G80cs unwell

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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G80cs unwell

Postby cbranni » Mon Jul 22, 2019 3:38 pm

I took my G80 out for a spin yesterday afternoon, started fine and off I went but wasn't running like it should, it was missing and just not right so I returned home and took a BSA out.

So today the G80 went onto the ramp for a sort out, it has done 700 miles since it's been on the road so time to tighten stuff up and check it all over. I removed the carb and stripped it down and to my amazement the float chamber had alloy swarf inside, now this was a new carb (club supplied) in 01/18 and was put straight on the bike and has run fine.

[url]Image[/url]

I have heard of swarf in new carbs but to actually see it is quite scary, surely Burlen have got the process sorted by now, I will be writing to them with a sample of the swarf, please note I am not having a go at club spares.

Moving along ............I wanted to tighten the head down so off with the rocker box and I found the inlet tappet gap was quite large, on inspection the the steel sleeve was worn so too the bushes, you can see oil groove marks on the steel sleeve where the sleeve wasn't turning in the bush.

[url]Image[/url]

So I placed order with club spares for new bushes, felt seal and steel sleeve, sadly the steel sleeve is out of stock so I ordered some 5/8 silver steel and will have to make one, I imagine this was a part that Andrews used to make.

Will check the mag tomorrow and hope I don't find anything nasty.

Colin
only dead fish go with the flow

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Re: G80cs unwell

Postby Mick D » Mon Jul 22, 2019 4:28 pm

Hi Colin

Isn't keeping these bikes alive fun :)

I bought my carb direct from Burlen in 2015 and, touch wood, it's been OK so far, what sort of scale, (sic), are those pieces of swarf? The club may have had the carb on the shelf for sometime.

From the photo of the rocker shaft assy it looks like it's suffered from lack of lubrication to me, I don't see evidence of the sleeve not rotating in the bushes, or rotating around the shaft, nor the bushes rotating in the box - of course this could just be the photo playing tricks.

Regards Mick

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Re: G80cs unwell

Postby cbranni » Mon Jul 22, 2019 5:15 pm

Hi Mick,

Thanks for the comments.

If you look at the steel sleeve you can just make out the marks the oil grooves of the brass bushes made which I take to be caused by the steel sleeve being static in the bush, and there was a ample oil within the assembly when I pulled it apart. My gut feeling is the steel sleeve wasn't clamped between the rockers for some reason which meant it didn't want to turn, it is rather complicated :D

Kind regards Colin

PS

It is fun, also discovered today both cast iron heads on my Douglas are cracked............isn't life a joy

[url]Image[/url]
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Re: G80cs unwell

Postby cfaber » Mon Jul 22, 2019 6:36 pm

Ouch

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Re: G80cs unwell

Postby cbranni » Thu Jul 25, 2019 9:42 am

Just to round off this post, (I hope) bought new bushes and made a hardened steel spacer as none were available, all fitted and running fine, as Mick questioned the oil feed it sowed a seed of doubt in my mind so I ran the engine with rocker feed oil pipe off and there was a drip every 3 or 4 secs, didn't seem a lot to me so checked the pin in the plunger, fine, pulled the front plate off, holes clear, no gasket over hole and put it all back together.

I now have a oil leak from said front plate :headbang: :headbang: :headbang: why didn't I leave it alone, :D

Colin
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Re: G80cs unwell

Postby cfaber » Thu Jul 25, 2019 4:37 pm

cbranni wrote:Just to round off this post, (I hope) bought new bushes and made a hardened steel spacer as none were available, all fitted and running fine, as Mick questioned the oil feed it sowed a seed of doubt in my mind so I ran the engine with rocker feed oil pipe off and there was a drip every 3 or 4 secs, didn't seem a lot to me so checked the pin in the plunger, fine, pulled the front plate off, holes clear, no gasket over hole and put it all back together.

I now have a oil leak from said front plate :headbang: :headbang: :headbang: why didn't I leave it alone, :D

Colin


Now it's back to normal? Leaking oil and what not? :D

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