My bike won't start when hot.

Hey guys,


I'm new here, but I have a 05 Suzuki Rm-z 250 and it won't start when hot. It has a brand new rebuild with like 8 or 10 hours on it. When cold it will start up 1st or 2nd kick no problem. It seems when I mess with the idle screw, it starts sometimes and other times not. Any ideas?


Thanks, Austin

Check the hot start plunger to make sure it is operating correctly & make sure there is the right amount of tension in the cable.


Also, set the idle according to the specs listed in the manual. A good tach/hour meter will help with that. 

Edited by fulton246

Ok I don't know much about bikes, but the plunger pulls and you can hear it ground back down again like it should. The cable tension feels good too. 


It's just frustrating getting stranded in the middle of a ride and having to walk all the way back or wait a hour.


My bike didn't come with a manuel. Ill have to check into a tach/hour meter.



When you say the tension feels good, do you mean it feels tight? If so, you need you have a little play in the cable -- approx 2-4 mm if I am not mistaken. 


Search online for a service manual. You can prob find one for free on Google -- search for "RMZ service manual pdf" or different variations of that text. 

No loose, but not overly loose. How can I tell what 2-4 mm is? 


ok, i've tried to find one before, but usually they make you pay for it. I'll try again.



Take a measuring device and measure the gap between the hot start lever and the cable guide. In other words, measure the gap between the red lever and silver cable guide in the pic below (you should 2-4mm of play): 



I doubt the issue is with the hot start if you have enough play in the cable and the plunger is working correctly... Pull the carb boot off and check the height of the throttle slide. If you turn the idle adjustment knob clockwise it will raise the slide, counter-clockwise will lower the slide. Check to make sure it isn't too far open or closed. If I am not mistaken, 32mm is a good starting point for the slide height.  

My 04 is the same way. It will start just fine when the engine is cold, but once its warm and I shut it off, I can expect to sit around for the next 10 minutes letting I cool off so I can start it. Its a pain in the ass.

Ok sorry for not replying sooner, but now it seems my dirtbike starts hot first or second kick every time. Do you think the rebuild may have had some type of flaw and now it just fixed itself? It seems that it does start easier when I don't pull the hot start.


Thanks for your time.

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