850 74 carburetor malfunctioning

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phliper

phliper

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hey guys

I started my bike this morning to go for a ride. The bike started at 2nd kick. When I pull the clutch, I am able to give gas but when I let go the clutch and try to accelerate the bike goes « beu beu beu ». I then pull the clutch and the motor runs fine.

I cleaned my carburetor yesterday and readjust the screws where they were.

Do you think it might be the air/gas mixture the problem? I tried to adjust it without success.

Thanks!
 
philper,

This is the New 961 Commando forum.
You need to post your question to the Norton Commando (Classic) forum.
Perhaps the moderator can move it there for you.
 
Check the needle is still attached to the slide by the little circlip thingy and not just rattling around loose in the jet.
 
850 74 carburetor malfunctioning
“Cleaned the carb”
With all due respect, tell us WHAT you cleaned in the carburetor. From there, we’ll have a better idea how to help.
The fact you are asking these air/fuel questions, indicates you need to do more.
 
check the choke is open.
check for loose needles.
 
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concours said:
View attachment 12207 “Cleaned the carb”
With all due respect, tell us WHAT you cleaned in the carburetor. From there, we’ll have a better idea how to help.
The fact you are asking these air/fuel questions, indicates you need to do more.
Click to expand...

Sorry for not having been more clear! I was frustrated! Lol.

I have a single mikuni vm34 on my commando. I dissembled the carburetor and cleaned it with carb cleaner. Reassembled it, every tiny holes are cleaned and cleared. Every thing seems normal.
 
You’ll need to revisit the idle passageS, and the pilot circuit. Don’t forget the air passage from the inlet side.
 
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Wait! What? Haven't we've been told Mikuni's are never needing attention? :p
 
Try adjusting needle clip position. I would raise the needle one notch and test ride. Also is the bike warmed up enough, do you use a choke?
When the temps drop as I don't have a choke I need to wait awhile till the engine warms up, plus a lot of revs and clutch slip to get going. (Twin Amals).
 
IF the engine runs normally in all RPM's when the clutch is engaged, then it sounds like something beyond the clutch basket is locked up or dragging. Since engaging the clutch allows the engine to run normally, you know that from the engine to the clutch is working.

It could be as simple as the brake shoes on the rear wheel are frozen against the drum and the resistance snuffs the engine, or your gearbox layshaft bearing self destructed and it's locking up the drive train when you engage a gear.... You need to investigate. I'd check the rear wheel by seeing if it spins freely on the center stand, then I'd pull the plugs, put the bike in gear and see if you can roll the engine over with the back wheel...

Then report back...
 
mikuni been on my bike going on 20 years , all I do is drain it at end of season , never been cleaned , seriously , this does not sound like a carb problem .... from what I read here ...
 
Curious wether you got a solution to your troubles Philiper ?
 
Craig said:
Curious wether you got a solution to your troubles Philiper ?
Click to expand...

Hey Craig, i tested every possibility and it was....

air in the circuit. My step-brother is a mecanics and told me to try to empty the fuel line of air. One of my petcock was not working, so we checked the petcock itself (it was working), and there were small bubbles of air in the fuel line. We purged it and voilà!

Thought you wanna know!

Thank you all for your replies.
 
phliper said:
Hey Craig, i tested every possibility and it was....

air in the circuit. My step-brother is a mecanics and told me to try to empty the fuel line of air. One of my petcock was not working, so we checked the petcock itself (it was working), and there were small bubbles of air in the fuel line. We purged it and voilà!

Thought you wanna know!

Thank you all for your replies.
Click to expand...
By design, it’s self purging.
You had a coincidence.
Glad it’s running.
 
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