i just purchased a 87 trail boss 250. IT has a couple issues for its age but is in otherwise great shape.

I have 2 questions. First i have a bogg in it. it idles fine but will only go about 15. I am thinking either carb or clutch at this point.

It hasn't been run in 3 years. The gas has been drained, and i ran seafoam through the carb. it is getting better but not great. should i just wait.

what should i look for on the clutches?
Should i look anywhere else?


2nd part is the 4 wheel drive on this unit. Is it always engaged? I don't see a on/off switch like the newer models? Is this right? Do the hubs automatically lock when the rear slips?


Does anyone know what primary and secondary springs it should be running? Also what belt number?

 

wouldnt hurt to pull the carb off to clean it. also could be badbuttons in the secondary thats work out. wouldnt hurt to take cover off to take a peak and maybe check and replace the belt if need be. imo

 

i tore the quad apart. it will not revv up even with the belt off. same symptoms. bogg at wide open throttle. i checked the carb and it looks good. cleaned it all up and same thing is happening. any ideas?

i checked the primary clutch seal. sprayed wd40 in it while on and the engine did not rev, so i am assuming the crank seal is still good.

 

Could be the reverse speed limeter, its mounted under the fuel tank up high under the frame tube. It can be disconnected by pulling the green wire I think.

 

how does the spark plug look? is the air and fuel filter clean? if you were to pull the choke and try reving it up does it help or hurt? this would give you an idea if its needs more or less gas. imo

 

pulling the choke has no effect on it.

I don't see a fuel filter. the spark plug is brand new, but wet after it runs for awhile.
idles forever just fine.


the fuel line doens't seem to have a fuel filter anywhere.

 

does anyone know for sure what wires to unplug for the speed regulator module? i will try that next. Everything else seems perfect on the atv.


also how does the 4x4 work with these quads. i do not have a on/off switch like the newer models.

How do i change/check the hub oil on these. Any other maintenance tips for a older 2 stroke?

What about primary spring colors for better perfomance? Are stock springs the best on this quad? Thanks for the help

 

did you pull both jets out of the carb and clean/inspect them?
with no fuel filter i'd be looking at the carb again
and your stock clutch spring is fine till it goes at least 25 lol

 

i pulled the jet out of the bottom of the bowl. Where is the other one?

 

this is a 400 carb but it should be the same , if you removed the main jet and its clean your prolly ok the pilot jet controls idle to 1/4 throttle, the main does the rest with the long jet needle controlling the midrange