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'87 250x bog
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Posted by: motob

Hi, found this site, lots of good info. Tried search but couldn't find what I need.

Just bought a 87 250x for my wife. Fines fine down low but bogs
then pops. Figured jetting? I now own every Kehien jet from 145-172 (172 for my cr). Checked vavle clearance-ok, timing-ok,
went thought the wiring looks ok. Have not opened the motor yet
but runs clean. Now this quad has a carb on it that likes Identical
to a 87 xr200. I don't know if I should open the engine and inspect or thy to find maybe a 300ex carb.

Also someone in the search said something about a revese rev limiter that sounded like my problem, but don't know which wires to check.

Wifes ready to sell, I say TLC

Any suggestions would help

Brian

Posted by: bradley300

does it bog or cut out? take off the stator cover and make sure the stator is not loose.

tell us what exhaust,air filter and any motor mods you have. also, what is the stock jets and what do you have in right now, and how does it run

Posted by: motob

Sorry no Idea what has been done the the engine. There is a supertrap exhaust, think the header is stock. I put a new uni filter on.
I would say it's a bog, if I hold the throttle when it bogs the bike dies, if I let off it will pop and idle. Shows lean right? Old plug was coffee brown. New one a shade litter but alot newer. Right now there is a 155 main, can't remember the pilot, needle is middle clip, air screw 1 3/4 out.
And does the same.
When I bought it a month ago that is how it ran w/ a 148 main. Tried almost all mains up yo a 172.
Forgot to add, with any main in it bittom to mid is fine and startson the 2-3rd kick.
I have not checked the stator, and won't be able to till tomorrow.
Thats gonna be done asap though.

Thanks Brian

01 xr88 sons- now- mine
00 kx65 sons
97 cr250 mine
87 trx250x wife
87 xr200

Posted by: bradley300

the bogging is a too rich main i would suspect, if you took off the air box lid, how does it run? better? the popping when you let off is a too lean pilot jet.

maybe another 250x 'er can tell you what jetting they are running with a pipe and air filter.
also, how big is the header? i am almost posistive the supertrap system is a full system only. if its the stock header, it is TINY, and you would be able to tell its a stocker

Posted by: bwamos

Main sounds really rich to me (assuming it's the stock carb).
I'm only running a 142 main on my big bore 330cc 300ex.

After leaning up the main jet (if it doesn't work) you may want to rent a compression tester from an autoparts store. That will tell you if you have leaky rings or valves.

I'm betting your just really rich on the top.

I know you're saying your plugs are a light brown.. but if your so rich on the main and it's killing the engine.. you never get a top end plug test.. so your only getting your plug readings from 10%-50% throttle.

Takes about 15-30sec of full throttle under load and killswitched w/ the throttle kept full and clutch pulled in until you stop and the engine is stopped, (no engine braking) in order to get a semi accurate reading.