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-   -   Ironhead oil drive and gear timing (http://xlforum.net/forums/showthread.php?t=2076289)

volvocanadian 7th April 2020 05:38

oil drive and gear timing
 
okay, it has been 7 years since I did this last and I am not sure I did it quite correctly

followed the factory manual about inserting the oil pump and rotated the flywheel to the single line timing mark in the center of the timing window on left side of the motor

turned the oil gear so the hole is in the window of the shaft and slid the oil pump drive gear on - there looks to be a timing mark on one of the teeth like on the cam gears but it did not line up with any of them - weird?

I then put the pinion gear on, it also had a timing mark on it and it did line up with the cam gear marks - all good?

the oil pump and pinion gears both have one longer recess than the other recesses for it to slide onto the pinion shaft in one way only, so the oil pump gear timing mark means nothing? there is no way for it to be the same spot as the pinion gear mark that slides directly over it...

next question - when the single line timing mark is in the window - should that put the front piston at the very top of the cylinder? TDC? the manual doesnt say whether the piston should be at the very top or not, it just says to get the line in the center of the window

my front piston sits about 3/4" below the upper lip of the cylinder but the rear pistons sits at the very top - or do I need to release the cam gears from the oil pump drive gear and rotate the flywheel again to the single line so the front cylinder is at the very top? does it go to the top if I do that? is this now 180 degrees off?

I dont want to go any further (actually I do but since Id ont have acompensating sprocket extension I cannot) until this is figured out

thanks
Robert

72 Ironhead XLH 7th April 2020 13:38

the vert line should be the advance timing mark so the piston would not be at TDC

I then put the pinion gear on, it also had a timing mark on it and it did line up with the cam gear marks

strange because you install the oil pump drive gear, then the pinion and then the cams?

72 Ironhead XLH 7th April 2020 13:47

click to enlarge
https://i.ibb.co/ZGBMhSG/Untitledtt.png

doodah man 7th April 2020 14:26

I believe any oil pump drive gear mark is coincidental? If the oil pump timing mark is in the window with the pump fully seated and the ignition advance Mark is centered then it sounds like you did it right to me.

The Doctor71 7th April 2020 14:57

Quote:

Originally Posted by volvocanadian (Post 5816266)
next question - when the single line timing mark is in the window - should that put the front piston at the very top of the cylinder? TDC? the manual doesnt say whether the piston should be at the very top or not, it just says to get the line in the center of the window

my front piston sits about 3/4" below the upper lip of the cylinder but the rear pistons sits at the very top.....

On a 900 motor, with stock flywheels:
  • the "|" vertical bar in window = 45° BTDC on the FRONT cyl
  • and, it just so happens, the "|" vertical bar in window also = TDC on the REAR cyl
The underlying premise is..... anywhere in the flywheel rotation, the REAR cyl always runs 45° ahead of the FRONT cyl.

kitabel 7th April 2020 18:35

The breather alignment to the timing mark is correct.
The cams do NOT line up at the same time.


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