Aircraftman
New member
OK, this ones drivin me nuts! i need a new set of eyes on this one.
01 SRX weak spark on center cylinder at idle. drops off completely at high rpm. changed the following
- volt reg
- all coils
- all plug caps
- stator
- trigger
- cdi box
- spark plug
disassembled and/or checked
- pipes
-reeds
- compression
- carbs
- fuel pump
- power valves
tried disconnecting
- hood wire harness
- kill switch
- teather
- tach lead
- TPS
cant get a timing light to fire off of center plug wire. fires good off other 2.
Is this a batch fire system or does it fire each cylinder separately?
01 SRX weak spark on center cylinder at idle. drops off completely at high rpm. changed the following
- volt reg
- all coils
- all plug caps
- stator
- trigger
- cdi box
- spark plug
disassembled and/or checked
- pipes
-reeds
- compression
- carbs
- fuel pump
- power valves
tried disconnecting
- hood wire harness
- kill switch
- teather
- tach lead
- TPS
cant get a timing light to fire off of center plug wire. fires good off other 2.
Is this a batch fire system or does it fire each cylinder separately?
YAMMIEGOD3:16
Active member
HOLY CRAP, I AM LOST HERE WITH YA. SOUNDED LIKE HARNESS RUB, BIT I GUESS NOT. DON,T KNOW BUD. 3:16 (yammie tony)
Aircraftman
New member
I am hooking an oscilloscope to it Friday. I will for sure post my findings. I hope it's something stupid!
I'm gonna beat this! Lol.
I'm gonna beat this! Lol.
Wow! Everything I would suggest, most you have listed as checked!...LOL!.. I will state them anyway:
-check/replace sparkplug cap
-check/replace coil + coil high tension lead
-check all electrical connections
-check for continuity on all leads leading to coils [maybe this harness from the stator to the coils is faulted]
-ensure coil grounded properly
-check that flywheel keyway in place
-check/swap flywheel with a known working one
-unlikely a stator as the other two cylinders have normal spark
-unlikely the trigger sensor as it fires the other two cylinders
Some questions:
-does the engine still have the original cases, stator, coils and flywheel?
I ask this as the cases + ignition system are not compatible from 1998/99 to the 2000/01/02s
JM.02
Bob
-check/replace sparkplug cap
-check/replace coil + coil high tension lead
-check all electrical connections
-check for continuity on all leads leading to coils [maybe this harness from the stator to the coils is faulted]
-ensure coil grounded properly
-check that flywheel keyway in place
-check/swap flywheel with a known working one
-unlikely a stator as the other two cylinders have normal spark
-unlikely the trigger sensor as it fires the other two cylinders
Some questions:
-does the engine still have the original cases, stator, coils and flywheel?
I ask this as the cases + ignition system are not compatible from 1998/99 to the 2000/01/02s
JM.02
Bob
try switching out wire harness with known good one,,,,. run over top just to check.........
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YAMMIEGOD3:16
Active member
SOUNDS LIKE YOUR TAKING THIS SLED TO THE DOCTOR. lol. 3:16 (yammie tony)Aircraftman said:
You didn't mention replacing the spark plug wire, just the cap. Also, check the ground wire for that coil to make sure that it is making proper contact. Maybe run an additional ground wire to it as a quick check.
Mills
Mills
Aircraftman
New member
Aircraftman
New member
still got the same carbs on it. gonna try another set.
The o-scope test was at idle- wont rev. you touch the throttle and it coughs.
cases, cyls, pistons stock with porting.
reeds good
just a note- to test if the stator is bad just disconnect volt regulator and hook a 12v battery to the sled side wire harness red and black on that connector, if it runs good- disconnect the battery you wired into the connector ad hook ur volt reg back up- if it runs bad again- there u go!
The o-scope test was at idle- wont rev. you touch the throttle and it coughs.
cases, cyls, pistons stock with porting.
reeds good
just a note- to test if the stator is bad just disconnect volt regulator and hook a 12v battery to the sled side wire harness red and black on that connector, if it runs good- disconnect the battery you wired into the connector ad hook ur volt reg back up- if it runs bad again- there u go!
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look for a vac. leak between the cases
Aircraftman
New member
Ok. Any suggestions for leak checking case halves other than carb spray?
What type seals are between center and outer cyls? Labrynth, ring, or rubber?
What type seals are between center and outer cyls? Labrynth, ring, or rubber?
There is a labrynth seal in the centre.
Your problem has quickly changed from "no spark centre cylinder" to "idles but won't accept throttle".
I would suggest maybe strting a new thread so it gets the proper attention from the members.
Some suggestions[start simple]:
-a search for everything I mention here will give you all the info you need
-this sounds like a typical tors issue
-check for a stuck choke plunger
-check your compression
-drain all your fuel out and refill with fresh fuel
-if the carbs have not had recent meticulous cleaning...do it and pay special attention to "Top Hat" fuel filters under each fuel inlet valve/seat
-swap with a known working CDI
-check the wiring harness for a rub through
-like mrviper says...check the cases for a leak
-stators can fool you...they test ok sometimes but can still creating problems
JM.02
Bob
Your problem has quickly changed from "no spark centre cylinder" to "idles but won't accept throttle".
I would suggest maybe strting a new thread so it gets the proper attention from the members.
Some suggestions[start simple]:
-a search for everything I mention here will give you all the info you need
-this sounds like a typical tors issue
-check for a stuck choke plunger
-check your compression
-drain all your fuel out and refill with fresh fuel
-if the carbs have not had recent meticulous cleaning...do it and pay special attention to "Top Hat" fuel filters under each fuel inlet valve/seat
-swap with a known working CDI
-check the wiring harness for a rub through
-like mrviper says...check the cases for a leak
-stators can fool you...they test ok sometimes but can still creating problems
JM.02
Bob
Aircraftman
New member
Ok. Fixed it. First of all, thank you all much for your help! Here's what happened;
The brand new trigger I put in was bad. It was from an aftermarket company. don't use any parts that aren't factory Yamaha parts! I didn't heed my own creed. Replaced it with a yamaha factory part and spark was excellent, fired right up but ran on 2 cyls
WTF? Well.....
After much investigating The center cylinder carb pilot circuit was found to be pouring fuel into the cylinder- too rich to run, didn't matter how you jetted it. Fixed the pilot circuit and ops check good!
WHEW!
NOW WE CAN TUNE FOR HP ON THE DYNO!
The brand new trigger I put in was bad. It was from an aftermarket company. don't use any parts that aren't factory Yamaha parts! I didn't heed my own creed. Replaced it with a yamaha factory part and spark was excellent, fired right up but ran on 2 cyls
WTF? Well.....
After much investigating The center cylinder carb pilot circuit was found to be pouring fuel into the cylinder- too rich to run, didn't matter how you jetted it. Fixed the pilot circuit and ops check good!
WHEW!
NOW WE CAN TUNE FOR HP ON THE DYNO!