V7 III 750cc valve adjustment : Safe to rotate engine backwards?

[Beavis]

 Need to adjust my Guzzi valves next weekend , already saw every tutorial available , but noticed that some turn the wheel/engine backwards when the TDC is passed? IT is safe/correct to do this?

[MattP]

Yes

[Beavis]

Yes

Many thx.

[Huzo]

It probably is ok due to the fact that the base circle of the cam is concentric, therefore if the camshaft is a tiny bit out of time, the clearance will still be in spec at TDC.
It should be recognised that rotating the engine backwards an amount, will put the tension on the tensioner side of the camchain and there will be some amount of time where the crank is rotating but the camshaft isn’t.
Albeit a very small amount I’ll concede.
But adopting a devil may care approach under some circumstances would be courting danger one would think, why the hell would you ?
If you do rotate it backwards, go 10-20 degrees then come back forward again.

[Beavis]

It probably is ok due to the fact that the base circle of the cam is concentric, therefore if the camshaft is a tiny bit out of time, the clearance will still be in spec at TDC.
It should be recognised that rotating the engine backwards an amount, will put the tension on the tensioner side of the camchain and there will be some amount of time where the crank is rotating but the camshaft isn’t.
Albeit a very small amount I’ll concede.
But adopting a devil may care approach under some circumstances would be courting danger one would think, why the hell would you ?
If you do rotate it backwards, go 10-20 degrees then come back forward again.

So if i pass TDC , I can go back a little and then I should rotate again to TDC.

[John A]

So if i pass TDC , I can go back a little and then I should rotate again to TDC.

Yep that’s it. You’ll notice that there is a few degrees of dwell where the piston doesn’t move at tdc as you rock it back and forth. I just try to get it approximately in the middle of that but it’s not that critical. If you pull both plugs and watch the valves as you rotate the engine you’ll see the intake open and close. If you put your finger over the plug hole, it will get harder to rotate the engine. Take your finger away and you’ll hear air come out, that’s compression.

[Moparnut72]

If you happen to go past TDC, rotate it backwards past TDC then bring it back up. That's what I do but it really isn't that critical but for us OCD types puts the mind at ease.
kk

[Beavis]

If you happen to go past TDC, rotate it backwards past TDC then bring it back up. That's what I do but it really isn't that critical but for us OCD types puts the mind at ease.
kk

That's my concern , I have tried on my my 2019 stone first time and never know where is the exact top point ( TDC ) always think that I have passed. I'm learning Guzzis , I was spoiled, honda guy.. 😆 ,  with tdc mark its easier.

I'm gonna put .005 / .007 , because already measure and it's .004/.006.