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360’ ... it didn’t occur to me both pistons rising and falling in tandem. The difference being which stroke they each experience. Hmmm
View attachment 738237
Allow me to think out loud: as one piston is on its compression stroke (both valves closed), the other must be on its exhaust stroke (exhaust valve open). So In 4 strokes, the engine -as a whole - experiences a compression/spark-inspired combustion event every other stroke.

From a timing perspective, shouldn’t the point for each cylinder close to make contact on its respective compression stroke as that cylinder reaches either TDC or just before? In your explanation, you indicate points are open at TDC... I’m missing something.
Hi
The coil fires through induced voltage, there are two coils of wire within an ignition coil, a high current low voltage primary and a ha high voltage low current secondary so works opposite to what you would think, when the points close they charge up the primary side of the coil, when the points open the breakdown of the charge causes a change in the magnetic flux in the primary coil, this induces a current in the secondary coil as the windings are wound so they are concentric with the primary coil windings.
The ratio of turns in the coil is roughly 100:1 - the voltage induced is in a similar ratio. Depending on the number of turns in the primary and The number of turns in the secondary, the induced voltage secondary windings when the points open can be high (20,000 Volts).

If your ignition timing is correctly set the points will open at 14 degrees before TDC, close enough to be an indicator of piston position for kickstarting.
Regards
Peg.
 

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Discussion Starter #142
Hi
The coil fires through induced voltage, there are two coils of wire within an ignition coil, a high current low voltage primary and a ha high voltage low current secondary so works opposite to what you would think, when the points close they charge up the primary side of the coil, when the points open the breakdown of the charge causes a change in the magnetic flux in the primary coil, this induces a current in the secondary coil as the windings are wound so they are concentric with the primary coil windings.
The ratio of turns in the coil is roughly 100:1 - the voltage induced is in a similar ratio. Depending on the number of turns in the primary and The number of turns in the secondary, the induced voltage secondary windings when the points open can be high (20,000 Volts).

If your ignition timing is correctly set the points will open at 14 degrees before TDC, close enough to be an indicator of piston position for kickstarting.
Regards
Peg.
Thanks Peg,

'found a pretty good video that illustrates the induction coils in motorcycles.


Yes, it's counter to what I thought. 20k volts is a pretty good jolt! 14' before top dead center ... Saturday I'll be looking for those open points relative to kickstarter 'feel'. Thanks to the sound advice from you and others, I'm getting close to 1 kick starting!

Good news - I received my speedo cable from the USPS. Bad news - I tested my speedometer using the new cable and a drill. The speedometer doesn't seem to work. The needle just jiggles around. Soooo I'll need to mail it off for repair. I've already got a few recommendations from Kadutz I'll likely use. I was just waiting until I knew for sure it worked or not. How I tested it: pushed one end of the cable into the center fitting on the back of the speedometer and screwed it down (not tightly). 'chucked' the drill onto the other end of the cable-wire. Pulled the drill trigger in short bursts. No spinning needle, just a wiggle here and there. However... I wonder if the drill is too fast for the speedo (why I use short, cautious bursts). Perhaps that's why it didn't register? At any rate, I'll try it again tonight or tomorrow with an older drill I'll have to dig out of the garage... I tend to recall it had a slower speed but I can't be sure.
 

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Hi vstevens, Did you try reversing the drill? Run it steady. Look at the odometer. If it moves backwards, change drill direction. Off top of my head I don't recall which way to run drill.

Running speedo backwards doesn't hurt anything. The odometer will count backwards & speed needle won't really move as it's against the stop pin.

Maybe the owner removed speedo & tack do to not working. If you don't care about original, the repro speedos, tachs work decently at a fraction of the cost of rebuilding. Several owners I know use them.
Don
 

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However... I wonder if the drill is too fast for the speedo (why I use short, cautious bursts). Perhaps that's why it didn't register?
Unlikely I think, I've used the same method to test my speedo with a Makita battery drill on fastest speed and it only got the speedo up to 60 mph. I've got a feeling the drill had to turn counter clockwise.
 

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Discussion Starter #145
Unlikely I think, I've used the same method to test my speedo with a Makita battery drill on fastest speed and it only got the speedo up to 60 mph. I've got a feeling the drill had to turn counter clockwise.
Good news - dug up my old plug-in variable speed drill. (the previously used newer battery powered drill - a gift- didn't have reverse or variable speed). The speedometer AND and tachometer work, although the speedometer is definitely worn. As suggested by Don and Rusty, the reverse speed is what it needed. The speedo needle moved pretty smoothly up to about 60... I didn't want to push it past that. However, the needle returned to rest in jerky movements. Maybe its the drill, I don't know. At any rate, I can use it until after the holidays (don't want to make any larger purchases for myself until after I get gifts for my kids and grandkids). Soooo I won't be sending Nisonger my 'clocks' until after the new year. Perhaps the tachometer doesn't need any work at all, it seemed to work flawlessly... too bad I don't have a tachometer gear on my bike. Guess that's yet another thing for my growing list. If I've time tomorrow, I'll attempt replacing the speed drive on the rear wheel and install the speedo bracket under the left-fork top nut.

Don - Based on your experience and my last few outings, I do think my carburetor slides are worn, somewhat. This morning, I won't have time to take a longer ride and make adjustments to idle and air (wife has other plans). Maybe later in the week.

As an aside... When my grandkids were babies, I decided that they got so many toys from everyone else, that I wasn't going to add to the pile of unused stuff. Instead, I've been buying them gold and silver coins (depending on what I can afford at the time). It's been 8 years for my grandson, and he has a handsome handful of valuable coins built up. One Christmas I gave him a model airplane and he was upset... he wanted the coins to add to his collection! My hope is that by the time they finish high school and are ready for college, they will have a small treasure.

In the meantime, I'm having fun tinkering and learning about the T140, and motorcycle mechanics in general... perhaps more than the riding itself.

vince
 

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I just bought for my Trident such a copy of Smith Speedo and it fits in bigger Trident rubber cups which are the same with T140 and works. Cost was $67 + shipping still 1/3 of the cost of repeating of original. I also read these copies are quite reliable.
 

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Discussion Starter #147
I just bought for my Trident such a copy of Smith Speedo and it fits in bigger Trident rubber cups which are the same with T140 and works. Cost was $67 + shipping still 1/3 of the cost of repeating of original. I also read these copies are quite reliable.
Thanks Adam,
The Smiths clocks are nice, but I’m not convinced they are 2/3 better than Taiwanese copies!
 

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Discussion Starter #148
738427

Inside the contact points cover, old specs sticker 45 years Yellowed.

738429


as Peg suggested. Rotating the points cam with the Kickstarter. Shouldn’t there be a gasket here? Just to keep out water?
 
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