Unstable Idle
These techniques will, however, find only the more coarse leaks. Very small leaks are missed by these techniques. So best to do a good job of sealing up the intake. I use the T-bolt [also known as aircraft style] clamps both for the intakes and for the exhaust headers.
Road Warrior
Joined: Sep 2006
Posts: 1,605
Likes: 82
From: nj
Speaking of this problem my 84 does have points and the idle goes up after she gets real hot. The bike checks out okay the the cables not binding and the idle screw goes back to normal position. Now the bike has a s&s carb. Now can the weights be my problem if the idle goes up when she gets really hot not on cool days Oil temp has to be over 200 deg. I am not famliar with the points system and can I visually see if there is a problem I do have a manual for this bike Thanks for your help
Cruiser
Joined: Jan 2008
Posts: 133
Likes: 0
From: Tulsa Ok
The weights themselves don't go bad, they just get sticky. My sporty had that problem when I bought it & I just went ahead & did the Mallory Unilite swap. Might try cleaning them with carb cleaner & using a light lube on them. If there's any burrs lnock them down with some light sanding.
Seasoned HDF Member
Joined: Oct 2007
Posts: 8,852
Likes: 2,494
From: Decatur, Alabama
Those little springs that hold the weights back in there have a tendency to break too. The bike won't accelerate worth a durn if the springs break.
If the idle is going up when the bike gets hot, it is not an ignition problem. It is an air leak.
If the idle is going up when the bike gets hot, it is not an ignition problem. It is an air leak.
Cruiser
Joined: Feb 2008
Posts: 118
Likes: 0
From: Athens, GA
Au contraire... Like any mechanical device, the weights and the pins they ride on can both wear out. The springs can also stretch and/or break. When the unit gets worn, timing can jump all over the place.
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The best solvent to use to check for intake leaks is propane. As a pure gas it has the finest particles. WD-40 is used often because it has finer particles than other choices such as carb cleaner etc. But propane is the best choice.
Even propane will identify only larger leaks. None of the usual choices will ID fine leaks.
If an intake leak is suspected the best is to remove then reinstall the carb and mani, using good o-rings/rubber bands, T-bolt style clamps [also referred to as aircraft style clamps], and a carb support bracket.
The T-bolt style clamps are also best to seal up the exhaust headers.