Knocking under load
-
- Posts: 31
- Joined: Sun May 19, 2019 1:01 pm
- Location: Montello, WI
- Motorcycle: 1981 GL1100
Knocking under load
81 Gl 1100 has what sounds like a rod knock under load. 1st and 2nd no noise but once in 3 and I hit 4500 rpm it starts making a low knocking noise. It was running fine now this. Carbs were rebuilt in August and bike was winterized and was running well. I have been told the carbs can be out of sync is there anything else that it may be.
- DenverWinger
- Posts: 1706
- Joined: Thu Jun 23, 2011 2:20 pm
- Location: Denver, CO
- Motorcycle: (s)
1980 GL1100 STD Vetter (2005-)
1993 GL1500 Aspencade (2017-)
1983 Trav-Lite Camper (2010-)
Past rides
1972 CL350 (1980-1988) sold
1978 Suzuki GS550 (1985-2005) sold
1977 GL1000 (2002-2006) sold
Re: Knocking under load
Doubtful it is Carburetor sync, that mainly affects the cylinder balance at idle and very light throttle. Once the throttles are opened to any degree the sync adjustment is insignificant.
♫ 99 Little Bugs in the Code, ♪
♪ 99 Bugs in the Code. ♫
♫ Take one down, Patch it around, ♪
♫ 127 Little Bugs in the Code. ♫ ♪
~Mark
♪ 99 Bugs in the Code. ♫

♫ Take one down, Patch it around, ♪
♫ 127 Little Bugs in the Code. ♫ ♪

~Mark
- Lucky07
- Posts: 53
- Joined: Sun Mar 03, 2019 11:21 am
- Location: Ottawa, ON Canada
- Motorcycle: 1983 GL1100A Aspencade
1984 CB550SC (Sold it :( )
Re: Knocking under load
Pull the plugs and see what they look like. If it's a combustion issue you should see it there, might have a cylinder running lean/heavy or with weak spark. If all plugs are the exact same I'd be leaning towards something mechanical (not so good) but easiest first would be checking the plugs.