56 G80 CS

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Re: 56 G80 CS

Postby Matchymarty » Sun Aug 12, 2018 5:53 pm

Both of my '55 and '56 G80CS's have breather hoses attached to the pushrod adjustment cover. Some people say they are absolutely necessary to vent rocker box pressure, and some say they cause other problems. Who knows. ahahaha.

This issue does sound a lot like the drains in the head are blocked or something. Be interested to hear what you find.

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Re: 56 G80 CS

Postby ajscomboman » Sun Aug 12, 2018 6:35 pm

Well Marty you were the closest! Pulled it down today and the bottom O rings had mushroomed out into the pushrod tubes and blocked the tappet drain holes. Absolutely nothing to do with anything Ken had done, I didn't expect that it would be as his work is second to none. He's been in contact offering to strip and rebuild the motor for free but I'll have no problems putting it back together. He's never heard of that issue ever arising before so at least I'm unique. Guess I'm lucky no damage has been done.

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Re: 56 G80 CS

Postby clive » Sun Aug 12, 2018 7:13 pm

Oh yes you are unique Rob! (good news you have identified the problem)
clive
if it ain't broke don't fix

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Re: 56 G80 CS

Postby ajscomboman » Sun Aug 12, 2018 7:14 pm

clive wrote:Oh yes you are unique Rob! (good news you have identified the problem)


Hmm! I think I'll have to digest that reply! :P :P :P

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Re: 56 G80 CS

Postby Mick D » Mon Aug 13, 2018 6:25 am

ajscomboman wrote:Well Marty you were the closest!


Hi

Missed my post on page one then :roll:

"Have you done anything recently that could result in a blockage to the return galleries at the bottom of the push rod tubes?"

Glad you've got it sorted.

Regards Mick

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Re: 56 G80 CS

Postby ajsph » Mon Aug 13, 2018 7:07 am

If you use viton o -rings, you will never have this problem.
regards Poul

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Re: 56 G80 CS

Postby ajscomboman » Mon Aug 13, 2018 11:28 am

Mick D wrote:
ajscomboman wrote:Well Marty you were the closest!


Hi

Missed my post on page one then :roll:

"Have you done anything recently that could result in a blockage to the return galleries at the bottom of the push rod tubes?"

Glad you've got it sorted.

Regards Mick


So I did, well you can both have a prize. I've done nothing to the motor except lap the head in as it started to weep last year. Done hundreds of miles since then, including 80 the week before the IWKR weekend and all was well. I guess they've been swelling for a while and the latest round of baking hot weather and oil was enough. It's a bit of a bugger as the bike has been running well right up to that point. Still it's on the way to being fixed.

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Re: 56 G80 CS

Postby SPRIDDLER » Mon Aug 13, 2018 11:59 am

ajscomboman wrote: It's a bit of a bugger as the bike has been running well right up to that point.

They all do that, Sir. ;)

(The gas in my motorhome always runs out when I'm in the middle of cooking something :cry: ).
I poke badgers with spoons.

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Re: 56 G80 CS

Postby REW » Mon Aug 13, 2018 12:48 pm

ajsph wrote:If you use viton o -rings, you will never have this problem.
regards Poul


I think I have a similar problem developing on my 350 though it has shown up as sudden copious leeks - seals at base of pushrod tubes are probably 4 years "old". What size Viton seals are required, do you know Poul?
Ron

1951 Matchless G3L, thumping round the Durham Dales

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Re: 56 G80 CS

Postby ajsph » Mon Aug 13, 2018 4:09 pm

Hi Ron
I don`t know the correct size for your 350, but on my 1959 18CS I have used 23 x 3 mm and 19 x 5 mm, sorry about mm.
Regards Poui

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