750 SF2 primary cover removal

murphus

murphus

Senior member
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Lost in the Midwest
I've looked and can't find the answer to this; does the ignition advance plate on a twin have to be removed before the primary cover will come off, or does it come off with the cover bringing the oil pump drive gear with it? First time inside my 750's primary ...
 
murphus said:
I've looked and can't find the answer to this; does the ignition advance plate on a twin have to be removed before the primary cover will come off, or does it come off with the cover bringing the oil pump drive gear with it? First time inside my 750's primary ...
Click to expand...

Yes.

piet
 
1. Release the wires from the points (compress spring and wires come out)
2. Remove the three screws holding the base plate to the alloy cover and gently pry out the entire points plate assembly (you can make an alignment mark with a felt pen on plate and alloy as a rough indicator of where it needs to go back together).
3. Remove the two little 8mm head M5 screw/bolts holding the advance unit to the flange. Pull advance unit off.
4. Undo the M6 10mm head bolt holding the advance flange onto the oil pump driven gear. To get the flange off the keyed oil pump shaft I just screw the little bolts in a few turns and a pair of small vice grips on each and pull or pry it off - it would be pretty simple to make up a more technically apt tool for this.
5. The primary cover is now ready to remove. I loosen the primary chain adjuster bolt so there's no tension on it. Remove all the M6 bolts holding it on. Can be stiff to remove the cover - I hold the front area, gripping inside the points cavity while tapping gently outward with a plastic hammer. A gap should start to appear between cover and cases. A blade or feeler gauge run around the gasket to break any contact points is a good idea. Once you can get fingers into the gap, with a little more tapping and/or prying by hand in the right places with the plastic hammer, the cover should come off. DON'T put a screwdriver into the gap as a prying tool.

Plenty of posts on the forum about removing the oil pump driven gear from the oil pump itself. It only comes out in ONE position.
 
Many thanks for the detailed run-through. I was concerned about removing the advance flange as the Green Book suggests using the correct factory tool, which I naturally assumed almost nobody has ...
 
I was going to suggest smashing it off with a crowbar, which certainly works and has the advantage of being quick and easy. The only slight difference between PB2's method and mine is that doing it his way allows you the option of reassembling it. I suppose if you want to be fussy ?  ::)
 
The plate doesn't want to budge . Would it be unwise to run two longer 4mm screws through the two advance mounting points until they touch the cover and slowly tighten against the cover to get the plate to pull off? Or should I fashion some sort of puller?
 
Up to you. It depends how deep the M5 threads go. If have a drill and tapping die of any useful size (eg M6 or M8) you could make something from a plate (4 or 5mm alu?) that butts up against the outer edge of the primary cover where the points cover contacts, drill two holes and bolt it into the two threaded holes in the flange (all-thread + nuts are cheap and your friend where long bolts are required!). Put something to protect the M6 threaded hole in the centre of the oil pump driven gear and then screw a bolt into your threaded plate. Once it tightens against the pump shaft it'll pull the little sucker off.

if you have a lathe you could fashion something far more elegant, but this will be simple and effective.

Make sense?
 
Or wrap some wire around the screws and use an impact puller to pull the advance off.
Once it's come off once, it just slip's off the next time.

Paul
 
I decided to go ahead and try running a couple of long screws through the plate to push against the cover. It took minimal pressure for it to release, working slowly one side to the other. If it had taken anything more than light pressure I would have switched to a puller, but it wasn't at all necessary in this case.
 

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murphus said:
I decided to go ahead and try running a couple of long screws through the plate to push against the cover. It took minimal pressure for it to release, working slowly one side to the other. If it had taken anything more than light pressure I would have switched to a puller, but it wasn't at all necessary in this case.
Click to expand...

Very artistic photo ;)
Miguel
 
if the ATD doesn't "snap" shut with a definite click, then you will need new springs, never listed as a Laverda part (on their own) and recently sourced by me through my niece in LA but they were wrong!!!
even though they came in Bosch packets and looked EXTREMELY as though they would be right, this has cause the ILOC editor no end of problems when trying to re-commission his 750, to the extent that he converted to electrocnic ignition.
(which he bought from me)
CLEM
 
They are quite light be cause they have to function at half crank speed, but there's a fair amount of adjustability in them. You can alter the bend on the tangs that the springs attach to, or undo the two screws holding that assembly onto the unit and pivot fwd or bwd to alter the advance curve.

Or you could just fit electronic ignition!! But in all the years of service and hundreds of thousands of km mine have done (including after I converted to ND elec ignition from an early GS Suzuki) I never once found the springs had 'softened'.
 
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