Very Hard Starting Dirtbike? - Snowmobile Forum: Your #1 Snowmobile Forum

WEATHERBY460 · 03-12-2006, 06:34 AM

1990 rm250 2 stroke.

new piston, rings, gaskets, porting job by eric gorr, boyesen power reeds, 40:1 premix, br8eix spark plug, runs pretty good when i can get it started and spark plug looks great.

spark I am not sure.......i have spark, but not sure if its the brightest spark I have ever seen.

If I roll it down a hill, it seems to fire right up, but to kick start it is almost impossible, sometimes it will fire, most times not....please give me some ideas.....eric gorr suggested stator.....but before I spend $130+ on that old of a bike I wanted second opinions...thanks.

SnowRida · 03-12-2006, 08:07 AM

You should consider running a mixture of 32:1. I believe you should run a br9iex (iridium) in that bike. What size is your jet?

WEATHERBY460 · 03-12-2006, 09:05 AM

ohmed out the stator...read fine as called out in the clymer manual.

ohmed out the ignition coil and read 11,000 ohms compared to 5,000-8,000 as called out in clymer.

could this be my problem?

the pilot jet is a 50 for the tmx carb
if I run a 9...wouldn't that be colder?

anything is worth a try...i will go try a 9, thanks for helping.

WEATHERBY460 · 03-13-2006, 02:35 AM

**smallengineguy** · 03-13-2006, 05:21 AM

Replace the coil if it's out of spec.

WEATHERBY460 · 03-13-2006, 12:48 PM

DO you really think that could make it that hard to start? (coil?)

**smallengineguy** · 03-13-2006, 07:56 PM

Since that supplies the spark to the engine, more resistance=less spark.

WEATHERBY460 · 03-14-2006, 04:45 AM

GOOD POINT!

letitsnow · 03-21-2006, 04:49 PM

i take it your on dirtrider.net too? if so check out the jetting stickies there, they have a procedure to tell if your pilot is to large or small that involves playing with the airscrew until you get the highest idle, the position will tell you whether to go bigger or smaller.

WEATHERBY460 · 03-22-2006, 10:00 AM

THAT WAS IT......

i had the wrong spark plug cap on (and basically using the wrong spark plug too)

I put on a 1 ohm resistance cap on and a non resistor spark plug, and the bike fires on the second or third kick everytime.

It picked up a lot of noticible power too.

Thanks for the help.....

Now I am going to work on the jetting................................

shawnyD · 03-22-2006, 03:55 PM

remember, a 2 stroke in 40 degrees has different jetting than the hot summer months. winter-more gas summer-less gas. i try to find a happy medium when bikes come into my work so they dont come back 2 months later saying there is less power than before

WEATHERBY460 · 03-22-2006, 06:02 PM

any idea what shops charge to jet a dirt bike?

At full throttle, it seems lean, but eric gorr in his book recommends to go leaner on the main jet...usually he is right, but didn't want to hurt anything.

shawnyD · 03-22-2006, 07:22 PM

its 17.50 for 4 strokes and 22 for 2 strokes where i work. ive never seen anyone bring in their bike just to get it jetted though. these prices dont include parts. so its at the most a 35 dollar job at the shop i work at. last one i did was on an old rm 125 and the kid got charged 28.50.
its a 10-15 min job for me. it shouldnt take you more than an hour. it costs at the most 5 bucks per jet. you will need anywhere from 3-5 jets, or if you can find someone on a forum with the same setup as you, ask what they are running and you only will need two.
its really easy to do though, u should get a jet kit if ur a beginner. but those are like 50 bucks. its actually cheaper to a shop. with the kit u get like 5 jets that a designed for ur machine. a lot easier than guessing what to get

and for the lean wot, it shouldnt do this, less gas=less oil=less lube=more heat=not good. it does give more horsepower if u jet it on the leaner side but i dont know anyone that recemends that