Another dilemma on my carb rebuild. So got the carb back together, then installed. Went to sync her up using my flow meter and found that #1 was only reading 1000 no matter which direction I turned the #1 sync screw. If I hit the throttle it then shoots up, but then back to 1000. I then removed the carbs, tore #1 down with the exception of the air shut off valve (as I would have to completely take the carbs apart). All looked good......put back together, reinstalled. Started her up, and still at 1000. Thats where I'm at now. Any suggestions? As always, any and all help is most appreciated.
#1carb refusing to sync
- Thread starter popo219
- Start date
- Joined
- May 6, 2008
- Messages
- 6,186
- Age
- 66
- Location
- Lompoc, California
- Bike
- 07 & 12 ST1300A
- SPOT
- LINK
- STOC #
- 8057
Sounds like you have an air leak somewhere?
Did you check to see if the idle jet is free from dirt and/or contamination? Are the idle mixture screws still intact with the factory plugs? If not, check the settings and make sure you have backed out at least two turns. If that does not work, try injecting some mmo (marvel mystery oil) with a small syringe in to the bypass jet while at a high idle. That's about all the ideas I have, but I'm not a carburetor expert, so someone else may have another idea.
I failed to write down the original idle screw turnout, so i set them all to 2 5/8. As far as an air leak, I suppose it could be the bottom most bolt on the #1 boot. I I'll have to pull the carbs so I can get to that bolt.
If you have never changed the carb boots, it would be a good time to do so. On a '97, they are very likely to be brittle and possibly cracked and leaking air.
......+2, since majority of time the major reason for removal is coolant elbow/o-ring replacement or upper hose replacement, and that seems to happen decades apart, those carb boots likely won't re-seal. To add to the mix, the clamps are bottom-stop clamps to keep from overtightening of the boots. With that kinda' age, IMO they are a one-time use thing. These are already a lean-burn motor. No need to add ventilated pistons to the mix
. Not worth it for the less than $50 for four new OEM replacements. I can say after replacing the carb boots with new OEM ones when making the coolant elbow/o-ring repair, doing nothing else, no carb sync or otherwise, the LD mileage went back up to their known 48-52mpg at 'slab' speeds from the previous gradual dropping to 44-46mpg same conditions. Operating temp. idle was rock steady so no re-sync and overall seat-of-the-pants smoothness felt improved
.