setting timing

[Topdad]

Naughty Dutch !! but impressive memory mate 

[RichardL]

For the 124 members who could have no idea what the joke is, having joined after the fact, here is the justifiable reason for the teasing:

http://www.a7a10.net/forum/index.php?topic=8695.msg61946#msg61946

Richard L.

[Topdad]

Nice one Richard.

[morris]

Ok Richard. And now off for some self flagellation... 

[pdg]

Thanks to everyone for their helpful suggestions and interesting anecdotes.

For my A7ST I'm going for 3/8" BTDC (or 9.525mm). Assuming (from a 2010 post) a con rod length of 6.5" (165.1mm) and a stroke of 82mm, I get a timing angle of 35.85 degrees (or 36 degrees to the nearest indicated on the timing disk and a width of the wire).

I'm planning on setting the timing with a dial gauge and checking it against the timing disk (and hoping as it's the first time I've attempted this).

Regards, Peter.

[chaterlea25]

Hi Peter,
If you use a dial gauge in line with the plug hole, its reading will not be accurate!
As the piston moves down the end of the gauge will move across the piston, giving a false reading
This factor depends on the shape of the piston crown so cannot easilly be calculated
I measured the dial gauge travel concentric with the plug hole, also using a degree disc.
0.375  vertical distance on the piston was equal to 0.440 in line with the plughole!
This was with raised crown pistons, so different with flat tops??

I made a piston stop from an old plug and a long threaded bolt with rounded end,
I set the crank position with a degree disc and then set the stop at that
Once made keep the tool for further use only on that particular bike

HTH
John

[muskrat]

G'day Peter.
If you've got a timing disk set up use a strobe light to check/adjust the timing, and check both cylinders are the same.
Cheers
John got in first.
With a timing plug I put it in wind motor over till it touches, mark the disk then turn the motor backwards till it touches again and mark the disk. Half way between the marks is TDC. I don't have a chart for the long stroke A7

[pdg]

Many thanks for your your messages. I was planning on taking the fuel tank off and making the dial gauge vertical, but I can see the timing disk is easier.

Could you give me advice about turning the engine over. I'm currently doing it by engaging a gear and turning the back wheel, avoiding the dangers of loosening the cush nut.

Regards, Peter.

[muskrat]

If you've got the primary cover off and the spark plugs out, the cush nut is OK to use. It should be 65ft/lb tight so turning won't be a problem. If it comes loose you just avoided a problem .
If your setting the timing you should have the timing cover off, in which case the crank nut is OK to use.
Cheers

[pdg]

Many thanks. Is there a recommended torque for crank nut on the timing side? Mine has a locking washer on it and I know that it moves if I try to use it to turn the engine over (with plugs removed).

Regards, Peter.

[Topdad]

Peter ,It's a left handed thread , Bob

[pdg]

How tight should it be?

Regards, Peter.

[muskrat]

Tight enough not to move. There's no torque listed for said nut. It's a lock nut for the oil pump worm. The worm is tightened (lets say 10-15 ft/lb) then the tabbed washer then the nut (same torque). the tab washer is then bent over the nut. So once all is good the nut should not move even when using it to turn the motor over with the plugs in.
Cheers

[pdg]

Sounds like I need to tighten mine, because it moves if I try and turn the engine over with it .