Author Topic: valve setting with tight cam followers  (Read 828 times)

Online Brandis

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valve setting with tight cam followers
« on: 18.05. 2023 20:59 »
Clearly, I should have paid more attention to ensuring that all the cam followers moved freely before proceeding.  One exhaust is stiff and it's hard to set the clearance.  I' ll just set it wide and get back when the engine has run a bit.

Still, remembering when you guys were talking me through crankshaft issues, the good news is that I'm setting valves.
And, for the record,  I followed the old Forum advice to cut the too long exhaust push rods to 205mm.  That works.  And the intakes are 180mm.

Soon, off to the DMV with dodgy paperwork to get a title and plate.   I did check at the beginning that it had never been reported missing or stolen and discovered that it had first and only once been registered in 1948. 
47 A7

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Re: valve setting with tight cam followers
« Reply #1 on: 18.05. 2023 21:08 »
G'day Brandis.
Good to hear (pics would be better) it's moving along. Dump a cup full of oil down on the lifters before you try to start her.
Cheers
'51 A7 plunger, '57 A7SS racer now a A10CR, '78 XT500, '83 CB1100F, 88 HD FXST, 2000 CBR929RR ex Honda Australia Superbike .
Australia
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Online Brandis

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Re: valve setting with tight cam followers
« Reply #2 on: 19.05. 2023 00:24 »
Got it as a heap of junk with 1/3 the parts missing.  I had never seen a complete A7.
47 A7

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Re: valve setting with tight cam followers
« Reply #3 on: 19.05. 2023 01:44 »
G'day Brandis.
Well done mate. For a rare one with bugger all info  *yeah*
Keep us posted.
Cheers
'51 A7 plunger, '57 A7SS racer now a A10CR, '78 XT500, '83 CB1100F, 88 HD FXST, 2000 CBR929RR ex Honda Australia Superbike .
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Online Brandis

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Re: valve setting with tight cam followers
« Reply #4 on: 30.05. 2023 02:53 »
I'm going back into the engine.  The exhaust cam follower didn't loosen up and there's no compression on that side.

Swarfy and Muskie are nodding wisely. 

It shouldn't take that long now that I have all the parts and know what not to do.

Off subject;     I've used the new Amal replacement carbs for 500 thumpers.  I didn't on this one 'cause I'm trying to stay original.   Opinions??
47 A7

Offline Swarfcut

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Re: valve setting with tight cam followers
« Reply #5 on: 30.05. 2023 08:28 »
 Are you sure the valve and rocker arm are both free to move? A binding exhaust follower could be an easy fix....simple lubrication. But if the binding is due to corrosion, or some other cause eg bowed follower stem or tappet guide problem, you know that it's maybe back to the start.....the motor is assembled around that central tappet guide, and  this is unlikely to come out without splitting the cases. If the binding is there, lift the barrel and try lubrication and heat as a first try...could save a lot of work.

 Strange to hear of this malady, I thought it was a complete teardown and a tappet problem like this would have been seen before the barrel went on. Those followers are usually  very free in the guide.

 As for carb choice, anything that gets a runner for now is fine. Final choice depends on the degree of authenticiy versus reliability required.

 Swarfy.

Online Brandis

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Re: valve setting with tight cam followers
« Reply #6 on: 30.05. 2023 12:38 »
I have been pouring oil on the springs and push rods and cranking it over on the assumption that it would loosen up.  No deal.  It's definitely not corrosion.  It was a bit tight on assembly. 
The rocker moves when I turn the motor but there isa perioding loud 'sproing' noise as something that's jammed releases and the the spring jumps.   And no compression. 
47 A7

Online Brandis

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Re: valve setting with tight cam followers
« Reply #7 on: 30.05. 2023 13:26 »
PS:  With the rocker assembly off, the push rod will rise when the engine turns but you need to tap it with a hammer to set it back down.  So it's not valve stem issue.
47 A7

Online chaterlea25

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Re: valve setting with tight cam followers
« Reply #8 on: 30.05. 2023 13:41 »
Hi Brandis,
If the follower is damaged when you get in there, I have a full set of new original BSA followers available

John
1961 Super Rocket
1963 RGS (ongoing)

Online RichardL

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Re: valve setting with tight cam followers
« Reply #9 on: 30.05. 2023 14:37 »
I wonder if it's possible for the tappet locating pin to be installed or distorted in such a way as to interfere with one of the exhaust tappets.

Richard L.

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Re: valve setting with tight cam followers
« Reply #10 on: 31.05. 2023 02:41 »
What is the 'tappet locating pin' .  I assume I have 4 but maybe I know them by a different name?
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Online RichardL

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Re: valve setting with tight cam followers
« Reply #11 on: 31.05. 2023 03:24 »
In the center at the back of the tappet tunnel. Goes between the cutouts in the exhaust tappets to keep them in the tunnel.

Richard L.

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Re: valve setting with tight cam followers
« Reply #12 on: 31.05. 2023 07:31 »
G'day Richard.
That's for a short stroke A7 and A10. Brandis has a long stroke.
Cheers
'51 A7 plunger, '57 A7SS racer now a A10CR, '78 XT500, '83 CB1100F, 88 HD FXST, 2000 CBR929RR ex Honda Australia Superbike .
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Muskys Plunger A7

Offline Swarfcut

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Re: valve setting with tight cam followers
« Reply #13 on: 31.05. 2023 07:48 »
 Brandis. RichardL is correct about the position of the locating pin.....but that is only used on the later engine where the tappets are fitted into the cylinder base.

 Rest easy. Your Longstroke does not have this feature.

 There are two oilways on your centre tappet carrier, The larger horizontal drilling feeds the two guide tubes. A smaller drilling at the rear feeds down to the tappet blocks and then oil passes to the cam lobes. These may be obstructed after the years standing idle.

 The tappet blocks have a straight and a curved side. On the inlet tappet guides there is room for them to go in either way, but on that central exhaust tappet guide there is a greater clearance between the opposing faces of the blocks if the curved faces are fitted to the outside, matching the curved periphery of the carrier. Bit late now to check, but with that centre carrier removed somehow, all will become clear.

 Swarfy.

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Re: valve setting with tight cam followers
« Reply #14 on: 31.05. 2023 12:46 »
Ah! OK, I'll stop "wondering."

Musky and Swarfy, thanks for the illumination. Brandis, sorry if I spawned consternation.

Richard L.