Rocker arms and torqueing the head down

[hardhat_harry]

Hi

I have set the engine at TDC and slackened of the rocker arms. I'm about to torque the head down but one of the rocker arms isn't moveable, it is the exhaust side and the one where the cam lobes are facing up not down.

Its not pushing the valve down but its not loose in anyway, is this normal?

Cheers

 

[5twins]

I don't think so. Usually, you can loosen the adjusting screws way up and put all sorts of play (or clearance) in the rockers. I always do that before removing or installing a top cover. I loosen the adjusters enough so I can easily move the rocker up and down and it has plenty of clearance between it and the valve and cam.

 

[hardhat_harry]

Here is a little video of the rockers

and some pictures

as you can see one side of the cam lobes down the other lobes up

Cam is in the centre

Cam timing mark is vertical

and rocker adjustment all the way back

I just dont get it

 

[hardhat_harry]

I have also measured the height of the valves.

3 are exactly the same and (2 exhaust and nearside inlet)

The far side inlet valve sits approx 1.5mm higher

 

[xjwmx]

Turn it until the cam would close that valve and see how it acts. Also, check then if the current problem has moved to the other exhaust valve. I have never backed off an adjuster (e.g to swap in a new one) with it in the open position so I can neither confirm or deny It very well could be normal - there would certainly at least be a lot less slack available in the open valve position. Or with the cover on just snugged see if you can adjust the valves. If so all's good.

 

[grizld1]

Harry, at TDC you're going to have valve-rocker contact on one side even with the adjusters backed off all the way. A .060" (1.5 mm.) difference in installed valve stem height would worry me, though. You might compare the two intake valves to see if there's a difference in length from valve face to collet groove. If there's not, you're looking at a difference in either depth of the seats or the cut of the valves. Make sure in any case to get the installed valve spring height equal.

 

[hardhat_harry]

I can see why there is a difference in valve spring height, the way the collects have grabbed the valve stems is slightly different, I assume a couple of revolutions will seat these peoperly

and

I think we should be ok now...... , unless someone says that the seating of the collects isn't correct

 

[ANLAF]

Harry, the collets in that exhaust valve should be re-seated. They have grabbed the ridge lower down on the valve stem. Take off the cylinder head and seat them properly.

Is you timing notch on the cam wheel pointing up at TDC> Looks a notch off in the photo, so this is your opportunity to make sure it is correct - when you put the head back on slide the camshaft back under the cam chain and jiggle that chain over the wheel *the cam adjuster will be out, of course), then (without the bearings on) raise the cam shaft with your fingers imitating the bearings being in there -the notch should point to 12 o'clock, if it doesn't, lower the cam and ripple the chain to the next notch along until notch is vertical when cam raised, them refit bearings.

Anlaf

 

[5twins]

Also, it appears you haven't fitted the bearings properly on the cam. They need to be slid in more, as far in as they'll go.

 

[retiredgentleman]

Only the left intake valve has the collets in the correct position. The right intake and both exhaust valves have the collets in the wrong position. The collets should be slightly recessed below the valve spring seats. As mentioned, you need to take the head off and use the valve spring compressor to compress those 3 valves and allow the split collets to fall into the correct position.

You might be able to re-seat the collets just by using a hammer and giving each of the 3 valves a good whack. If it works you wouldn't have to take the head off.

Besides the index mark on the left side being at 12:00, you want to check that the punch mark, on the right side of the camshaft gear, is exactly even with the top surface of the head.

 

[NONclow]

I'm not sure on the years, but I've had both rounded, and squared ridge/valley collet/valve combinations. Maybe a mixture of parts, rounded collets in square valve groove? Or even collets from another make/model?

 

[TwoJugs]

make sure you have the matching collets, very early motors used squared notches in the valves, later used rounded.

 

[hardhat_harry]

yes mystery solved

there is 3 with the early valves and one with the late valves.

I had to change one valve as the stem was rusted and perforated, obviously it got replaced with the later valve and collets.

Was down as stoneage motorcycles today and was talking to Roger who imports these and he said it would be ok to run the mix just give each a hit with a softhammer to ensure they are seated correctly

Also reseated the bearings good spot whoever said that.

Made sure the camchain is still central and away we go

 

[TwoJugs]

you can use the valves as long as the keepers are matching the round or squared notches in the valve stems.