got a fourstroke!!! 250R problem

[rideREDrider]

Hey I got a question for you mechanics out there

i got a 250R with a 350X engine that i just bought a couple days ago, and it smokes really bad. The guy that i bot it of of said that he just got the top end rebuilt and that it just smokes because the rings didn't set up yet. But then i ran it and it went though about a half of court of oil in a small amount of time. But it didn't foul the plug??

Do you know what my problem is? Do I need new rings or what???? Any help is greatly appreciated.
:confused: :huh

[4TraxRider]

I'm pretty sure you'll need a new piston and sleeve, and to go over the valves. Sounds like the guy never really did anything too it.

[MotoX3]

sounds rigged:eek2: ....can you get us a pic

[remlapr]

Your getting oil in the chamber one way or the other, either from the bottom or the top. I would have someone pull the head and check the valves and seals. If they look good then maybe he did just redo them and you are O.K. there, but you need at the very leave a hone and new rings. Why did you buy a quad that was smoking like that in the first place???

[ReconRider25]

if i were you id ditch the 350x motor and find a 250r motor to put back in it.

[Martin Blair]

yeah put a 250r in it why would you put a 350x motor in a 250r anyway? :rolleyes:

[JTRtrx250r]

Uhhhhhhhhhh for an RX conversion? gee I dunno:rolleyes: lol

Yeah, why did you buy it if it smokes?:confused:

[rideREDrider]

i bought it because it was dirt cheap. i bought it for 1800, and i figured it had at least $3000 worth of after market stuff.

[Moded86R]

Like the other said sounds like it's time for a top end rebuild.Bore,new piston and rings.And your good to go.


I haven't riden a RX conversion.But I have rode a 350x and a moded 92 250x with a race built 350x stroker motor in it.(It was my buddies brother's and he didn't know to much about it.But his dad said it was a stroker.


After kicking it for ever.She finnally fired to life.I let my buddy ride it around for a minute.Then he gave me a spin.That bike was more than a hand full with the short chassis.It had enough torque to life the front tires anytime you want to.


I think a moded 350x motor in an a well setup R chassis would be alot of fun.I think I will stick with my 400ex though.No kick starting.And it's already built.

[ghak99]

Hey man don't listen to those idiots that have never rode one set up like you have just bought. And if you want your money back out of it ship it my way. Anyways, Do a compression check on it and that will give you some sort of a clue of what you need to do to it. I would guess if he really did just go through the top end, he either broke it in totally wrong, or has the ring gaps lined up, or in wrong.

Good luck with your quad!

it could be valve seals, valve seats, piston or rings n othing major, but a pain in the ***, fun ride you picked up

[JTRtrx250r]

chit...I wouldn't mind havin' one myself:cuss:

[rideREDrider]

and it has a lot. its hard and tiring just trying to kick over. its hard to start because of it too. this pennsylvania weather isnt being kind to us either. last time i had it out it was under 10. i noticed that last time too that the muffler was litteraly wet with oil in the end as in it was spitting out oil. it uses as much oil as it dus gas. really!! we put about 2 quarts in b4 we went riding and checked it the next day and it was all goneand we only rode it for about an hour. I'm going to take it to Lost Creek Cycles(Jason #19 Dunkelberger's mechanic) i thikn soon and see what they say. thanks for te input.

we have a quadsport 230 does same thing we cant find the problem and weve changed everything:mad:

[lil400exman]

Originally posted by Controversial
we have a quadsport 230 does same thing we cant find the problem and weve changed everything:mad:
i was looking at one for a spare quad and it just smoked to smoke and i was there when they did the whole engine..........and it was put together right and it still didnt work.............weird huh?:confused:

yeah i dunno wtf we changed heads, cylinders etc....it just smokes

[joedirt]

Did you call the guy who sold it to you.

[JTRtrx250r]

Could it have a bad case gasket allowing it to oil leak into the crank area?:confused: ,

[Jay300ex]

First I would do a compression test, see if is holding compression. It's a fourstroke then the only way oil is going to get into the combustion chamber is past the rings or through the valves.

If it is though the valve he might not have lapped them enough for them to seal properly, or the valve guides might be worn out, or the valve seals are damaged. Either way, oil is getting past one of the valves and then out of the exhaust. You said the plug wasn't fouled, but when you took it out was it wet and oily? If not, then your exhaust valve seal or guide is probably worn. That can be determined when it's apart.

If he reuilt the topend, a lot of people consider that just new piston and rings, bore and hone, sometimes a liner, not the valves. When it's taken apart, if the piston is old, then you were told a lie about it being just rebuilt. If the problem does lie at the piston, it might be to big of ring gaps , or maybe the oil clearance is to big and the ring's arn't seated tight enough.

I just did a topend on a XR200 that smoked like crazy, bored, and did the valve job. When I started it up and tuned the carb, there was just smoke from the rings not being seated all the way, which is normal on a virgin motor :)

Hope things work out for you.

[Jay300ex]

Originally posted by JTRtrx250r
Could it have a bad case gasket allowing it to oil leak into the crank area?:confused: ,

Your thinking of a 2stroke, 4 strokes are wet sump.

[rideREDrider]

a friend of mine has a kart shop and said that they put bigger oil rings in them to get better performance out of them he said that the guy that rebuilt it couldve put too big of an oil ring in it

is this true

[markk]

well its not the rings smoking, and thos old honda's will run forever smoking, but u mabey be able to just bore it and put a new piston and rings in it

[JTRtrx250r]

Originally posted by Jay300ex
Your thinking of a 2stroke, 4 strokes are wet sump. Damn..I had already spaced it was an R w/ a 350X in it:o :o :o ...2 strokes on the brain I guess:rolleyes: :o :D

[Jay300ex]

Originally posted by rideREDrider
a friend of mine has a kart shop and said that they put bigger oil rings in them to get better performance out of them he said that the guy that rebuilt it couldve put too big of an oil ring in it

is this true

I'm not sure what you mean bigger oil ring? Maybe a stronger oil ring expander, but cylinders are machined to exact tolerances according to oil clearance and piston size. A bigger ring doesn't make much sence.

[rideREDrider]

i took it to Lost Creek Cycles last night for his to check it out.

till tell you what was wrong with it when i get it back

[Sportrax10]

Can we get some pics already!! Sounds cool... Although if I were you I would find a nice 250r motor to put in there just because I want an R.

[rideREDrider]

Sorry i won't be able to get any pics of it for a while, because its at lost creek cycles. But when i get it back i will try to get my hands on a digi camera. But i can tell you some of the stuff that is on it so so you have a image of it.

I has maier blue racing plastic
douglas racing front wheels and douglas beedlocks on rear.
cobra exhaust
holeshot tires
pep steering stabilizer
Racing Cam with good compression and good duration
works shocks all around
extended swingarm i think
extended 4+ axle
4+ A-arms
custom airbox
Nac's seat cover
East Coast ATV graphics
lone star adjustable shock linkage
moose handlebars
lone star handle bar clamps
K&N air filter
HJE steering column
yamaha throttle
AC nerf bars

i know theres more but im having a mental breeakdown
il post the other stuff next time

[rideREDrider]

Hey I finally got it back from Lost Creek Cycles and it runs great.
All he had to do to it was put new rings in it. he said that whoever did it before didn't know what he was doing.

[Jay300ex]

Originally posted by rideREDrider
Hey I finally got it back from Lost Creek Cycles and it runs great.
All he had to do to it was put new rings in it. he said that whoever did it before didn't know what he was doing.

Yea the ring gaps are suppose to be 120º away from eachother on four strokes, and the rings have to be installed in the correct groove and correct side up. He probably didn't know that, even though it says it on most piston instructions.