Here’s my problem. I have a 96 787 GSX. PTO side piston which was already bored .050 over, upper ring broke breaking top edge of piston causing score in cylinder wall, had to replace cylinder with used one that was then bored .050 over, put 2 new pistons and rings, split the crank case to remove debris and reset counter balance which was 30% off timing from last tear down when crank was replaced. When I got the engine back, and installed, I had gone out for three rides and it ran 100%. On the fourth ride, it would not fire when I tried to start it. I removed the spark plugs, had spark, then re-installed and still would not start. Repeated multiple times and it eventually started, and ran 100%. After turning it off it would not start again. So this is what I have figured out so far…
I have my spark plugs grounded off on the engine not being threaded into the engine, and when I turn it over I have good spark. When threading in an extra plug into the engine, (creating resistance) 50% of the time I would lose my spark. When threading in a second extra plug, 95% of the time I lose spark. (I still had the original 2 plugs and wires grounded out on the outside of the engine while I was trying this so I could have a visual of the spark) I have found that I lose spark when I put any resistance on the engine. I am using my car battery at this time with the car off and the old battery unhooked from machine. It has something to do with when I put load on the engine.
I am using a good battery.
Starter was tested and came back good.
Solenoid is good.
All fuses are good.
All grounds are good.
All spark plugs are good.
DESS self diagnostic test is good.
Start Stop switch is good.
Could it be…
stator issue(removed magneto)
trigger coil(don’t think so)
rectifier(battery boiled dry)
mpem
cdi(low voltage)
timing issue (magneto timing)
This is what I think it could be… (keeping in mind that when I had it running, it was running 100%)
Low voltage at cdi (12.8 volts at the battery not under load and 10.15 volts under load)
I heard that the cdi is low voltage sensitive below 10.1 volts
My battery boiled dry, manual says that it could be a faulty rectifier causing excessive voltage. But unable to test unless machine is running. (I use a battery maintainer, could it possibly cause it to boil dry)
Is it my starter drawing too much voltage (there is a little hesitation at first only when engine under load even though battery tested good)
Magneto was removed, could the timing be off because I heard that it is threaded on, not on a key way and if not placed back in same place timing will be off
I am having a hard time checking ohms for some reason, I have service manual and specs.
READY TO GIVE UP!!!
I have my spark plugs grounded off on the engine not being threaded into the engine, and when I turn it over I have good spark. When threading in an extra plug into the engine, (creating resistance) 50% of the time I would lose my spark. When threading in a second extra plug, 95% of the time I lose spark. (I still had the original 2 plugs and wires grounded out on the outside of the engine while I was trying this so I could have a visual of the spark) I have found that I lose spark when I put any resistance on the engine. I am using my car battery at this time with the car off and the old battery unhooked from machine. It has something to do with when I put load on the engine.
I am using a good battery.
Starter was tested and came back good.
Solenoid is good.
All fuses are good.
All grounds are good.
All spark plugs are good.
DESS self diagnostic test is good.
Start Stop switch is good.
Could it be…
stator issue(removed magneto)
trigger coil(don’t think so)
rectifier(battery boiled dry)
mpem
cdi(low voltage)
timing issue (magneto timing)
This is what I think it could be… (keeping in mind that when I had it running, it was running 100%)
Low voltage at cdi (12.8 volts at the battery not under load and 10.15 volts under load)
I heard that the cdi is low voltage sensitive below 10.1 volts
My battery boiled dry, manual says that it could be a faulty rectifier causing excessive voltage. But unable to test unless machine is running. (I use a battery maintainer, could it possibly cause it to boil dry)
Is it my starter drawing too much voltage (there is a little hesitation at first only when engine under load even though battery tested good)
Magneto was removed, could the timing be off because I heard that it is threaded on, not on a key way and if not placed back in same place timing will be off
I am having a hard time checking ohms for some reason, I have service manual and specs.
READY TO GIVE UP!!!
