[Steve_M90]

Thanks for the recommendations.

In the end I opened up the timing chamber (partly for curiosity). The shaft and the cam for the lifter were intact. I tested it in situ and it seemed to function. It looked like the tappet was slightly out of adjustment which I set up according to the book. Timing rebuilt and lifter adjusted as suggested by Rick. All functioned normally so, as they used to say on the back of the work order cards, NFF (no fault found)!!

Steve

[Rick Parkington]

Hi Steve, as Vic says, the lever is attached to a cam which acts on an overhanging ear on the exhaust cam follower. Other than the (unlikely) breakage of something there's not much that can go wrong so I'd say the best approach is 'back to basics'. First make sure the tappet settings are right, if the exhaust is too slack then the valve lifter cam might be moving the pushrod but not opening the valve.
Next is the cable adjustment, it's generally a good idea to set a valve lifter cable with quite a lot of slack so it only just lifts the valve off its seat; otherwise there's a danger of the valve hitting the piston, so it's possible the cable needs tightening. Obviously you can't lift a valve that's already open, so turn the engine until it is on compression and try pulling the lever then. If nothing happens tighten the cable adjuster until the valve is just lifted off its seat at the end of the lever travel.
If you still can't get any lift, disconnect the cable and move the lever by hand, it has a square hole for a square shaft and it's possible (but pretty unlikely) that it has been fitted 90 degrees out. With the engine on compression again, turn the lever by hand until you feel it touch the cam follower and then re set it so that works with the cable. Realistically there should be no need to pull it apart, as if it is mis-timed in this way you should be able to rotate the cam until it makes contact again and reset the cable from there.

In this I am assuming it's an OHV bike, if it's a side valve there is an additional possibility that worn valve seats have affected the relationship between valve and lifter.
If all else fails with a valve lifter, remember you can always roll it backwards in gear onto compression and kick it from there.
Cheers Rick   

[VicYouel]

Sounds to me as though you have done all the checks...... the lifter inside the timing chest simply butts under the "lip" or "ear"  of the cam follower.... it may have over ridden it.

No real choice except to go through the nausea of stripping out everything to see what has gone wrong!

Vic

[Steve_M90]

I cannot get the decompressor lever to operate the exhaust valve. I have moved the bike backwards and forwards in gear and the exhaust valve moves in sequence, suggesting the cams, pushrods and tappets etc are fine. However, when I pull on the decompressor lever on the handlebars there is no resistance at all. The cable is connected to the bell crank lever and the lever is attached to the spindle. I can see the spindle is turning.

I was riding the bike. I was pulling up at a junction and trying to change down to first. I stalled the engine and then couldn't restart it. (Fortunately this was a test ride very close to home).

It looks like a time-consuming task to get to this spindle as I will have to dismantle the oil pumps and magneto timing chain. I'd be grateful for suggestions of other checks or remedies before I start the strip-down. The bike is a 1932 Model 90 with a foot change gearbox.

Thanks

Steve