Read my plugs--suggest options GR 650 twin

[Guest]

Been running great.

Took it out today and it stalled at a stop sign. Just not typical. Seemed to be idling low, so stopped and boosted the idle a bit. Again, not typical.

Started feeling a miss in the left cylinder and a bit of popping on deceleration.

Pulled the plugs when I got home.

Here's what I found:

Right cylinder- Fairly obvious that it running lean.
Left cylinder-
Obviously running rich.

I have not adjusted anything in the fuel chain since I cleaned the carbs last summer. Adjusted the valves at that time too.

Have been gathering the parts (wire, connectors, etc.) to install a newer R/R and do the coil relay mod.

I adjusted the air mixture back when I did the carbs, but haven't checked it since. I also just adjusted the air mixture until the bike seemed to be running happy.

Any thoughts as to what steps I need to take?

[hikermikem]

check you have good spark to each cylinder, verify the plug caps are connected well to the wires.

maybe replace the plugs with new as well.

Sorry, don't know much about these Gr's

[Agemax]

try cleaning the plugs and switching them to opposite cylinders, see if the misfire transposes. could be simple as worn out plugs. or it could be a lot more sinister!

[oldrookie]

I'll check into these ideas. Like the idea of swapping plugs and seeing if things change.

hikermikem, so far the GR is more similar GS's than dissimilar to them.

[Mekanix]

Its the next step up from the 500 with only a few added features.

Piston cooling jets
flywheel mass
auxiliary intake ports.

Besides that everything else should act the same. Some parts are different in design but identical in function.

I'd consider it an innovative gs.


For your issue it seems like something is clogged on that side or just not igniting.
In addition to swapping the plugs and checking for spark, Try pulling the carburetor bowl off and check for a clogged needle valve.
Check for air leaks on that side and check the Auxiliary intake line for cracks.