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Discussion Starter #1
hi

HELP!!!!!!!!!!!!!

my 99fx needed a new motor after being stolen and crashed. it still ran but had a large piece of the case broken off, so i purchased a motor but ended up with a f4i motor.

i removed the original motor, put the f4i case/gearbox in my bike and replaced the efi with the original carby setup. i am using the original wiring harness from my bike.

Pretty much everything connected straight up, except for the alternator plug (yellow 3 wire plug)which was modified to fit my harness. there appeared to be only one plug not connected which is at the front left of the motor. i think this is a timing sensor for the efi motor and isnt present on the carby motor.

i changed over the water pump cover and thermostat cover to the ones from the carby motor.

i didnt have the service manual at the time i took out the original motor, so i didnt realise the throttle position sensor shouldnt have been removed.

i put it all back together and it wouldnt start.

after a lot of messing around i purchased the clymer manual, found out about the t.p.s. I looked on the net and tried to figure out how it worked. i think i have it back on correctly.

the readings are as follows-
voltage Va 4.73
at idle 0.44
full throttle (wot) 4.24

are these values correct?

so...........

the motor cranks over.

it wont start, but it gets fuel and does a backfire sporadically with a flame out of the exhaust. im guessing this is due to incorrect timing but i dont know why? ive resorted to hooking the bike up to a car battery so it doesnt go flat trying to start it.

the bike ran with the original motor.

im getting really frustrated. is there some difference with a sensor or something in the motor that im not aware of?

can anyone offer any help or suggestions. i can provide more info if needed;
 

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hi

HELP!!!!!!!!!!!!!

my 99fx needed a new motor after being stolen and crashed. it still ran but had a large piece of the case broken off, so i purchased a motor but ended up with a f4i motor.

i removed the original motor, put the f4i case/gearbox in my bike and replaced the efi with the original carby setup. i am using the original wiring harness from my bike.

Pretty much everything connected straight up, except for the alternator plug (yellow 3 wire plug)which was modified to fit my harness. there appeared to be only one plug not connected which is at the front left of the motor. i think this is a timing sensor for the efi motor and isnt present on the carby motor.

i changed over the water pump cover and thermostat cover to the ones from the carby motor.

i didnt have the service manual at the time i took out the original motor, so i didnt realise the throttle position sensor shouldnt have been removed.

i put it all back together and it wouldnt start.

after a lot of messing around i purchased the clymer manual, found out about the t.p.s. I looked on the net and tried to figure out how it worked. i think i have it back on correctly.

the readings are as follows-
voltage Va 4.73
at idle 0.44
full throttle (wot) 4.24

are these values correct?

so...........

the motor cranks over.

it wont start, but it gets fuel and does a backfire sporadically with a flame out of the exhaust. im guessing this is due to incorrect timing but i dont know why? ive resorted to hooking the bike up to a car battery so it doesnt go flat trying to start it.

the bike ran with the original motor.

im getting really frustrated. is there some difference with a sensor or something in the motor that im not aware of?

can anyone offer any help or suggestions. i can provide more info if needed;

Sounds like the cam position sensor on the head - which shouldn't make any difference at all.
You're running all the original electrics including the ECU?
The fuel pump primes and the engine cranks fine?
The backfiring would indicate either incorrect valve timing or a breakdown in ignition spark or timing.
Are the plugs new?
Have you removed the valve cover to check cam timing?
Was the camchain tensioner removed at all?
I can't really comment on the TPS but the easiest way to rule it out is to borrow a set of carbs and try those.
 

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Discussion Starter #3
update

i havent been able to get the bike to run yet. what i have noticed is that the timing is different on the injected f4 motor. the timing is not adjustable and is set at the factory.

due to the amount of damage done to the ignition and system and wiring when it was stolen, ive decided to purchase a second hand HISS set and run with the the fuel injection. given that i will have to purchase a lockset anyway, the cost of the HISS system is not really much more than a new lockset so it seems like a feasible way to go.

and it will stop me from wanting to wreck my bike in frustration. ill repost once i get the hiss and hopefully get my cbr running.
 

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32,034 Posts
update

i havent been able to get the bike to run yet. what i have noticed is that the timing is different on the injected f4 motor. the timing is not adjustable and is set at the factory.

due to the amount of damage done to the ignition and system and wiring when it was stolen, ive decided to purchase a second hand HISS set and run with the the fuel injection. given that i will have to purchase a lockset anyway, the cost of the HISS system is not really much more than a new lockset so it seems like a feasible way to go.

and it will stop me from wanting to wreck my bike in frustration. ill repost once i get the hiss and hopefully get my cbr running.

The HISS is not much more than a lockset?
You must've found a great deal on it.
To run the F4i's injection on the F4 you'll need the full harness, ECU and instrument cluster as well as the throttle bodies. Possibly the airbox as well. Aand check the wiring diagrams as periferals like the switch blocks may have different wiring. You'll also need the bank angle sensor and all the engine sensors.
 

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I would say replace the timing advancer with the carby one... you know the thing under thet chrome cap on the clutch cover, sorry if that sounds like an idiot wrote it but I had no other way to discribe it.... I think that might be the problem.
 
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