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low power

1101 Views 14 Replies 4 Participants Last post by  gazx10
i have been asked by a friend to look over his 2014 race bike, it is down on power ( 145 on dyno). no known codes showing however unkown fault comes up. thought it might be top rail injectors blocked but they are working, then i thought secondry butterflies, nope opening fully, has a flashed ecu, no power commander. can any one point me in the direction of a common fault before i start testing all sensors etc etc
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Well, if there's a FI light then you need to pull the code. There's no point in even speculating or checking random shit until you figure out what is causing the FI light. Pull the code.
fi light

hm dash no fi light, pulled codes from ecu only came up unknown fault hence the call out
hm dash no fi light, pulled codes from ecu only came up unknown fault hence the call out

Welp, unless you're using the Kawasaki diagnostic system (not available to the public), there's no way to retrieve stored codes from the ECU. And there's no such thing of an "unknown" code. If it was a valid code, and active, it would light the FI light. So it sounds like you're chasing a non existent problem.
140bhp on dyno is a major issue, compression is spread from 120 to 130 across the 4 cylinders, no leak down, no smoke, fuel pump and filter fine mix when it was on the dyno was slightly rich. going to clean injectors and start the long process of testing everything through. bring back carbs so so simple

the bike has been to 2 dyno's and neither could identify the reason for the poor performance and it is from one of those i have the unknown fault. all other issues they found were corrected whilst there. started with 121 and after 2 visits got it to 140 but long way to go
are u measuring compression in psi at 120-130 with throttle wide open? if so with good leakdown cam timing incorrect and the problem.
ok i was thinking cam timing was going to be top of the check list.
yes 120 to 130 psi and throttle wide open. did each cylinder three times to confirm reading, engine spun 5 times per test to ensure i see max. same way i have always done it
compression within 10psi each cylinder, good leakdown on cyls., low reading as 120-130 throttle open, is a cam timing problem. power comes from cyl pressure, cant generate much power with those accurate compression readings. rings/valves sealed as verified by leakdown test only factor left is int/ex valve opening/closing events are off. this is ur problem, know what im saying thru experience.
i wouldnt have thought it possible for the valve timing to slip but having said that i have just found out he cart wheeled the bike at Cadwell on his first outing. i agree with you valve timing would do this and i will start there tomorrow night and report back
i am assuming ur compression gauge was sealed and accurate.
yes of course sealed and very accurate
valve timing is correct, exhaust and inlet are in the right positions and all shim settings are within tolerance.NEXT!!
Check how many notches tensioner is advanced (remove center bolt and spring before), if it is many more than 5 then chain may be streched. If manual tensioner, then put back stock tensioner just to judge chain strech. Checking visual valve timing marks shows only that chain has not skipped, but if timing is off some five degrees (per crank), then it cannot be seen by naked eye.

If sensors are good too and you cannot figure it out, then do cam degreeing with degree wheel and indicator.
hadn't thought of cam chain stretch very common on some nissan engines which brings same fault. also going to redo leak down test
compression readings u stated indicate actual compression ratio of about 9.0 to 1 which would limit power dramatically as ur experiencing. good leakdown, valve clereance in spec., cam timing correct, those #'s dont add up. reverify before moving on.
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