Starting trouble

[tippi11]

Another two hours in the garage this morning to check some basic things: changed spark plug with one that proofed to be ok even under compression (previously used in another bike), adjusted ignition timing to less than ½” (circa 10mm) before TDC, unscrewed pilot air screw 1.5 turns from fully closed, applied easy start aerosol to carb mouth. Nothing happened during several kicks, no response from engine, like “dead”.

My personal resume: There is a spark, not necessarily a perfect but at least a clearly visible one, there is compression and there is fuel in the form of easy start aerosol – from a logical point of view the only remaining thing is (wrong) valve timing, e.g. inlet valves opens at the wrong time/crank position and prevents a correctly timed flow of the air/petrol mixture.

I will send photos of the timing side later today.

Dick: I will drain oil later today. No, my SR-1 hasn't attached this unit, the auto A/R. With this bike ignition timing is adjusted by getting the magneto lobe to a position where the contact points just start to open (1/2” before TDC). This is achieved by slackening the magneto drive sprocket and slightly rotating the drive shaft, which carries the lobe, until the lobe opens the contact points at the desired moment.

Regards, Peter

[Dixter]

Hi Peter. This is 100% proven to work ..... every time.

http://archives.jampot.dk/technical/Gen ... e_Dots.pdf

Did you use this procedure for timing your valves?

Ciao, DC

[Mick D]

Hi

Have you checked that both valves are operating after you adjusted the valve timing? you could have dislodged a push rod during the process.

Did you confirm the tappet clearances post valve timing?

Are you sure you are setting the ignition timing on the compression stroke?

And thinking a long way out of the box - are you sure you have an inlet and exhaust cam, are they compatible and in the correct, (inlet / exhaust), position?

Regards Mick

[tippi11]

Good evening,
Here are the requested photos of the timing side:
(roughly painted the dots for better identification on the dark gears)

1. exhaust valve gear and pinion dots current positioning
2. inlet valve gear and pinion dots current positioning
3. at TDC, dot on pinion is in line with the key (checked this by unscrewing the nut)

What do think?
Regards, Peter


PS: There is one other thing: When I removed the timing side there was more oil dripping out of the casing than expected for timing gear lubrication. Could that be from the (wet) sump after only 20 kicks or so?

[tippi11]

Mick D,
What is your method to make sure it is on the compression stroke? I put my thumb on the plug hole to feel the pressure...
Regards, Peter

[Pharisee]

Mick D,
What is your method to make sure it is on the compression stroke? I put my thumb on the plug hole to feel the pressure...
Regards, Peter

When you're setting the valve timing, there isn't a 'compression stroke' until you've defined it by setting the cams. Until that time, there is only T.D.C.

[Mick D]

When you're setting the valve timing, there isn't a 'compression stroke' until you've defined it by setting the cams. Until that time, there is only T.D.C.

Are you sure you are setting the ignition timing on the compression stroke?

Hi

I thought it was fairly clear I was referring to the ignition timing

Peter

No that's not how I would determine the compression stroke - if you rotate the engine so as the piston is at it's highest point, (put a wire or pencil down the spark plug hole to do this), then go to the push rods and see if they are both free to rotate, if they are not rotate the engine another turn, (360 degrees), and check again, if they are then free to rotate that's TDC on the compression stroke, if they are still not free to rotate either the tappet adjusters are incorrectly set or the valve timing is wrong.

Regards Mick

[spookefoote1956]

So your inlet cam should be at 2 o'clock and using the lower dot. Rotate clockwise and fit exhaust cam at 10 o'clock. The nearest dot on the cam to the pinion should be used. Correct pushrod adjustment is vital.

[tippi11]

Mick, I am sorry: I missed to say that I use an old spoke inserted into the plug hole to feel the piston´s TDC (the mentioned "thumb method" is only a quick check verifying the piston moves upwards for compression). With the valve timing shown on the photos I have free rotation pushrods at TDC.

skookefoote1956, Inlet and exhaust cam are currently fitted in the way you describe (this according to Ken De-Groome´s article "Joining the dots").

Regards, Peter

[tippi11]

Dixter, Yes I used this procedure - both cams are fitted according to the "Cams with 3 dots" section in the article. You state this is 100% proven to work - so, you would agree that my valve timing is ok?
Thanks, regards, Peter