Honda 90 battery ignition. CT90, C90, all 90's

Egor's garage

[jstrano]

Great video! Thanks for putting this up. I’m working on a ‘66 CM91 and although they made so many millions of these bikes there is remarkably little info on things like this!!!

[smid]

Informative and to the point. thanks -

[christopherpearsallii]

Bottom line. Honda 90s need a battery to run. Some will produce a visible spark without a battery. However there usually isnt enough power to spark under compression. Some do run, but very poorly and dont usually idle. Venturing out with a weak battery can leave you stranded.

[AB-kufu]

Hey David, I have a CT 90 with no wiring loom so the motor cant be started. Are you able to do a sketch of basic wiring just to prove the motor a runner please. My stator has 1x green with red line, 2 x white and 1 x yellow. Also can it be started with no battery? Thanks.... Alan from Australia

[GSALLAN]

Hello David and thank you for this excellent simplified and comprehensible ignition video! I have a 1975 ST90... This year I have gone through 2 batteries and 1 rectifier thinking one or the other was the cause of mid-flight motor "dying" - moreso when the is on... turn the light off, motor kicks back up... but eventually dies... After replacing both the rectifier and battery same time last week, the problem came back... So I am thinking the stator is shot... but if it looks good it sounds like the issue maybe just be points? Would that be fair assessment? When the battery is charged there are no issues, for about 15 minutes of drive time then the mid-flight dying starts all over... Thank you!

[deweyself]

Thanks I been wondering how a rectifier wires, that was very helpful.you explain it so good, me a cave man can understand.lol.

[mechanibro]

can you tell me that that honda cub 90 made in1974 is a magneto or it needs a battery.

[blair]

Hi David. Just have a question that I thought you could help me with. I’m currently fixing spark problems on my 1972 CT90. I have 6V throughout the whole system. Up to the key. At the red wire going to the coil but still no spark. I discovered today that I’m only getting 2V at the points on the little spring arm. Is this an issue? Also the little spring arm gets very hot when I turn the key on? Is this normal? Do you know what might be the reasoning behind this? Thanks

[diesel]

Thank you for the fantastic explanation.

[Ataxia]

Thanks for the rundown David. Im actually having some troubles here with my 67' CL90. When i turn the switch to the "night-mode" you mention (Low beam or High beam position) the battery voltage starts going south and eventually the bike will shut off.. This is with the engine running and a multimeter hooked up to the batt. Im getting around 6.2v (with engine running/ light off) with a slow increase when i rev the throttle then as soon as i flick the headlight on the voltage falls off and keeps dropping pretty drastically until it cuts off... Does this sound like it could be the rectifier or the maybe stator? hmm mystery to me.. . I would welcome any wisdom here. -Thanks

[robertmontero]

i have a 1969 cl90 and 6 months ago when i purchased it it didnt have a battery and before starting a restoration on the bike i checked for spark several times and it did, now that the bike is all put back together i dont have a spark unless i hook a 6 volt battery, i replaced the selenum rectifier and checked all the wires from the stator to the rectifier and ok, i cant figure out why i dont have a spark with out the battery,

[freackjoe]

Hello when I turn on the lights in my ct90 1977 the engine start to fail when I turn of everything it’s ok.
It’s that a problem in de voltage regulator thanks