Rm 125 wont start

[smyers33]

This is my first dirt bike. Yesterday I rode it for a couple hours then it ran out of gas. Put some gas in it, and it would not start at all. Last night I checked everything, made sure it was getting gas, cleaned the whole carb, checked the spark, airfilter was clean. Then after I got done putting the gas tank back on, It fired right up. Ran for about 5 minutes, then I shut it off and started it back up again. Now this morning, It won't start again!!! whats causing it to do this?

 

[Mx yz 219]

sounds like a jetting problem if it runs then shuts off as long as the plug is good and oil in the gas. try playing with the jetting see if that works.

 

[f4istunna]

id get a new plug after all of this also, may still show spark but i've had plugs spark on a few bikes that would fire all the time, changed the plug and they fired right up/

 

[harobiker620]

well i had a rm 125 2004 and simething like that happened to me and we did everything with it and it still wouldnt start then i messed with the ideal a little and it started right up..

 

[Runester]

Pull the plug spray a little starter fluid in there, about a half teaspoon or less equivalant (I use chemtool B12)
and it should fire right up...sounds to me like maybe your rings are going, hows the compression? if its below 100 thats your problem but the starter fluid will still get it going or a good long push start without starter fluid, another way to gauge compression is if its real easy to kick the kick starter the easier the kickstarter goes down the worse the compression when you kick over a bike the harder it is to kick the better the compression (generally)
Good luck,
R

 

[Morvo]

Sounds to me like your floats are stuck causing the needle valve to stay shut, or almost shut, effecting the flow of fuel to the bowl in the carb. Does fuel flow out of the overflow pipe if the bike is tilted all the way over?