Hot starting issues

[gigero]

Well,
This is the 3rd time this has happened so I wanted to post and see if anyone has had the same issue.
 
Warm/hot bike from riding longer then 20min. Parked in the direct sunlight in the middle of the day approx mid to high 80s in temp. Sat for 30-60min. Then get back on and try to start, no go. Turns over but doesn't start. Crank it 3-5 times at 5 seconds each time. Still no go. Then cracking the gas a bit while cranking then it starts.
 
I tried cracking the throttle during the first 1-3 tries but it sounds like it floods the throttle bodies.
 
If I park in the shade on a hot day this doesn't happen.
 
My bike is stock engine wise.
 
I'm stumped.
Anyone has had the same experience or know a solution??
 
Thanks,
 

[norcal616]

all i can think of is if you messed with the throttle body synch or do what some ppl when shutting off the bike, some ppl dont use the red thumb switch to turn off motor and use the key insted..i tested this and found the bike takes longer to start compared to turning off motor via the red thumb switch...

[magicmikey]

But the red thumb switch is meant to kill the engine in case of emergency etc. it is like on any other motorcycle. So switching the bike off using the key would seem normal procedure. Yes you can shut it off with the red thumb, but the rest of the electric circuit remains on (light for example remains on)
 
Back to the original question.
Only during warm days and when engine is warm and sun is on the bike you have starting issues. Fuel vaporize quicker on hotter days but it doesn't sound logical as it is not Sahara hot temperatures.
Is your fuel pump engaged when you turn your key?
 
When was the last time you changed the spark plugs?
 
Did you do anything to the air filter or cover?
 
Using different fuel or octane level lately?

[Guest Ralph]

Wonder if you could have a trapped breather pipe from the tank,
tank gets hot pressurises and forces to much fuel into the engine,
If your bike as a evap canister don't know what Yamaha call them
and not all market bikes have them maybe something to do with that.
Mine starts first time but can turn on the starter slightly longer
than expected at times.
 
 

[rick]

I use the key almost always to shut off the motor and don't have any issues with starts - hot or cold. None of us have ever had a kill switch in car I suspect.
 
These FI motors (all of 'em including cars) are set up to start, hot or cold, w/o touching the throttle. Something is not right if you have to resort to that to get it to start.
 
You can try opening the fuel cap right before start up and see if that changes things. If you hear pressure being released, Ralph is onto something.
 
My guess is that the idle air control valve - it sits right between the throttle bodies - is not allowing enough air into the motor at start-up when it's hot. Hate to revert to experience with Italian electrics, but I'd start with making sure the connector to it s clean and tight. The water temp sensor is right beneath the TBs and I'd check that connector as well.
 
A look at the air filter and snorkel can't hurt as we've already seen some evidence of critters getting in there.

[yotaman02]

mime has done it a few times. It's just a little vapor lock no biggie.

[Beemer]

If the sun is shining directly onto a fuel line it's possible it could be vaporizing the fuel in the line but it would have to be really hot to do that, I would think. Do you have an EJK Controller? Are your fuel settings too high maybe? How many miles on your bike? Checked your plugs? Are you at a high altitude? I found this info on a reputable site: "Operating a vehicle at a high altitude increases the chances of experiencing vapor lock. At the higher elevation, atmospheric pressure is lower, and the boiling point of gasoline is lower. Ethanol also has a lower boiling point than regular unleaded gasoline, increasing the likelihood of vapor lock."
 
http://www.linnbenton.edu/auto/perform/no_start.html
 
Good luck!

[gigero]

Thanks for the insight guys.
 
My bike currently has 9600 miles on it. It's a '15, stock engine, no fuel controller, stock exhaust. Only thing after market is the suspension, brake lines, and brake pads. Maintained regularly and use premium gas. Unfortunately I live in CA and there's ethanol in most of the gas available here. Elevation wise, I live at sea level.
 
I did change out the spark plugs myself at 8200mi with recommended oem ngk's and I double checked the gap to be sure. When replacing the plugs I may have done what you guys have pointed out. I'll retrace my steps and see if there's anything askew. Also I'll recheck my sync on my tb's since I haven't done so since the 600mi mark.
 
Cheers.
 

[rick]

Doubt your gasoline has anything to do with it. We all suffer with ethanol in the fuel. You might consider a different brand however as the companies add that EtOH at the point of distribution. A different distributor might give a more accurate E-5.
 
Needing to open the throttle a bit is consistent with the TBs out of balance.
 
When the throttles are closed - unlike with carbs, they are completely closed and the only place air can get in at idle is thru that IAC valve. The air screws compensate differences in manufacturing. Keep in mind that the left side air screw is already closed. If the right side screw needs to allow more air to balance the vac at idle/start-up, When hot, the mixture is already very, very lean. If the air getting in is out of balance, that will can make starting difficult.
 
Opening the throttle plates sorta bypasses those air screws and IAC and lets air in more evenly. And even though you think you are also adding more fuel by cracking open the throttles, I believe that the ecu knows the motor is not yet running and meters fuel to match.

[gregjet]

Hard hot starting May be due to using ultra hi octane fuel ( it's 98RON here, can't remember what it is in the US), particularly BP.
However you could try a idle re-set.
Start the bike WITHOUT touching the throttle. let it idle until the fan comes on.
Switch off ( with the KEY). Let it cool down.
Next start : start and don't touch the throttle. Should start and idle.
Might help.
Throttle body synch might be worth a go if the idle reset doesn't help
 

[markstertt]

This problem sounds similar to one on -09 forum and only to Calif. bikes with charcoal canisters. If you park the bike in the hot sun, the fuel tank will vent into the canister and some fuel may be evident out of canister drain also. Now when you go to crank the engine, your engine is pulling that over rich mix from the canister into the manifolds and you have a flooded condition. Either don't park in the hot sun or remove the canister system and vent overboard like every other bike not in Calif...Mark

[gigero]

This problem sounds similar to one on -09 forum and only to Calif. bikes with charcoal canisters. If you park the bike in the hot sun, the fuel tank will vent into the canister and some fuel may be evident out of canister drain also. Now when you go to crank the engine, your engine is pulling that over rich mix from the canister into the manifolds and you have a flooded condition. Either don't park in the hot sun or remove the canister system and vent overboard like every other bike not in Calif...Mark

Checked my TB sync and was pretty close to spot on. So, I went ahead and ditched the evap can and rerouted the vents.
 
Hasn't been super hot here in SoCal but I believe that this will do the job.
 
Thanks again, all!!

[rick]

Those evap canisters usually aren't an issue unless you overfill the tank to the point tat raw gas gets into the hose. They're designed to handle vapors, not raw gas.
 
FI motors usually run lean after sitting hot. Carbed motors tend to run rich. So I'd think that some extra fuel would help, not hurt.
 
That said, whatever works.