C650GT Runs On 1 Cylinder, Then 2

[drb930]

I just got this bike.
Cant seem to find a repair manual.
It usually starts on 1 cyl then you rev it and the 2 comes on.
Does the same thing taking off from a stop.
Seems like it started when it got low on gas after refull.
Bad plug, coil or plugged injector?
I pulled the coils and plugs and they look ok.
Anyway to test them and the injectors?
Kinda lost without a service manual.
Not really wanting to take the shotgun approach to it.
I could start it and spray water on the header at the head to see which cylinder is not firing and then swap coils and plugs?

Thanks,
Dave

 

[RollaCosta]

Buy the manual, or take it to a dealer/mechanic.

 

[Ceesie76]

Service manual is on DVD for sale on Ebay typically - not expensive, a bit quirky to use but lots of good info there.
You can get the Motoscan app (around $50 it was when I bought it, full professional version) and the bluetooth OBD2 dongle it needs to communicate with the bike (another $50 or so, make sure you get one of the few compatible ones, check Motoscan website) to read fault codes. Bad coils don't always but sometimes do set a code.
Yes you can swap coils and read exhaust manifold temperatures to check which cylinder is not firing, to see whether it's a coil. I would replace the plugs just because they are cheap and rule out that possibility easily.
It could also be a weak/broken wire, which is harder to diagnose. Could also be on the wiring to one of the injectors, you can get a 'noid light' to check for that.
Sounds like something simple, coil would be my guess. Best of luck diagnosing and fizing this issue!

 

[drb930]

Forgot to add the bike only has 5200 miles on it.
Amazingly at 5400 miles 1 spark plug was bad.