Vmax540
VIP Member
1990 Exciter sitting in a warm garage at 55F it takes a fair amount of cranking before it starts and then you need to let it idle for at least a minute or two or it dies instantly if you touch the throttle ? It then barely idles around ~600 rpms then all of a sudden it will rev and you're good to go. once warmed up it idles near 1400. If you stop along the trail for a break sometimes I have to repeat the cold start up procedure and let it idle for a minute or, if I give it gas it just bogs and acts like it's flooded or a fouled plug but, once again all of a sudden, it will rev and away you go. Giving it choke doesn't seem to help it rev. Sled runs good once under way altough, it is very thirsty 8-10mpg. The carbs are clean, new spark plugs and the whole engine is fresh including the seals. I have dropped the mains and pilots, raised and lowered the needles, adjusted the air screw in and out, checked the float height and none of this helped the slow starts ? Thanks for any input !
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1.) carb sync
2.) leaking needle and seat
3.) choke plungers not seating down all the way and making it run rich, check freeplay on plungers should be a good 1/8th of slack in cables, and plungers must seat down inside carbs to seal off orfice inside carb.
The reason it will run after it idles for a time is the plug has gotten hotter and burned off the extra fuel/oil off it. Rich engine has low rpm, lean has high rpm and sticky idle speeds on tach.
2.) leaking needle and seat
3.) choke plungers not seating down all the way and making it run rich, check freeplay on plungers should be a good 1/8th of slack in cables, and plungers must seat down inside carbs to seal off orfice inside carb.
The reason it will run after it idles for a time is the plug has gotten hotter and burned off the extra fuel/oil off it. Rich engine has low rpm, lean has high rpm and sticky idle speeds on tach.
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Vmax540
VIP Member
Thanks again !
siudog
New member
Make sure the choke/enrichener lever is not too tight, plungers may be pulled out slightly. Try moving them with your hand (push them in) when it is having the problem and see what happens. Good luck.
blue missile
New member
if it's the 540 it will be thirsty. my 90 ran 8-10 mpg and ran like a top.
Vmax540
VIP Member
blue missile said:
The Exciters are 570cc ?
racerrob6m
New member
YEP!!
Unless non stock motor, it is a 570cc, from '87 to '93
Unless non stock motor, it is a 570cc, from '87 to '93
Check your plugs in the no start / slow start condition. Then again after it starts but idles poorly. This will tell you a lot about what is going on. Something just isn't right. Personally I would do a crankcase leakdown test when it is cold. Basically block off all extrernal ports and put 5 psi pressue in it through a spark plug hole with a bicycle pump. Then check at minute intervals to see how well it retains the pressure. If it was rich enough to not start semi-cold, it should run very poorly once warm. Does it start just fine if it has set out for a couple hours or more in cold (freezing or below) weather?