250sx cold start

[Atc_200xman]

Any solutions to getting a 250sx to start in the cold? Primer???

[wonderboy]

Honda addressed the cold start issues by issuing a revised starter jet.

http://www.3wheelerworld.com/showthread.php/164618-Honda-Service-Bulletins-Through-January-1987/page2

Check post #25, I pasted all the service bulletins for the SX in this post. The cold start issue is the 3rd bulletin. I'm not sure if this "Kit" is available anymore, but you may be able to modify your original one. Search on "250SX cold start kit" and you should get some hits.


EDIT: Here you go, FlyingW has this all figured out:
http://www.3wheelerworld.com/showthread.php/150975-85-250sx-cold-start-kit-or-cold-start-mod

[Atc_200xman]

OK thanks. I always heard that you hook all the vacuum lines from the carb together into a four way split and that supposedly takes care of the problem.

[shovelryder]

Drill the start jet out a bit bigger.......Very easy with a finger drill. Just did two of mine and works great.

[redsox]

there is a quick fix for this issue. its called FlyingW. look him up in the search bar. he has a ES/SX/350X carb rebuild tutorial thread that will walk you through it. Or, ship your carb to him and he does it for a small fee. worth every penny.

[dougspcs]

there is a quick fix for this issue. its called FlyingW. look him up in the search bar. he has a ES/SX/350X carb rebuild tutorial thread that will walk you through it. Or, ship your carb to him and he does it for a small fee. worth every penny.

Highly second 'redsox' suggestion..

Since buying one of FlyingW's rebuilds last year I've bought one more and shipped him one of mine for rebuild..

I'll never lay hands on another SX/ES carb again..just to remove and replace! And since he does the cold start update during his rebuilding it's even better!

[Atc_200xman]

Drill the start jet out a bit bigger.......Very easy with a finger drill. Just did two of mine and works great.

How big did you drill it out. I tried that but probably didn't go big enoughf.

[Flyingw]

Drill it to .081mm not inch but millimeters. Its a metric micro drill.

[YTZ drew]

By the look of the 250sx carb, its similar to, if not the same as my '87 TRX250X carb. That machine has always been hard to start in the very cold as well, harder than any other bike/trike/quad I own (and there's 18 machines in the basement to compare to!). Does anyone know if the starting jet mod is applicable to my 250X as well?

[Flyingw]

The TRX250X carb is different. The SX, ES, 350X, and 85 TRX250 are QA series carbs and the only models used in this series. The 250X carb is a QB series carb and is not part of that series.

[YTZ drew]

Got it. The plastic cover over the throttle linkage is what had me fooled. Thanks for the reply Flyingw! One of these days I'll mess with that carb, but right now I'm finishing a KDX175 restoration for a friend, and dropping a V8 in my ford ranger. After that starts the resto of my Tri-Z!

[250sxboys]

Any solutions to getting a 250sx to start in the cold? Primer???

Honda made a cold weather kit that has since been discontinued. What works for us is to remove air box lid and air filter, choke on, then hold your hand over intake tube until machine sounds like it wants to fire. If you hold your hand over the too long you will flood it. This is an easy way to start the machine if your electric start works. We tried changing the plug, checked the valves, cleaned the carb. All of that made no difference.

[Jmoozy27]

If y'all are just referring to the '85 model es/sx the way I solve that problem is just search for an '86/'87 model carb. Mine starts every time and runs like a charm.

[Jmoozy27]

Oh, didn't realize this thread is almost a year old...

[B-1B]

Oh, didn't realize this thread is almost a year old...
Oh Crap! You had me cracking up here Buddy!

[Flyingw]

Hey B-1B, is your namesake for the B-1B Lancer?