How to start a Single Cylinder Q ?

I’m at a loss to understand how the inlet tract fills with spent charge by using the valve lifter - does the Velo valve lifter act upon the inlet valve rather than the exhaust? Surely when the exhaust valve is held off it’s seat by the valve lifter the piston will force the cylinder’s contents out the exhaust port regardless of valve timing.
What am I missing?
 
On my Venom the previous owner wrote this:
Then perform a little modified Hall Green Procedure. Modified because the primary transmission ratio is a bit different on this bike.
First move the kickstart lever against compression, then activate the valve lifter and move the kickstart lever ABOUT HALF it´s total stroke. Then let go of the lifter and release the kickstart to its initial position and give a healthy kick. It should start first kick. If it has been standing for a while, sometimes oil is collected in the bottom of the crankcase and then it will never start until the crankcase is emptied by the drain plug in the bottom. I always use the small kill button on the lh electric switchgear to stop the engine, not the valve lifter.
The standard procedure is full stroke, not half.
 
Richard Tool said:
I’m at a loss to understand how the inlet tract fills with spent charge by using the valve lifter - does the Velo valve lifter act upon the inlet valve rather than the exhaust? Surely when the exhaust valve is held off it’s seat by the valve lifter the piston will force the cylinder’s contents out the exhaust port regardless of valve timing.
What am I missing?
Click to expand...
Lifter only opens the exhaust valve. I can see how it could happen, depending on where in the 4 strokes the piston is when the exhaust valve is lifted. For example if just starting intake stroke, air will be drawn in not only from the carb, but also from the exhaust header. But, a good kick through all 4 strokes should certainly refresh the intake charge for next start attempt.
 
Good discussion. Applies to my Matchless too. I shut it down with the valve lifter as there's no provision for cut-out on my competition mag. A 500 Matchelss has a very heavy flywheel, so I use that to my advantage. I've had to hoist them onto the bench and up onto the V-blocks many times to align the crank. Don't know if they stay that way but at least they're straight to begin with.

On cold startup with no throttle, mine will fire once only, as many times as I want to kick. After two attempts I give it about 1/3 throttle and it fires up every time.

Before I installed a BriteSpark capacitor in the mag it would start with no throttle, first kick when cold, most of the time. That is, until the cap died altogether at which point it would not start when warm unless one pushed it down a hill. Bad scene if you shut it down in the dirt with no hill around.
 
Mike40M said:
On my Venom the previous owner wrote this:
Then perform a little modified Hall Green Procedure. Modified because the primary transmission ratio is a bit different on this bike.
First move the kickstart lever against compression, then activate the valve lifter and move the kickstart lever ABOUT HALF it´s total stroke. Then let go of the lifter and release the kickstart to its initial position and give a healthy kick. It should start first kick. If it has been standing for a while, sometimes oil is collected in the bottom of the crankcase and then it will never start until the crankcase is emptied by the drain plug in the bottom. I always use the small kill button on the lh electric switchgear to stop the engine, not the valve lifter.
The standard procedure is full stroke, not half.
Click to expand...

Thomasa said:
Good discussion. Applies to my Matchless too. I shut it down with the valve lifter as there's no provision for cut-out on my competition mag. A 500 Matchelss has a very heavy flywheel, so I use that to my advantage. I've had to hoist them onto the bench and up onto the V-blocks many times to align the crank. Don't know if they stay that way but at least they're straight to begin with.

On cold startup with no throttle, mine will fire once only, as many times as I want to kick. After two attempts I give it about 1/3 throttle and it fires up every time.

Before I installed a BriteSpark capacitor in the mag it would start with no throttle, first kick when cold, most of the time. That is, until the cap died altogether at which point it would not start when warm unless one pushed it down a hill. Bad scene if you shut it down in the dirt with no hill around.
Click to expand...
Is that some sort of capcitive discharge ignition (CDI) from the mag? My BTH mag is the newer EI type with an externally mounted Capacitor/CDI. Form what I've learned, mag provides a 300-600 Volts DC to the CDI, which then steps that up to 80-100K Volts range outto sparkplug. The CDI unit is no bigger than a modern flasher relay....which is what I thought it was when I first saw it on the bike. Wonder why we do not see these on our Commandos?

As for flywheels, apparently the Velos do not have any pins/bolts/pegs holding the flywheels aligned....its just a good taper fit. Some cautions are found on the Velo forums about using e-start setups as they can dislodge the flywheel alignment....though no such worries for roller starters (presumably b/c they work through the drive &, primary chain arrangements).
 
Tornado said:
Lifter only opens the exhaust valve. I can see how it could happen, depending on where in the 4 strokes the piston is when the exhaust valve is lifted. For example if just starting intake stroke, air will be drawn in not only from the carb, but also from the exhaust header. But, a good kick through all 4 strokes should certainly refresh the intake charge for next start attempt.
Click to expand...
I see your point and agree that can happen but the flywheel goes through several revolutions while winding down , all the while the exhaust valve stays open and the inlet valve opens/closes by the cam , seemingly enough to purge any spent fuel / air .
( emphasis on “ seemingly “ - I certainly may be wrong)
It has never made my ES 2 more difficult to start but Velocettes
( at least some models ) are certainly more highly tuned/ sensitive.
 
Tornado said:
Is that some sort of capcitive discharge ignition (CDI) from the mag? My BTH mag is the newer EI type with an externally mounted Capacitor/CDI. Form what I've learned, mag provides a 300-600 Volts DC to the CDI, which then steps that up to 80-100K Volts range outto sparkplug. The CDI unit is no bigger than a modern flasher relay....which is what I thought it was when I first saw it on the bike. Wonder why we do not see these on our Commandos?

As for flywheels, apparently the Velos do not have any pins/bolts/pegs holding the flywheels aligned....its just a good taper fit. Some cautions are found on the Velo forums about using e-start setups as they can dislodge the flywheel alignment....though no such worries for roller starters (presumably b/c they work through the drive &, primary chain arrangements).
Click to expand...
Flywheel alignment: Ray Thurston of KTT services explained that the electric start connects to the crankshaft outboard of the engine drive sprocket. That original sprocket is very close to the main bearing and is a good design. However, the electric start now has a mod. from the Owners club ( which I don’t know details of), to reduce tendancy to disturb flywheels.
 
Mike40M said:
On my Venom the previous owner wrote this:
Then perform a little modified Hall Green Procedure. Modified because the primary transmission ratio is a bit different on this bike.
First move the kickstart lever against compression, then activate the valve lifter and move the kickstart lever ABOUT HALF it´s total stroke. Then let go of the lifter and release the kickstart to its initial position and give a healthy kick. It should start first kick. If it has been standing for a while, sometimes oil is collected in the bottom of the crankcase and then it will never start until the crankcase is emptied by the drain plug in the bottom. I always use the small kill button on the lh electric switchgear to stop the engine, not the valve lifter.
The standard procedure is full stroke, not half.
Click to expand...
Do we know what stroke a half depress on kicker past compression places the engine versus a full depress? End of power stroke, exhaust stroke or intake stroke?
 
Tornado said:
So if killing with lifter is a no no, what is correct way to shut it down? Braking while in gear with no clutch so it stalls?
Click to expand...
Preference is grounding the magneto with a switch. My thruxton has no kill switch so I put it in second gear and let out the clutch to kill the engine.
 
Richard Tool said:
I’ve been shutting down my Garden Gate ES 2 for years by
using the valve lifter with no apparent problems . It is my understanding that there is some valve overlap with this motor.
Click to expand...
Nothing compared to a thruxton. I also have a garden gate es2. Unfortunately mine is still in boxes.
 
Tornado said:
Lifter only opens the exhaust valve. I can see how it could happen, depending on where in the 4 strokes the piston is when the exhaust valve is lifted. For example if just starting intake stroke, air will be drawn in not only from the carb, but also from the exhaust header. But, a good kick through all 4 strokes should certainly refresh the intake charge for next start attempt.
Click to expand...
I think the problem has to do with the fact that the intake is open before the end of the exhaust stroke so the mass of the intake charge starts being pulled into the cylinder with the inertia of the exhaust. Don't know why it happens but know that I can start my thruxton almost immediately if I kill it at a stop light or it has been sitting 20 minutes. But if I kill it with the valve lifter at a fuel stop it takes quite a few kicks to clear the intake and start it. I learned this the hard way, had to carry a small bottle of wd40 to use as starter fluid. You could see and smell spend exhaust come out of the carb. Although I doubt it matters mine is one ofthelast 50 that was supplied with 38mm concentric and was originally spark ignition although now with original BTH mag. Neither my MAC or KSS has this peculiar operational trait.
 
The Brite Spark I mentioned a few posts back is just a replacement for the waxed paper cap that came from the factory. You can change them without dismantling the mag. I'll try stalling the motor with the clutch and see if it starts differently.

Aligning Matchless flywheels is an art form involving a large pry bar and C-clamps along with a couple of BIG spanners for the pin nuts. Sometimes there is the temptation to use the lead hammer mostly used for straightening bent dirt-bike rims. But in the end one is dealing with a few thousandths of an inch. As I said I have no idea if they stay that way. Velos sound like a more precision proposition.
 
I had a buddy with a Velo. He would never have ridden it if he didn't live on a hill. It had the shortest little kicker I have ever seen on a bike.
 
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