1985 250sx

[Tking]

I have a 1985 250sx that wont start very well in the cold weather. It starts on full choke, runs a little then dies. It will do this many times before it stays running. When its warmed up it starts and runs fine with no choke. I would like to keep it in the warm garage for the winter but my wife says her car gets first priority for the garage stall. Is there any fix for cold starting?

[little ridder]

put a 1986 or 1987 250sx carb on it. I recently read that the newer carbs work better for cold starting the 250sx.

[Tking]

Thanks, but I was thinking there must be a simpler lower cost solution than replacing the whole carb.

[zainyD]

Search in the Trikesylvania portion of the forum. This topic has been discussed recently. I believe if you drill out your main jet to .080(5/64" drill bit) that may resolve you're problem.

[tri again]

yupp, lots of headaches.
You're lucky it starts with the choke at all.

Slosh the trike side to side violently to slosh gas in the carb.
Take it off and clean, boil, compressed air, clean cold start jet,
make sure choke piston has full travel..it's an enrichment circuit instead of
the good ol' flapper choke.

There was a cold start recall but replacement jets are impossible to find.
Mine sorta reamed itself out when I tried to remove it with a sheetmetal screw like they say in the factory
bulletin.
Now it starts with 1/2 kick, full choke and warms up normally.

yeah, search key for 'cold start' will give you tons of info.
Mine kept me aggravated for over a year and replacement carbs are not easy to find WITH the choke piston
intact.

[Tking]

Thanks, thats exactly what I need. Ive been struggling with this for years great to know there is a solution to the problem.

[tri again]

Thanks, thats exactly what I need. Ive been struggling with this for years great to know there is a solution to the problem.

Did you happen to see a number on your keihin carb?
like QA 01 or anything?

yupp, I would not have believed that a slight ream on the press in cold start jet would
make such a World of difference.

Mine went from most hated to top favorite.
I even kept a sparkplug on the woodstove so it was HOT and sometimes hung a hairdryer
aimed at the carb before I needed to use it.
Hated to use start fluid but did.
I mean, we use these things on the farm and need stuff to work.
Even got one with a pumper carb that squirts gas into the engine when you hit the throttle..
kinda like a priming choke.
I actually bought a couple more trikes just because this one wouldn't start without
a major pain.

Sounds like you're one the road to hope and a machine that starts they way it should.

[little ridder]

The 250sx starts easy in the cold if you dump about one or two table spoons of gas in the spark plug hole. I often do this to my 250sx because i live in Alaska. Dose anyone know it this is bad for it?

[Tking]

Drjoe171 I live on a farm also and use the sx all the time it just a hassle starting it in the winter when its in the shed, I used to keep it in my heated shop but it's to full in there now.
I did the same thing you did I bought a couple more trikes too because of the starting problems with the sx.
I got carried away with it and now have 7 Honda atc's

[tri again]

Drjoe171 I live on a farm also and use the sx all the time it just a hassle starting it in the winter when its in the shed, I used to keep it in my heated shop but it's to full in there now.
I did the same thing you did I bought a couple more trikes too because of the starting problems with the sx.
I got carried away with it and now have 7 Honda atc's

Yupp,
These things will go where even boots won't.
We have a clay that gets wet and will just take your boots off.
I've been known to go barefoot in that muck just to save shoes and socks.
4 wd quads get terminally stuck imMEDiately.

Anyway, there is hope for that old machine.
I tried to get the cold start jet out with the sheet metal screw like they said in the bulletin and
just by trying that a few times withOUT breaking the carb casting, it opened it up enough. so it doesn't take much.
The very next sized drill bit up?
or what was that? .080" or 5/64ths.?? MAYbe?

I also found an emulsion tube under one of the screw in jets that was plugged with rust muck.
Missed it 2x during cleaning. I forget which one it's under but it's about an inch long,
full of holes (and muck) and can be pulled out with a toothpick.

Eventually just threw the whole carb in some boiling water with vinegar and blew it out with compressed air and
gently blew into all the passages with mouth pressure and a piece of clear fuel line to see where the bubbles came out.
But also had the luxury of comparing it to a known working carb..
Jets can be clean or new but that doesn't mean the internal passages are clear.

Yeah, bought at least 3 more trikes in the time I couldn't figure this one out.
Even had one appear in the driveway when I wasn't looking.
Apparently someone knew I 'collected' these things and they just dumped one off here.

Guess ya gotta keep them under cover or they act like duck decoys and attract more.

Guess I'm up to 6 of the 250 models that I can walk up to any time of the day or night and blast off with a chainsaw
to clear a road or fire extinguisher, so yes, we NEED these things to run.
(plus an orchard full of others waiting for attention)

OEM Replacement carbs usually don't have the choke piston and cable with them.
Some place in Florida (listed on ebay) has a carb for 140$ with a regular flip choke but I wasn't convinced.

Then I got an sx with some aftermarket Keihin with an accel pump and it's a dream.
I posted the carb number on here but could also go look at it again in a couple days.

Love the big reds but only one fits in the truck.
Now 2 sx's fit with room for other stuff so we have to have both types.

Hey, any excuse will do.

Hang in there and I'll check back in a couple days.