Cafe Racer Forum banner

1977 Suzuki gs750 cold cylinder

2164 Views 37 Replies 6 Participants Last post by  TrialsRider
The bike has one cold cylinder on the far right of the four. It gets spark but I’m not sure how it’s not getting gas or air. The bike is having a loss of power and I believe this it, I’ve been debating on getting new carbs but I don’t think that would fix this.
1 - 3 of 38 Posts
Probably the first thing to do would be adjust valve clearances.
Suzuki only use 0.001" to 0.003" clearance and tight or burned exhaust valves are a possibility.
Being 'shim over bucket' they were rarely adjusted at correct interval after first year or two.
It's a real good idea if you find any where bucket can't be rotated with cold engine to set things at least 0.001" larger than stock as it will close up within a few hundred miles. (don't go too large though as if you rev it too hard the shims can get 'spat out' and pretty much destroy head)
Seeing base circle of cam scuffed is also a dead givaway that clearances got too tight
I guess OP just want's to play with carbs rather than fix any real problem.
I did this work professionally in a Suzuki dealers in the 1980's and the far left carb is the one that usually gives problems due to bike being parked on side stand.
The most common cause of a cold cylinder was always valve adjustment, but, of course, people are 'afraid' of doing it so it doesn't get done (plus the gasket was pretty expensive even in 1980, around $23.00 from Suzuki)
The far right carb could easily be oxidised internally as it would 'dry out' sooner than the others if bike is left on side stand for many years so cleaning may be a good idea but as carb removal and replacement with stock air box will probably be 'difficult' without buying new manifolds and air box to carb connectors I would avoid it until everything else is checked
See less See more
  • Like
Reactions: 1
TrialsRider, the accelerator pump (usually on #2) is for acceleration, the air cut valve is to prevent after-fire on deceleration and is 'automatically' operated by intake vacuum
  • Like
Reactions: 1
1 - 3 of 38 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.