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

[durtkillon]

Hey guys. I need some help. I'm new to this bike and don't have much history. I purchased it from a mechanic who was selling it for a third party. He told me it had a high temp cut out, but it was resolved when he changed the engine temp sensor. He said he also checked the valves and said they were bang on - no changes required.

It seems to start fine, but the battery seemed weak. It would turn the start unless I topped off the battery with a trickle. I replaced the battery and now it starts fine, but it REALLY struggles to turn the motor over if it's at times. Seems like it's fighting really high compression. Still, it turns starts cold and sounds great.

After i ride around the block and the bike gets to temp, it stalls. Then it's impossible to start. It turns over, but no fire. Let it cool five minutes and starts right back up, but stalls within seconds.

I replace the plug and found the gas was the color of a good IPA. I dumped the gas and put fresh stuff in with a bottle of injector cleaner. No change. Same symptoms. Starts cold, runs fine for 5-10 mins, then when the idle drops, it stalls and is hard to start. I can keep it running with more throttle, so it's not a "cut out", but rather a stall. Like its a timing or fuel management issue.

I called the KTM Husky dealer. They said they will order parts, but will not service the bike. I called the BMW dealer (former red head dealer) and they said they stopped servicing the bikes and don't order parts.

I though I was buying a turn-key. I'm pretty handy, but problematic FI 4 strokes are new to me. If you have suggestions, please fire away. If you know of a Husky mechanic in the Denver area, I'd like to know. I may need help with FI mapping.

 

[Johnrg]

Hard to say but I figure 2 things. If seems like high compression and feels really stiff at the kicker, it may be the decompressor. With the 310s most of us have had to tighten the related valve clearance tighter so it actuates. That should solve one issue, unless by chance the bike has starter gears that were a warranty fix on te 13 310s. If so you replacement of starter gears may be needed. As far as fueling, it sounds like you are rich. Maybe verify what equipment is on the bike regarding exhaust and try and ascertain the map on the ECU. I assume the TCX may have 2 maps.I might call ZipTy, Bills or Halls who have experience with it possibly. Otherwise you can install a PCV and it will sort all running issues but you need to do your own install. I run the PCV and autotune and sorted the fueling issues on my 310 that you describe. I really have not much info on the 250 version as most here have the 310 but it sounds quite similar to what many of us have experienced.

 

[Trenchcoat85]

After you tighten up that left exhaust valve, here are a few places to look:

if the gas was that bad... clean the injector too.

How did the old gas smell? Old gas has a sweet, varnish-like smell... very different from fresh gas. A gas can that's been empty for a long time may have this odor you can reference. And your gas cap may still retain the smell for a while, even after you refilled the tank.

does it run any better with the "choke" pulled out, even when hot? does it idle at all? (the word "stall" almost implies you're moving, usually; "dies" can mean the motor quits while idling.)

Lithium batteries seem to provide more instantaneous starting current- lots of happy customers here. Although I run a lead-acid battery.

how does it kick start?

is it possible the fuel pump/system is losing pressure? (bad pump, regulator, split or cracked internal fuel line or filter)

 

[Johnrg]

Short somewhere/discharging or TPS needs resetting?

 

[durtkillon]

Thank you all!

After reading in this forum about the high number of starter issues on these bikes, the high compression observation I made may a starter issue. I'll sort that out by verifying the valve clearance. For now, I'll verify the fuel system is healthy, then verify compression, then start poking at the ignition system.

The bike has stock exhaust (and stock everything), so I don't think any special fi mapping should be required. Is there anything special about these fi units that causes them to lose the tps positioning?

The gas was sweet and very varnished. I've pulled the tank, replaced the filter and have the injector out, ready for servicing and testing this week. The filter looked bad, but fuel gravity drained out of the filter, so that wasn't too bad. The rest of the tank looks fine.

To clarify the stall/dies terminology, the bike dies if I let go of the throttle. It stays running if I'm on the throttle. I have not tested to see if it will affect idle by pulling it out, but I've gone 15 click in either direction from the prescribed 34 clicks and it seems to have no effect.

I had the old lead battery tested and it's fine. The bike is just requiring too much juice to turn over.

I ohmed the coil out and it meets spec when cold. I'll call on Monday to see if any shops can test it under load.

I'll check valves tonight. How does the auto auto decompression work exactly? Does the exhaust valve clearance play a role in proper functioning? If I err to one side or the other, should they have less clearance? That seems to make sense to me.

 

[Green Mtn Rider]

Just for the fun maybe a chance your water temp sensor on the cylinder could be bad

 

[mike haupt]

i have pretty much the same prob on my 2012 te 449. was having a hard time with hot starts but would always fire up then run good. But today it ran good after 2 or 3 hot starts then would hardly fire up . And when it did ,wouldnt idle. Had to keep it running with throttle to get almost home. then wouldnt start and had to push home five blocks. just bought bike used in january. what is a PCV?, heard alot about this on other forums,seems to solve alot of issues. by the way, brass screw on throttle body came 3/4 of a turn further out than what is recommended. bike wont start with recommended turns!?!? would appreciate any help as dealers are few and far away.

 

[durtkillon]

I think I have a clue. I took the plug and valve cover off to check the valve clearance I checked the two easy ones on the left side and they were fine, but my feelers were too wide to test the right side valves. The interesting part is that the motor was REALLY hard to turn. I could not turn the motor in second gear and it was actually quite difficult to turn it with the kicker in neutral. With zero compression, is should turn like butter, no? Then I checked the timing chain ad it is VERY tight and will not deflect. I'm wondering if the tensioner has failed. Anybody know how tight they should be? Should I be able to deflect the chain with my fingers?

Other suspects might be the starter or the water pump, but I would think the water pump would be squealing like a pig.

Off to the auto parts store to find some skinny feeler gauges.

 

[durtkillon]

Uninstalled and reinstalled the tensioner. No issues there. It operates fine. It keeps the chain tighter than I expected. It's still tough to turn the motor to align the cams with no plug in. I find that curious.

The head temp sensor was just reportedly replaced by the mechanic I picked it up from. The water temperature sensor is original however (still has factory hose clamps). I'll add it to my list of things to check .

 

[Trenchcoat85]

Just for the fun maybe a chance your water temp sensor on the cylinder could be bad

Sounds like the mechanic did before he bought it.

 

[Trenchcoat85]

i have pretty much the same prob on my 2012 te 449. was having a hard time with hot starts but would always fire up then run good. But today it ran good after 2 or 3 hot starts then would hardly fire up . And when it did ,wouldnt idle. Had to keep it running with throttle to get almost home. then wouldnt start and had to push home five blocks. just bought bike used in january. what is a PCV?, heard alot about this on other forums,seems to solve alot of issues. by the way, brass screw on throttle body came 3/4 of a turn further out than what is recommended. bike wont start with recommended turns!?!? would appreciate any help as dealers are few and far away.

PCV=Power Commander 5.

Mike, start another thread for your 449 as the issues are probably different and the threads will diverge insanely.

Good luck

 

[Trenchcoat85]

Thank you all!

After reading in this forum about the high number of starter issues on these bikes, the high compression observation I made may a starter issue. I'll sort that out by verifying the valve clearance. For now, I'll verify the fuel system is healthy, then verify compression, then start poking at the ignition system.

The bike has stock exhaust (and stock everything), so I don't think any special fi mapping should be required. Is there anything special about these fi units that causes them to lose the tps positioning?

The gas was sweet and very varnished. I've pulled the tank, replaced the filter and have the injector out, ready for servicing and testing this week. The filter looked bad, but fuel gravity drained out of the filter, so that wasn't too bad. The rest of the tank looks fine.

To clarify the stall/dies terminology, the bike dies if I let go of the throttle. It stays running if I'm on the throttle. I have not tested to see if it will affect idle by pulling it out, but I've gone 15 click in either direction from the prescribed 34 clicks and it seems to have no effect.

I had the old lead battery tested and it's fine. The bike is just requiring too much juice to turn over.

I ohmed the coil out and it meets spec when cold. I'll call on Monday to see if any shops can test it under load.

I'll check valves tonight. How does the auto auto decompression work exactly? Does the exhaust valve clearance play a role in proper functioning? If I err to one side or the other, should they have less clearance? That seems to make sense to me.

Good info.

Your CTS is also known as the WTS and is on the back right side of the cylinder, right near the cam chain tensioner. Hopefully it's white. The thing with hose clamps (and wires) is you fan's thermoswitch- and is probably not a factor here.

The sprag for the electric start may be causing the resistance to turning... or maybe not. CCW IIRC. Using the kickstarter or e-start should've spun the motor freely. If you're in gear, turn the wheel forward. Unless you're hearing and feeling mechanical resistance, I'm thinking we don't have a problem (and compression is ok I'm betting). Also- do not depend on the clutch to fully disengage during starts, even with the spark plug out. Clutch drag can be major on this bike. It sounds like you were in neutral most of the time, which is good.

Autodecompressor (ADC) is a small actuator that opens your exhaust valve slightly, and disengages when the rpms increase; it makes the motor easier to turn over during starting. If valve clearance is too big, it's not as effective.

TPS- I think you're instinct is correct. let's save it for later.

Idle: 40+ clicks out. the manual has the wrong direction IIRC. Idle speed 1950rpms. or even higher.

Do you know if all of the "power up" options have been done? (air filter cage, velocity stack, backfire screen, catalytic converter removal... ECU re-map is sometimes considered a part of this too). Most stock bikes have had this done by now but it might be worth checking. And it should idle just fine "corked up".

Spray/soak that injector with carb cleaner- inside and out. (well, inspect it first). If you're able to do the pressurized cleaning method that would be great (some videos here; many hosted on youtube). With your "gas" report, this is my biggest suspicion.

 

[Trenchcoat85]

Wait... why are you aligning the cams? did the valve timing change when you released tension and re-tensioned?

also, I am guessing you're on probation so communication is not timely (we only have 2 moderators). and you're getting a lot of unrelated crap thrown at you; of which I'm doing a lot of the throwing, I guess. But let's go slow and just do a couple things at a time now. You're doing a great job of reporting back the details and we will probably get this solved. but lets bring the pace down a bit.

oh yeah- if you see something interesting or confusing, post some pictures. They're always a big help.

 

[durtkillon]

Here is a walk around video of the bike. I believe the majority of power up mods have been done now that you pointed them out. I think the cat is gone as well. The JD power 6x was not been installed on the bike when I got it.

View: https://m.youtube.com/watch?v=Y5X8_QORdxI

 

[durtkillon]

Wait... why are you aligning the cams? did the valve timing change when you released tension and re-tensioned?

No worries. I didn't change the timing, I just bumped the motor until the cam dents were aligned with the case so I could check the valves per the clearance check procedure.

 

[durtkillon]

Here are my valve clearances:

Left exhaust 0.229 mm (spec = 0.20)
Right exhaust 0.178 mm (spec = 0.20)
Left intake 0.152 (spec =0.15)
Right intake 0.102 (spec = 0.15).

 

[Trenchcoat85]

Here are my valve clearances:

Left exhaust 0.229 mm (spec = 0.20)
Right exhaust 0.178 mm (spec = 0.20)
Left intake 1.52 (spec =0.15)
Right intake .102 (spec = 0.15).

Get that left exhaust to about the same as the right one (0.008" is 0.20mm, so maybe between 0.15mm and 0.20mm, closer to 0.15mm). I don't know why OHC motors are spec'd so loose... 0.004" 0.10mm seems fine to me. Anybody wanna edjumacate me?

whats the deal with the left intake? that's insanely fat.

For "bang on" valves, those are all over the map. Are you sure this mechanic looked at it?

 

[durtkillon]

Left intake was a typo. It's actually right on the money. I just corrected it.

 

[Trenchcoat85]

Here is a walk around video of the bike. I believe the majority of power up mods have been done now that you pointed them out. I think the cat is gone as well. The JD power 6x was not been installed on the bike when I got it.

View: https://m.youtube.com/watch?v=Y5X8_QORdxI

My bad.... a TXC comes with the mods (oxygen sensor and backfire screen are ok to stay).

Good vid. Let's do the valve adjust and injector clean and go from there.

Nice bike.

 

[durtkillon]

Trenchcoat85,
I wanted to ask you about the move to make the left exhaust valve clearances tighter. I just finished speaking with the owner of the local Kawasaki dealership and he suggested reducing exhaust valve clearance would make things worse. His logic was if the tolerances are tight, the valve fails to close as the engine heats up, so you loose compression. He explained that this condition actually causes hot start issues.

If I understand you position correctly, the auto decompressor may not function correctly if the tolerances are too loose, so the compression may be too high.

Any thoughts? Do you believe the documented specs are inadequate? It's not that big of a deal to treat it as a loose/tight experiment.

Thanks for all the help. I'm learning a lot about this bike and thumpers in general.