2013 TXC 250 starts cold, stalls hot, then won't start.

How was your fuel flow? (if you can keep it running above idle speeds, I'm guessing your filter is fine). try that restart with the air filter off... when it does not restart, quickly spray starting fluid in the throttle body and retry. If it restarts instantly, we still have a fueling problem (split internal hose or filter etc) else we better step back and look at other possibilities- like maybe the pulse trigger coil.

What fuel pump did you end up with? any install issues or lessons learned? how much?

Is your vacuum port capped or do you have any vacuum leaks such as a cracked manifold or TB? maybe you have the first ever bad MAP or ATS sensor on a husky.

look at the coil ground (well, you have a stick coil... so just inspect the wiring. ECU also. Actually, inspect all the wiring- and trouble will look insignificant: rubs or small arc signs). Run the bike in the garage in the dark, looking for wayward sparks.

I will admit I'm a little surprised you haven't tightened up that exhaust valve- OTOH, it seemed to start okay.

yes, judging by your video we have EXACTLY the same issue.

i replaced the fuel filter last week. Old one seemed fine too.

I tried the starter fluid trick and it started up even though it was hot. Not cleanly, but she fired up. Here is the video


View: https://m.youtube.com/watch?v=rRXiv0Q_Utw


The pump was a ca cycleworks for $130. There were many posts suggesting to stay away from the eBay units. The install was cake and no observed oddities.

I ran the bike in the dark and didn't see any sparks. I'm going to try it again tonight. I'll check all the low hanging fruit you mentioned above.

Not sure where the vaccum port is, but I'll try spray some starter fluid around the throttle body while it's running and see if I can detect a leak.

vacuum port: The TXC may not have one. It's on the right side of the intake manifold, close to the head.

Pump: yeah, I've heard the same "chinese junk" thing; and I've never seen any direct evidence of this (I've heard a lot of "friend-of-a-friend stuff though). Also my stock pump (2010) is made in china. And actually, we just wanted to test it to see if the stock pump was failing.... my thinking was that a $20 gamble wasn't a big issue.

hot start: ok, our next mystery is what would make the bike lean when hot. Especially at idle.

let's get that exhaust valve tightened up. As long as you have more than zero clearance, you're fine. Actually less clearance is easier on the valve too (less slamming shut or kicking it open, because it's riding the lobe all the way up and down). And we need to eliminate this issue from our list.

Well, I adjusted the left exhaust (that the ADC uses) to about 0.178 to match the right and I am seeing an improvement. The bike now idles hot and cold, but I still cannot re-start it when hot. The idle does wander slightly, but not terribly. The starter does not seem to be struggling as hard either. I checked the ADC and it looked perfect with virtually no wear and the spring was nice and snappy. I'm calling the ADC good.

I also verified the fuel pump relay and starter relays are good. It ran 0.2 ohms with 12 volts on the coil on both of them.

Trenchcoat85, thanks again for all your help. I was reticent to change the valve clearances, but I'm glad I did before throwing more money at the bike. I think I made some progress tonight. Unfortunately, I'm off to the the beach for a week for mandatory R and R, per the wife.

This is good news. And have fun at the beach. Listen to that wife- I should know... I have 2 ex's.

(but you're still a bit too loose on that exhaust. hah.)


ps- I will point out that Johnrg mentioned the exhaust valve clearance in the very first response.

Don't think this will solve your problem, but saw that you have a YUASA YTX4L-BS batteri. Standard on my bikes are YTZ7S, much stronger than yours. I am running JMT HJTZ7S-FP lithium batteries on two of my bikes and that makes wonders to me.

Thanks MorganD. That Yuasa came with the bike and I replaced it with a TUSK Lithium Ion. I just didn't want to burn up my new battery in the troubleshooting. The lithium ion battery had warnings about trickle chargers that I did not take the time to fully comprehend. I'm basically leaving the trickle charger on the Yuasa all night.

What is the CCA rating on your lithium battery? Just curious.

Plug the the JD back in so you can try and tweak low speed and 0-20% throttle fueling. I fixed my hot start issues with a rich Map 3. Stock ECU Map 1 was lean, Map 3 was rich.

I'll do that. Thanks Johnrg.

cca 150.....

Also have a Earthx ETX12A, but think the JMT is more powerfull and half the price.

Here's the latest

I charged both batteries and tried my lithium ion again. No change

I installed the JD Power Surge and fiddled with the idle RPM mixture. I fattened up the low end quite a bit. It makes a the throttle response 1000% better, but does not resolve the hot start issue. The bike used to suffer a lean bog if I snatched 1/2 throttle quickly. With the JD unit dialed in, it rev's like champ. In the end, I set it to the recommended settings from JD. This does not seem to affect the hot start issue.

The bike is idling now with the idle screw at 44 clicks open instead of the prescribed 34. It is not stalling at temperature. I don't know if this is masking another issue or this is necessary for my elevation (~5500 ft). The idle seems higher than I like, but I'm guessing it's close to 2K. The idle still has a feint hunt or wander to it. Something odd there.

I went another round of tighter valve clearances. My left exhaust is now 0.15mm (spec 0.20) and the right is 0.13 (spec 0.20). I'm now in the range I would consider out of spec tight. With tighter settings, I noticed the starter does not struggle at the top of the compression stroke as much, if at all. The battery does not die down as fast as a result. I believe the ADC on this bike is marginal and it only functions when the valve clearance is on the small end of the spec. I'm not noticing a big difference between this valve adjustment and the last (previously they were both at 0.18mm). The bike also seems to run cooler, which makes sense.

I'm going to take the decompression (left exhaust) valve clearance to 0.10 and see if that changes anything.

I also need to check on the voltage regulator wires. I noticed this morning that they are pinched between the frame and the aftermarket radiator guards.

Adjusted the decompression (left exhaust) from 0.15 to 0.10 (spec is 0.20) No improvement.

Voltage regulator wires were not pinched after all. There was a little channel they fit in that I couldn't see until I removed the radiator. Reading 14.5 volts at the battery when running, so no issue there.

Man, if I didn't stop 10 times a ride, I'd say the bike is running well, but if I kill the motor, I'm going to need an hour to get it started. What am I missing?

Head gasket leaking at temp?
Coil failing at temp, but not when cold?
CDI failing at temp?
Vapor locking? I am testing with near empty tank since I have it so much.
Water pump not functioning?
ECU corrupted or failing?
Air horn or exhaust mod having unintended consequence?

Being that lean and being a '13, I still think the ECU is seeking something from the O2 sensor. It just sounds like Map 1 on the TE 310R's. Each map but map 1 ignored the sensor. Never tried unplugging it when I had Map 1 and it may indeed not do much so just curious if it could affect running. I question why it may have been removed and the map not re-flashed. Just trying to isolate what may be the cause since the 13s were unique as far as power up and ECUs. I assume you don't have the part? I think .18 is what my left exhaust is and .2 the right. Occasionally will stick at TDC but quick stab of the starter button a second time is all mine takes to spin up.

I believe my TXC did not come with an O2 sensor as it was never intended for road use.

The different maps you are referring to. Is that on your PCV or did your bike have an option to toggle maps on the ECU?

The 13 ECUs required reflashing and just held one map. I reflashed to Map3 just to get the bike to run properly. Then I installed the PCV to sort the minor richness at low rpms and at elevation which had a big effect on hot starts. The 310s had 3 maps and I assumed the TCX 310s came with Map 2 as a starter. Map 3 probably for a more open pipe. I wonder how the 250s were delivered.

Searched for the early reviews and as you said it appears they didn't have the o2 sensor. In CA both TCX's were considered red sticker so I'd assume were mapped properly for racing. A dual Map switch was mentioned but I think that is part of the optional accessory GET ECU and switch.

Thanks Johnrg. That makes sense.

I believe the Husqvarna Service Tool (AKA Diagnostic Kit) is required to change the maps. Is that correct? I haven't found anybody locally that has one or will admit to it.

I do not think this JD Power Surge 6X is active during the start sequence, which is why it may not be helping. During the start, it flashes all LED's. Once running, it settles down to 2 led's. I don't know what the led's are indicating at those times. I fired JD an email to find out.

I am able to start my bike hot with starter fluid. It's not graceful, but it will start.

Just created a hot start condition by warming up the bike and pulled the coil pack while it was still hot. I then put another plug in the coil pack and grounded it to the motor. The spark is there, so I think that rules out the coil and CDI.

Yes.... The Husky Service tool is required to remap. I assume ZipTy, Bills and Halls can do it.