Author Topic: cylinder head  (Read 3157 times)

Offline Swarfcut

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Re: cylinder head
« Reply #30 on: 02.07. 2020 11:22 »
Bergs Hits the Jackpot!!!!

  Building up a rocker box for my Plungy, noticed that the rocker spindle oil feed ends were being drawn below the level of the casting face when the acorn nuts were tightened. With the spindles located correctly, so the spindle annular oilway to the rocker  coincided with the oil hole on the underside of the rocker, there was a definite gap between the casting and the shoulder at the threaded acorn nut end of the spindle, like space for a washer.

  My early parts book indicates all the plain washers are the same, but later '54-'57 edition shows a pair of 67-0061's to be a different washer fitted at the Acorn Nut end of each spindle. This will bottom against the inner face of the casting and prevent the spindle being drawn too far  towards the timing side. I reckon I have never seen different washers on this bike, just a set of 8 big hole washers. So looks as if I have a pair of small hole washers missing, and big hole standard washers in their place. Drags catalogue confirms the ones required  as being "Small Hole".

 With a small holed washer added, the acorn nut will draw the shaft to its correct position...... and may solve the problems of the leaking banjos for some of you folks, and worth checking you have small holed washers here  next time the top comes off.  It's one aspect of the rocker gear we take for granted, but as these bikes have been through hell in some cases, assembly mistakes and mis-matched parts are an answer for some of the strange faults experienced.

   Without them the spindle will move further into the rockerbox, displacing the drive side thrust washers tighter against the rockers, which ain't so good, as well as removing some of the positive location for the banjo/rockerbox sealing washer.  There is also the possibility of the rocker spindle rotating slightly as without being pulled hard against the casting by the acorn nut, it is just suspended between two threads, rather than being positively located and clamped tightly in place.

 So searching for information came across berg's note above, and that helped me find the answer.

 Thanks bergs.



Offline terryg

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Re: cylinder head
« Reply #31 on: 02.07. 2020 12:43 »
Useful information indeed. I’ve often wondered why there was no hard stop when tightening the acorn nuts.
I’ll know what to look for next time.
'57 'SR', '59 SR, '63 RGS

Online berger

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Re: cylinder head
« Reply #32 on: 02.07. 2020 13:25 »
cheers swarfy, I knew I might be useful for something . I also found that the spring washer next to the small washer can be a bit of a pillock and trap itself on the shaft not letting the shaft pull fully home to the small bore washer, a bit of screw driver pokery was needed to make sure everything was in situ. oh and a bit of what's up with this ******* thing NOW!!!