'74 -850- mikuni 34 - pazon ign -idle too high

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drones76

drones76

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I just got her running this am. What a feeling. Right now the issue is that she starts with choke after a couple of kicks, but dances across the driveway on the centerstand. It idles at about 5k and will not go down. After a few seconds it is all I can do to cut it off. My kill is not working. :oops: So I have to reach for the key. Oil seems to be circulating into the tank.

When if first started there was a pretty bad smell although sitting for 20 years and breaking the cylinders free with ATF may have contributed.

It has a 34mm Mikuni and a Pazon ignition. I have tried adjusting the screws on the carb and am having the same result. Both are set right now to 1.25 turns out. I am wondering if I have a timing issue.

Thanks for any guidance. It sure feels good bringing the old girl back to life.
 
will it run w/ out the choke? - if not i suspect a manifold leak - make sure the mikuni manifold is tight!! - all 4 screws (!) that bolt it to the head - frequently the 2 screws that can only be reached through the inlet are missing or loose which allows excess air, and the need for choke to be on to run. Try removing carb also and refitting it into rubber inlet and tighting down - sometimes not seated correct
m
 
It does the same thing with choke on or off. I am suspecting an air leak also. I was just outside checking the bolts. They are all tight.
 
almost too obvios to ask, but the slide is all the way down in the carb body isn't it, cables adjusted, needle secure?
 
are you sure carb slide is resting all the way down too? not hanging up on cable and idle screw (not fuel mix screw) is all the way out?
 
The throttle slide and throttle cable/retaining disc may be installed incorrectly in your Mikuni which prevents the slide from going all of the way down and contacting the idle speed adjustment screw....Easy to do..don't ask me how I know this.......... :cry:

Sorry Mike your post was quicker than mine.
 
mikegray660 said:
OldBalz said:
Sorry Mike your post was quicker than mine.
Click to expand...

see those 4 cups of coffee in the am do work!
Click to expand...

I've only had three but the "little woman" did make breakfast for me......She must want somethin' that's gonna cost me some money! :evil:
 
It seems that my cable is the issue. I think it may be for euro bars and it is pulled too tight. There does not seem to be enough adjustment to make it work in its current state. I disconnected it from the throttle at the handle bar and it was a more manageable 2.2k idle. I still have to tweak that down but at least it is not running away.

Thanks
 
drones76 said:
I just got her running this am. What a feeling. Right now the issue is that she starts with choke after a couple of kicks, but dances across the driveway on the centerstand. It idles at about 5k and will not go down. After a few seconds it is all I can do to cut it off. My kill is not working. :oops: So I have to reach for the key. Oil seems to be circulating into the tank.

When if first started there was a pretty bad smell although sitting for 20 years and breaking the cylinders free with ATF may have contributed.

It has a 34mm Mikuni and a Pazon ignition. I have tried adjusting the screws on the carb and am having the same result. Both are set right now to 1.25 turns out. I am wondering if I have a timing issue.

Thanks for any guidance. It sure feels good bringing the old girl back to life.
Click to expand...


That 1.5 turns out is a baseline for IDLE MIXTURE screw settings. NOT what you should be adjusting here (yet). The IDLE SPEED screw is located elsewhere... if it's a VM34 (round slide), then it's on the side of the body near the round vertical slide housing. If it's a TM (flat slide), it's the knurled knob/screw on the left side of the rectangular slide tower. With no load on the engine, a single turn could rev you to 5,000.
 
There does not seem to be any question that your carb slide is not being returned to full down.

To verify this take the air cleaner off and look in the back of the carb to see if the slide is almost all the way down.

You should see, or feel, only about a 1/16 inch or so gap.

Either your bars are too high which is stretching the throttle cable or maybe the cable itself is now pulled away
and jammed in position out of the top of the carb, it should rest nicely inside the carb top receptacle.
 
1up3down said:
There does not seem to be any question that your carb slide is not being returned to full down.

To verify this take the air cleaner off and look in the back of the carb to see if the slide is almost all the way down.

You should see, or feel, only about a 1/16 inch or so gap.

Either your bars are too high which is stretching the throttle cable or maybe the cable itself is now pulled away
and jammed in position out of the top of the carb, it should rest nicely inside the carb top receptacle.
Click to expand...

The quick field test is to let the throttle snap shut (engine off) and listen for the slide clacking as it hits the idle stop screw.
 
concours said:
1up3down said:
There does not seem to be any question that your carb slide is not being returned to full down.

To verify this take the air cleaner off and look in the back of the carb to see if the slide is almost all the way down.

You should see, or feel, only about a 1/16 inch or so gap.

Either your bars are too high which is stretching the throttle cable or maybe the cable itself is now pulled away
and jammed in position out of the top of the carb, it should rest nicely inside the carb top receptacle.
Click to expand...

The quick field test is to let the throttle snap shut (engine off) and listen for the slide clacking as it hits the idle stop screw.
Click to expand...


I ran over to the Brit BIke shop in town. He had a cable with enough play in it and long enough to fit the bars. I put it on and now I have full throttle control. I do get the snap back when I let it go. The idle is still a bit high. I have to go through the Mikuni book and dial it in. I do not think I have any air leaks. I am afraid of running it too lean for too long of a time. Slow and steady now. I have been very deliberate so far. As much as I want to ride the snot out of it, I want to make sure it is ready.

Monday morning at work, my damn leg was sore. I could not figure out why. When I went home that night and kicked it once, the light bulb over my head lit up. The first bike I had, the kicker was busted. Then next one is a Goldwing. This is my first kicker only bike.
 
during your rebuild have you changed the throttle cable? I had this issue with my bike and found that the outer cable was about 1/4 of an inch longer than it should have been, so that the carb slide was not going down fully, as suggested by previous posters. I cut down the outer cable with a dremmel and fixed the issue. Mine only revved to between 3000 and 4000...
 
you can check for manifold leaks, by spraying wd40 around the intake joints, any change in engine speed and there is your leak.

Cheers Richard
 
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