Using a 1972 GT380 petcock with three outlets. Cleaned it up & am using new lever & float bowl gaskets.
Using a new Kawasaki H1 diaphragm kit.
The kit includes the little rubber washer for the diaphragm vent — its a slightly different size the the original Suzuki part.
The kit washer doesn’t seal correctly & gas pours out of the vent when the petcock is flowing.
Switched back to the original washer, which stopped the leak at the vent.
Tested the petcock with a little hand vacuum pump & its working fine.
The diaphragm slowly weeps gas around the mating surface where its screwed together.
Do you need to put a key onto the petcock surface so the diaphragm seals? And what would that mean?
Or what else?
Early GT triple petcock with Kawasaki H1 diaphragm assembly
Moderators: oldjapanesebikes, H2RICK, diamondj, Suzsmokeyallan
- jabcb
- Moto GP
- Posts: 4241
- Joined: Mon Dec 13, 2010 4:32 pm
- Country: USA
- Suzuki 2-Strokes: 69 T350 thru 75 GT750
- Location: southwestern Pennsylvania
Early GT triple petcock with Kawasaki H1 diaphragm assembly
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more
Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
-
- AMA Superbike
- Posts: 1769
- Joined: Tue Oct 14, 2008 6:47 pm
- Location: Blythewood, SC, USA
Re: Early GT triple petcock with Kawasaki H1 diaphragm assem
You've got me. The kit should work. If not it's a bad kit,,,,,,,,,,,,,,,
If you stroke it more than twice; you're playing with it.
Too many bikes, too much time, ENOUGH SPACE, FINALLY! Never enough money.........
Too many bikes, too much time, ENOUGH SPACE, FINALLY! Never enough money.........
- jabcb
- Moto GP
- Posts: 4241
- Joined: Mon Dec 13, 2010 4:32 pm
- Country: USA
- Suzuki 2-Strokes: 69 T350 thru 75 GT750
- Location: southwestern Pennsylvania
Re: Early GT triple petcock with Kawasaki H1 diaphragm assem
I have it fixed.
I used 320 grit sandpaper on a flat surface to give petcock surface just a bit of key. Only did the wet side.
Lightly tightened the diaphragm screws & installed the petcock.
It barely leaked a smidgen so I tightened it a bit more & its now fine.
Perhaps some residue from the old diaphragm prevented a proper seal with the new one & sanding eliminated the residue.
The H1 diaphragm + o-ring worked fine.
There is a little air vent in the diaphragm chamber. Its sealed with a little rubber washer. The OD of the washer in the kit was just a little too big but that wasn’t a problem because the original one was fine.
I used 320 grit sandpaper on a flat surface to give petcock surface just a bit of key. Only did the wet side.
Lightly tightened the diaphragm screws & installed the petcock.
It barely leaked a smidgen so I tightened it a bit more & its now fine.
Perhaps some residue from the old diaphragm prevented a proper seal with the new one & sanding eliminated the residue.
The H1 diaphragm + o-ring worked fine.
There is a little air vent in the diaphragm chamber. Its sealed with a little rubber washer. The OD of the washer in the kit was just a little too big but that wasn’t a problem because the original one was fine.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more
Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE