I'm uselas with carbs but are the rubbers that join the carbs to the manifolds slightly cracked?
Mechanical mystery
HELP!
Worked on an ‘01 750 for a friend. Plugs/belts/valve clearance check/carb balance/oil & filter/CCW ignition coils, and…he asked me to install a jet kit. I advised against it mentioning the bike was running fine, the plugs indicating things were already on the rich side of the scale. He insisted, so I tossed the kit on.
So began my ‘dumpster fire’ of a job.
Bike ran like shite from the moment I tried to start it.
Off came the carbs and the jets it ran well with went back in.
Now, it starts easily with the choke though you have to fiddle with the choke as the motor warms up to keep the revs below 3,000rpm. as well keeping the motor from stalling. Once warm the motor will hold an idle of 1,100-1,200rpm., but will likely stall in the first few minutes. And…after riding in local traffic for 15 minutes the idle climbs back to 3,000rpm. on its own and will not come down. And yes, the throttle plates are absolutely closing. It acts just like there’s a vacuum leak, or the timing is advancing on its own.
I’ve had the damned carbs off more times than I can recall…no bueno.
I’m thinking it’s something simple I’m not seeing like maybe a mixed-up wiring connection.
I am totally at a loss and implore the brain trust here for advise.
Thanks so very much for any help you might offer.
Mike C.
Worked on an ‘01 750 for a friend. Plugs/belts/valve clearance check/carb balance/oil & filter/CCW ignition coils, and…he asked me to install a jet kit. I advised against it mentioning the bike was running fine, the plugs indicating things were already on the rich side of the scale. He insisted, so I tossed the kit on.
So began my ‘dumpster fire’ of a job.
Bike ran like shite from the moment I tried to start it.
Off came the carbs and the jets it ran well with went back in.
Now, it starts easily with the choke though you have to fiddle with the choke as the motor warms up to keep the revs below 3,000rpm. as well keeping the motor from stalling. Once warm the motor will hold an idle of 1,100-1,200rpm., but will likely stall in the first few minutes. And…after riding in local traffic for 15 minutes the idle climbs back to 3,000rpm. on its own and will not come down. And yes, the throttle plates are absolutely closing. It acts just like there’s a vacuum leak, or the timing is advancing on its own.
I’ve had the damned carbs off more times than I can recall…no bueno.
I’m thinking it’s something simple I’m not seeing like maybe a mixed-up wiring connection.
I am totally at a loss and implore the brain trust here for advise.
Thanks so very much for any help you might offer.
Mike C.
1 - 7 of 7 Posts
Nope, they are in minty condition, as are the clamps. Thanks for chiming in.I'm uselas with carbs but are the rubbers that join the carbs to the manifolds slightly cracked?
I've had flakes of deposits clog the vent circuit in the carb before. Dried fuel residue that closed off partially the vent circuit. I did a complete cleaning of the carb bodies and thorough blow out of the circuit. Problem solved.
2 things usually lead to the high idle problem other than tight or kinked cable. First carbs need to be synchronized. Second check for vacuum leaks. Happened on a 4 carb yamaha I used to own. I made my own vacuum synchronizer. Check Youtube for that.
Nope, both carbs are squeaky clean. Thanks for the suggestion though.I've had flakes of deposits clog the vent circuit in the carb before. Dried fuel residue that closed off partially the vent circuit. I did a complete cleaning of the carb bodies and thorough blow out of the circuit. Problem solved.
Thanks for the suggestion, but cables are in good condition/adjustment and the synch is spot on. I’ve been using this tool for years, it was a garage sale find. Works amazingly.2 things usually lead to the high idle problem other than tight or kinked cable. First carbs need to be synchronized. Second check for vacuum leaks. Happened on a 4 carb yamaha I used to own. I made my own vacuum synchronizer. Check Youtube for that.
1 - 7 of 7 Posts
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