Fouled plug on # 2

What are some of the causes?

Checked the main jet, it is clear

It seems to be getting a spark .

I checked the valve clearances and they are right where I set them.

When I get home I'll check the compression again but when I checked earlier they are all above 110 /cold.

I have one day to figure this out before the bike ships out to Califoria :pinch:

JD

I’ll make 2 assumptions –

The fouling is caused by fuel; not oil.
The carbs are squeaky clean.

Given that, here’s my list of possibilities – obviously, there may be others.

- The fuel level may be set higher than spec or the float valve may be sticking open intermittently.

- If you have a vacuum actuated petcock it may have a damaged diaphragm. There have been cases where the damaged diaphragm allows fuel to pass through the vacuum line that is attached from it to the #2 carb. If this happens that carb will tend to flood the cylinder depending on how bad the diaphragm is damaged.

- The enrichment mechanism (choke) may not be working properly and could be sticking in the choke “on” position for carb #2. Check to make sure the little plastic collar on the carb that the choke lever raises isn’t damaged and works properly when the choke is operated.

- If your carbs have air screws maybe the screw is turned in too far.

- If your carbs have pilot adjusting screws maybe it is turned too loose.

- The jet needle could be set in the wrong clip.

- The jet needle could be bent or other internals could be damaged.

- The main jet could be loose or fallen into the carb bowl (this actually has happened to some folks), but it sounds like you already checked it.


Ed

Ed you amaze me , I checked the float levels this morning and checked the main jet this afternoon ,
when I drained the bowl I noticed that the petcock was still seeping gas, I never thought about the vacuum line being attached to the #2 carb .

After I found the seeping I looked on bike bandit and found that all the parts to rebuild the fuel tap are available.

I did clean the carbs pretty good inside and have replaced all the gaskets and O rings, we did not get the rebuild kits.
I do not believe it is oil related, I sure hope not.

Tomorrow I'll run some more tests and see if gas is coming through the vacuum line, I thought that I had seen some wetness earlier.

Also I have been using a manual for the 77 650 and the carbs are different from the B2's, there is no pilot screw inside the carb.

But there is a screw on the out side that appears now to be the air passage plug, I had it confused with the pilot screw and was told somewhere that it needed to be turned out between 1 1/2 to 2 turns.
I have it set at 1 3/4 and I'm wondering if they are out to far :blush:

Thanks for all the suggestions, Zach will have to deal with the petcock out West but now I have a good punch list.

JD

The air screws should be ok at 1 3/4. The book calls for 1 1/2 turns out for the 1978 model (2 turns for the '77) after seating LIGHTLY. Be sure not to tighten those screws at all, that will damage them (they are pointed). Also, remember that the air screws adjust the air that flows, so as you turn them out (counter-clockwise) they make the mixture more lean. Given that, I doubt that they are the problem at 1 3/4 turns out. Ed

Well what do you know , the diagram is shot ! along with all the other rubber bits I suspect.

When I got home from work I put the tank back on and fired her up , lo and behold the vacuum line was filling with gas and headed towards the # 2 carb and to think that I was pissed that he wanted to go with a clear vacuum line over the black one I found :laugh:

I wish I had posted a day earlier I could have save myself some time checking Valves :pinch:
Still good by the way

Any way problem solved hopefully and an easy fix for Zach when the parts come in.

Your the greatest Ed !!!!