Whitetrashrocker
Inmate #952016
Nibbi carbs are good replacements.
VM22 Mikuni Clone Carb Tuning
- Thread starter hmpumpkin
- Start date
Edwin Spangler
Well-known member
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I got a knock off Nibbi thats doing pretty good!
Wicked_Daddy
Burnt Rubber
I like Nibbi as well. I have 2 on 2 different motors and they both perform flawlessly.
If the breather port on the valve cover is breathing, then nothing to do there. I don't have any hoses on mine and they work fine, no drips, etc.
The white smoke/oil burning thing is a mystery (at least to me). I've never seen/heard of a carb that has no oil connection to it have influence on oil burning or creating a white exhaust output.
If the breather port on the valve cover is breathing, then nothing to do there. I don't have any hoses on mine and they work fine, no drips, etc.
The white smoke/oil burning thing is a mystery (at least to me). I've never seen/heard of a carb that has no oil connection to it have influence on oil burning or creating a white exhaust output.
Edwin Spangler
Well-known member
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What did you use to seal the bowl on the 'smoking carb'??
hmpumpkin
diy everything
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Alas, it's not over...
Today I installed a PZ20 carb that I had laying around and drove it around for a while. After a bit of driving, it started smoking again. Same smoke as before. I unbolted the header pipe and the gasket was dripping with oil. I guess there is an oil problem after all...
The only other thing that I can think of it the gas line to the carb. With the stock carb, its a direct line of high-ish quality line. With the PZ20 and VM22, the gas inlet is on the wrong side so i have to do a fuel filter and then a length of cheap line. I highly doubt this is a problem tho...
At this point I think it must be an oil problem. Maybe it was just coincidence that it started when I installed the VM22 carb.
I am, however, still perplexed on a few things.
1.) After installing the PZ20, it was not smoking for a little while. After letting it cool down, I can get another small amount of runtime before it goes again. (idk why this didnt happen with the VM22).
2.) The stock carb didnt smoke after reinstalling it after the VM22. (Granted, I did not run it that much with it installed)
What do yall think I should do? (I could really use some help rn)
thnx
Today I installed a PZ20 carb that I had laying around and drove it around for a while. After a bit of driving, it started smoking again. Same smoke as before. I unbolted the header pipe and the gasket was dripping with oil. I guess there is an oil problem after all...
The only other thing that I can think of it the gas line to the carb. With the stock carb, its a direct line of high-ish quality line. With the PZ20 and VM22, the gas inlet is on the wrong side so i have to do a fuel filter and then a length of cheap line. I highly doubt this is a problem tho...
At this point I think it must be an oil problem. Maybe it was just coincidence that it started when I installed the VM22 carb.
I am, however, still perplexed on a few things.
1.) After installing the PZ20, it was not smoking for a little while. After letting it cool down, I can get another small amount of runtime before it goes again. (idk why this didnt happen with the VM22).
2.) The stock carb didnt smoke after reinstalling it after the VM22. (Granted, I did not run it that much with it installed)
What do yall think I should do? (I could really use some help rn)
thnx
Whitetrashrocker
Inmate #952016
Clean the plug. Or put a new one in.
Run it a little and show us a picture of it.
Edit: cause im dumb.
The last plug pic you posted, I said it looked oily.
Can you do a compression test?
Testors can be rented from parts stores.
I bet a cold test would fail but test OK after you ran it around a bit and the rings get full of oil.
Run it a little and show us a picture of it.
Edit: cause im dumb.
The last plug pic you posted, I said it looked oily.
Can you do a compression test?
Testors can be rented from parts stores.
I bet a cold test would fail but test OK after you ran it around a bit and the rings get full of oil.
Master Hack
Well-known member
Is the crankcase properly vented?
Guess #1 Worn rings could be allowing crankcase to persurize and force oil into the combustion chamber?
guess #2 wrong oil viscosity? Oil gets hot, thin and burned?
try putting some "motor honey" shyt in there and see if it helps.
do a compression test.
Guess #1 Worn rings could be allowing crankcase to persurize and force oil into the combustion chamber?
guess #2 wrong oil viscosity? Oil gets hot, thin and burned?
try putting some "motor honey" shyt in there and see if it helps.
do a compression test.
Denny
Canned Monster
Change the oil to 20w50. Put the stock carb back on and run it until it blows up.
Wicked_Daddy
Burnt Rubber
At this point, I am doing a tear down - check the rings, check the amount of play in the valve guides. No more guessing.
To check the rings, I would remove them from the piston and insert them into the cylinder to test for a tight fit and check the ring gap. I would also be inspecting the cylinder walls for scores, excessive wear, etc. That being said, I never reinstall used rings once removed. But checking them would tell the story anyway. I already went through the valve guide process. If you open it up and see a worn/scored cylinder, that pretty much defines your issue - the motor is toast at that point. If that level of wear/abuse is obvious, the guides and most other metal to metal surfaces are probably out of tolerance as well. Buying a new motor is less expensive than getting it bored/honed/machine all new fitments/guides, etc., unless you're just into that kind of thing.
To check the rings, I would remove them from the piston and insert them into the cylinder to test for a tight fit and check the ring gap. I would also be inspecting the cylinder walls for scores, excessive wear, etc. That being said, I never reinstall used rings once removed. But checking them would tell the story anyway. I already went through the valve guide process. If you open it up and see a worn/scored cylinder, that pretty much defines your issue - the motor is toast at that point. If that level of wear/abuse is obvious, the guides and most other metal to metal surfaces are probably out of tolerance as well. Buying a new motor is less expensive than getting it bored/honed/machine all new fitments/guides, etc., unless you're just into that kind of thing.
hmpumpkin
diy everything
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Ok ummm...weird but good news
I ran it again today with the PZ20 carb. This time I was able to run it for about 15 minutes until there was smoke. I tried it again, and even after a while, there was very little smoke. I was able to actually drive it and man that thing is FUN. I think I am mostly done because it works fine. My guess as to what happened is i overfilled the oil and then put the VM22 on and it was just coincidence that it started smoking right then. After I drained the extra oil, It had already leaked oil into the exhaust pipe. Now it smokes after runnning for a while because the exhaust heats up. I think i have burnt thru all of the leftover oil in the exhaust so thats why its no longer smoking.
I may try to put the VM22 back on, as it is a nicer carb then the PZ20. (i swear if it starts smoking again...
)
Ok since thats basically resolved, I have another question.
How do I make it as quiet as possible? I already have a large muffler on there, so currently the main source of noise is mechanical (clutch, chain, crankcase internals) I have thought of the idea of building a wooden box around the outside with fiberglass insulation (or some other fireproof stuff) on the inside. The problem with that is airflow. Maybe I could cut a hole in the front and back? Idk. Do yall think thats a good idea or is there another idea for making it quiet? (driving past ppl and smiling awkwardly as they glare/smile awkwardly back is kinda not ideal...)
I ran it again today with the PZ20 carb. This time I was able to run it for about 15 minutes until there was smoke. I tried it again, and even after a while, there was very little smoke. I was able to actually drive it and man that thing is FUN. I think I am mostly done because it works fine. My guess as to what happened is i overfilled the oil and then put the VM22 on and it was just coincidence that it started smoking right then. After I drained the extra oil, It had already leaked oil into the exhaust pipe. Now it smokes after runnning for a while because the exhaust heats up. I think i have burnt thru all of the leftover oil in the exhaust so thats why its no longer smoking.
I may try to put the VM22 back on, as it is a nicer carb then the PZ20. (i swear if it starts smoking again...
)Ok since thats basically resolved, I have another question.
How do I make it as quiet as possible? I already have a large muffler on there, so currently the main source of noise is mechanical (clutch, chain, crankcase internals) I have thought of the idea of building a wooden box around the outside with fiberglass insulation (or some other fireproof stuff) on the inside. The problem with that is airflow. Maybe I could cut a hole in the front and back? Idk. Do yall think thats a good idea or is there another idea for making it quiet? (driving past ppl and smiling awkwardly as they glare/smile awkwardly back is kinda not ideal...)
Whitetrashrocker
Inmate #952016
No. Air cooled engines need air flow. Do not build a box around it.
Embrace the awkward looks and just smile as you zoom past.
They are just jealous.
Embrace the awkward looks and just smile as you zoom past.
They are just jealous.
Denny
Canned Monster
Or offer them a chance to drive it so they can be just as guilty of being noisy as you.