I have tryed just about everything for my baby and still nothing. I have read alot of websites and tried there suggestions but still nothing. I will start to list them all, cleaned all conections--replaced the HES--replaced all fuel injectors--the fuel brain--the other electronic brain--checked plug wires for resistance--new fuel filter--checked tps--replaced ignition switch--temp switch--kill switch--cleaned starter--checked for vacumm leaks--replaced fuel lines and hoses--unpluged and repluged all conectors. I even took it to the local certified trained mechanics 4 times. They replaced the fuel pressure valve and replaced the air-fuel sensor, put it on the dyno and said everythings fine. ""Trust me it's not"" Every time it hits the 3k to 4K rpm it starts to miss--then it bucks--then sometimes a backfire. It's been timed and the throttle bodies snychronized--I'm running out of ideas and getting tired of working on it--any ideas???

Heres my idea
Suggest testing the coils?
As they can fail under load when they get hot, then back to normal when not under load, have seen this many times on cars
the same go's for the high tension leads

Coils sound like a good idea as they can develop cracks. Might be worth running it in a darkened environment to see if there is any spark leakage.

I had a strange miss on mine as well...at Idle and when you started off...ran great otherwise.
Ended up being a coild failing. I'm running a 3 ohm honda coil right now...looking into getting a set of the Dynatec 3 ohm coils.
Might be worth a try... My coils aren't cracked and I did the dark garage test...never saw any indication of leakage, so that might not be a definitive test.

Talked to the dealer today. He suggested that I swap all the wires from the first coil to the second and vise versa. Something about this is a way to trouble shoot your coils--Has anybody ever heard of this?

This would work if the bike was miss firing while idling and you know which cylinders were miss firing, as swaping the wirs will move the miss fire to the other cylinders, great way to diagnosis which coil it is, the problem you have is that it happens under load and your not sure which cylinders are miss firing.

how about this - in the shed rev it up to 3500rpm and get it to miss, then while its missing pull of 1 coil lead at a time and see which cylinders are missing, then swap your coil wires over and do it again, if the coil is faulty then the miss will move to the other 2 cylinders, then coil is faulty

i agree with these guys a coil is my first thought but could also be a lead or bad plug.there are coil lead testers u can buy relativle cheap 15-30 aud from repco or an abw dealer, that u clip the lead to 1 end and the other to the plug .. the abw 1 has a clear chamber with a set gap so u have to rev it to the miss piont and check each cyl indervidualy, the repco 1 connects the same way but has an adjustable gap so u can idol the bike and slow wind out the gap till the spark starts to miss,, chack all cyls and if theres a faulty lead or coil it will only jump a small gap ie 1 cm , where at the good coils will jump about an inch,...
hope this is able to help u

Just a thought it is not recommended to run the ignition coils without a spark being able to be present because the resultant voltage surge can cause the insulation in the coil to break down.
Regards,
K-BIKE

no no the 2 spark testers rout the spark from the ciol lead to the tester back to the plug, while its still in the bike running

These are inline testers.

pretty close 2 the 2 i have, the large 1 is spot on.

I understand the device but when you pull the gap out to diagnose the point where the spark stops jumping then surely you are stressing the coil insulation?
Regards,
K-BIKE

yes thats the piont to find the 1 that can not jump as far... ie ciol 1 can spark 3 cm befor missing, coil 2 can spark 2.7 cm befoe missing ciol 3 can spark 3 cm before missing and coil 4 can only spark 1 cm befor missing,,,, ciol 4 is weak and faulty. under load/ stress the coil cannot handle the load it is being given. and under revs ect or hill clime this will cause a miss. as in i belive a direct relation to this the amount of voltage this coil is able to produce is the distance it can jump before missing..

its also under ability of the plug or lead as if a lead has high resistance or an open circut. it can cuse a miss, poor isulation on the plug or surverly fould plugs, the k100 has a tube on the end of the leads? yes these are comon leak spots on cars, as the revs increese the voltage from the coil increases makeing the spark able to jump further, this enable it to jump threw a verry small split or imperfection in the tube bypassing the plug and earthing on the rocker cover or head out side the head. easy way to check for spark leaks, at night with the cover off and rev her to til she misses and look down each the hole to see if theres any blue/yellow flashes. but u can usally hear the tick tick tick...,.

but the spark miss to me is eliminated buy the pig root and back fire, which says to me either the spark has built up in the lead or ciol due to hi resistance and the let loose buy over coming the resistance. the only other way i know u get a back fire is hot raw fuel entering the exhaust and coming in contact with fresh cold air. . but no mention of an exhaust leak. so the hes has been replaced ( hall effect sensor ) for clarity, no ehaust leaks for back fires,the fi ecu replaced, assuming the mech did his jobproper and chacked the pump is able to produce enuogh flow, the injector have beeen replaced.. the miss has to be spark and sound typical of a coil or ht lead or ignition module

there is the possibilty of a lean backfire, can something shut the pump down for a sec or the injectors... have each of the injectors been tested while running with a led test light. just watch the flashes to see if 1 goes out of sync or stops. or just goes stupid in its flashes, u need to chack 1 at a time and rev the bike up slowly, the test probe needs to be in 1 wire or the injector plug and the earth clip, attach it to a paper clip and probe the same injectors other wire, u need to probe both wires or it wont flash.

so in breife get the fuel pressure east and flow test again..
check for a weak coil, or bad lead,
test each injector pulse,, will also i am assuming in 99% of automotive industry chack the pulses to the coil to.
sorry it massive post .

The K100 has two coils which are double ended and has a wasted spark when one cylinder is empty and the other is on compression. The K75 has two coils.
Regards,
K-BIKE

I guess you are most of us and have fat fingers. I am sure that you wanted to hit the key "three" but in stead hit the key "two"

lol i have dislexic fingers

That is exactly what I meant to type and the problem with knowing what I meant to type is I read what I intended rather than what I did. Doh!
Regards,
K-BIKE

Problem fixed:)

I went ahead and bought 2 new coils and a set of NGK wires. This has fixed the bucking problem that I had but not the hesitation that was the 3200-3500 rpm range. I went ahead and replaced the air fuel sensor--this was the third one--and I'm telling you this bike runs just like brand new. Thanks guys for all your input !!