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Honda two stroke points question - help please.

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Hi there,


Thanks for taking the time to read my question.


I am a little confused with the wiring on my Honda MR175- any help greatly received!


The manual advises checking the points gap by rotating the engine and using a battery/bulb to see when the light goes out.


The bulb on mine doesnt go out - even if I jam the points open.


The wiring diagram seems to indicate that the points and ignition coil are both earthed.


The other end of the coil seems to be wired to the isolated part of the points. If this is right then I dont get how the bulb would ever go out - as it always has an earth path independant of the points?


As advised in the manual - the battery / bulb checker is used as follows - negative from battery to earth. Positive to bulb, then other side of bulb to stator wire (yellow / black on the mr175)


Can someone please explain the wiring of the ignition coil relative to the points?


Thanks again




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First off, does the bike run?


Second, make you life REALLY easy, get an old school timing light (you can RENT timing lights at many auto part stores such as Auto Zone, just google "timing light"), use a battery to power the light (some lights even have their own build in power) and connect the timing light to the spark plug wire. Start bike let bike warm up and then idle. Point timing light at the flywheel at the mark and the case mark and the "F" mark should line up if the timing is set correctly.


If the "F" mark and the  case mark do not line up, open or close the gap as necessary. Closing the point gap retards the timing so the spark fire later, opening the gap advances the point timing so the spark fire earlier.


As a teenage I tried to use the light bulb method, it can work but using a timing light is so much easier, accurate and faster.


Here is a video on setting the timing on a Honda CT70, the principles remain the same even though the bike is different.



Hope this helps.

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Hi Thanks so much for the reply - I will get a strobe light and give it a go.


Great video - thanks for your help!

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