Rocker Play On Pin

youngjohn

Well Known and Active Forum User
Non-VOC Member
There's a bit of play on my Rapide front exhaust rocker between the rocker itself and the pin, which means that the rocker looks to be rotating around the pin rather than the pin rotating in the bearing.

The tunnel appears to be in good shape and from what I can see, there is no play between it and the bearing.

I've got a good spare rocker/bearing assembley but before I set about exchanging it, are there any gems of advice or caution I need to know?

I'm hoping to do this in situ (as I'm using the bike regularly at the moment), then have a proper look at it when the season ends, so I guess I'll have to wait until then to fit the modified feed bolt.
 

Marcus Bowden

VOC Hon. Overseas Representative
VOC Member
Some one might have fitted Torrington crowded needle roller bearings so future repairs are less expensive only having to replace bearing & pin, so long as you have the captive rocker feed bolts in, just keep riding as damage is already done if standard set up and that'ill do ee the rest of the season. 1965 or 6 the captive feed bolts appeared in MPH so I made my first set as an apprentice in HMD Devonport, my mate John Southern (VOC er) was contemplating drilling a hole through at the bottom inline with rocker then hacksaw it through and drive a taper pin in, spreading the bearing to tighten it in the tunnel to stop tunnel wear but by doing this on some it pinched the rocker pin in bearing so rocker rocked on pin, captive feed bolts are essential for long-levity.
bananaman
 

Bill Thomas

Well Known and Active Forum User
VOC Member
Ron and me just did a captive rocker mod, But we had to take a lot of metal off the top of the rocker, Each side at the top, To allow it to rock enough, Cheers Bill.
 

Len Matthews

Well Known and Active Forum User
VOC Member
There have been all manner of mods to the rocker assembly over the years, some well engineered and some horrible bodges. One I've seen involved turning the existing treads off the rocker feed bolt, forming 1/4"BSF threads on the tip and inserting a 1/4" BSF Helicoil in the top of the rocker bearing. Seemed to me to be a lot of work when ready made captive rocker feed bolts have been around for ages. Another mod I came across was where the rocker was bored out, a bush inserted and the pin made a press fit in the bearing-why? The worse one was where someone had rammed a self tapping screw between the bearing and the cyl. head in the vain hope that mechanical noise would be reduced. Often the press fit of the pin in the rocker is lost-would making oversize pins be a worthwhile idea?
 

youngjohn

Well Known and Active Forum User
Non-VOC Member
Turns out that the rockers do have the modified feed bolts - didn't look close enough!
Couple of questions:

What's the best way to pull the rocker & bearing out of the tunnel? With the feed bolt removed it won't budge with hand pressure.
Maybe a small slide hammer?

Also, when pressing a new pin into the rocker, is it necessary to make up a cradle or jig so that the bearing doesn't distort? Saw an example on a recent 'Tools' thread.

Thanks for any help & advice.
 

Bill Thomas

Well Known and Active Forum User
VOC Member
Hello John,It should come out OK, We used a slide hammer but it should not need too much force, Just protect the threads, When putting back in, Push down on the adjuster so the rocker goes above the valve coller, cheers Bill.
 

stumpy lord

Well Known and Active Forum User
Non-VOC Member
Turns out that the rockers do have the modified feed bolts - didn't look close enough!
Couple of questions:

What's the best way to pull the rocker & bearing out of the tunnel? With the feed bolt removed it won't budge with hand pressure.
Maybe a small slide hammer?

Also, when pressing a new pin into the rocker, is it necessary to make up a cradle or jig so that the bearing doesn't distort? Saw an example on a recent 'Tools' thread.

Thanks for any help & advice.
re fit the feed bolt a couple of turns and give it a light tap down, to ensure that the captive nut is below the top surface of the rocker bush, and then remove said item. the captive nut has to be only a few thou above the rocker bush to make things hard, and using a slide hammer in this situation can put a lovely score down the tunnel.
stumpy lord
 

Hugo Myatt

Well Known and Active Forum User
VOC Member
Turns out that the rockers do have the modified feed bolts - didn't look close enough!
Couple of questions:

What's the best way to pull the rocker & bearing out of the tunnel? With the feed bolt removed it won't budge with hand pressure.
Maybe a small slide hammer?

Also, when pressing a new pin into the rocker, is it necessary to make up a cradle or jig so that the bearing doesn't distort? Saw an example on a recent 'Tools' thread.

Thanks for any help & advice.

In the bad old days when many Vincent owners were mere heavy handed motorcyclists rather than the precision engineers they all are today the method for removing the rocker bearing from the tunnel was thus - Find an open ended spanner that just fits the thin part of the rocker arm. Slide it on from below. Use a strip of wood across the mouth of the tunnel as a fulcrum and to protect the cylinder head. |Lever down and out pops the rocker bearing. Of course I would not condone such a barbaric practice today.
 
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