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Paulrxs650
XS650 Enthusiast
Hi, you can make your own if you've lost the originals. Turn the engine til the left hand (sitting on the bike) cylinder is at the top of its compression stroke. You can then place mark on the rotor and the engine case to denote TDC. Using a degree wheel you can then mark on the advance range, firing marks etc as per the specifications in the manual.
rider119
XS650 Addict
Alright, I'll see if i can figure if out then, thanks.
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rider119
XS650 Addict
Alright, got my tdc marked on mag and cover, now how do I go about getting my firing marks?
Paulrxs650
XS650 Enthusiast
Hi,
Double check in a manual. However, if my memory serves me right, full advance is 40 degrees before TDC and firing is between 13 - 15 degrees.
Double check in a manual. However, if my memory serves me right, full advance is 40 degrees before TDC and firing is between 13 - 15 degrees.
You can have your timing marks in two different formats.
On the stock bike, the 'reference' mark is on the rotor, the 'timing' marks are on the case, below the rotor, with the firing marks to the LEFT of the TDC mark.
You can put the firing marks on the rotor/flywheel, leaving the 'reference' mark only on the case, but the firing marks on the rotor/flywheel need to be to the RIGHT of TDC, assuming the case mark is below the rotor.
This is more of an 'orientation awareness' posting than a how-to...
On the stock bike, the 'reference' mark is on the rotor, the 'timing' marks are on the case, below the rotor, with the firing marks to the LEFT of the TDC mark.
You can put the firing marks on the rotor/flywheel, leaving the 'reference' mark only on the case, but the firing marks on the rotor/flywheel need to be to the RIGHT of TDC, assuming the case mark is below the rotor.
This is more of an 'orientation awareness' posting than a how-to...
rider119
XS650 Addict
Alright, I think I get it after looking at it. So basically I need a reference mark on my rotor, tdc mark should be aligned with the right edge of the little notch of the left engine cover hole, firing mark like .5 in to the left (front) and the advanced in the corner of the little flanged area?
rider119
XS650 Addict
How do I know the firing for left and right cyclinders?
rider119
XS650 Addict
http://www.gofastforless.com/junk/Per-Mag-Alt-Instructions.pdf
Using this as a guide, just below the pic of the flanged part of the left engine cover, page 5.
Using this as a guide, just below the pic of the flanged part of the left engine cover, page 5.
Paulrxs650
XS650 Enthusiast
So, you only need one mark on the rotor. When the left hand (sitting on the bike) cylinder at the top of its compression stroke (you can tell by looking through the plug hole and observing which valves are closing) mark a corresponding notch on the case where the rotor mark is. You can then use a degree wheel to mark 13 - 15 degrees BTDC (clockwise from the TDC mark) and then 40 degrees (again clockwise from the TDC mark) for your firing and full advance.
Brian902
XS650 Junkie
This is the reason a PMA is not for everybody.
Lose of timing marks.
Most people should keep there old system so they can re-install the basics and be able to time ignition systems.
Valve maintenance is easy done without any timing marks.
Ignitions not so.
Other issue with PMA is most if not all have 5mm woodruff keys and crank is 4mm, leading to owners making their own, which can lead to small inaccuracies in timing. Not critical but still possible.
I don't recommend leaving a woodruf key out because if you ever have the rotor come loose at all, it spins and ruins your crank shaft. Key helps to prevent that even if it's the 4mm key in a 5mm rotor.
Others use degree wheels and establish new timing marks, something not for the average DIY guy.
Using a piston stop to find TDC for a degree wheel I found backing off both intake/exhaust valves for the cylinder helps to prevent bent valves due to valve contacting the piston stop.
Best advice, get a knowledgeable mechanic to do the work, use old system for this purpose or get educated and acquire the tools, degree wheel/piston stop, and do it yourself.
My 2 cents.
Lose of timing marks.
Most people should keep there old system so they can re-install the basics and be able to time ignition systems.
Valve maintenance is easy done without any timing marks.
Ignitions not so.
Other issue with PMA is most if not all have 5mm woodruff keys and crank is 4mm, leading to owners making their own, which can lead to small inaccuracies in timing. Not critical but still possible.
I don't recommend leaving a woodruf key out because if you ever have the rotor come loose at all, it spins and ruins your crank shaft. Key helps to prevent that even if it's the 4mm key in a 5mm rotor.
Others use degree wheels and establish new timing marks, something not for the average DIY guy.
Using a piston stop to find TDC for a degree wheel I found backing off both intake/exhaust valves for the cylinder helps to prevent bent valves due to valve contacting the piston stop.
Best advice, get a knowledgeable mechanic to do the work, use old system for this purpose or get educated and acquire the tools, degree wheel/piston stop, and do it yourself.
My 2 cents.
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I agree with brian. To find TDC accuratly you do need a piston stop and degree wheel. The piston will barely move from either side of TDC so you could be off quite a bit. Then when you try to set your firing marks they will be off also.
Paulrxs650
XS650 Enthusiast
Agreed, there are different methods to find TDC, I prefer the dead stop method. I use an old plug with a hard rubber bung on the end.
Re-acquiring timing marks is not that complicated or beyond your reach. Read up about timing and what it does, so you have a working knowledge of it. Take your time and with assistance off the many helpful people on this forum, you will do it, no problem at all.
Re-acquiring timing marks is not that complicated or beyond your reach. Read up about timing and what it does, so you have a working knowledge of it. Take your time and with assistance off the many helpful people on this forum, you will do it, no problem at all.
rider119
XS650 Addict
Yeah, it's fairly straight forward stuff. Even goes along somewhat with my engineering circuits class!
Paulrxs650
XS650 Enthusiast
Good man, let us know how you get on 
I think Hugh makes a sticker for the timing marks. It installs on the cover on that flange. You stick the sticker then find TDC, mark the rotor to correspond to TDC on the sticker. Then you have all the right marks for idle timing as well as full advance.
I think having a key is the best way. The taper of the crank and rotor should hold the rotor from spinning on the crank but a key insures it won't. This keeps your timing marks right.
Leo
I think having a key is the best way. The taper of the crank and rotor should hold the rotor from spinning on the crank but a key insures it won't. This keeps your timing marks right.
Leo
rider119
XS650 Addict
Where would I find one of said stickers?
Paulrxs650
XS650 Enthusiast
Hugh's Hand Built.
I've seen them as part of his PMA, although I'm sure he,ll do them separately, he's a good guy.
I've seen them as part of his PMA, although I'm sure he,ll do them separately, he's a good guy.
rider119
XS650 Addict
Ok I just couldn't find them separately. I guess I'll send him an email. Thanks for the help guys! Now to just find time to get it done!
