Loud Valve Tick

Yesterday I went for a 250 mile ride. Upon initial startup, I noticed a light valve tick, that became louder along the way. By the time I returned home it was loud, and very noticable. It is only one valve, and I was too tired and too much heat upon return home, so did not bother to even figure out which cylinder it was coming from. About 7500 miles ago, I replaced all four rocker shaft needle bearings on the right side, and adjusted all valves, on left & right cylinders. I doubt it is valve adjustment, since valve clearances close with mileage, but anything is possible. I am looking forward to removing the rocker covers tomorrow to check it out. Will let y'all know what it turns out to be. Hopefully not rocker shaft bearings again. I bought all eight bearings before, but only changed out the right side. Need to get out in the garage early in the morning, before the heat comes. Will update later.

Certainly need to open her up. It's possible that the nut on the valve clearance adjuster loosened up...that's always been a fear of mine that I didn't snug it up enough.

Standing by...

20774 said:

Certainly need to open her up. It's possible that the nut on the valve clearance adjuster loosened up...that's always been a fear of mine that I didn't snug it up enough.

Standing by...

Click to expand...

That was my first thought for sudden onset, progressive ticking.

Rocker Arm Needle Bearings Again

It did not take long to discover the problem. When I removed the right side valve cover, 16 bearing needles were in the oil that drained, along with a few slivers of the bearing cage's lower lip. They all came from the intake valve rocker, which caused clearance gap to increase to .035". Though the shafts looked serviceable last time, only 7500 miles ago, I probably shoulda replaced them. So I will order four shafts from Ted Porter in a few minutes but, as last time, will only replace the two on the right side. The left side is still doing well, so, if it ain't broke I ain't gonna try to fix it.

As last time, it appears the lower lip of the bearing cage is what fails, and allows the needle bearings to drop down and eventually work their way past the gap in the trunion block. This time, I plan to install some kinda nylon ring in the recess between the lower lip and trunion block, or at least an o'ring. That way, it will take much longer for the needles to work their way down and out, if the cage's lower fails again.

If gravity is an issue in this application, either the upper or lower bearings are in upside-down, as the cage lips are different; one end is tapered, and the other is rounded. Since the upper bearings have not failed, their rounded lip (placed on the bottom) seems less likely for the needles to rupture. It is always the lower, tapered lip that has failed on this Airhead.

I see all Airheads, from 74 on, had these needle bearings, but wonder why I never experienced a failure before, with the older, twin shock Airheads, in over 200,000 miles. I'd prefer bushings, at least they could not cause catastrophic failure, as the needle bearings can, and do.

Hers is the link to my post, he last go round with these same bearings:https://forums.bmwmoa.org/showthread.php?100130-Rocker-Arm-Needle-Bearing-Failure

Ask Ted what he might recommend.

Snowbum discusses the need to properly orient the rocker shafts. Link to his discussion follows -

https://bmwmotorcycletech.info/headassy.htm

Flat End Up

robsryder said:

Snowbum discusses the need to properly orient the rocker shafts. Link to his discussion follows -

https://bmwmotorcycletech.info/headassy.htm

Click to expand...

My 95 RT has the rocker shafts clearly marked with huge 'drill marks' on one end, so hard to reassemble improperly. I agree with Snowbum, the bearings should all be installed with the flat end up, and rounded end down. This is in contrast to factory assembly, which installs the top bearings with rounded end down, and bottom bearings with flat end down. Per Snowbum, Tom Cutter prefers the factory install, and he prefers rounded end down. After two different failures of bottom bearings, all in bearings with flat end down, I will be installing the next ones with rounded end down, as Snowbum prefers. I had noted that oddity the last time and thought, assembled that way, made one end upside-down. it seemed rounded end down was preferable, but I went with the factory, and reassembled accordingly.

I disagree with Snowbum that the failed bearings were a bad batch, made early on. The ones I installed three months ago were repros, made in Taiwan by Emerald Isle, and sourced from Ted Porter. I also did not note any problems with crimping of the ends that would lead to cage lip failure. Though I agree the problem is with cage lip failure, and not the bearings themselves. What a mess! This has destroyed my confidence in even considering a cross country trip on this Airhead. I plan to ask Ted about bushings, to replace the bearings, when he returns my call.

robsryder said:

Snowbum discusses the need to properly orient the rocker shafts. Link to his discussion follows -

https://bmwmotorcycletech.info/headassy.htm

Click to expand...

Yes, this is critical. On reassembly I always like to drain the float bowls then crank the engine with valve covers removed until I can verify oil is flowing through the rockers. Especially following a reseal with new pushrod seals and cylinder base reseal, as it’s all too easy for any excess sealant to block the oil passages on the upper studs.

Best,
DeVern

Rocker Shaft Availability

Ted Porter's shafts are on backorder from his SOS, with no estimated date of arrival. So I found 2 shafts on eBay, which should be here by next Friday. Sure glad the Airhead is not my only motorcycle. Meanwhile, maybe I will change the front tire, and install new jet needles in the Bings.

Would all sources for shafts be on backorder? I wonder what Tom Cutter has...or Anton?