Timing reference

My 102 pug doesn't quite look like the manual or the wiki post for timing...is my reference the little notch at the top, or is it still the wiring harness on the left? No little arrow on it like the manual/wiki has.

It ran okay before taking the magneto off...not great, just ok. Decided to replace points and check/adjust timing. Now it isn't running.

If my fingers can handle the cold, I'm heading to check spark now. Fuel is good.


Re: Timing reference

Ok, spark looks weak. Couldn’t really see it on the plug, hooked up test light and it kinda glows...first time using that tool, was expecting something brighter though. I’ve only touched points and magneto, so I don’t expect the problem to be something other than that.

Re: Timing reference

That stator looks different because you have the upgraded 5-coil star Magneto.

that is good.

notch is your mark.

what did you set the timing to?

Re: Timing reference

Not sure what I was doing wrong, or just not doing, but it’s running again. But no better than before. Set it roughly 3/4” to right of notch like the wiki article shows for pug timing. Sounds decent on the stand, but gutless under load.

Next step is checking compression and more than likely down jetting. Just replaced carb with 15/15 sha with a 68(I think) jet and exhaust with MLM pipe.

Unless anyone has other input on what to check next???

Re: Timing reference

Gotta get timing spot on, 1.5 - 2mm btdc. Did you use the timing light? I would also oil the felt pad and put a dab of grease on the trailing arm of the points. If it suddendly runs wo you knowing then its something loose... Check all connections for cleanliness and tightness and grounds as well, always suggested to add another ground wire from your coil mount to one of the cylinder studs.

Re: Timing reference

your symptoms sound like late ignition timing.

what method are you using to establish top dead center?

check your timing again, and maybe your process as pat suggested.

make sure to also check that your top dead center mark ( >3/4") still corresponds, not just that points open at notch. any rotation of the crank during the process will alter timing.

highly suggest a micrometer ignition gauge.

Re: Timing reference

I tried using the depth rod on my dial calipers to measure TDC, but with it not being spring loaded, I couldn’t get a good read, had to just use a small rod and “feel” for TDC.

I don’t have an actual automotive timing light if that’s what you’re referring to for me to use. I will see if I can get a more accurate TDC reading and check/adjust again.

I still plan to check compression...just because it probably should be checked.

Manual also states to clean out exhaust port...probably a good idea to do that too.

Just put new tires and brakes on, I need to get out and abuse them!

Re: Timing reference

something like this:


it acts as a LIGHT piston stop to come up against while locking rotor down, and finds tdc easily.

and/or find a good way to lock the clutch bell, or otherwise work the other side of the crank so nothing budges when you put the rotor on.

timing light is a great tool too, shows how accurate your process is, and is a quick easy way to check things out.

Re: Timing reference

I also have a 102 with the same 5 coil, carb, and exhaust. I’m experiencing blowback out the carb as well as total lack of power. I’ve been seeking help on the thread titled blowback out carb. You probably know more than I do but I thought I’d just let you know about my thread and maybe you’ll find an overlooked solution on it.

Re: Timing reference

Apparently my new compression gauge is shit or I just don't know how to use it. Was showing about 40psi. Pulled the head and cleaned around the decomp valve and piston top. After assembly I realized it probably never would have ran at 40psi...so I proceeded with carb and timing.

I was able to hold my tongue just right and use my calipers to get a real measurement for piston movement. Looks like it was probably firing right at TDC, so I made the adjustment there.

Fired it up and sounded just fine again.

Checked the plug and decide I needed to down jet. Was a 68, dropped to 56 and took it for a spin.

The little shit was actually able to pull me up our drive. Still needs some tuning. Much better though.

New brakes are just as worthless as old ones. Better off doing Flintstone stops.

And holy shit does this thing feel unstable on a gravel road. Is it just this bike, or all peds in general that feel like you're on the fine line between upright and roadrash? I don't remember it being this way when I was younger...I also didn't have much sense then either.


Re: Timing reference

gravel roads just kinda dances the front tire all over for me, sketchy.

Re: Timing reference

These small tires and minimal suspension were not designed for gravel roads .

Heck , some of the stones are as wide as these tires .

Slow way down for curves . You're running on marbles .

Look for the smoothest parts and definitely stay away from any ruts .

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account