ET: Engine (Twin) Rocker Bearing (ET26) diameter

[eharris]

Hello all,

What is the OD of a standard rocker bearing (ET26)?

I am currently fitting them and they seem rather tight. Naturally one is now jammed part way in, but I am sure that will give in to suitably coarse language…!

It seems unlikely that the tunnels are undersize, so I am wondering if they might be oversize ones.

Cheers,

Ed

 

[greg brillus]

Bearing and tunnel are 1.350" diameter less a half a thou here or there.......they should be a light drive fit into the head.......be doubly sure the rocker pins are not slightly overhanging the sides of the bush as the pin will gouge a groove into the head........heating the head somewhat will help, but I generally install them cold with a light coating of oil in the tunnel bore........a soft hammer and tap the rocker works ok........keep the adjuster end of the rocker downward as the fork passes over the valve collar to sit on top of it.......a light coat of molly grease on the fork faces is good practice.......removal is best with a slide hammer using a piece of 5/16" rod with a right angle bend in it hooked through the tappet adjuster bore.

 

[eharris]

“A slide hammer” yes that was the gubbins I was trying to think of.

Thanks.

 

[kettlrj]

I don’t like Gregg’s advice of using a 5/16” rod bent at right angles to hook into the rocker. This has the possibility of damaging the thread. The thread is 1/8” BSP, so I use a hydraulic system banjo centre bolt of the same size to attach to the end of my slide hammer via a small right angle bracket that is bolted to the 5/16” BSF thread of the slide shaft.
The 5/16” BSF thread is important as it fits the far end of the oil pump sleeve, if you ever need to extract it.
Richard Kettle

 

[Alyson]

now I feel like a cave-woman. I usually just grab the end of the rocker and yank it out Sheesh !!

 

[eharris]

now I feel like a cave-woman. I usually just grab the end of the rocker and yank it out Sheesh !!

You must have much stronger fingers than I, as I has to use a significant amount of leverage, and bad language, to get this one out!

It would have been my father who inserted this one, almost all the way, some years ago. I suspect he used some persuasion and stopped when it would go no further.

The thread was quite mashed by the time I was done. New ones on order!

 

[davidd]

I use soft wire, the type of wire available in a hardware store as utility wire. It does not damage the hardened threads in the rocker. I make a double loop through the rocker's threaded hole and grab it with the puller if it is relatively easy to extract. If it is difficult, I wind the wire around the nut that normally holds the puller in place, but with the puller removed, or the puller arms removed.

I normally use the wire for hanging parts that need painting.

David

 

[ilikevelos]

I carry some of that utility wire with me on the road to tie up a part that has broken or lost a proper fastener. I find it is better than safety wire for that purpose and is part of the travel emergency kit along with zip ties, duct tape and hose clamps.

 

[Michael Vane-Hunt]

Hay wire.

 

[oexing]

Instead of safety wires and all I use a selection of Loctites in assembly where it looks useful. So never carry that type of last help for keeping the bike together.

Vic