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D1 Cam Specs
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cocorico
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January 13, 2020 - 8:18 am
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These from a relatively unused D1 cam. Excuse the terms used. The pcd looks to be concentric with the base of the cam.

Height & Length

Height.JPGLength.JPG

Dwell width & Counter bore for holding screw

Dwell-width.JPGOuter-inner-id.JPG

Counter bore of outer

Outer-counterbore-depth.JPG

Bore for shaft & base to 'cam' area

 

Inner-inner-id.JPGBase-to-cam-lift.JPG

1956 D3 running, lights to sort. 7 other bikes in the Barn. 1950 D1 engine being rebuilt (slowly).

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SpacedMarine
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January 13, 2020 - 9:01 am
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cocorico said

Blue Heeler said
...but I can do a primary school effort, in drawing around one, with a nice sharp HB pencil or fine-point pen, if that helps?...

Do they still teach stuff like that in Primary Schools?  

Eeh kids these days cant even draw around and elliptical cam.Disgrace!🤣🤣🤣

Awesome coco.With the "fat" bit of the cam at 12oclock.Looking at it as if it was on the bike at "what o clock" is the key way and how big is it?

Ta👍🏼

James.

What's 7/16 in mm again?

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SpacedMarine
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January 13, 2020 - 9:25 am
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Please forgive my drawing but I was never taught to "freehand draw ellipses" 🤣🤣🤣

What are the 2 dimensions shown?my thinking is that I could turn the cam so the thing is round and concentric with dimension 1 and once that is done turn the thing "off centre" to get dimension 2 then somehow "blend" the 2 diameters together if that makes sense?

20200113_092517.jpg

I'm guessing the originals were ground to shape on some kind of jig?

sp_PlupAttachments Attachments

What's 7/16 in mm again?

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cocorico
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January 13, 2020 - 12:09 pm
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SpacedMarine said
20200113_092517.jpg

1) 3mm. 2) 2mm. Cam keyway is 1mm wide, 0.75mm deep, the right hand corner of the keyway is at the 12 O'Clock position as best I can measure and then runs radially outwards (presumably at whatever degree is equivalent to the timing point BTDC). I have run mine without a key with no problem.

If you took a 13.5mm diameter blank and drilled it on a 6mm centre I think you would not be too far off. If you search the forum there are (unsized) drawings of the early and later cam which could be used for measuring angles and exact 'cam' positions, I imagine.

Sorry - I've changed to metric measurement here. More accurate for me to guess at measure.  So for the earlier photos, multiply by 25.4 for mm.

As quoted in many current adverts - all measurements are within +/- 25mm tolerance whistle

Maybe this section should be transferred to a Cam topic?

1956 D3 running, lights to sort. 7 other bikes in the Barn. 1950 D1 engine being rebuilt (slowly).

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SpacedMarine
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January 13, 2020 - 12:23 pm
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Ta coco I'll write all the measurements down in my homework book and make up some kind of contraption so I can grind them watch this space!

What's 7/16 in mm again?

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Blue Heeler
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January 13, 2020 - 1:01 pm
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If all-else fails, knock me up ( Mill-workers version, ahem...I lived in Owdham), and I`ll loan you one.

Unfortunately Tech Drawing was not one of the 4 subjects I was top of my school for...but artistic licence permitting, I can draw you a pretty version and colour it in 🙂

Blue

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SpacedMarine
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January 13, 2020 - 2:29 pm
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Blue Heeler said
If allf-else fails, knock me up ( Mill-workers version, ahem...I lived in Owdham), and I`ll loan you one.

Unfortunately Tech Drawing was not one of the 4 subjects I was top of my school for...but artistic licence permitting, I can draw you a pretty version and colour it in 🙂

Blue  

You and coco can have the first of the production line and be my "road testers" 👍🏼

What's 7/16 in mm again?

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