Posts
6161
Joined
1/31/2018
Location
Mansfield, OH
US
Edited Date/Time
9/18/2018 7:13pm
Some of you may know ive been chasing my tail with this 09 kx450f having starting issues. Ive had a dealer and kawasaki try to diag this bike with no success.
Ive narrowed the problem down to the bike only having starting issues when its hot. It starts cold no problem. 3 kicks and its running and stays running. The bike has passed all compression and leak down tests performed by the dealer and myself. Entire motor has 4 hours on it.
The ignition coil, spark plug cap, stator, rectifier, spark plug, killswitch, and ecu have all been replaced so far. I did replace the fuel pump, but it does have a small dribble from the outlet tube, and i want to think that could have an effect on the bike as it shouldnt leak. It seems weird that heat would make a difference here?
I guess im looking for some insight from more experienced guys like pawpaw or others on where to go with this thing. Can a bad coolant temp sensor cause this to happen?
Im about to order another fuel pump, coolant temp sensor, and fuel injector and see if that fixes it.
Ive narrowed the problem down to the bike only having starting issues when its hot. It starts cold no problem. 3 kicks and its running and stays running. The bike has passed all compression and leak down tests performed by the dealer and myself. Entire motor has 4 hours on it.
The ignition coil, spark plug cap, stator, rectifier, spark plug, killswitch, and ecu have all been replaced so far. I did replace the fuel pump, but it does have a small dribble from the outlet tube, and i want to think that could have an effect on the bike as it shouldnt leak. It seems weird that heat would make a difference here?
I guess im looking for some insight from more experienced guys like pawpaw or others on where to go with this thing. Can a bad coolant temp sensor cause this to happen?
Im about to order another fuel pump, coolant temp sensor, and fuel injector and see if that fixes it.
Yes a bad coolant sensor will also cause it.
Does you bike have a tip over sensor? They do go bad also.
Your fuel leak can also cause fuel pressure issues.
Your injector can also have a very small leak that causes the bike to load up when shut off hot and cause hot start issues. Remember the old hot start lever on carb style 4 strokes?
Paw Paw
I did try to pull the high idle while the bike was hot in hopes it would act as pulling a hot start lever. No luck.
I do get a little bit of smoke from the exhaust that i dont get from my 250f, so i feel like the bike is running rich. If it helps, i have 2 ecu’s. One is stock and one is mapped by tokyo mods. The tokyo mods one was mapped to fix decel pop, im assuming they richened the map. That ecu does not allow the bike to start hot or cold. What this is leading me to believe and to kindof go along with what youre saying is: a combination of a leaking pump, potentially leaking injector, or a faulty coolnt sensor is causing an overly rich condition that prevents hot starting.
Ill also note, i was able to turn it off and IMMEDIATELY restart it, but was not able to if i let the bike sit for 3-5 mins.
Paw Paw
If i remember ill report back as to what the fix is.
The Shop
Also, thanks for the info but i dont think my foot peg springs and pins are causing the bike to not start. Haha jk
https://www.rockymountainatvmc.com/p/989/52831/Motion-Pro-Fuel-Injector…
Paw Paw
I do still strongly suggest the use of the injector cleaning tool as the best way to do the job, plus you can also get paid by folks to clean their injectors and thus the tool will pay for itself. Watch the video of the tool in action.
Paw Paw
http://www.proride.com/smfforum/index.php?topic=75295.0
SoCal local so I ended up at the shop listed on Page 3; never had a problem after that.
Today, the bike starts and runs as normal. Let it get nice and warm, let it sit for 5-10 mins and it starts up. Definitely weird. Still moving forward with the sensor and stuff. They dont fix themselves.
Paw Paw
Pit Row
Wont be till spring before i can ride it again. So for now i feel confident that the coolant sensor did the trick
Paw Paw
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