Wet sumping while running

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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Re: Wet sumping while running

Postby Dixter » Wed Dec 18, 2019 4:45 pm

Hi Neville: I hope you are staying warm in Ole Blighty. This is a frustrating problem for owners, and I feel for Mr. Faber. With only 1 moving part, the pump is about as simple a machine as one can get. Compound this with the difficulty of getting to the pump bore with the engine in the frame, the nature of the failure being all but invisible, coupled with most of us having common tools, and it's a crying shame. It would be wonderful if it is something simple, such as an errant drain plug fouling the pick-up.

I had a early 50s Ajay that when measured was within the specs under Col 2., Acceptable upon over haul, and about 1,000 miles later quit scavenging. I tried everything we've seen discussed here and finally had to pull the engine and sleeve the pump bore. Not a fun job!

Here's a video on a short stroke G80CS I'm building for a friend. This was filmed about 1 month ago, and shows the basic nature of the measurement. https://youtu.be/llXG0A6benA

Hope St. Nick is still stopping at your house...
DC
Dick Casey
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Re: Wet sumping while running

Postby SPRIDDLER » Wed Dec 18, 2019 5:57 pm

Mostly grey and very wet sadly, but it'll be the shortest day on Sunday. Hurrah! At least for Colin he's not losing fine biking weather with this conundrum.
Excellent video Dick. Very envious of your workshop as I have to clamber around lawn mowers, harvested onions and nearly empty paint tins whilst getting bayoneted in the ankles and kidneys by hibernating footpegs and handlebars.
Excuse me for drifting off topic a bit but for our January Club Night I'm doing a demo with projector and large screen of what's to be found within the Jampot website and Christians Archive and on these Forums as I've long had the feeling that they are very under-used by the membership, probably because they don't know what a fantastic resource they are and partly because there's nothing like showing rather than telling. I have a couple of your excellent practical videos lined up which I guess will be o.k. with you since they are in the public domain.
St Nick will be welcome as I want to have a word with him about his elves playing silly games by moving and hiding stuff in my shed.
I poke badgers with spoons.

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Re: Wet sumping while running

Postby Dixter » Thu Dec 19, 2019 5:15 pm

SPRIDDLER wrote:......for our January Club Night I'm doing a demo with projector and large screen of what's to be found within the Jampot website and Christians Archive and on these Forums........

Neville, I wish I were 'within commuting distance'. With your excellent sense of humor, I'm certain your talk will be well attended, and I'd love to be in the audience. Over the decades, you and your brethren have been most kind and helpful to me and many others. Feel free. I'm pleased to help in any way I can.

Ciao, DC
Dick Casey
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Re: Wet sumping while running

Postby SPRIDDLER » Thu Dec 19, 2019 6:19 pm

Dixter wrote:
SPRIDDLER wrote:......for our January Club Night I'm doing a demo with projector and large screen of what's to be found within the Jampot website and Christians Archive and on these Forums........

Neville, I wish I were 'within commuting distance'. With your excellent sense of humor, I'm certain your talk will be well attended, and I'd love to be in the audience. Over the decades, you and your brethren have been most kind and helpful to me and many others. Feel free. I'm pleased to help in any way I can.

Ciao, DC

Thanks Dick. :beer:

In view of such glowing sentiments I simply can't wait to hear what I'm going to say.
I poke badgers with spoons.

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Re: Wet sumping while running

Postby cfaber » Sat Dec 21, 2019 4:05 pm

Thanks for all the replies folks. So what's the recommended solution to fixing the bore?
Fix it until it's broken!

Otherwise how will
anything get done?

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Re: Wet sumping while running

Postby oldandsmelly » Sat Dec 21, 2019 7:35 pm

As I mentioned earlier, a friend of mine had the oil pump bore sleeved as in:

http://www.jampot.com/article_read.asp?id=325

Hopefully, this link works. The actual boring and sleeving was beyond his and my skills so he entrusted it to a local machine shop. The bike now scavenges fine.

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Re: Wet sumping while running

Postby Dixter » Sun Dec 22, 2019 11:37 pm

cfaber wrote:Thanks for all the replies folks. So what's the recommended solution to fixing the bore?


Colin: There are two distinct paths, if the desired end is to be able to ride this motorcycle for many miles, over many years, with a minimum of maintenance, the best is to sleeve the bore.

Alternatively, modifying the pump spindle with the addition of a Quad Ring® (X shaped O-Ring) has proven a robust solution to this writer. Twenty years ago I had a scavenge failure on a circa 1949 AJS M18. A remote location and lack of equipment dictated I modify the pump spindle to continue my journey. I ultimately sold the bike several thousand miles later, and periodic inspection of the pump left me with great confidence in this field expedient.

Central to the decision is how your motorcycle will be used, and availability of a machinist willing to tackle the job. If you modify the spindle, you should be prepared to remove the spindle every few thousand miles to inspect the sealing media, and install a new Quad Ring®.

The link provided by oldandsmelly has been used by this writer on one occasion. It works, but concerns about using the supply port bore for the rotation of the tool left me unsatisfied and I resorted to other specialty tooling on two other engines I repaired. I suspect you understand that sleeving requires the pump bore be opened up sufficiently to accept a phos-bronze sleeve, which is then accurately ported and cemented or affixed in proper alignment without any internal or external leaks.

Rather than take up a lot of bandwidth with options and techniques that may not appeal to you, I'd suggest you ponder your choices. If you think I may be of further help, please respond in the affirmative.

quadring.jpg


Ciao, DC
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Re: Wet sumping while running

Postby 56G80S » Tue Jun 16, 2020 4:51 pm

Well, I didn't see this post and I'm mentioned in it. So no shame in resurrecting it.

But it tells me a story:

"I think the designed clearance axle to bush is 1 thou and the top limit of acceptable wear between axle and bush is 4 thou." said Sprid.

I reckon I've got 5-6 thou at least. Good thing is there is no play whatsoever in the drive side bearings. I've yanked and pulled and help, nurse!

So now I'll slacken off the shock absorber nut, the clutch nut and anything else I can think of that's a PITA if you don't do it first, aahhh, timing pinion L/H of course. Please to see it's not damaged and neither are the camwheel teeth.

Johnny B

Who did I borrow reamers from previously?

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Re: Wet sumping while running

Postby SPRIDDLER » Tue Jun 16, 2020 6:45 pm

56G80S wrote:Who did I borrow reamers from previously?

Well it couldn't have been my pal 'Thrifty Peter' or you'd still have the invoice.
(Sorry John, no help at all).

Depending upon the year the pinion will pass through the timing side bush so you don't have to remove it.
It's often the case with a worn t/s bush that the pump splines are badly worn, partly from 'hammering'.
I poke badgers with spoons.

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Re: Wet sumping while running

Postby 56G80S » Wed Jun 17, 2020 6:24 am

Sprid

Thanks. Mine will pass through the bush. Cheeky but where is the data on wear limits? I'll need to check that, if I'm lucky enough for the splines to be OK. At least the drive side feels OK.

Fact is, I'm likely to put the whole job into the hands of Alpha Bearings and get the big end replaced while the cases are split.

Thanks for you interes.

Johnny B

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