Power valve sticking

[Jacob 'Berg]

My power valve is intermittently getting stuck open. This has been occurring when the suspension is absorbing a harsh hit or g-out. It will stick open for a few seconds or couple of minutes and then back to normal. It will happen a couple of times throughout a 40-50 mile ride.

I have read on the forum of this occurring to others. Can anyone tell me if this is typically caused by 1) improperly adjusted power valve linkage/free-play 2) bearing issues 3)carbon build up?

Just trying to figure out what I will need on hand and how big of job I am looking at.

Thanks!

 

[Jakobi]

I'd pull it apart and service it. Check 1 2 and 3.

 

[Jacob 'Berg]

I'd pull it apart and service it. Check 1 2 and 3.

Can I address 2 and 3 without pulling the jug?

 

[n_green]

You can adress all three without pulling the jug. Pipe comes off as do both power valve side covers, and main clutch side cover. You can check adjustment etc at governor and PV linkage isn't getting jammed in the access hole between jug and rhs case.
To pull the PV undo the bolts on either side, push out the retaining pin and with the piston at bdc wiggle the flapper around til it comes out.

 

[Jacob 'Berg]

You can adress all three without pulling the jug. Pipe comes off as do both power valve side covers, and main clutch side cover. You can check adjustment etc at governor and PV linkage isn't getting jammed in the access hole between jug and rhs case.
To pull the PV undo the bolts on either side, push out the retaining pin and with the piston at bdc wiggle the flapper around til it comes out.

Thanks! I appreciate the info.

 

[Jakobi]

You can probably hold off removing the rhs engine cover for the governor until after you check the PV tension. If its loose it'll need to come off for adjustment. If a ball bearing is dislodged the arm won't be sitting correctly. I doubt this is your issue.

In most cases its carbon build up on the side edges of the flapper/pv drums that get caught and cause sticking.

Once the rhs PV cover is off, use a little heat and remove nyloc nut. Disconnect the actuator arm by pulling it towards you. Don't try and move it through its range of motion or you risk dislodging a bearing in the governor. Once its removed you should be able to cycle the whole PV drums and flap a full 360 degrees plus in both directions. Any notchiness or grabbing (check when changing directions at top of stoke) indicate something binding.

You may find it easier to remove the flap with the head off. Alternatively you could try cleaning the drums first, and leave the flap in there.