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9/27/2023
Location
La Carlota, Negros Occidental
PH
Hello fellow riders,
Please help, need advice with my bike problem.
The bike starts okay, however when gets hot for about 40sec. It dies and hard to start again. Seems like its losing its idle or spark.
Things already tried:
-Check and readjusted all valves to specs
-New regulator
-New stator and pulser
-New sparkplug
-changed the capacitor
-wiring harness all tested ok
-throttle body squeaky clean.
-we tried hooking a battery on the bike It starts in 1 to 2 kicks and the bike runs okay no problem at all, (so this may waive any problem with fuel pump) However when we return it to its original connection and no battery the problem occurs again.
Please help, fellow rides and dirt bike lovers.
Long shot but have you tried unplugging the kill switch?
wow! thank you for the quick reply brother. could it be...? I doubt it however it's definitely worth a try. We actually ran out of ideas of what to do.
update: now it's running okay only when the choke is turned ON. if the choke is off it dies and hard to start.
idk man have you tried turning it on and off again
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paging the RMARMY bros
Just throwing this out there, but the idle hasn't been turned right down has it? It would make sence as to why it only runs with the choke on.
Had this happen to me on a 17 Honda. Wasted a whole day going to the track for it not to start, get home and buddy unplugs the kill switch, fired right up. Didn’t even know that was an option
Could be a fuel related issue. I would hook up a fuel pressure tester to see if there is proper fuel pressure (RM sells an inexpensive tester that works great). Also, I would pull the injector and clean it. I fix plenty of bikes of different brands with both erratic fuel pressure and/or dirty fuel systems that lead to slightly plugged injectors. It's not out of the question to have just a malfunctioning injector. BTW I routinely use aftermarket injectors and haven't had a problem. If they are available for your machine, cheap aftermarket fuel pumps are dodgy at best. If that's what's wrong, steer clear of those or the cheap rebuild kits. Buy a quality brand for pump. Best of luck.
I just want to report that my buddies KTM 250 XCF was running terrible for a year. After a valve adjustment and a bunch of futzing with the clutch (he had a rekluse), it turned out he had it on choke (enrichener, whatever) with the idle turned wayyyy down.
What a doofus.
On my 2014 I had an air leak. Fixed that and then realized the spark plug wire needed replaced. Ran like a champ after that.
Double check this. If I remember right the manual says something like screw it all the way in and then out 6 clicks. It won’t idle at that setting. It needs to be turned out like 30 clicks.
Thank you so much for the reply brothers.
Idle is on max with choke on it runs for about 30 to 40sec then loses the idle and dies and hard to start again. When it's running and we give it a bit of gas it keeps running however its not steady there is kind of bogging and backfiring popping in the exhaust. We will clean the tb and injector today and see if that fixes the issue.
I will keep you guys updated. More advice and tips is greatly appreciated.
This is what it will be. Have seen it on multiple Rmz 250s. Actually saw one where the choke broke and had been glued back together. So it basically adjusted the idle and never ran right.
turn the know anti-clockwise and it will increase the idle from memory. I could be wrong. Just wind it all one way then back. Should find the sweet spot.
Turn the “knob” anti-clockwise.
Also sounds like the cam timing could be set wrong. ie-not aligned with the timing marks so the timing is wrong. The popping is a sign of this.
Yeah I would most definitely double check cam timing.
Really long shot, but make sure you muffler packing isn’t blocking the exhaust. Rev engine and you should feel quite a bit of exhaust blowing out.
The exhaust is newly repacked brother.
Pit Row
thank you brother. I will say that to my mech.
Did your head ache issue start around the same time when you repacked the exhaust?
Sounds like an air/fuel mixture problem... But first question is how old is the gas? have you cleaned out the fuel system, replaced the filter, and inspect the TB making sure nothing is stuck in there? check for cracks in the TB and boot, check the air filter, some filters have a screen cage that can get clogged up too.
I’m probably not the only one following this thread. Perplexing
Fuel pump?
On my 13 rmz250 I had a bunch of weird problems after putting a bunch of aftermarket stuff on it. Bike wouldn’t start at all, me, jimmy weinert, and a trainer stayed up till like 2 am ripping the thing apart trying to figure it out. Weeks later another mechanic and I finally figured out it was a cracked injector….thing ran fine for a few weeks and then issues with staying running popped up again. The 2nd time it turned out to be a blown head gasket
Have you tried a different coil ?
Because you say it runs for 30-40 seconds then dies and is hard to start again, if you let the bike sit for 5 minutes or so is it easy to start again? If so my guess would be a fuel delivery issue possibly related to a dirty fuel filter, pinched fuel line or injector/fuel pump issue.
Did you let the bike sit for any long period of time?
I have worked on all types of small engines for most of my life I would bet that your problem is from restricted fuel delivery. The reason it will only run with the choke on is because it's allowing it to run rich until it runs out of fuel. The fact that when you turn the throttle it studders and backfires is a indication it's starving of fuel (running lean). Since it does restart after stalling I would suspect the fuel pump is working but I would not rule it out completely starting out with a complete inspection and cleaning of your fuel system is where I would start.
Bad gas cap?
hello brothers. again much appreciation for your replies.
we tested the fuel pump with a gauge and hooked it to a 12v battery this is what it shows in the gauge.
the injector is working fine as well after we had it ultrasonic cleaning.
TB also fully cleaned.
now, either with the choke on or not it runs with 2 kicks but still dies after 40sec or so.
tried unhooking the kill switch too to no avail..
we do not know what to do anymore.
new stator, pulser, sparkplug, valves clearance in specs, is there something else?
Mentioned earlier, but try running it with the fuel cap off yet?
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