- Joined
- Nov 20, 2001
- Messages
- 17,028
- Location
- Ely, England
help me out here! 
had a customer call last night and question my principle that the ignition timing is out and how i came to the conclusion that it was "out".
essentially, having prognosed it all a few years back i have essentially left it at that ever since but it did stop me and i had a think about it.
essentially wherever you put a marker around a flywheel and then do the dead stop method we are agreed that midway between the two stops is the real TDC.
now those of you that have done this with me over time will have noticed that TDC is indeed out IF THIS WAS ALL WE WERE AFTER!
the system fails when we no longer time the bike from the top screw hole that has just been used to get that TDC mark. to be clear, the ignition inspection hole doesn't sit below the screw. it doesn't matter that the screw isn't in a vertical plain up the middle of the cylinder but it does matter that we don't time the engine from the screw hole that we had used to get TDC!!!!
what's really needed is a TDC marker that is stationed on the engine directly in line with the middle of the inspection window. that that marker is then used to find the true TDC using the "dead-stop" method. NOW you should be able to strobe the engine and 30-33d of advance corrected on the strobe should bring the mark also into the middle of the window.
or instead of a marker in the middle of the window why not have the factory place the marks off centre like the hole is?
someone run this by themself please?
regards
Taffy
had a customer call last night and question my principle that the ignition timing is out and how i came to the conclusion that it was "out".
essentially, having prognosed it all a few years back i have essentially left it at that ever since but it did stop me and i had a think about it.
essentially wherever you put a marker around a flywheel and then do the dead stop method we are agreed that midway between the two stops is the real TDC.
now those of you that have done this with me over time will have noticed that TDC is indeed out IF THIS WAS ALL WE WERE AFTER!
the system fails when we no longer time the bike from the top screw hole that has just been used to get that TDC mark. to be clear, the ignition inspection hole doesn't sit below the screw. it doesn't matter that the screw isn't in a vertical plain up the middle of the cylinder but it does matter that we don't time the engine from the screw hole that we had used to get TDC!!!!
what's really needed is a TDC marker that is stationed on the engine directly in line with the middle of the inspection window. that that marker is then used to find the true TDC using the "dead-stop" method. NOW you should be able to strobe the engine and 30-33d of advance corrected on the strobe should bring the mark also into the middle of the window.
or instead of a marker in the middle of the window why not have the factory place the marks off centre like the hole is?
someone run this by themself please?
regards
Taffy
