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Just wanted to clarify that this is TDC.
- Thread starter PickleSlice
- Start date
It's the line to the right of the "T". The "T" is just the label. The "F" marks to the left of that are a different story. The 2 short slashes indicate the beginning and end of the idle timing "range". The long slash in the center just to the left of the "F" is the middle of the range. It's acceptable to set your idle timing anywhere in this range but exactly where you need to put it will be dependent on where the full advance timing falls. You don't want the full advance timing to go past it's mark AT ALL. If that requires setting the idle timing more towards the little right slash mark (more retarded) then so be it.
PickleSlice
XS650 Addict
So I'm just a little off of TDC then? I've installed Hugh's PMA and just want to make sure I'm at TDC so that I mark it correctly.
PickleSlice
XS650 Addict
If I pull the plug, and use a rod on the piston and mark it at it's highest point, that will find TDC, so I can mark it, yeah? I've already installed the PMA and would rather not install the old system to verify.
glennpm
Another Old Biker Nut!
One thing you may want to consider if so inclined is to modify some key stock or a Woodruff key so once you find TDC and mark it, you won't have to do it the next time again if you have to pull the PMA down the road.
The crankshaft takes a 4mm Woodruff key. the PMA that Hugh sells has a 3/16" keyway. I bought the 3/16" straight key at Lowes (they don't stock Woodruff keys) and with a little plastic and wood for a fixture in my vice, filed a step on both sides of the key in the form of a fat T. Once it fit in the crank snugly, I cut it a little longer than the crank key slot and with my Dremmel, arced it on both ends to fit the crank slot, i.e. made a pie shape Woodruff key out of it.
When you go to install it, use some heavy grease to hold it in the keyway, placing the keyway straight up to make it easier and slip the PMA on. You can check with a good light on the end to verify that it stayed put.
I think the keyway will be at 6:00 when the left cylinder for a rephased engine is at TDC. For an engine that it not re-phased, both pistons have the same TDC. You need to verify TDC using a degree wheel anyway.
The crankshaft takes a 4mm Woodruff key. the PMA that Hugh sells has a 3/16" keyway. I bought the 3/16" straight key at Lowes (they don't stock Woodruff keys) and with a little plastic and wood for a fixture in my vice, filed a step on both sides of the key in the form of a fat T. Once it fit in the crank snugly, I cut it a little longer than the crank key slot and with my Dremmel, arced it on both ends to fit the crank slot, i.e. made a pie shape Woodruff key out of it.
When you go to install it, use some heavy grease to hold it in the keyway, placing the keyway straight up to make it easier and slip the PMA on. You can check with a good light on the end to verify that it stayed put.
I think the keyway will be at 6:00 when the left cylinder for a rephased engine is at TDC. For an engine that it not re-phased, both pistons have the same TDC. You need to verify TDC using a degree wheel anyway.
glennpm
Another Old Biker Nut!
BTW, I wanted my key centered and that is why I made a T out of it. You could file a step on just one side since you'll be setting TDC anyway, but then you would have to remember to always put it in the crank keyway with the same orientation.
PickleSlice
XS650 Addict
Thanks for the all the info!
