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Exhaust Valve Lifter #586850
02/22/15 10:59 am
02/22/15 10:59 am
Joined: Oct 2014
Posts: 63
Lancashire. England.
R
resingled Offline OP
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resingled  Offline OP
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R

Joined: Oct 2014
Posts: 63
Lancashire. England.
[Linked Image]
[Linked Image]
[Linked Image]
[Linked Image]

Sorry. Managed to find the rest of the instructions. Incidently, the cam is central to the rocker when the rocker is pushed to it. Regards. Dave.

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Re: Exhaust Valve Lifter [Re: resingled] #586877
02/22/15 1:00 pm
02/22/15 1:00 pm
Joined: Feb 2012
Posts: 1,273
Middle East,
Kerry W Offline
BritBike Forum member
Kerry W  Offline
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Joined: Feb 2012
Posts: 1,273
Middle East,
Remember the split-pin on the end of the lifter shaft..


No generalisation is wholly true, not even this one.
Oliver Wendell Holmes
Re: Exhaust Valve Lifter [Re: resingled] #586879
02/22/15 1:06 pm
02/22/15 1:06 pm
Joined: Feb 2012
Posts: 1,273
Middle East,
Kerry W Offline
BritBike Forum member
Kerry W  Offline
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Joined: Feb 2012
Posts: 1,273
Middle East,
...after looking at your other post...the parts should be fine. Do a dry assembly, and rotate the lifter shaft to put the lifter cam against the rocker and then position the lever. The usual manuals' instructions are very vague about clearances, etc. I set mine up to have just a little clearance from the rocker when pushed back by the spring in the lifter cable end. As you say, lifting the valve only a fraction will allow the release of the compression.

WARNING: do note the part off the manuals that says not to operate the lifter at high RPM. The consequences are not spelled out, though I can say with some authority that the exhaust lifter cam will ride past the rocker. The lifter will then be slack. If the lifter arm was then to be repositioned on the shaft in an effort to get the lifter working again, all you will get is a lifter than is immovable, as it is trying to 'lift' the inside of the rocker box..


No generalisation is wholly true, not even this one.
Oliver Wendell Holmes
Re: Exhaust Valve Lifter [Re: resingled] #586884
02/22/15 1:33 pm
02/22/15 1:33 pm
Joined: Sep 2001
Posts: 2,802
Comox BC Canada
G
Gordo in Comox Online content
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Gordo in Comox  Online Content
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G

Joined: Sep 2001
Posts: 2,802
Comox BC Canada
When I look at the end of the rocker in your photos I am of the opinion that the previous owner may have taken too much off the contact pad. The lifter cam might be just swinging past the rocker without touching it.

Gordo

Here are a couple of examples, BB GS on left and BB31 on right.

[Linked Image]


Without frequent roadside repairs there is no fun in riding!
Re: Exhaust Valve Lifter [Re: resingled] #587019
02/23/15 7:11 am
02/23/15 7:11 am
Joined: Oct 2014
Posts: 63
Lancashire. England.
R
resingled Offline OP
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resingled  Offline OP
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R

Joined: Oct 2014
Posts: 63
Lancashire. England.
Thanks for all your input. Yes Kerry. The split pin has been in and out so many times it is now in the bin. I will remember to put one in though. I have done a dry assembly several times and with the exhaust valve loose in the guide and pressed against the seat I can rotate the lifter cam completely past the rocker arm. I think that the photo from Gordo says it all. Both rockers in his example have much more depth than the ones in mine. So it seems I need an exhaust rocker if I want to use the valve lifter - which I do. Now the engine is not stamped GS. It has BB32A crankcases but, going off the numbers stamped on the castings and measurements, the crank assembly, piston, head, and perhaps the rocker box are BB34. To me the rocker boxes may be identical on the 350's and 500's. I don't know but I'm sure someone out there does. After all that, any ideas where I can find an unmolested rocker arm to put in my mongrel engine? Thanks again. Dave.

Re: Exhaust Valve Lifter [Re: resingled] #587100
02/23/15 7:58 pm
02/23/15 7:58 pm
Joined: Sep 2001
Posts: 2,802
Comox BC Canada
G
Gordo in Comox Online content
BritBike Forum member
Gordo in Comox  Online Content
BritBike Forum member
G

Joined: Sep 2001
Posts: 2,802
Comox BC Canada
Dave: I think the early rockerboxes are all the same 350 and 500. I am trying to figure out what you have for an engine. The BB32A or BB32 GS cases for that matter are the same as the B31/33 with the small drive side roller bearing, smaller drive side shaft and the lack of steel support plate. I am guessing you have a BB34A crank with a 500 barrel and head.

One solution for your lifter problem would be to get a B31/33 rocker and have it lightened to match the GS version. Below is one of the B31/33 rockers I had turned down. My machinist was surprised how hard it was to grind them down. The only thing to look for would be the passageway to oil the top of the pushrod. The early rockers did not have this feature.

Gordo



[Linked Image]

The oil hole is shown below

[Linked Image]


Without frequent roadside repairs there is no fun in riding!
Re: Exhaust Valve Lifter [Re: resingled] #587475
02/26/15 1:56 pm
02/26/15 1:56 pm
Joined: Oct 2014
Posts: 63
Lancashire. England.
R
resingled Offline OP
BritBike Forum member
resingled  Offline OP
BritBike Forum member
R

Joined: Oct 2014
Posts: 63
Lancashire. England.
Thanks for the photos Gordo. They illustrate the difference between my skinny rocker arms and the originals. I believe you are correct that I have BB32A crankcases with a crank, barrel and head from a BB34. I suspect the rocker boxes are all the same apart from engines which have eccentric rocker spindles. Hopefully some pictures will appear below to confirm my (our) thoughts about the make up of this engine. Fingers crossed. I've not mastered this yet. Ha.
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Re: Exhaust Valve Lifter [Re: resingled] #588864
03/06/15 12:15 pm
03/06/15 12:15 pm
Joined: Oct 2014
Posts: 63
Lancashire. England.
R
resingled Offline OP
BritBike Forum member
resingled  Offline OP
BritBike Forum member
R

Joined: Oct 2014
Posts: 63
Lancashire. England.
Just an update on the rockers, new and old. Someone has obviously spent a lot of effort on the original(assuming it started life as the new one). It seems a shame to take it out. However, I will settle for a valve lifter that works.
[Linked Image]
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