1st time prob=frustrated!!!!

Kawiman80 wrote:

Ok guys,
I have a new problem! I keep fouling my plugs on all the cylinders. Thick,black carbon. I tried cleaning the plugs,but no diffrence. This has happened twice now. Battery is fully charged and timing is set. The air mixture screws are out 1.5 turns and runs good,but only fouls at start up after sitting. And also is hard to start after riding(good and warmed up) and stopping for an 1hr or so and then restarting. Please help. It is very aggravating.
I remember seeing this same problem on here,but can't find it.
Thanks,
Mike

1st! Check to make sure that while running, your coils are recieving 13+ Volts at all times (idle/revving).

If coils OK, then...

Fouls plugs black... too rich at idle. Its not the plugs, its your idle mixture.

On carbs with the mixture adjustment screw closest to the engine front of the carb, counter-clockwise (out) = more fuel mixture @ idle.
Carbs with screw near the back/filter side of carb, clockwise (in) = more fuel.

I think you have Mikuni BS34's with the mixture screw on top centre front of carb. (1st example above)

Adjust/move tank so that you can adjust all 4 screws relatively easily.

With engine running, tank aside, turn all your mixture screws out 1/2 turn (add fuel to idle circuit).

If the engine idle immediately drops (watch/hear), your idle circuit is getting too much fuel. This is what I suspect!

Because you are starting at so few turns out already, you will need to go to a leaner/lower # pilot jet.

After installing new jets, set them at 1 1/2 turns out to begin with. Repeat the procedure above, until you find the highest idle. Remember to kep turning all 4 screws equal increments.

Then your good to go!

I'm not suggesting your carbs are your problem. This is just some carb fine tuning info. It's not to debate what anyone else is pointing out either.

The first place to start with any carburetor is fuel level check and adjustment. If the fuel level is not correct, you'll chase your tail trying to get the carbs to respond correctly .

Another common problem is missing pilot fuel screw O-Rings, washers or damaged screw tips. Any / all can cause an incorrect running condition. Very important that those parts be in place and not damaged.

Also, you can't rely on the basic premise that all 4 carbs will want the same pilot fuel screw setting. In theory, yes they would. In practice, that's not always the case. In fact, it's quite common to have want different settings.

The OEM CV carbs were set at the factory on some type of flowbench.

Why?

---

Because of manufacturing tollerences.

When CV carbs were the norm on bikes, it was not uncommon at all to remove the fuel screw plugs and find the screw settings were all different, right from the factory.

The correct setting is the setting that produces the highest idle. You may find that's 2 turns out on one carb and something different on another. It could be 3 turns or 1-1/4. Just depends on the carbs and the overall health of a particular cylinder.

The pilot fuel adjustments should be your final adjustment, after fuel levels have been verified to be correct and a good carb synch is performed. ONLY THEN will you truly be able to fine tune the pilot fuel circuits properly.

To do it correctly, you need a very accurate tach or use restricted down carb synch guages. The new electronic guages would be best but it's possible with mercury column guages if you verify their calibration first.

To do that, pick one cylinder and hook up the guage hoses one at a time to that cylinder. This will verify they all read the same, on the same cylinder. Some of the cheaper guages may read differently between columns on the same cylinder. Those kind, you're better off just discarding and buying a good set.

larrycavan wrote:

To do it correctly, you need a very accurate tach or use restricted down carb synch guages. The new electronic guages would be best but it's possible with mercury column guages if you verify their calibration first.

Good pro info man...,

Larry, could you expand on this portion a little?

Specifically, how accurate a tach is required? Down carb sync guages? etc...

Thanks!

Muse,
timing is spot on and spark is good. And it is just on start up.

roy-b-boy-b wrote:

Is this the bike in your signiture. G1? Does it still have the fuelie head?

Do you have a manual petcock or vacum? Roy

I am assuming it is the fuelie head ansd the petcock is a pingle single outlet. I added the petcock,and the motor was already built when I bought it. It also did this with a stock petcock on it.

I think you have Mikuni BS34's with the mixture screw on top centre front of carb. (1st example above)
Tek they are RS34's as indicated on the carb sides. The pilot jet is 17.5's Maybe go to 15's?