apexltxgt11
Veteran
I just picked up a vintage ride. Cleaned the carbs and serviced the unit. It seemed to run really well off the start(first 2 days); however now once it warms up it bogs and will hardly pull itself. I can remove the mag side spark plug cap with no change to the way it runs, however if I remove the PTO side it dies. I am suspecting a mag side crank seal; however wanted to ask if I was going down the right road with my train of thought.
The unit has plenty of spark, and new plugs do not help the one cylinder running symptom.
The unit has plenty of spark, and new plugs do not help the one cylinder running symptom.
striker606
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Have you done a compression test on that cylinder?
apexltxgt11
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yes 100 psi in both.
striker606
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K I don't know much about the older sleds but maybe you have a problem with an adjustment on your mag side carb. How do the plugs look? Is the one thats not firing wet? Or lean looking?
apexltxgt11
Veteran
It's a single carb. It does appear wet. If I swap the plug and cap between cylinders the pto side runs. I'm ruling out fuel issue or electrical I think
Sent from my SM-G920W8 using Tapatalk
Sent from my SM-G920W8 using Tapatalk
nbsledder
TY 4 Stroke Junkie
Coil or weak stator.
apexltxgt11
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Coil is new. Unsure about condition of the stator


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Have you posted and registered on Totallyamaha.net forums?
apexltxgt11
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No


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Have you posted and registered on Totallyamaha.net forums?
Way more Vintage guys over on that side of TY.
apexltxgt11
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Pulled the recoil off. Found its oily behind the flywheel. Crank seal it is


Farmer 73
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That is exactly what I had happen on the 340 I own. Man those sleds were simple ran good and so dam reliable!


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yup they where reliable. could be a spark plug cap as well. they some times go out of spec.
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