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Discussion Starter #1
Before I pull the belts, I want to make sure I understand the sequence so that I can put everything back together properly.
According to LT's book, I should rotate the engine until the timing mark on the output shaft pulley lines up with the mark on the crankcase. At this point, I should mark the vert and horiz cam pulleys' position in relation to the cylinder head marks.

I'm confused about how to put it all back together. If I maintain the relative position of all 4 cams and the output shaft, proper timing will be maintained, correct? So my goal is to restore humpty dumpty to that state. When the output shaft mark is lined up, my vertical cylinder is at TDC. Obviously, the horizontal cylinder is not (it's 270deg away).

Am I supposed to:
1. treat each cylinder individually--resulting in 2 marks on the output shaft, one for each TDC? So putting it back together would mean placing one belt on with cams at the appropriate TDC orientation, then rotating the engine 270deg to place the other cylinder at TDC and then putting those cams on?

or

2. puts the both cylinders' belts/cams back on without turning the engine at all? meaning that one cylinder would not be TDC and the cams would be at some stage of rotation and the valves partially open.

Or am I thinking to much about this?

Any help would be appreciated. this particular aspect of the job isn't clear in any prior threads.
Thanks,
Chris
 

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Just finished replacing my belts. I found this article helpful.

http://scandalon.com/2009/06/ducati-4v-timing-belts-diy-howto-writeup/

And this one with a lot of pictures.

http://www.tassell.co.uk/belt_change.htm

I would buy one of the tools for $20 to hold the vertical cylinder intake cam pulley while the belts are removed. It made the job a lot easier for me. Remember to replace the nuts on the tensioner pulleys.

http://www.motoreva.com/item.cfm?itemid=101&categoryid=171

I used the "easy tune" app. on my iPhone for the tensioning. Later I double checked it with the Harmonic tool and all was fine. There are other methods you can find by doing a search. Mic's and a computer with free software can also be used.

Harmonic tool:

http://www.desmotimes.com/
 

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Mark the timing pulleys to a point on the cases before you take the belts off. Then simply line all the marks on the pulleys to the cases when you assemble the belts and you are good to go.

Mike
 

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Mark the timing pulleys to a point on the cases before you take the belts off. Then simply line all the marks on the pulleys to the cases when you assemble the belts and you are good to go.

Mike
You're kidding! After trying to walk through the above pics and captions on how to replace/tension belts, you forget all that and just simply make new marks on the timing pulleys and corrsponding cases, take the belts off, then align these marks when you install new belts. Tighten, check for tension and your done. Even w/ a testastretta:D I guess the acronym K.I.S.S. applies here.
 

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Discussion Starter #5
Thanks to all for the helpful info.

Just to reiterate and make certain i got it straight (because it does seem easy...almost too easy):
1. make marks before removing belts.
2. do valves, etc.
3. put all 4 cams on, lined up appropriately
4. put on both belts
5. set tension.

that's it?! i was looking for a chicken to sacrifice or something.
 

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Have yet to try my valves (only 4.5K), but the belts are much easier than automotive timing belts.

+1 on the Iphone tuning app.
 

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Be careful with this method that you don't turn over the crankshaft once the belts are off because some valves will be open.
 

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Mark the timing pulleys to a point on the cases before you take the belts off. Then simply line all the marks on the pulleys to the cases when you assemble the belts and you are good to go.

Mike
Like Ducati used to do on the Desmoquattro engines....
 

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Be careful with this method that you don't turn over the crankshaft once the belts are off because some valves will be open.
So once the belts are off are you saying to keep the horizontal cylinder at TDC throughout the valve clearance check and adjustment. I thought once the belts were off that each cylinder had to be set at TDC when adjusting and checking valves i.e. when working on the vertical set the vertical to TDC and when working on the horizontal set the horizontal to TDC. Correct me if I'm wrong when the valves are all done and checked reset the crankshaft so that TDC is acheived on the front horizontal cylinder and then line up the cam pulleys before placing the timing belts.
 

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Discussion Starter #10 (Edited)
I'm probably the last person who should chime in, redliner, but i'll tell you how i'm approaching it and hopefully someone with wisdom/experience will either verify/validate or set us both straight.

i left the belts on and turned the engine using the rear wheel (on rear stand, in 6th gear) to find TDC on each cylinder. I verified it was TDC of the compression stroke by putting a long chopstick in through the spark plug hole. I did the measurements of all clearances on one cylinder, then turned the engine 270deg to reach TDC on the other cylinder and measured those clearances.

Then I took off the belts, journals, cams, etc. So one cylinder is on TDC and the other is not.

I'm not planning on turning the engine, so I just need to rebuilt it so that the cams all go back in the way I took them out.

Heading to the shop now to swap out shims.
 
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