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Thread: Shocking driving and high irregular idles Reply to Thread
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  Topic Review (Newest First)
07-15-2019 09:45 PM
Spockster
Quote:
Originally Posted by Panarock View Post
I ordered some parts for repair, last thing I'd want some advice on. If the petcock vacuum seal is broken could that also cause the air leak?
It's possible, but the most usual problem is gas flowing through the vacuum line into the carb. It makes the mixture rich, and keeps flowing even with the petcock and engine turned off, then it fills the crankcase with gas.
07-15-2019 04:45 PM
Panarock
Quote:
Originally Posted by Spockster View Post
Quote:
Originally Posted by Panarock View Post
I opened my carb and saw gas in this piece its part of the rear carb. Is this suppose to be a vacuum? Or should gas be in here? The front one was dry and never seen gas in there.

That's the coast enricher. I don't think there should be gas on that side of the diaphragm. It works off vacuum, the diaphragm opens a port on the inside and allows a small amount of fuel into the mixture on deceleration. Could be it's leaking through the diaphragm. Could be the source of the air leak too.
I ordered some parts for repair, last thing I'd want some advice on. If the petcock vacuum seal is broken could that also cause the air leak?
07-15-2019 08:47 AM
Spockster
Quote:
Originally Posted by Panarock View Post
I opened my carb and saw gas in this piece its part of the rear carb. Is this suppose to be a vacuum? Or should gas be in here? The front one was dry and never seen gas in there.

That's the coast enricher. I don't think there should be gas on that side of the diaphragm. It works off vacuum, the diaphragm opens a port on the inside and allows a small amount of fuel into the mixture on deceleration. Could be it's leaking through the diaphragm. Could be the source of the air leak too.
07-14-2019 02:39 PM
Panarock
Quote:
Originally Posted by Spockster View Post
I tend to think so too, except we've gone from revs spiking at idle, to erratic revs when throttled, to now erratic and un-driveable at any rpm.

Edit: You might go back and try the spray test again, using something flammable this time.

Starting fluid, unlit propane torch, carb cleaner (but not brake cleaner).

If you do use propane, do it quickly to avoid gas buildup, but be sure to go all around the sealing areas.
I opened my carb and saw gas in this piece its part of the rear carb. Is this suppose to be a vacuum? Or should gas be in here? The front one was dry and never seen gas in there.
07-09-2019 12:49 AM
Panarock Will airleaks for this problem only occur inside the carb upto the connection with the engine? If that's the case I might further inspect the carbs to see if I missed anything now that their out

Edit: I did found out that the rubber seal in the petcock has had its time, it continuesly let's out gas. Could this be the problem? With the seal I mean the one that let's through gas if a vacuum pulls on it (the middle tube from the petcock) , that one now let's through gasoline even without a vacuum(the seal)

It's not leaking the seal is just in a state of always vacuum if u know what I mean.
07-08-2019 10:12 PM
Spockster I tend to think so too, except we've gone from revs spiking at idle, to erratic revs when throttled, to now erratic and un-driveable at any rpm.

Edit: You might go back and try the spray test again, using something flammable this time.

Starting fluid, unlit propane torch, carb cleaner (but not brake cleaner).

If you do use propane, do it quickly to avoid gas buildup, but be sure to go all around the sealing areas.
07-08-2019 06:51 PM
TonyO I still favor an air leak somewhere. Spark and gas variations will not make RPM's rise unless there is increased airflow.
07-08-2019 06:47 PM
Spockster The diaphragms are indexed and seated correctly?

I'm running out of ideas. If it's not fuel, you could take a look at the spark and see what it's doing.

Take an old plug and check each wire. Start it up and see how well it sparks, and what color the spark is.

Edit: See what happens if you pull the choke while it's running.
07-08-2019 01:57 PM
Panarock Alright, I checked the diaphragms, and they look brand new.

Also the motorcycle is undrivable now, what is shown in the video is happening even when the bike is cold. And at all rpm ranges.

Any ideas?
07-07-2019 05:19 PM
Panarock I'll report back after work tomorrow. gotta use the bike once more before i can take the carbs out and have a look.
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