FH - wear in the valve train

 Last time we were here, I wrote about some wear I detected in the valve train through not being able to set up the valve clearances properly. What I've done now is remove the rocker box again to have a close look at the tappet adjusters and the push rods. 

Removing the push rods and measuring them revealed that the inlet pushrods are correct to the measurements shown in Draganfly's pages of information. Strangely enough the exhaust push rods are actually slightly too short, which is unexpected since I was able to set up these valve clearances easily.

I also measured up the tappet adjusters. I made some posts on the club Facebook page about both the tappet adjusters and the push rods which revealed some useful advice from fellow members. It appears that the tappet adjusters are more or less the correct length, however the later BSA or Triumph adjusters (which are the same length and thread, 5/16" CEI) are provided with hex socket heads and are consequently easier to use. Looking closely at my original Ariel adjusters showed that the square heads were deformed slightly and would not go into the lock nuts, limiting the adjustment available.

I resolved to take the club member's advice, and bought a new set of adjusters and lock nuts.

Further advice from a gentleman who races Ariels had me looking at the extent of the heat treatment of these adjusters. Some of the ones on the market are apparently prone to breaking around the hexagon socket due to over hardening in that area; it appears that the extent of heat treatment on the ones I bought is limited to the area that makes contact with the valve stem, so that should be all right. Hopefully...

Today I fitted the rocker box again, with a longer bolt inside the inlet end. This is a much better approach than the stud and nut that Ariel specified (you will lose the nut down the pushrod tunnel) and is actually a BSA approach to fixing the rocker box shown to me by Steve, a long distance Huntmaster rider. 

Unfortunately tightening the rocker box bolts revealed that the nuts in the two rear corners could not be fitted with the box fully down. I loosened the main bolts and jacked up the rocker box using the inlet valve adjusters high enough so that I could get the reduced hex nuts in place on the rear corners without losing the pushrod location in the rocker cups.

That done, it was time to pack up for the day but not before I had temporarily fitted the rocker box covers and one of the head steadies. One of the rocker box covers doesn't fit very well due to burring on the locating pins which I'll have to fix later.

Here's a wider view of the engine, with both exhaust pipes temporarily in place:

Next, we can finalise the valve clearances, which are 0.010" for both inlet and exhaust; these new Triumph adjusters need a 1/8" hex key, one of which will have to go in the toolkit. When that's done, we won't need to have the facility to turn the engine easily, so we can close up the gearbox. Before I do that I will fit the pear nipple on the clutch cable; I'll adjust the inner clutch cable length later as I want to replace the handlebar end nipple with a brass one. I'll do the air lever nipple at the same time.

Offline from all this I can replace the dynamo chain and fit the timing cover. Then we can seriously think about first start.