73 T90 no neutral light and no spark!! Any suggestions?

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Sean McCarthy

New Member
Hi guys new to forum! I have a 73 ST90(got wk ago) I’m trying to restore for my dad(was his first bike) because he deserves it(has had pancreas and kidney transplant due to juvenile diabetes)... I have changed the coil(factory OEM)... filed the points...I am getting 6 volts at end of coil and everywhere else on bike you need power... but I can’t get any spark??!! Bike is in neutral but I have no light... changed the bulb(it was burnt out) and had voltage in the light plug... trying to figure out if the bike is not getting spark due to the fact that it is not does not know it is in neutral or if it’s not getting spark for another reason? I also changed the rectifier! Any info would be very much appreciated ... bike is rolling as we speak in N fine... I also took off crank case and found neutral switch looked good so I’m at a lose! That’s my dad in photo and my dog Logan
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kirrbby

kirrbby

Well-Known Member
b52bombardier1 is the resident ST90 guy. I imagine he will be piping in to help you when he sees your post. But I've "heard" him say, many times, "you need a GOOD battery to get spark on these bikes"

Welcome to lilHonda.
 
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Sean McCarthy

New Member
Thanks for quick response... really appreciate it.. I have brand new battery filled it with acid my self and it’s showing 6.7 volts when tested... I’ve also heard that about the battery and that is why I’m so stumped! Thanks again
 
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b52bombardier1

Well-Known Member
Yes, definitely a good battery. Use your multimeter at the actual points (under riders left side cylinder cover) to see if you have six volts there. If not, backtrack your way through the points wire through the run stop switch and key to see where you have lost six volt power. Fix whatever you find there.

There is no safety lockout for starting these bikes when not in neutral. You may also need to unscrew the spark plug cap and cut a quarter inch off and then reinstall the cap. The cap can also be internally broken for no spark continuity.

All of these bikes need a tuneup when found by guys like us. Points gap. Adjust valves. Set timing at the points plate. Clean the centrifugal oil slinger sludge from the interior of the clutch and clean the screen.

The battery is the voltage regulator that keeps you from blowing bulbs and its wiring needs to be good. What rectifier did you use?

Rick
 
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