2013 TE310R Hot Start Issue - Can Not Solve It!!

I know the hot start issue is well known on these bikes and I've probably read through 50 threads on it over the past few months and nothing is fixing the issue.

Typical problem... bike will start up fine. Once fully warmed up it WILL NOT RESTART. Not with the button or kicker. If I wait 5 min it'll stumble into running again.

What I've tried:

- Set idle to 2000rpm
- Set and checked the valves 4+ times. Tried them stock (.15mm in / .20mm ex), tried with the decomp valve at .15, tried with all 4 at .15. Currently 3 are at .15 and right Ex. is at .20.
- Replaced the cylinder water temp sensor (oem)
- Replaced spark plug..
- New Spal fan and fan temp switch.
- Set TPS to stock .685mV.... tried .605mV and .725mV as well.
- Ultrasonic cleaned the injector and checked spray pattern.
- Replaced fuel filter and bench tested fuel & return system off the bike (got 60psi).
- Bench tested coil, capacitor and pickup coil per FSM.
- Pulled the head, cleaned out all carbon, decked it, lapped valves, replaced valve seals, checked timing chain length, all new gaskets.
- Rebuilt starter motor, replaced starter gears, and installed Antigravity battery.
- Sprayed carb cleaner all around and didn't find any leaks.
- Ran with gas cap off to check vapor lock.
- Most recently installed a wideband O2 and Power Commander V to read realtime AFR and try fueling adjustments. ECU is still on stock Map 1.

With PCV tables all 0'd out the bike will start out idling at 13.3.
AFR will climb a little once bike reaches 165F to 13.6ish.

Here's where the magic happens... Once the bike reaches 180F the AFR starts climbing aggressively.

180F - 14.7
185F - 15.2
190F - 16+ until it chokes itself out.

Once the bike is hot, if I kill it and try to restart it the cranking AFR is up around 18 and will not start. It also won't start if I shoot brake cleaner into the filter bringing the AFR down in the 12's.

I found out that if I unplug the cylinder temp sensor the hot cranking AFR drops to around 10.5... and still will not start!

This behavior of the rising AFR will also happen if I use the PCV to add fuel trim. ex. I added 10% to the idle range, which brought the idle AFR down to 12.8. The temp will still climb as will the AFR until it gets to the high 14's.

Please help.... I feel like I've tried everything at this point and I'm just pulling my hair out.

Small update, just realized my TrailTech water temp gauge was installed by the previous owner downstream of the radiators. So if it's reading 190F AFTER the radiators the motor's probably significantly hotter. Seems like i have a cooling issue. It's hitting 190F (maybe more like 210??) even with the new Spal fan blasting away. Going to check the thermostat and try flushing the coolant system.

Does anyone know how the water temp sensor & ECU respond to 200+ temps? Does it shut down fueling / ignition?

I think it is the trigger for the fan and 210 or so sounds about right. I know someone had done some testing on here years ago to figure out what temps it was set to.

This is my setup after removing thermostat/stock hoses.

John, when I asked about how the temp sensor effects the ECU i was referring to the one on the back of the cylinder.

Since then I tested that temp sensor and it has a smooth voltage/resistance fluctuation from 70F to 210F. It appears to be working correctly (as I would have hoped since it's pretty new). I also tested the thermostat out of the bike and it's working as it should. I read that distilled water has something like twice the thermal transfer capability of glycol and ditched the 50/50 mix for straight water. That and a coolant flush seems to have helped a lot to keep the bike cooler. The other issue contributing to this is likely how lean these things run stock.

Some other major updates:

1. The Smoking Gun
I finally tracked down the issue at the "top of the pile". At some point since replacing the starter gears the woodruff key was sheared. I could see markings on the flywheel showing it had been shifting back and forth changing the timing.

FYI the KTM part number for a woodruff key that's the same size is # 088030050. Dealers don't have the Husqy one in stock anymore but had bags of the KTM ones. I lapped the crank / flywheel and put everything back together.

Now I'm back to square 1 with this bike where it again runs good, starts easily with the button when it's cold, starts with 1 kick when it's hot, but still will not start with the button once it gets above 165F.





2. PCV Disappointments
This is where I was hoping the PCV would come into play, allowing me to fine tune the fuel ratio to remedy the no-hot start issue. Unfortunately I found out through talking with Dynojet support that the PCV doesn't start making adjustments until the bike is running!! So it's zero help for starting issues. This is a huge let down considering I just spent $400 on this thing.

Here's the pertinent info from Dynojet support:

"The PC5 doesn't work for the first few cranking pulses.
It only starts working after the crankshaft is spinning fast enough to establish a synchronization.
So it typically only starts making its adjustments about 20 milliseconds after it has finished cranking and has started."

The other big letdown is that the "Startup Fuel" feature is only configured for cold starts. When you have it make adjustments based on temperature, it's duration is controlled by temperature. i.e. You program it to "Add 10% fuel until the temp reaches X" then it will shut off. This operation doesn't work for hot starting issues because the bike is already at the top of it's temp range. If you tell it to add 10% fuel when the temp is at 165F or higher it will add 10% continuously until the bike is below 165F. There is no duration built in.

You could use the Startup Fuel feature based on time duration (instead of temp) but then you're adding the same trim percentage at startup whether the bike is 70F or 170F. Not very accurate...

And again, just to restate it, you have to get the bike running before any of these PCV adjustments start happening. So it doesn't really help you start the bike, it just helps you keep it idling. It really should be called "Warm Up Fueling."

At this point I'm thinking the main issue is the stock TE map. Getting it reflashed to Map 3 seems like the only thing that will have an effect on startup issues. I just wish I could find someone local to flash it instead of putting the bike down for 2 weeks to ship it out to Zip-Ty. All the dealers I call say "CA CARB doesn't let us do that."

I commend your patience with all of this. Zip-Ty was where I went first for Map 3. Resolved all my issues until I wanted to perfect the mapping a bit more.

Well I rode the bike around town yesterday to do some PCV fine tuning and it was working great. Still didn’t like hot starting with the butting but would start with a single kick.

Took it to a offroad park today and again it fired right up and was idling great. I made it 0.3 miles, 2/3 of the way up a hill and it completely cut out. Threw me into the bars. It did not want to start after that. I threw it in gear and tried to bump start it back down the hill and got nothing. I pushed it back to the parking lot and spent 2hrs trying to figure out wtf happened. I finally got it to start again but it would only run for about 5sec. The AFR is super lean. Starts up at around 14:1 then chokes itself out at 17:1 within a few seconds. This is a completely new symptom. I was about to just leave the bike there and drive home.

No idea what this is. I pulled the PCV off. I checked and was getting spark. I emptied 2gal out of the tank by hotwiring the pump so that works. I pulled the injector and rigged it up to a battery and that thing blasts fuel. I pulled the flywheel to check the new key and it’s still in tact. I have no idea what is going on. At this point I’m thinking my ECU is fucked. Ive bench tested everything else on the bike so many times at this point. What a shit bike.

I would be thinking ECU needs swapping out.

I troubleshot this issue a few years ago on my TCX250R. A fellow Cafe Husky member sent me a throttle body for testing purposes and the problems went away. It turned out to be my fuel injector that would fail at temp. I did many of the same things you did, including sending the injector out for cleaning/testing. My stator was also failing around that same time, but I doubt that contributed.