Rocker arm shimming + head timing - Ducati.ms - The Ultimate Ducati Forum
 
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post #1 of 5 (permalink) Old Aug 1st, 2019, 7:20 pm Thread Starter
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Rocker arm shimming + head timing

Hello all,

2 questions regarding a head rebuild:

1 - Are shims required in the locations circled in red? According to the service manual it only stresses that the rocker arms be "perfectly centered" to the valve, free movement of arms but no end play.

I have found the opening rockers are mostly evenly spaced to the valves on one side without any shims, and the other side with only 2 shims on the side where the black clip goes in.

2 - How do we correctly time the heads? I have two sets of heads. One is the OEM pair I removed and the other is a modified V2 but same cams. When I removed the OEM heads I ensured all three pulleys were aligned on the dot (vert/horiz/crank).

I was able to replicate the cam timing on V2 heads from the OEM heads by eyesight only, but something tells me that's not a good idea - maybe I am wrong...

Cheers.
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post #2 of 5 (permalink) Old Aug 1st, 2019, 9:41 pm
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opening rocker only has the two shims (sometimes there was a third) at the clip, nothing on the other end of the rocker.

if you have fitted solid oem cam pullies then you use the marks to set the cams. how else do you think you would do it? you can watch a video of me banging on about it here: https://www.ducati.ms/forums/80-hall...nt-videos.html 4th video down.

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post #3 of 5 (permalink) Old Aug 2nd, 2019, 8:00 am
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I have seen early heads with plenty of shims on both sides, maybe USA got the good ones again

Bottom line the rocker needs to depress the valve and NOT contact another rocker in rotation or be misaligned on the camshaft. You need the large two Od shims , one on either side of the spring clip to prevent the movement of the rocker from trying to eject the spring clip. IIRC by mid 1990's the shims were usually down to 2 on the openers but hey its a lol Ducati you can NEVER leave any thing to chance.

As Brad said on fixed pulleys there is one way to install the cam with straight keyways and the single mark on the pulley SHOULD line up with the factory timing marks. Same as the shims though

but hey its a lol Ducati you can NEVER leave any thing to chance.
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post #4 of 5 (permalink) Old Aug 2nd, 2019, 10:22 am Thread Starter
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Quote:
Originally Posted by belter View Post
opening rocker only has the two shims (sometimes there was a third) at the clip, nothing on the other end of the rocker.

if you have fitted solid oem cam pullies then you use the marks to set the cams. how else do you think you would do it? you can watch a video of me banging on about it here: https://www.ducati.ms/forums/80-hall...nt-videos.html 4th video down.
Neat video, thanks for sharing. Some things in the past haven't clicked for me regarding timing. I'm still trying to put two and two together. I will have to watch it a few more times to really understand how to set cam timing. Also, I've never seen anyone smile as much while degreeing cams lol.

I have adjustable pulleys, and am installing a new set of heads I rebuilt.
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post #5 of 5 (permalink) Old Aug 2nd, 2019, 10:30 am Thread Starter
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Quote:
Originally Posted by ducvet View Post
I have seen early heads with plenty of shims on both sides, maybe USA got the good ones again

Bottom line the rocker needs to depress the valve and NOT contact another rocker in rotation or be misaligned on the camshaft. You need the large two Od shims , one on either side of the spring clip to prevent the movement of the rocker from trying to eject the spring clip. IIRC by mid 1990's the shims were usually down to 2 on the openers but hey its a lol Ducati you can NEVER leave any thing to chance.

As Brad said on fixed pulleys there is one way to install the cam with straight keyways and the single mark on the pulley SHOULD line up with the factory timing marks. Same as the shims though

but hey its a lol Ducati you can NEVER leave any thing to chance.
Lol. I am not sure where these heads came from but each opening rocker came only with three shims (2 for clip, one for adjusting).

Well I finally have an answer to my question, thank you! So the larger shims are required on either end of the clip - that makes sense.

The other set of 2V heads I'm replacing the OEM ones with were rebuilt by yours truly, and they have adjustable cam pulleys. I thought I have no reference point on how to degree the cams for the 2V heads due to the two reasons above, except for opening the cam caps on both the OEM and 2V heads and replicating the OEM timing by copying the position of the cam + valve from the OEM head which IS correctly timed. That sounded a bit dicey (but maybe not necessarily bad) so I thought a more exact science of using a degree wheel was necessary for precise degreeing and any marks on the 2V heads were useless until the cams were dialed in first.

Am I misunderstanding something here?

Edit: I wanted to take a trip up to Lake Tahoe this weekend for a camping trip. I know I won't have time to properly degree the cams before tomorrow morning (I'd have to order the tools online) but maybe just eyeballing it will suffice. Granted, the OEM heads which are 98' Monster have OR/VR and are ever so slightly different than the older 2V cams (OHT/VHT) but based on how similarly the valves between the OEM and V2 heads were actuating once I timed the V2 heads by eyeballing only I wonder if it will be okay. I expect some loss of performance until I really dial these in. Idk =)

Last edited by samadhi; Aug 2nd, 2019 at 11:35 am.
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