When I pulled the valve covers off, I found loose needle bearings in the left valve cover when I was tearing down the top end. This is not uncommon as the bearing cage lip wasn’t wide enough on the earlier needle bearing cages and can fracture. So I replaced all the needle bearings in the heads. Each rocker has a pair of needle bearing cages so there are eight total.
I removed the valves and cleaned the heads to see what I could see. Some of the valve faces are worn down and the valve springs are sacked past the minimum. I suspect the exhaust valve seats are original so I’m planning on having new exhaust seats installed. I’ll also replace all the valve guides, springs and the valves so these heads, which are dual-plugged, should last for a long time.
Here is the link to the write-up on how I did this work.
Here are a couple of pictures from the write-up.
Left Exhaust Rocket-Bottom Rocker Needle Bearing Cage Damaged
Left Exhaust Lower Rocker-Recovered Needle Bearings, Some Broken, and Pieces of The Cage Lip (Tooth Pick For Scale)
Rocker Arm Bearings in Bottom of Oil Pan
Left Exhaust Top Rocker Needle Bearings-Note Gap Between Needles at Bottom Which is Normal
Ready to Drive Bearing Cages Out of Rocker Arm
Valve Spring Compressor
Valve Spring Compressor Ready To Remove Valve
Portion of Valve Face is 1 mm Thick
Portion of Valve Face isΒ 0.5 mm
I start worrying when I just see metallic sparkly dust bits in the valve cover….much less entire needle bearings!
Hi Domingo,
The good news about the needles is they are quite large, all things considered. So they can’t get circulated by the oil pump. And, the only path they can take out of the head is via the push rod tubes to the oil pan, so they don’t have the opportunity to mangle anything.
Small shiny bits of metal, particularly if magnetic, indicate failing bearings, so that is a much larger concern.
There are always surprises when you work on almost 40 year old bikes π
Best.
Brook.
Gosh i’ve been reading your upates and you’ve been tackling some tuff stuff. Dog gone it, I wish I had your knowledge and know how. HA, and tools. Any way great job and I’ve enjoyed your posts and pics. Thanks so much for all your efforts and sharing.
Hi Danny,
You’re most welcome. Sometimes you just keep slogging through the swamp.
Best.
Brook.
Keep up the Great work!
Thanks Britt. I’m looking forward to starting to reassembly the bike; maybe starting in January. I still have a number of projects to complete and a lot of “clean and preparation” work to do on the pile of parts sitting in zip lock bags.
Best.
Brook.