86 250sx lacks top end power, what could cause that?

[Deathrocket]

Took my girls 250sx out for a ride after a long slumber.. (like 10 years) cleaned out the tank, replaced the fuel lines and filter, changed the plug, and cleaned out the carb. after getting it running again it has power issues, mostly in the top end, no popping / farting and it is easy to start, but it doesn't have the power it should. what can cause this? thanks folks!

[viking]

sticky rings clean out the piston and ring grooves if its a 2 stroke..
sometimes leaky head gasket or worn rings will give you no power ..
what i would do is get some seafoam from Napa auto parts add a little to the tank not the oil...
or high quality carb cleaner with a amild acetone base for autos
spray up the piston and rings if you can see them through the intake or exhaust port...
,, Best way though take it apart measure your ring end gap and again clean the ring grooves on your piston..
IF this a 2 stroke only if she is a four stroke then dont do it your problem could be the lil springs in your advance under the cdi cover on the end of your OH cam

sometimes those springs dont let the centrifugal force open them properly it will keep your trike motor slugish
because with out proper advanceing / timing will give you crappy no power..
Check un that cdi cover.. or where the advancing is on your SX...

Check valve clearances and change the plug lol

[Deathrocket]

its also running rich, the carb is flooding out. the needle seems to be working, how do I adjust float level? its a plastic float with nothing to bend. thanks again folks.

[tri again]

If it's like all mine, the mice Love to make nests in the airbox or frame
intake air channels.

Bees nests too.

Floats do stick.

I've cheated and blown some sort of 2 stroke or marvels mystery oil into the fuel line that goes into the carb.

The first thing it hits is the float needle and seat.

You may get lucky.

If you do take it apart,
remember there is a teeny tiny spring plunger in the float needle
smaller than a pencil lead that compresses about as much as a spark plug gap.

Sometimes they get stuck.

As far as adjusting plastic float tangs?
never heard of a way.

What some people do is:
put a short piece of see thru fuel line onto the float bowl drain and hold it up to
the carb and it should tell you exactly where the fuel level is.
Gotta open the float bowl drain so it has somewhere to go.

somewhere near the junction of the float bowl and carb body.

x2 on viking's comment.
There's usually some rust dust under the cover by the cam.
I think there are springs in there that get stuck and won't let the plate advance.

Unless I'm thinking about the 200 engines.

[viking]

Well then thats simply your prob then
if its flooding over the overflow tube? ..
yep the floats are sticking clean the carb and a idle pilot jet
take it completely apart..run a very fine wire through the main port and through the idle port .
disasemble the floats take out the seat where the needle sits and steel wool the seat,,
dont change the float level no need too..before putting back together make sure the flaots and needle move freely ,,
But before taking it a part and you see it flooding out the over flow,,
i generally give the carb a quick crack with the end of a rubber screw driver watch to see if its still pissing out..if not thats good if so then shake the hell out of the trike once or twice to see if i can shake loose the problem before ripping apart..
its like a toilet bowl float if its not right the fuel will be pouring in and not stoping it..
its just dirty clean the hell out of it ..
blow it out with air if you have it..
very important to clean the idle pilot to..Again disasemble the carb ASAP
hurry your wasting valuable honda trike riding time lol

[H250SXRdR]

Does anyone know the best oil to run in a 1987 250sx? Ive heard 10w-30 and i read an article a while back to use rotella 15w-40 because its cheap and easier on the wet clutches. Doin the tune up to go riding in the morning. The weather is finally gettin better here in misery.

[AtcFactoryRacer]

I dont agree with what viking said about using a fine wire to clean the jets out, you can damage jets by doing that if you arent careful brass is a really soft metal. In my opinion the best way to clean them is take the jets out and soak them in fresh gas and or use carb cleaner to spray in them then blow them out with compressed air.

[thestud25]

I dont agree with what viking said about using a fine wire to clean the jets out, you can damage jets by doing that if you arent careful brass is a really soft metal. In my opinion the best way to clean them is take the jets out and soak them in fresh gas and or use carb cleaner to spray in them then blow them out with compressed air.

I disagree with that comment. I have worked in several bike shops and we used a metal wire jet cleaning kit manufactured by Moose Racing to clean the jets. It is very similar to a torch tip cleaning kit. I have never damaged a jet in the 18 years I have been using those tools.

[viking]

Oh sorry to tell ya BOYZ SOME carb cleaner can really do damage to a carb aswell,,
it can react to gaskets and orings.
LOL @ Damage the jets NOPE been werking on bikes while most of you were jumping around in yer daddys
nutsack,,
USE the dam wire to clean it because blowing it out with air will not allways clean it out properly

[thestud25]

Oh sorry to tell ya BOYZ SOME carb cleaner can really do damage to a carb aswell,,
it can react to gaskets and orings.
LOL @ Damage the jets NOPE been werking on bikes while most of you were jumping around in yer daddys
nutsack,,
USE the dam wire to clean it because blowing it out with air will not allways clean it out properly

Viking, most intelligent people remove the gaskets and rubber O rings before they start the cleaning process.