Gremlins

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jbruney

jbruney

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Had one pop up about three weeks ago which has caused considerable consternation. It shows all the signs of being overly rich; black on the plugs, popping out the exhaust( both sides, but not always the same time).
Timing Checked - Good 28*
Went through Amals - Good, new Stay up floats & needles - set levels & seating properly - 260 main - 106 needle jet - 4 ring - clip in center - cranks fast & easily, but shortly begins popping & running roughly.
Compression when kicking feels same as always - pull stick in oil tank & no more than usual blow-by.
Turn Air adj. in to 3/4 turn out & popping ceases, but power gone. Bike runs evenly at this point though performs & sounds like a slug.
Spark on plugs is even, smooth & bright orange(Vape Wassell w\NGK BP7-ES) - All is as it was installed and no changes. Carbs show no great signs of wear either & function smoothly. New coils & all connections also.
About to go out and pull carb for eleventy-sebenth time and switch to top ring on needle before I jump into the abyss.
 
This is the problem....I've done it all, and all is as it should be. I'm down to calling a priest or witch doctor....either one suites me.
Right now I'm going to the top ring on the needle....
 
Fuel feed good from tank? No vacuum build up from clogged lid vent?
Air leak at manifolds? What about that little balance tube 'tween mani's?
 
Good flow, new tube, no leak...I've been dancing with this fat girl for two weeks now and been all up her skirts.
 
I recall the Hobot suggested using some grease on carb slides to see if it would temporarily resolve some tuning issues...if so, then suspect air leaking at worn sleeve to bore interface. Resleeve or replace carbs.
 
Popping is usually associated with a lean condition. You say you turn air screw in to 3/4 out and popping stops but runs bad. This would indicate you are having to reduce the air because the fuel is reduced due blockage to get correct stoichiometric mixture, but for the swept volume there just I ain't enough energy, I am assuming we are talking about an idling bike and not when u have it pinned on the highway.
I have mentioned this previously and have had success doing this. If instead of coming at the pilot jet from the fuel side with the number whatever drill bit, tackle it from the float chamber fuel line end. I have found a wire with the right combination of stiffness and bendibility (I have used a gas axe nozzle cleaning tool, thinnest wire) worked into the fuel line carb body, plus loads of compressed air and a bit of carcinogenic carb cleaner seems to work. There is a 90deg bend upstream of the pilot jet that you just can't get at poking through the jet itself without a bit of luck.
 
Steves said:
Popping is usually associated with a lean condition. You say you turn air screw in to 3/4 out and popping stops but runs bad. This would indicate you are having to reduce the air because the fuel is reduced due blockage to get correct stoichiometric mixture, but for the swept volume there just I ain't enough energy, I am assuming we are talking about an idling bike and not when u have it pinned on the highway.
I have mentioned this previously and have had success doing this. If instead of coming at the pilot jet from the fuel side with the number whatever drill bit, tackle it from the float chamber fuel line end. I have found a wire with the right combination of stiffness and bendibility (I have used a gas axe nozzle cleaning tool, thinnest wire) worked into the fuel line carb body, plus loads of compressed air and a bit of carcinogenic carb cleaner seems to work. There is a 90deg bend upstream of the pilot jet that you just can't get at poking through the jet itself without a bit of luck.
Click to expand...
Yes, that fuel pickup port is a real bad one to service. I'm thinking to remove the blanking plug to properly get a straight reach into it. Same with the other blanker at the far side from air screw (removing that one is recommended in the Bushman guide).
 
Senior moment with the choke?
I have a friend who forgets which way is off at the start of each riding season.

Best regards

Esme
 
Idling, highway, in my dreams... I have already shot, blown, thrown, rodded, and poked my way through every orfice and hole in these carbs. There is free flow through everything.
As I said I shall go With the First ring setting on the needle, but first I'll give a final poke & prod to it all after a prayer to the old gods and see what comes of it.
 
I've had it once before the earth to electronic ignition under point cover that is on female male bolt that points screw screw into came loose which caused backfire and loss of power or wouldn't be tank tap filter blocked by chance just a couple of possibility
 
Nope. Went over every earth connection on the bike & added a couple in questionable spots....I don't believe the cap would exhibit signs of overly rich fuel mix even if it could seal well, which it doesn't....Just well enough to prevent sloshing over.
Anyway I'll not lose sleep and shall see what the leanest needle setting offers tomorrow.
 
How much milage on the carbs?

Have you done a WOT main jet test with brand new plugs? If you have and it is still rich, maybe new smaller main jets are in order.

If the plug chop is in order and not rich, maybe the needle jets are worn?
 
Reassembled carbs and the bike is rich,...

Survey says:
- needle clip didn't seat properly in the inner carb body. Pull the bowls and unbolt the jets. Are the needles hanging down evenly? If one is lower than the other, one of them is Effed up...

- you poked the air idle jet clear, but not deep enough to actually poke the jet out. (guess how I know that...) I ended up doing the bushman modification where you drill out the opposite side of the idle jet port on the carb to inspect the jet, which in my case was clogged even though I swore that I had poked it out with a guitar string. Then I threaded the hole and put a set screw in it with blue locktite.
 
as has been asked above, have you put in new plugs? will you now buy new plugs?

not just clean the "black on the plugs" as you describe them in your opening post
 
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