannot find any other occurrence of this problem, but it might be that I
am using the wrong wording when searching, so if anyone can offer any
advice, it will be much appreciated.

Harry

 



Thanks Gregg, if they say that the juddering is normal at very low
speeds, I can now mention a possible cause and cure for the problem. I
hadn't even considered that the clutch bell might be out of round, but
the snatching and knocking would fit in with what you say.

 

wrote:

If it's still under warranty, they can fix it. It's not an acceptable
thing. They will test ride it, or you can insist that they do. Don't
let them say "Oh, that's normal." It's not.

 



Thanks Joe, I agree it's not normal, but it is better to argue when you
have a few facts to back up the argument. :-)
I am just waiting now for the transfer into my name to take place, then
I will be ringing up to book it in under warranty. It has probably been
like this from new, but the previous owner seems to have accepted it, or
not even noticed it. The dealer hasn't seemed to notice that although
the speedometer is reading mph, the odometer is in km, not miles, the
last service is registered in the service book at 4,000 miles, but the
scooter has only now done 3,000 miles, (5,000 km). This was better for
me as it was sold as having done 5,000 miles, when the true figure was
3,000 miles, this makes a nice change from the usual clocking of motors
though.

 



Just an update.
I took the scooter in today for repair under warranty, after getting the
paperwork sorted. It didn't take them long to fix it, (under 1 hour),
and it now seems to be running OK. I asked what the problem had been and
was told that they had given it 'a good clean out', but if the fault
re-occurs they will fit a new clutch. This would seem to fit in with
Bozo's solution, (lightly sanding the clutch shoes), as no parts appear
to have been fitted but it now seems a lot smoother at low revs.