Author Topic: Dodgy parts  (Read 1531 times)

Offline duTch

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Re: Dodgy parts
« Reply #15 on: 23.09. 2015 22:20 »
 
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The steel caps are called 'lash caps'

 That's the term I had in mind (didn't)... *smile*

 That looks like a handy piece of kit Klaus... *wink2* ..but also
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Like the part. Not crazy about modifying the rockers.

...Also gives extra tappets in the cups and balls... *fight*
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Online RichardL

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Re: Dodgy parts
« Reply #16 on: 24.09. 2015 00:08 »
...Also gives extra tappets in the cups and balls... *fight*

Is that something to look forward to? *whistle*

Richard L.
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Offline Rocket Racer

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Re: Dodgy parts
« Reply #17 on: 24.09. 2015 00:31 »
or that given BSA used almost every thread form known to mankind is the rethreading of parts to metric forms  a natural progression or heresy?  *eek*

I'd err towards burn the heretic  *whistle*

Just as well we're a diverse bunch  *wink2*
A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
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Offline duTch

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Re: Dodgy parts
« Reply #18 on: 24.09. 2015 04:32 »

 
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I'd err towards burn the heretic  *whistle*
.....hhmmm *conf*

 I kinda like the idea of roller rockers...but that's not why I'm here; No work today, so figured I'd check the clearances- in@0.009 /ex0.012 might close the ex to 11...but that's also not why I'm here...

  While doing this check I remembered that the way to do the clearances on my '69 Daytona was to close the adjuster in to zero clearance, and then wind it out something like a quarter turn, to give whatever it should be maybe ~7-8 thou *dunno2* ...sounded a fairly dodgy at the time, but have since figured that depending on the thread pitch (maybe 1/4bsf on that?), seems logical, so I've applied that logic to the A10 and wasted time over a cold tongue lube :P, and created a tool which I'll paste later........but that's also not why I'm here....

       I had a thought, and another look at Morris's photo, and going by the shape of the indents it kinda looks like maybe the rocker geometry could be a bit wrong, maybe the pushrods are too short/long, (could be a consequence of gasket thickness?) and also maybe the thackery/shims are a bit flaccid...
  I asked about rocker geometry awhile ago, but can't remember any outcome..??
 
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Offline Rocket Racer

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Re: Dodgy parts
« Reply #19 on: 24.09. 2015 06:31 »

       I had a thought, and another look at Morris's photo, and going by the shape of the indents it kinda looks like maybe the rocker geometry could be a bit wrong, maybe the pushrods are too short/long, (could be a consequence of gasket thickness?) and also maybe the thackery/shims are a bit flaccid...
  I asked about rocker geometry awhile ago, but can't remember any outcome..??
 

A mate sketched these notes up for me for checking my a75, which is slightly different but are very sensitive to rocker geometry for valve wear (typically stems and guides) , but the intention was that at half lift the tappet should be in line (at 90 deg) with the valve stem. Not sure how to best articulate this.
With the A10's and A7's having various cam lift and some with after market pushrods or skimmed heads or differing gaskets its quite likely mainly are not quite optimal
A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
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Offline duTch

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Re: Dodgy parts
« Reply #20 on: 24.09. 2015 09:20 »

 I'll look at the pics later, but;
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at half lift the tappet should be in line (at 90 deg) with the valve stem. Not sure how to best articulate this.
  It's the same principle as brake/clutch cable geometry...??

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With the A10's and A7's having various cam lift and some with after market pushrods or skimmed heads or differing gaskets its quite
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likely mainly are not quite optima
l
Yep I'm inclined to degree to agree-  *whistle*(sorry-just had a play on words there).....but also I think you mean
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likely many are not quite optima
..?
    It kind've makes sense that if there's a bit more lift involved, geometry will change some- depending maybe on the base radius *????*
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Online morris

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Re: Dodgy parts
« Reply #21 on: 23.10. 2015 21:57 »
A little update. I think the adjusters where to pointy and to hard as well. Tried to give one of them a couple of file strokes but that didn't even make a scratch on the surface. Don't understand why they have to be that hard. After all, they're a lot easier to replace than a valve.
I have ordered a set of adjusters at another supplier (bottom of the picture). They have a much flatter surface and are softer to.
The valve train seems to be a lot less noisy now. Gonna run it for a while like that and see what it does.

hi guys, Morris is it possible to get steel caps for them? cheers

Yep. B31 valve caps fit. I ordered a set but decided not to install them for the moment
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Online edboy

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Re: Dodgy parts
« Reply #22 on: 24.10. 2015 17:56 »
hi morris, do you mean b31 lash caps fit the a10 valve. if thats a yes i may use them with mushroom adjusters myself on my next project.

Online morris

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Re: Dodgy parts
« Reply #23 on: 24.10. 2015 21:48 »
hi morris, do you mean b31 lash caps fit the a10 valve. if thats a yes i may use them with mushroom adjusters myself on my next project.

Yes, tried them on and they fit. B31 stems have exactly the same diameter as A10's
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Online muskrat

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Re: Dodgy parts
« Reply #24 on: 25.10. 2015 09:46 »
The problem with fitting lash caps to valves not designed for them is the added length to the stem and the geometry to the rocker.
Cheers
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Re: Dodgy parts
« Reply #25 on: 25.10. 2015 17:08 »
yes muskrat your right but there might be space to grind down the valve stem, use slightly shorter pushrods or even worn cam followers would compensate.no harm in experimenting if you like fiddling.