Fouling plugs and i have no idea why.

[jchristy456]

ok fellas, http://www.amckayltd.com/carbguide.pdf <------ so after reading this thing like 5 or 6 times i'm still having a little trouble with my bike. i can get it to start but it idles really fast and only when the choke is on. as soon as i turn off the choke it dies. i sometimes i try to restart it and it back fires a bit and sometimes fuel spits out of the back of the carbs. When I pull the plugs and they are fouled. i'm running a 77 650D Bs38 carbs. Pandemonium Hot Rod exhaust. i'm running NGK BP7ES plugs gapped at .028. i'm running an all new ignition from mikes and a HH PMA and e-advancer. I HAVE NOT DONE THE TIMING YET. i cant get it to run long enough for me to try and do the timing. i have all my stock setting in place. And i have all new needles and jets. the only thing i haven't
replaced is the mix screws. i'm working on that. Attached is a picture of my mix screw next to a new one. My compression is pretty good. i'm sort of at a loss. i know i'm not doing something right. A this point i have to ask myself what would 5twins and XSleo do? Please help me XS gods! lol

 

[Paulrxs650]

Check your timing. You can check it statically, which will get you close enough.

 

[pamcopete]

jchristy,

Sounds like you have a lot of balls in the air. Carbs, ignition and charging system. I would suggest that you eliminate the PMA and just temporarily connect the PAMCO red wire and coil to a separate fully charged battery sitting on the floor not connected to the bikes electrical system. Jumper from the batteries negative terminal to the frame and use that as an ignition switch.

You can also try just slightly advancing the timing by moving the PAMCO plate very slightly clockwise from the recommended starting position. If the timing is too retarded, then there is not enough time for the mixture to completely burn so you end up with fouled plugs.

 

[XSLeo]

Generally if a bike runs with the choke on and quits when it's turned off means the idle circuits are not passing fuel.
With the float bowl off, mix screw out if you put the tube on your spray can of carb cleaner in where the mix screw goes and spray it, does carb cleaner come out the pilot jet as well as the tiny holes by the throttle plate?
If not your pilot circuit is plugged.
You don't mention the type of fouling on your plugs. Black and wet is oil, Black, dry and fluffy is fuel.
You mention good compression, how did you check it, by holding your finger in a plug hole or use a gauge? If a gauge what was the readings?
You mention all new needles and jets. If these came in a rebuild kit then they are probably the wrong parts. I would put the stock parts back in.
What are the numbers on your all new needles and jets?
Leo

 

[jchristy456]

XSleo: I just tried your test and yes, I'm getting spray through the pilot jet.
It's a black foul, it's dry but not fluffy.
I used a gauge, 100R and 105L.
I didn't buy a rebuild kit. I bought the needles and jet you spec'd for me.
This is what I got:
1 x #122.5 Main Jet (Pr.) Sm. Round type (48-0209)<----These are the jets I'm currently running.
1 x #125.0 Main Jet (Pr.) Sm. Round type (48-0210)
1 x #25.0 Pilot Jet - (Pr.) - VM22/210 (48-0505)
2 x Needle Jet - Z8 (48-0656)
2 x Jet Needle - 4M1 (48-0657)<----I'm running the clip in the middle slot. Do you recommend me running a different setting?
1 x Fuel Idle Mixture Screw - (76-77 BS 38) (48-5009)

 

[jchristy456]

5twins- i'm trailering this puppy down to fla. on thursday i will be working on this thing for a few days. your test will be one of the firsts. thanks for your help!!!!

 

[jchristy456]

i mean pamco* shit sorry!

 

[NONclow]

it's dry but not fluffy.

.......

Seriously, those comp #'s are a bit low. Maybe leaky valves or rings. Pour a little bit of engine oil, or ATF into the cylinders, retest, if #'s rise the rings are failing/faulty. If no change (and with fuel spitting back through carbs I would expect), the valves aren't sealing.

 

[XSLeo]

The compression numbers are a bit low. If your engine sat very long before you got it, it may get better once it runs a few hundred miles.
Before you go much further with the carbs you should get the mechanical and electrical issues out of the way. Do these things in this order;
Adjust the cam chain tension
Adjust the valves
Adjust the timing.
The first two steps eliminate mechanical issues with valve timing and sealing. This may improve the compression.
The last step eliminate the electrical issues with ignition timing. With the Pamco just follow the install instructions and it should be close enough to get it to run then use a timing light to set it right.
Now once you get those done you may find most of your carb issues are much less.
On the spray test I suggested did the spray come out the tiny holes by the throttle plates as well as out the pilot jets?
On the plug fouling, black and dry indicates fuel issues, black and wet oil issues.
Jetting, the 25 pilots are stock size, the 122.5 mains are stock. A good place to start.
As mentioned if the idle circuits of the carbs are restricted this prevents the bike from idling. Using the enrichener to keep it idling is probably why the plugs are fouling.
One thing at a time. You can't get the carbs right till you have the other things right. Carbs are the hardest part of the equation. Some symptoms from ignition can mimic carb symptoms. Carb symptoms can mimic ignition symptoms.
Leo