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 Post subject: Positioning of pick up sensors
PostPosted: Fri Dec 08, 2017 6:35 am 
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Joined: Thu May 16, 2013 10:07 am
Posts: 20
Location: Australia
model: 750 Sport
year: 1988
Hi Guys,

I had to replace the pick up sensors as one of them died, i changed them for the 440 ohm type aftermarket sensors as thats all i could find on eBay, i also had to change the regulators as one of those had died. The guys i bought the regulators from recommended the 440 ohm type.

My question is this, i don't have a crank angle gauge so have been finding TDC by sticking a pencil inside the vertical cylinder, it seems to be reasonably close to the timing marks on the flywheel but when i try again the marks are in a slightly different position. I then lined up the dots on the OH valve gears and tried again and the dots came up pretty close to the position of the pick up sensors, is my methodology about right in finding TDC ?

PS i stripped her down, got the frame powder coated due to a battery leak, had the tank re painted, she's looking like a new bike now and only a genuine 11000 km on the clock, it sat around for a long time !

Thanks in advance

Mike


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 Post subject: Re: Positioning of pick up sensors
PostPosted: Fri Dec 08, 2017 8:52 am 
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paso grand pooh-bah
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Joined: Sun Jul 18, 2004 12:00 am
Posts: 5178
Location: southern Germany
model: 750 Paso
year: 1987
If you line up the marks of the belt pulleys with the ones on the engine the flywheel mark will line up as well. If that is done you have the TDC of the front cylinder.
There are no TDC marks for the rear cylinder. If you had a timing disc installed you would have to turn the crankshaft 270° counterclockwise.
It's impossible to find TDC using a pencil :huh:

In case you didn't know. One full camshaft rotation corresponds to two crankshaft rotations. So if your marks are lined up you have to turn over the crankshaft twice to get them to line up again.

What do you mean by 'the regulators'?

G.


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 Post subject: Re: Positioning of pick up sensors
PostPosted: Fri Dec 08, 2017 10:04 am 
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paso grand pooh-bah
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Joined: Thu Nov 03, 2011 10:13 am
Posts: 585
Location: Scotland
model: 907 I.E.
year: 1994
I don't think that using the lower cam pulley gives an accurate enough location of TDC on the horizontal cylinder. The pulley is running at 1/2 engine speed and due to backlash in the drive gears could be a few degrees out and, as you say there is no way without a degree disc of accurately moving the engine through 270º to TDC on the vertical cylinder.
A thought though. There are marks on the flywheel for TDC of each cylinder that should line up with the pointer in the sight glass of the alternator cover. The cover could be fitted temporarily with 2 or 3 screws then TDC lined up using a pencil and the flywheel marks to confirm. The pickups are lined up to the flywheel marks with the horiz cylinder at TDC.
I presume that "the regulators" are the ignition control units.

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 Post subject: Re: Positioning of pick up sensors
PostPosted: Fri Dec 08, 2017 11:55 am 
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paso grand pooh-bah
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Joined: Sun Jul 18, 2004 12:00 am
Posts: 5178
Location: southern Germany
model: 750 Paso
year: 1987
Quote:
I don't think that using the lower cam pulley gives an accurate enough location of TDC on the horizontal cylinder.

Maybe I was lucky because when I had the cylinder head off and checked TDC with a dial gauge the marks lined up perfectly. I was curious to verify that as some reports say they can be some degrees off.
The drive gear backlash is not a problem as long as the crankshaft isn't rotated clockwise.


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 Post subject: Re: Positioning of pick up sensors
PostPosted: Fri Dec 08, 2017 2:43 pm 
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paso grand pooh-bah

Joined: Thu Jun 21, 2007 12:00 am
Posts: 1432
Location: Gothenburg, SWEDEN
model: 907 I.E.
year: 1991
Have you moved the pickup bracket?

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907 I.E. -91
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 Post subject: Re: Positioning of pick up sensors
PostPosted: Sun Dec 10, 2017 7:00 am 
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Joined: Thu May 16, 2013 10:07 am
Posts: 20
Location: Australia
model: 750 Sport
year: 1988
Thanks very much guys,

Just confirmed my suspicions, the manual stated to find TDC on the vertical cylinder but i noticed when the dots lined up on the camshafts the horizontal cylinder seemed to be at TDC, i couldn't get the dots to line up using the vertical cylinder.
Yes i meant the ignition control units, i couldn't for the life of me think of the correct term. The other bike a 73 Bonneville i used a pencil to find TDC as described in various Youtube videos but i also have a TDC tool which inserts behind the barrels in the crankcase and a pin drops into a hole machined in the crankshaft. I also have a tool that goes in place of the spark plug and it has a rod with mm graduations on it, but it doesn't fit the Ducati.

Many Thanks for your help fellas


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 Post subject: Re: Positioning of pick up sensors
PostPosted: Sun Dec 10, 2017 7:05 am 
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paso grand pooh-bah
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Joined: Tue Jul 29, 2008 9:50 pm
Posts: 3174
Location: Hilltown,Pennsylvania
model: 906 Paso
year: 1990
Quote:
It's impossible to find TDC using a pencil :huh:


No, It is not. Impractical,Yes but not impossible :lol: :lol:

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