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....was literally a little old man bike, 2900 miles - he sold it to a college kid who dropped it and dented the tank - then sold the bike to me running (but poorly) - invested in a NOS tank and now trying to get it to run properly with no luck.
Symptoms: will not fire consistently on the left cylinder, at idle, will fire about every 5 seconds and puff visible exhaust out (sounds more like a backfire), revved up it fires at about the same rate, enough to slightly warm the pipe, cylinder is getting fuel but possibly not enough? doesn't soak the plug or anything, under load (riding) the left cylinder seems to start firing for a few seconds and the bike surges ahead, then it cuts out, backfiring occasionally, right cylinder seems to run fine, bike responds to choke, but only on right cylinder
What I did to fuel system:
1. cleared out petcock, changed oil in case fuel in crankcase
2. replaced plugs
3. new intake boots with o-rings
4. new o-rings on the balancing ports
5. cleaned carbs in ultrasonic cleaner
6. checked slides for stickage, they are fine as are diaphrams
7. cleaned out all jets, passages, replaced idle air screw o-rings and set those at factory setting
8. set floats at level specified in the manual, apparently GS450's are different than literally all the others
9. with an electronic balancer on the carbs, the carbs appear to be drawing equally, spraying brake clean around carbs while running showed no obvious air leaks
What I did NOT do to fuel system
1. take apart the choke plungers (critical mistake?)
Valves:
1. checked these, they were on the tight side but within spec, both cylinders were the same
2. compression: both cylinders the same - within spec
Bike was still doing the exact same thing, so I went after the electrical system:
1. Both spark plugs seemed to have a fat spark with the threads grounded on the head, nevertheless i replaced the left coil with a good used one. no effect. Unplugged every connector in the ignition system and cleaned with contact cleaner and re-plugged in
2. Replaced pickup assembly with an other from a known running bike, no effect.
Questions:
1. Does this sound like a fuel or electrical issue? Anything I missed in the carbs? Is there an easy way to test the ignition box to see if it is failing? (odd way for one of these to fail though, intermittent spark on one cylinder) - plus, i believe the spark looked fine with the plug out and grounded.
I am at my wits end, the bike is a fabulous creampuff with only 2900 miles and will make someone very happy but after having the carbs off 3 times i am ready to chuck it in a lake.
Keith
Symptoms: will not fire consistently on the left cylinder, at idle, will fire about every 5 seconds and puff visible exhaust out (sounds more like a backfire), revved up it fires at about the same rate, enough to slightly warm the pipe, cylinder is getting fuel but possibly not enough? doesn't soak the plug or anything, under load (riding) the left cylinder seems to start firing for a few seconds and the bike surges ahead, then it cuts out, backfiring occasionally, right cylinder seems to run fine, bike responds to choke, but only on right cylinder
What I did to fuel system:
1. cleared out petcock, changed oil in case fuel in crankcase
2. replaced plugs
3. new intake boots with o-rings
4. new o-rings on the balancing ports
5. cleaned carbs in ultrasonic cleaner
6. checked slides for stickage, they are fine as are diaphrams
7. cleaned out all jets, passages, replaced idle air screw o-rings and set those at factory setting
8. set floats at level specified in the manual, apparently GS450's are different than literally all the others
9. with an electronic balancer on the carbs, the carbs appear to be drawing equally, spraying brake clean around carbs while running showed no obvious air leaks
What I did NOT do to fuel system
1. take apart the choke plungers (critical mistake?)
Valves:
1. checked these, they were on the tight side but within spec, both cylinders were the same
2. compression: both cylinders the same - within spec
Bike was still doing the exact same thing, so I went after the electrical system:
1. Both spark plugs seemed to have a fat spark with the threads grounded on the head, nevertheless i replaced the left coil with a good used one. no effect. Unplugged every connector in the ignition system and cleaned with contact cleaner and re-plugged in
2. Replaced pickup assembly with an other from a known running bike, no effect.
Questions:
1. Does this sound like a fuel or electrical issue? Anything I missed in the carbs? Is there an easy way to test the ignition box to see if it is failing? (odd way for one of these to fail though, intermittent spark on one cylinder) - plus, i believe the spark looked fine with the plug out and grounded.
I am at my wits end, the bike is a fabulous creampuff with only 2900 miles and will make someone very happy but after having the carbs off 3 times i am ready to chuck it in a lake.
Keith
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