what is this from?

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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DickV
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what is this from?

Post by DickV »

20210921_203936.jpg
I got extra parts with the bike. Does anyone know what bike the one with the question mark is from? thx. Dick
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Pharisee
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Re: what is this from?

Post by Pharisee »

Yep... That's a pushrod rocker arm for one of the "lightweight" models. You can use it on the inlet side of the G80 if you so desire. It will change the ratio of the rockers arm assembly and increase the valve lift. It will give you a little improvement in performance.
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ajscomboman
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Re: what is this from?

Post by ajscomboman »

Pharisee wrote: Wed Sep 22, 2021 5:50 pm Yep... That's a pushrod rocker arm for one of the "lightweight" models. You can use it on the inlet side of the G80 if you so desire. It will change the ratio of the rockers arm assembly and increase the valve lift. It will give you a little improvement in performance.
That isn't a rocker from a L/W John. A L/W rocker arm has a very squared off nose towards the pushrod end as opposed to a rounded point. The smaller arm is from an Iron head original part No FE 60

It may well be that the L/W arm is dimensionally the same or very similar though.
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Pharisee
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Re: what is this from?

Post by Pharisee »

Pharisee wrote: Wed Sep 22, 2021 5:50 pm Yep... That's a pushrod rocker arm for one of the "lightweight" models. You can use it on the inlet side of the G80 if you so desire. It will change the ratio of the rockers arm assembly and increase the valve lift. It will give you a little improvement in performance.
Ya live and learn..... Thanks for putting me right. I fitted a lightweight rocker arm to my M16S, and from memory, they looked the same. Sorry if I confused matters. :oops: :oops:
John
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Rob Harknett
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Re: what is this from?

Post by Rob Harknett »

ajscomboman wrote: Wed Sep 22, 2021 6:31 pm
Pharisee wrote: Wed Sep 22, 2021 5:50 pm Yep... That's a pushrod rocker arm for one of the "lightweight" models. You can use it on the inlet side of the G80 if you so desire. It will change the ratio of the rockers arm assembly and increase the valve lift. It will give you a little improvement in performance.
That isn't a rocker from a L/W John. A L/W rocker arm has a very squared off nose towards the pushrod end as opposed to a rounded point. The smaller arm is from an Iron head original part No FE 60

It may well be that the L/W arm is dimensionally the same or very similar though.
FE 60 Used on prewar AJS from 1935 inlet & exhaust 250 & 350's also WD Matchless up to 1948 I believe ( iron heads ) was given new pt. no. 017216.
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ajscomboman
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Re: what is this from?

Post by ajscomboman »

Pharisee wrote: Wed Sep 22, 2021 10:01 pm
Pharisee wrote: Wed Sep 22, 2021 5:50 pm Yep... That's a pushrod rocker arm for one of the "lightweight" models. You can use it on the inlet side of the G80 if you so desire. It will change the ratio of the rockers arm assembly and increase the valve lift. It will give you a little improvement in performance.
Ya live and learn..... Thanks for putting me right. I fitted a lightweight rocker arm to my M16S, and from memory, they looked the same. Sorry if I confused matters. :oops: :oops:
John
I have done the same conversion and currently have 2 arms sat in a box that's why I can tell the profile isn't the same, however John they may well be dimensionally identical and do the same job. Without laying one on top of the other I couldn't say.
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