What's wrong with my studs / bolts?

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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What's wrong with my studs / bolts?

Postby cfaber » Tue Apr 02, 2019 3:37 am

This is a '54 18S

What's wrong with the bolts I'm using? Are these the correct bolts in these positions (if you can tell from these images)
Image

Here's the other side
Image

Is there a spacer here?
Image
And on the other side?
Image

This bolt is interfering with the prop stand on the drive side, there's plenty of room on the timing side
Image
Image

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Re: What's wrong with my studs / bolts?

Postby ajscomboman » Tue Apr 02, 2019 6:39 am

In order, there should be 3 spacers on the footrest bar, either side against the rails and one between the engine plates. Second, the bolt that fits through the engine plate by the crankcase oil unions should have no washer and should be a special thin head bolt to allow clearance for the unions to be tightened. Lastly, again there should be no washers under the nuts on the bottom g/box stud and some times the nut has to be shaved to allow clearance. In later years the factory resorted to half nuts.

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Re: What's wrong with my studs / bolts?

Postby Rob Harknett » Tue Apr 02, 2019 9:05 am

Check your parts list. Most of the studs will have thread size and length stated. So you can confirm some of them yourself. They did omit some standard fitting sizes in circa 1952 onwards parts lists, when the new pt. no. series was introduced. So you need to check if the pt. no. converts to an old part number. You can do this here. http://archives.jampot.dk/book/Spares_l ... ements.pdf
I gave that file a title starting with three zero's on purpose so it went top of the list, making it easy to find. If the stud/bolt converts to an old part number you may see dimensions given, if your 54 parts lists shows no dimensions.. Also take note of what Rob ( combie man ) says, as omission / addition of washers etc may make the stud appear too short or long. With the correct stud, starting off with the nut fully on one side, the nut should go fully on the other side. Not appear too long or short. I can see some of your studs have thread showing through the nut, on the other side the nut only goes halfway on.

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Re: What's wrong with my studs / bolts?

Postby Dixter » Tue Apr 02, 2019 10:37 am

Colin, the guide screw for the oil pump plunger looks peculiar. Items #5 & #6 are readily available new. Any deviation on these critical parts will result in massive damage.

Two other things I’d recommend at this juncture is begin working on oil leaks, there will be many: screws #4, adjacent to the guide screw, quantity 3 need red fiber sealing washers under the heads to prevent leaks, and the three welsh plugs sealing the primary side of the gearbox should be sealed on the outer face to prevent oil leaks, as should the OD (outside diameter) of the sealing collar on the oil seal for the output shaft on the gearbox.

My preference for sealing the above is a thin brush-on gasket goo like Yamabond, or Wellseal, but a thin smear of common RTV silicon will work as well.

Ciao, DC

26AED6F9-69D8-4496-8077-F45094354558.jpeg
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Dick Casey
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Re: What's wrong with my studs / bolts?

Postby cfaber » Tue Apr 02, 2019 5:39 pm

ajscomboman wrote:In order, there should be 3 spacers on the footrest bar, either side against the rails and one between the engine plates.

Any idea what part number this would be? I'm having a hard time finding them in the 54 parts book (green book)

ajscomboman wrote: Second, the bolt that fits through the engine plate by the crankcase oil unions should have no washer and should be a special thin head bolt to allow clearance for the unions to be tightened. Lastly, again there should be no washers under the nuts on the bottom g/box stud and some times the nut has to be shaved to allow clearance. In later years the factory resorted to half nuts.


Thank you!

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Re: What's wrong with my studs / bolts?

Postby Mick D » Tue Apr 02, 2019 6:39 pm

1954 Spares List:

54 Spares Footrest.png
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Re: What's wrong with my studs / bolts?

Postby ajscomboman » Tue Apr 02, 2019 6:48 pm

cfaber wrote:
ajscomboman wrote:In order, there should be 3 spacers on the footrest bar, either side against the rails and one between the engine plates.

Any idea what part number this would be? I'm having a hard time finding them in the 54 parts book (green book)

ajscomboman wrote: Second, the bolt that fits through the engine plate by the crankcase oil unions should have no washer and should be a special thin head bolt to allow clearance for the unions to be tightened. Lastly, again there should be no washers under the nuts on the bottom g/box stud and some times the nut has to be shaved to allow clearance. In later years the factory resorted to half nuts.


Thank you!


Cheat and make your own spacers, I use old handlebars and cut them to suit.

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Re: What's wrong with my studs / bolts?

Postby cfaber » Tue Apr 02, 2019 7:36 pm

Dixter wrote:Colin, the guide screw for the oil pump plunger looks peculiar. Items #5 & #6 are readily available new. Any deviation on these critical parts will result in massive damage.

Interesting. This was the screw and hardened guide pin that came with the engine. I do have another (new) screw however after examining it against the existing one they're identical with the exception of the head itself. I may replace it as someone slotted the smaller hex, but it's original.

Dixter wrote:Two other things I’d recommend at this juncture is begin working on oil leaks, there will be many: screws #4, adjacent to the guide screw, quantity 3 need red fiber sealing washers under the heads to prevent leaks, and the three welsh plugs sealing the primary side of the gearbox should be sealed on the outer face to prevent oil leaks, as should the OD (outside diameter) of the sealing collar on the oil seal for the output shaft on the gearbox.

Thanks, the plugs all have seals on them, the gear box itself has a paper gasket from the seal kit, if this isn't sufficient I'll try some gray RTV

Dixter wrote:My preference for sealing the above is a thin brush-on gasket goo like Yamabond, or Wellseal, but a thin smear of common RTV silicon will work as well.

Ciao, DC


Got it, thanks, if I run into problems once it's oiled up I'll go back through and re-seal with the gray RTV I have.


26AED6F9-69D8-4496-8077-F45094354558.jpeg
Last edited by cfaber on Tue Apr 02, 2019 7:37 pm, edited 1 time in total.

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Re: What's wrong with my studs / bolts?

Postby cfaber » Tue Apr 02, 2019 7:36 pm

ajscomboman wrote:
cfaber wrote:
ajscomboman wrote:In order, there should be 3 spacers on the footrest bar, either side against the rails and one between the engine plates.

Any idea what part number this would be? I'm having a hard time finding them in the 54 parts book (green book)

ajscomboman wrote: Second, the bolt that fits through the engine plate by the crankcase oil unions should have no washer and should be a special thin head bolt to allow clearance for the unions to be tightened. Lastly, again there should be no washers under the nuts on the bottom g/box stud and some times the nut has to be shaved to allow clearance. In later years the factory resorted to half nuts.


Thank you!


Cheat and make your own spacers, I use old handlebars and cut them to suit.


I'm actually just going to have my machinist friend make some up for me out of round stock.

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Re: What's wrong with my studs / bolts?

Postby ajscomboman » Tue Apr 02, 2019 7:44 pm

[quote=" I'm actually just going to have my machinist friend make some up for me out of round stock.[/quote]

Good plan. :beer:

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