Testing the ignition system

[alke46]

OK so here comes more questions from another member that is not the most electrical inclined.
I'm testing the ignition system with information I have from BikeCliffs website and this is what I have so far. The battery is an AGM type but it has been in the bike since I purchased it 8 years ago.
The voltage across the terminals is 12.5 maybe on the low side but seems OK.
The voltage at the coil connector plug is just shy of 12.4 (12.36-12.38).
The voltage across the terminals while cranking the engine over with starter is only showing 10.8V. And with the headlight on it shows 10.7V.

Should I continue with any more testing at this point or is this a sign the battery is too low for proper testing?

Also at the points, the 2-3 side is only showing 10.98 and the 1-4 side is showing 11.04.........

Thanks for looking and hopefully providing some good information.

Larry

[tom203]

The 12.5 is a little low, but other numbers seem fine.. What ignition problem are you having?

[JTGS850GL]

Voltages are low. Either your battery needs a good charging or replacing. 8 years old, I'm betting on the replacing.

[alke46]

The 12.5 is a little low, but other numbers seem fine.. What ignition problem are you having?

No ignition problems, just trying to make sure everything is good so I can get a bike that is fine tuned. I have carb issues and when I have done plug chops, the 2-3 plugs always seem a little darker than 1-4.

I just dipped and installed new O-rings on this bike back in early spring but #2 carb has no response to the air screw being adjusted.

So that's where I am. Just trying to get all those little ducks lined up so I can maybe get this thing to perform better. Basically, it runs really well on the open road but around town it has some issues. The worst being a hanging idle. Looks like #2 carb needs further cleaning.

[tom203]

Ok, new carb o-rings, new boot o-rings too?? And #2 is second from left as you sit on bike?

[alke46]

Ok, new carb o-rings, new boot o-rings too?? And #2 is second from left as you sit on bike?

Yes, #2 is on the left as you sit on the bike. Had new O-rings as well as new O-rings in the manifolds as well as new boots from carbs to air cleaner.
Last week I was trying to set the carbs to the highest idle rpm with the air screws and #2 would not change the idle even with the screw turned fully in and as many as 5 turns out. No change.
Also with this the spark plug naturally looks very sooty. Something wrong inside that carb for sure.

[Buffalo Bill]

Have you measured the voltage across the terminals while it's idling, and at 5000 rpm?
You should get high 12Vs or 13V at idle, and almost or more than 14V at 5000 rpm.

[alke46]

Have you measured the voltage across the terminals while it's idling, and at 5000 rpm?
You should get high 12Vs or 13V at idle, and almost or more than 14V at 5000 rpm.

Yes, it passes these tests.

[hillsy]

Plugs 2 and 3 being darker than the others could mean a coil issue - maybe check the coils resistance (both).

[alke46]

Plugs 2 and 3 being darker than the others could mean a coil issue - maybe check the coils resistance (both).

That's what I was thinking also but the 1-4 coil shows 4.6 ohms and the 2-3 coil shows 4.5 so I don't think I have a problem with the coils. But thanks for responding.

[hillsy]

Are the carbs jetted any different for the middle two cylinders? I know the later 1150's had one size up main jet in the middle two to compensate for them running hotter (less fins / airflow than the outer cylinders).

[alke46]

No, all four carbs have the stock set-up -- #95 mains and #15 pilots.
Since my troubles appear to be carb related and not ignition, I guess this thread needs to end. I am going to be pulling the carbs off to see if I can determine what the issue is.

Hoping to find an absolute problem, one which can be corrected so I will have peace of mind when done.

Thanks for all the comments everybody. I will post in the carb forum when and if I can get this issue resolved. Wish me luck.

Larry