Author Topic: B29 EW 350 Gudgeon Pin  (Read 285 times)

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Offline Waz e James

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B29 EW 350 Gudgeon Pin
« on: 25 Sep 2019 at 14:40 »
Any leads or advice from members would be great as new to Douglass Motors. The bores, piston etc are all serviceable on this EW. Rear gudgeon pin seems to have had a brass sleeve, assume that original sleeve was brass. The pin is also worn and hollowed in the centre. Can you buy a honda pin, as i see you can use cb750 pistons. Any advise from a member that has done similar repairs would be greatly appreciated.
« Last Edit: 25 Sep 2019 at 14:55 by Waz e James »

Offline Jonathan Hewitt

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Re: B29 EW 350 Gudgeon Pin
« Reply #1 on: 25 Sep 2019 at 17:45 »
Hi, I think that your starting point will be the diameter of the pin holes in the piston itself then you will know what size pin you will need.
  CB 750 pins are according to info freely on the net are 15 mm.
  The bush will be of phosphor bronze  not brass . hope this helps
Regards
Jonathan

Offline oily bloke

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Re: B29 EW 350 Gudgeon Pin
« Reply #2 on: 25 Sep 2019 at 18:07 »
I did the CB750 conversion a few years ago. The Honda pin is larger but within the size of the existing bush which can be reamed to size. Your easiest fix if the Douglas pin is OK and you intend to reuse the Douglas pistons is to have the bushes replaced and reamed to size.

Offline cardan

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Re: B29 EW 350 Gudgeon Pin
« Reply #3 on: 25 Sep 2019 at 22:11 »
For old, low-stressed engines I often make my own gudgeon pins using "linear shafting" which is stocked by the larger bearing houses. It comes in a range of diameters and is hardened and ground on the outside, with reasonable tensile strength. It's solid, but can be drilled if required. That said, if you can buy an off-the-shelf pin in the correct size that's a better way to go. Phosphor bronze for the little end bush, but brass is fine for the end caps. Just make sure the caps are domed to a smaller radius than the bore so the edges don't cause damage.

Leon

Offline Waz e James

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Re: B29 EW 350 Gudgeon Pin
« Reply #4 on: 28 Sep 2019 at 23:32 »
Thanks guys, we will make a start!