[Terj]

How’s it goin everybody,

First time posting on here so I apologize if this is the wrong place for this kind of post. But I just recently bought a 2008 crf250r from my brother as it has some issues and he was getting frustrated from it. Got it for a steal of $500 and figured I might be able to figure it out.

So the problem it has is it will start up then immediately die, like immediately. No sputter, no bogging down or anything, just immediately cuts out. This all started from day 1 that my brother bought it it was hard to start, but once started it would run good, but was still hard to start back up. We thought it was just a gunked up carb so he took it to a shop and they went through it completely, fully taking apart and cleaning the carb, valve adjustment and everything but couldn’t figure it out.The only thing they told him was that is has an aftermarket hot start and didn’t know how to adjust it or find parts for it. My brother then looked into it and tried to do a hot start delete, but something got messed up on the hot start and now it’s at the point it is now of starting but instantly dying.

So after doing some research I learned that it has a boyesen QuickStart with the hot start that screws on as the accelerator pump cover. They had no idea what it was and I didn’t even know what it was until doing some research, but it has an adjustment screw and a broken hot start cable. My thought is that possibly that adjustment screw was not adjusted properly, causing the hard starting, and then my brother trying to delete it made it not run at all.

I’m really just spit balling here cause I have very minimal experience working on dirt bikes, but I ordered the oem accelerator pump cover, hot start assembly and hot start cable. I’m hoping this will fix the issue but wanted to get some input from you guys on here as well. Any help is very much appreciated. Thank you!!

[JimDirt]

Welcome to the site !!

That is not a Hot Start , that is a Adjustable Leak Jet , and most likely the issue if the valves are in spec ..... To me they are too complex for a novice carb tuner , and completely unnecessary for most purposes and most riders ... I have messed with them , and they are a pain to get right , and are real temperamental ..

The leak jet controls the amount of gas that goes to the accelerator pump , if the adjustable one is not adjusted correctly the bike will not get that squirt of fuel needed to start and not bog or die every time you touch the throttle , otherwise the massive air volume from opening the throttle will overwhelm the gas flow sucked up thru the main jet and the bike will usually bog and die the accelerator pump gives that extra squirt to keep the bike running till the engine vacuum takes over pulling the gas thru the intake , or otherwise be a pain to start ..... you need to look inside the bowl (remove the bowl) and look for a brass jet down in the bottom , if it is not present , then you need to order one of those as well , or if getting one soon is a issue , because of shipping delays , then just locate a 250R float bowl on EBay , and replace your bowl with that one , but yes , go back to the OEM or even a aftermarket (Boysen or Outlaw Racing) pump cover ..

Leak Jet in bowl:


The Leak Jet for your bike should be a # 70 , and should be stamped into the jet at the top by the screw slot (you will need a magnifying glass to read it usually)

The Hot Start will also cause a lean condition if it is not working correctly , not present , or stuck , so that does need to be addressed as well , you can use a choke knob directly into the carb body where the Hot Start Plunger would go , or just go back to a cable system like OEM , and some aftermarket clutch perches have the ability to use the stock lever or they provide their own and either should work with the OEM cable

Hope that helped

[Terj]

Awesome!! Thank you so much for the info JimDirt.

I will be pulling that bowl to check for the jet when I get home from work in a couple days, hopefully that will be all good. Have the new (oem) accelerator pump cover, hot start assembly and hot start cable coming in the mail in a little over a week. Hopefully with all that back to oem and the proper jet in there it’ll work! Really appreciate the help, I’ll let you guys know how it goes!

Welcome to the site !!

That is not a Hot Start , that is a Adjustable Leak Jet , and most likely the issue if the valves are in spec ..... To me they are too complex for a novice carb tuner , and completely unnecessary for most purposes and most riders ... I have messed with them , and they are a pain to get right , and are real temperamental ..

Hope that helped