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Hot start issue, please help!!

2K views 11 replies 5 participants last post by  donald.a.davis113 
#1 ·
Hello all, my names damian and im new to the forum.

So i recently aquired a 2002 zx12r with roughly 14k miles, the engine build seemed pretty extensive, je +3mm pistons, built/ported head, cam gears, nitrous, air shifter, myrtle west swingarm, pc3r, msd launch control, etc etc

the bike starts up cold just fine, little hesitation, but after maybe one or two cranks (@35 degrees) she fires up and idles great. once she is up to temperature i will have slight hesitation from idle to 2500-3krpm then she starts pulling wonderful.

my problem is when this bike is at normal operating temperature i will shut it off, go to start it again and it will chug slower than normal like a bad battery almost, or like the ignition timing is too far advanced. But if i let the bike cool down it will start up no problem. today while trying to do some diag i was riding it around the block a couple times and temp got to about 3/4 and then as i was about to shut it off the fans kicked on.

This is driving me nuts trying to figure it out, battery, rectifier, stator are all new and wired correctly.

so heres a question, this problem leads me to advanced timing possibility, too advanced keping it from being able to hot start

Does the coolant temperature sensor have anything to do with timing or fuel on these bikes, is there a diag procedure to test these on the bike (resistance values etc)

the bikes tune is a mess on the power commander 3r, and in cell 0% throttle 500rpm it shows a fattening of 5, which doesnt seem normal to me. i dont want to erase the map and start over, but if i was to post the map would someone be able to tell me if it looks right on a larger bore zx12?

i apologize for the long post but im trying to provide as much info as possible for you kawasaki gurus to shed some wisdom on me, wanted to say thank you in advanced and i hope i can find the answers to my woes.
 
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#9 ·
Does it have a manual timing advancer ? Pull the crank trigger cover on the right side to see.

disassemble the starter and check the brushes?

86mm pistons may be 13:1 compression. Do you have a battery with enough amperage?

does the crank have added stroke? To tell quickly, is there a large spacer/shim between the block and case?

what are the cams degreed to? What cams are being used?

have you checked the starter solenoid, cables and ground? No corrosion

Handle bar start switch needs to be clean and make sure all the contacts are good.

when it’s hot, use a regular car battery and jump start at the starter. This will provide plenty of amperage. If it spins and starts then you know you need a stronger battery?

just some things to check.

cmg
 
#11 ·
Just a comparison. My 1361 zx has bigger bore and stroke. Timing is advanced in the ecu. (Scott Davis flash) no advance down low. 415”/265° cams
13:1

starts fine when hot. I am using a AG801 240 amp battery. All cabling and switches are stock. Made sure the battery box connections are clean and tight.(I did bypass the ignition with a woodcraft zx14 ign delete)

cmg
 
#12 ·
Hello all, my names damian and im new to the forum.

So i recently aquired a 2002 zx12r with roughly 14k miles, the engine build seemed pretty extensive, je 3mm pistons, built/ported head, cam gears, nitrous, air shifter, myrtle west swingarm, pc3r, msd launch control, etc etc

the bike starts up cold just fine, little hesitation, but after maybe one or two cranks (@35 degrees) she fires up and idles great. once she is up to temperature i will have slight hesitation from idle to 2500-3krpm then she starts pulling wonderful.

my problem is when this bike is at normal operating temperature i will shut it off, go to start it again and it will chug slower than normal like a bad battery almost, or like the ignition timing is too far advanced. But if i let the bike cool down it will start up no problem. today while trying to do some diag i was riding it around the block a couple times and temp got to about 3/4 and then as i was about to shut it off the fans kicked on.

This is driving me nuts trying to figure it out, battery, rectifier, stator are all new and wired correctly.

so heres a question, this problem leads me to advanced timing possibility, too advanced keping it from being able to hot start

Does the coolant temperature sensor have anything to do with timing or fuel on these bikes, is there a diag procedure to test these on the bike (resistance values etc)

the bikes tune is a mess on the power commander 3r, and in cell 0% throttle 500rpm it shows a fattening of 5, which doesnt seem normal to me. i dont want to erase the map and start over, but if i was to post the map would someone be able to tell me if it looks right on a larger bore zx12?

i apologize for the long post but im trying to provide as much info as possible for you kawasaki gurus to shed some wisdom on me, wanted to say thank you in advanced and i hope i can find the answers to my woes.
When I had this problem started fine cold once it got hot turned really slowly and would not start. Once in a while I could role start it. Here is the fix I used. zx12r service manual and in sections 16-96 and 16-97 I saw that there are relays in the junction box. I ordered one off ebay for 9.99 shipped. Didn't want to pay the $140 for a new one if it didn't work. part number 26021-1089 (the one that came out of my bike was 26021-1106) seem to be the same fuse box plugged right in and the bike ran great. Box is right in front of the fuel cap. Take off the plastic cover (looks like the gas tank, But we know the gas tank is really under the seat) and it is plug and play.
 
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