One final issue to resolve: stutters/stalls/misses under power after a while.

[jrobertfox]

Ok here is exactly what happened.

• Started the bike, ran fine, good oil, seems great, short ride… everything great!
• Took a drive home, got a little lost, ended up doing about 37 miles to home. 2 hours or so tooling around back roads. WORKED GREAT.
• Mile like... 35, right near home, under normal acceleration, a feeling of power loss starts.
• Gassing eventually causes it to stutter a bit.
• Stalls on side of road. Have trouble getting it back started.
• Have to keep throttle on and ride slow through 2/3 gear or it will stall
• Stalls at stop sign.
• End up pushing it into garage (good thing it happened so close to home)
• Now won't start, seems like no spark.

From other posts I've read, it sounds like this could be a faulty vac advance, or wiring related to that? Perhaps just a loose connection in the wiring?

[dpotter58]

not to be a smart ass but you didn't run out of gas right? If not, drain the float bowls into a cup and look for trash. Sounds like you weren't getting fuel. You were the one with the overflowing carb right? sounds like you may have crap in the tank. Do you have fuel filters on the lines?

[jetmechmarty]

It won't run with a dead battery. Check it first. If it starts after it returns to cold, you may have faulty coils.

[jrobertfox]

brand new battery, filters on the petcocks looked in good shape. i bet i got some **** into them... it's sounding like i'll need to rebuild those mothers.

[jrobertfox]

what's the preferred carb rebuild kit for a 79 special?

[donebysunday]

what's the preferred carb rebuild kit for a 79 special?

Clean the entire fuel system, tank and the carbs save the kits for last effort.
Maybe change the lines and check the petcocks for little bits of rubber and crud and hang the fuel filters low so as to act as a sediment bowl.
Just for fun pull the float bowls without draining them and see what's in them floating around on the bottom. Might want to leave them sit for some time to let the little bubbles of water collect/settle so you can see them.

[James England]

There are small hemispherical filters above each float needle valve. ie 4 in total.
If you have had contamination from the tank, then these may be blocked.

The only sure way to sort things is to remove the bank of carbs from the bike and clean them. As I mentioned in your other thread (why do we have a new one??), carb cleaning is the same thing four times over. It's not as daunting in reality as you may suppose.

[3Phase]

If the battery didn't run down, the tank vent in the filler cap could be plugged. When the vent gets blocked the outside air can't bleed into the tank to replace the fuel flowing into the carburetors.

If the engine loses power and stalls, then after it's restarted it keeps stuttering and stalling until it finally quits running and won't start any more, open the filler cap and listen for air rushing into the tank.


.

[jjz28]

Just to let you know, these carbs are very easy to take apart and clean and you will probably not need a kit, just clean them. Be easy with the floats and don't bend them or squeeze on them.

[skids]

Try switching to Prime when this happens. I have two standards that do that. I believe that vacuum is weak at certain rpms and perhaps not enough to keep one of the petcocks open all the way. If you have the special, it would affect all 4 rather than a pair of cylinders.