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1986 Yamaha Moto 4 YFM228 bogs down under load

chuckcnm

By chuckcnm
in Yamaha ATV Forum

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chuckcnm Rookie

chuckcnm

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I have a 86 Yamaha Moto 4 YFM228 that bogs down under load, seems to improve as I go to a higher gear. Does not die but just no power.

new plug

new coil

new pistons and rings, was doing this before a replaced them.

Any ideas

 

quadmaniac Mentor

quadmaniac

Posted
Posted

Carbon fouled is usually from an overly rich fuel condition. I would put a new plug in it, run it to see if that caused the issue. But more than likely your carb needs an adjustment or rebuild. Also check your air filter, because if its clogged and dirty, you can get an overly rich fuel condition.

gears Contributor

gears

Posted
Posted

Exhaust can be clogged too. Did you mess with the needle's clip setting on the carb slide? Does turning the choke on while riding change anything? See if running it with the aircleaner lid removed changes anything - could be restriction in the intake tract ducts (mouse nest) going to the airbox.

chuckcnm Rookie

chuckcnm

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I have ordered a rebuild kit will wait till I get before I open it up. Only setting I have mess with is the idle screw. I have been thinking about the choke, will try that tonight. I did pull the air filter off and I am still getting black exhaust and I put in a new spark plug.

Thanks ALL will let you know what I find.

 

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