E: Engine Problem

[powella]

When timing a Comet engine with a " Timing Rod " the rod decided to fall into the combustion chamber.See Pic 1.
A 3 inch long rod won`t go through a Spark Plug hole so the head had to come off.
See Pic 2 for the solution without splitting the bike into 3 pieces. The lower engine stands need to come off.
Jack and magnet ( Pic 3 ) are required.

 

[Peter Holmes]

I would have played very long and very hard with a small head telescopic magnet before I resorted to lifting the cylinder head, perhaps you did.

 

[powella]

I DID for 2 DAYS !!!

 

[teunvandriel]

Such a top dead centre gauge costs just £19 at Spares. I made one myself in the last century from an old spark plug, the pin can never fall into the hole and I made the pin (which is loose in the sparkplug dummy) so long that the piston taps the pin at exactly 35 degrees. And should you still use a magnet, a handy aid for tuning, many still struggle with a cigarette paper, use a tuning aid with a light and acoustic signal, see https://www.beckelektronika.nl/

 

[vibrac]

I dont quite get the moving pin bit
I have a fixed pin in a spark plug I set up tdc with a screwdriver (+- 6 degrees normally)
plug goes in head say 9 turns
I bring up piston till it touches note the degrees
I unwind plug say 6 turns thats where originally setting the length of the rod saves time (I did it years ago never touched it since) otherwise you could take it right out and put it back
go over center
wind plug back in to the 9 turn point
turn back till it touches piston note the degrees
add the two figures together divide by 2 and set zero accuratly
got a different plug for a triumph as well as the Vincent one

 

[bmetcalf]

I made this with the wire loop after dropping it in but got it out. Nice and low-tech! I filed notches at TDC and 34 deg btdc that align with the top of the spark plug hole. It is just short enough that the pain on my thumb under the head bracket is bearable.

 

[bmetcalf]

Is that Beck device made for magnetos?

 

[LoneStar]

I use one of these: https://www.aircraft-tool.com/Detail?id=LED51

 

[bmetcalf]

Search for "inductance " and there should be a thread or two that mention Magnetoman's recommendation on using the L setting on an RLC meter to see when the mag points open.

 

[Cyborg]

I haven’t tried using the LCR tester for setting timing, but used it to find the flux reversal or flip point (learned that from Magnetoman). I like the synchronizer because it has an obnoxious sounding buzzer and you don’t have to take your eyes off what you’re doing to read the meter. Tells you right away if something moved. That said, if I had to choose between the two, I’d take the meter because it’s more versatile.