Sachse Ignition on Pantah

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smellybeard
Cucciolo - the Lil Pup
Posts: 7
Joined: Mon Jun 15, 2020 5:36 am

Sachse Ignition on Pantah

Post by smellybeard »

I'm the proud owner of a ZDG3 set for the Ducati Pantah.
All very nice - except for the installation manual. I have no idea of what orientation I need to put the new rotor on. here is no mention of it in the manual.
It's aluminium with a couple of embedded magnets in the rim about 60º apart.
Marked around the rim are "V" (at what I'll call 0º) , "H" (+90º), "S" (with the first magnet at about +120º) and "N" (+180º).
"H" and "V" sound like something obvious but I only make assumptions when I'm working on BSAs.

I have the outer case off but have not started removing anything from the crank yet (I'll need a pesky tool t hold the rotor).

Has anyone fitted this and can they help?
smellybeard
Cucciolo - the Lil Pup
Posts: 7
Joined: Mon Jun 15, 2020 5:36 am

Re: Sachse Ignition on Pantah

Post by smellybeard »

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81mhr900ss
750 GT
Posts: 168
Joined: Tue May 31, 2016 3:49 pm

Re: Sachse Ignition on Pantah

Post by 81mhr900ss »

OK, I've read the manual and there are a few differences between your Pantah and my MHR! The manual sucks. Logically, V is vertical and H is horizontal but the location of H and V, albeit 90deg apart don't make sense. The picture of the trigger ring on the crank is not clear enough and there's nothing in the manual referencing how to position it. Here's what I'd do:

Manual in bold:
With plugs removed and the trigger ring mounted loose but not locked on the crank:

First bring the horizontal piston into TDC position. Best adjustment of course you get with a measuring clock, but also degree disk or the original setup disk through the (mounted) side cover are possible.

I used a chopstick stuck in the front plug hole; it was really easy to see exactly where TDC was but if you have a dial gauge and plug-depth-tool-thingie then use it.

Then turn the pickup carrier to the ccw stop.
Self-explanatory but I'd ignore this, go all the way CCW then back off CW about 3mm. Hand tighten one carrier bolt to stop it moving for now.

Now turn on the ignition switch - both test LEDs on the PCBs are indicating. Now shift the carrier quite slowly in clockwise direction until the LED on the bottom PCB goes off. Last tighten both screws of the carrier - the adjustment is complete.
Here's what I'd do differently: From the photos, I'm confident that we are looking at the bottom right trigger for the front, horizontal head. Turn the trigger ring clockwise and watch the lower right LED. It should come on when the "S" magnet passes over it; very slowly continue turning until the LED goes off. Hand tighten the trigger ring lock bolts/screws. Now slowly crank the engine by hand and watch the LEDs, at every horizontal TDC, the bottom right LED should go out, swap the chopstick over and at every vertical TDC, the bottom left LED should go out. If this does not happen, we have the pickups reversed so repeat above but looking at the lower left pickup, when turning the trigger ring with the horizontal head at TDC

Very carefully tighten everything up and check again. Sachse really make awful manuals. Good luck!
smellybeard
Cucciolo - the Lil Pup
Posts: 7
Joined: Mon Jun 15, 2020 5:36 am

Re: Sachse Ignition on Pantah

Post by smellybeard »

81mhr900ss wrote: Wed Oct 14, 2020 2:16 pm but the location of H and V, albeit 90deg apart don't make sense.
I think the Pantah engine rotates in the opposite direction to bevel heads.
Anyway, I'll read through that carefully in the morning (taking account of the direction of rotation) and see where it leaves me.

Thanks.
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81mhr900ss
750 GT
Posts: 168
Joined: Tue May 31, 2016 3:49 pm

Re: Sachse Ignition on Pantah

Post by 81mhr900ss »

You are correct, Pantahs run a ccw crank as seen from the left side. I figured that maybe it would have made sense to have the the V and H stamps pointing towards the cylinders that they were referring to at horizontal TDC. I can't work out why the stamps are there as they are not referenced in the manual.

It looks like one of the six holes is not threaded. Is it possible that this locates the trigger ring on a pin? If this is the case then the trigger ring can only be put on one way and in one position on the crank. This would make much mores sense and explain why the Sacshe manual doesn't state how to locate the trigger ring. In this case, put the trigger ring on and lock it in the only way it can go and follow the manual; set front TDC and tweak the pickup plate position to make the LED go off (whichever one it is).

See this pic:
Image
smellybeard
Cucciolo - the Lil Pup
Posts: 7
Joined: Mon Jun 15, 2020 5:36 am

Re: Sachse Ignition on Pantah

Post by smellybeard »

81mhr900ss wrote: Wed Oct 14, 2020 6:37 pm It looks like one of the six holes is not threaded. Is it possible that this locates the trigger ring on a pin?
Exactly. Well spotted. Thanks.

I'd think I'd have spotted that when I dismantled the old setup but I really wanted a good picture in my head before taking anything off.
I'm still waiting on a rotor locking tool anyway.
Ed
Cucciolo - the Lil Pup
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Joined: Sat Aug 29, 2009 5:29 am

Re: Sachse Ignition on Pantah

Post by Ed »

Did you resolve your installation questions regarding the flywheel/trigger plate position on your Pantah?

I have a similar problem with the instructions. See attachments for my comments. I have also sent this to Sachse for them to clarify
Attachments
Capture 4.JPG
Capture 3.JPG
Capture 2.JPG
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