Welcome Aboard !

Assembling the choke parts into the wrong carb body is a recurring issue. This is why we advise everyone to rebuild one carb at a time.

Before the choke change was done... if the engine was difficult to start but ran great, then the issue is most likely with the pieces you assembled. You may still have some parts installed incorrectly, choke cables incorrectly adjusted, or pieces installed from another model bike. Mixing and matching of parts on a 40 year old machine is VERY common.

Every previous owner adds their special "something".... even if it's wrong. 😛

What you say is right, so I took my time to take the carb apart again and really paid attention during reassembly. The choke disk is in the correct position. Everything else also looked ok. I lowered the fuel bowl level from 20 to 15mm, put a small rubber plug on the choke brass tube going into the corner of the bowl to disable the choke, checked compression and did a leak down test, changed plugs, checked the spark. The plug is still black and the RPM increases when I turn the mixture screw all the way in. I know I am missing something but what.

Some questions. Help will continue as long as you answer every question.

• Question Number 1: Were the plugs being blackened BEFORE you started this "repair" ?

• Is it one OR both plugs that are being blackened ?

• When was the last time you replaced the air filter and checked the air path through the starter cavity ?

• When was the last time the ignition timing was set at full advance with a strobe ?

• Are the float and float needle certified as being ethanol fuel proof (that is to say, the latest issue) ?

• What brand and grade fuel are you running ?

• How old is the oldest fuel in the system (tank, lines, carbs) ?

• What brand and number plugs are you running ?

• Do you run in-line fuel filters ?

Yesterday I posted answers to all questions plus an idea what could be a problem. The post does not show anywhere. It was done on my PC. I tried again and got an error message. This was done from my iphone.

Sorry that you're having computer issues. Sometimes we are called to "Moderate" files before they can be posted. That is not the case in this instance. There don't seem to be any lingering posts on the forum.

All I can say is restart your computer and your modem, and then try again.

And this time, answer one question. Submit the answer to see if it works. Then Edit your answer to add additional responses. No need to loose everything a second time.

test post, this time with VPN disabled

This is a "test response". 😛

1) Both plugs were very dark from the beginning. Lowering the needles to 2nd position from bottom took care of that.
2) After my "choke fix" only the right plug is pitch black.
3) Air filter is clean and no obstruction in intake hood.
4) Timing at high RPM tested with strobe several months ago.
5) The floats look very old and a bit twisted. Hinge pin has marks on it. Valve looks new.
I ordered new floats and pins.
6) I am only running non ethanol fuel, don't know about previous owner.
7) All fuel is fresh.
8) Plugs are Champion #9. I am using the same in my /5, no problems
9) I am using inline fuel filters.

One thing I noticed during assembly of the choke, there was very little spring pressure when I installed the cover with the four screws. Could it be that because the plates with the small fuel passages are not firmly pressed together that fuel is simply leaking past them and ending up in the carburetor?
It will be at least a month before I can work on the bike again and I will post what finally fixed the problem.

Thanks for the details from your Bing book. I will compare the numbers and also
replace needles and needle jets. Can't tell if I really need to but with a gas mileage of
only 38 mpg it may help. By the way , the carbs do not have an enrichener spring.
When it comes to float position, I just measure the fuel level in the bowl.

• Scot is correct. The needles wear against the needle jet and slowly enrich the mixture. I highly suggest new pairs on both sides.

• If your Bing diagram call for enrichener springs, then install them.

• Bing calls for a specific way to set the float level. The level of the fuel in the bowl directly controls the fuel mixture.

• I don't think "9" is a Champion plug number.

All the best.