I have a ‘rollerised’ 2011 Stelvio 8V. I have recently completed the 30,000 miles service, conducted to the book. However on post service rides I am noticing a slight hesitation from very light throttle and at low revs, almost like its is missing for a fraction of a second. Could this be a throttle body balance issue? I have not touched the injection side of the bike and have only changed the spark plugs. Note: I did have to make a repair to an open crack in the rubber of one of the HT plug caps with a tiny amount of silicone sealant, a thin rubber strip and insulating tape following a misfire which has now gone away.
Firstly, the Plug Cap issue is fairly common.
Ditch the originals, and replace with the one-piece all-rubber NGK Caps.
They’re slightly longer than the originals, and stick out a little, but as the top is only rubber, they fold over and fit under the HT Lead Cover nicely.
I have nearly 27,000 miles on mine since fitting them, no issues, and have been through several torrential downpours since then.
The ‘missing’, is it like the kill switch has been flicked off for a split second, or does it feel like only one side is misfiring/cutting out?
At only 30,000 miles, I doubt the Throttle Bodies/Plates need cleaning, unless the Engine Oil has been filled to the upper mark on the Dipstick all it’s life, in which case they’ll need checking, and cleaning if required.
Engine Oil should be kept at a level mid-way between the upper and lower marks.
Fill it to the top, and it’ll breath the excess out into the condensing/separation Canister at the Headstock, some of which will go into the Airbox, as the Oil Vapour Hose goes there.
The liquid drains down the other Hose, into the Sump.
Did you balance the TBs during the service, and reset the TPS with GuzziDiag?
If it still does it after replacing the Plug Caps, and once the TBs have been checked/cleaned, I’d try another Map.
The standard map is well known to give poor running just off idle, to 3000rpm or so, a decent Map will cure that.
Maps can be had for free (PM me for a good source), or you can get one from ‘Beetle’ at https://www.griso.org/
You need a Laptop, the £25 connection cables from Lonelec, and the free-to-download programs.
It’s all here . . . https://www.thisoldtractor.com/moto_guzzi_quota_guzzidiag_howto_-_a_tutorial_for_beginners.html
If you haven’t already got the plug caps then these fit nicely with moderate bending
NGK SB05E or SB05F [the E should be right one]
I am too are having a intermittent tickover miss, feels like one side.
from the maintenance side I have replaced the HT leads and caps and plugs, it was happening before I did this and still is happening - it manifests itself more when I am starting off on a cold engine in traffic than when I go via the lanes where speed is higher. Usually at tickover but sometime low speed/revs. When engine is hot (warmed up) it doesn’t happen.
so maybe worth checking if it is consistent