Unit Single goodies from the Autojumble.

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lathejack
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Unit Single goodies from the Autojumble.

Post by lathejack » Fri Mar 10, 2017 11:59 pm

My regular pilgrimage to the Autojumble manages to pay off every now and then.
As I quickly move across the site making sure I glance at every plot, I passed by a stall selling some unrelated items.
I gave a final look over my shoulder at this stall, and spotted a crankshaft on the floor. So I walked back and could see it was a Unit BSA crank with roller big end bearing and end feed lubrication.
The conrod is stamped 41/234 with a 3/4 bore in the little end bush, so I assume it must be from the WD B40 engine.
Apart from some odd spots of light staining on the flywheels, the main shafts, crank and rod look to be in as new unused condition. The little end bush has never had a gudgeon pin in it, and the flywheels don't have the slightest mark to suggest they have been knocked about to separate or refit them.
The only sign that it has been installed is a faint line around the quill where the oil feed seal sits.
I would have prefered to find a B44 crank, so I am a bit unsure what to do with it.
image.jpg

On another occasion, while rummaging through a box full of used conrods, I pulled out a late type B25 rod. I was dissapointed to find that the big end eye was wrecked by the shells having spun.
I grumbled out loud that just when you think you've found something usefull it turns out to be knackered.
I was overheard by the stranger next to me, who had also been looking round the pile of parts on offer.
"Oh I have one of those" he said. "I have a new unused one on my stall over there, pop over later if you are interested"
So half an our later I found his stall, and sure enough there was this unused genuine BSA late type B25 rod, still with original preservative on it. This is the rod without the oil hole drilling. If I hadn't have grumbled out loud I might never have known.
What are the chances of that?
image.jpg

Some sellers are not to be trusted though. On this stall the seller, who can be seen stood at the bottom right, claimed this was a special BSA camshaft gear with anti backlash adjustement that would fit all models of the Unit Single engine.
He seemed to be very keen to get rid of it, so that he didn't have to take it back home I would think.
I couldn't quite put my finger on it, but there was just something about him, and the gear wheel, that suggested he just might have been talking bollocks.
image.jpg
Last edited by lathejack on Sat Mar 11, 2017 12:41 pm, edited 3 times in total.

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Re: Unit Single goodies from the Autojumble.

Post by HPbyStan » Sat Mar 11, 2017 3:28 am

I didn't realize any of the B25 rods came without the oiling hole. Shows ta go ya what I know these days.

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Re: Unit Single goodies from the Autojumble.

Post by lathejack » Sat Mar 11, 2017 4:51 am

HPbyStan wrote:I didn't realize any of the B25 rods came without the oiling hole. Shows ta go ya what I know these days.
Actually Stan you are right, the B25 rods had the oil hole. The new rod I bought is in fact a late type T100 rod, which I think on the timing side do not have the oil hole.
But as I only dabble with BSA Unit Singles nowadays, I think of it as a B25 item coz it fits.

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Re: Unit Single goodies from the Autojumble.

Post by Barry Creary » Sat Mar 11, 2017 6:01 am

I think Kamando post on here you don't need to drill the oil hole it will work with out it fine but if do put the oil hole de-berr very well :uhu

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Re: Unit Single goodies from the Autojumble.

Post by lathejack » Sat Mar 11, 2017 12:46 pm

When I found the conrod I was pleased to see it did not have the oil hole, as I have no intention of drilling one through it.

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Re: Unit Single goodies from the Autojumble.

Post by kommando » Sat Mar 11, 2017 2:59 pm

I recommend no hole, if you want extra oil at the top end you can get the timing side oil to divert into the crankcase instead of going direct to sump plus you can put wide but shallow slots in the side of the con rod big end to send the oil coming out of the big end upwards instead of all directions. For a 250 I doubt you need it, it seems to have come in as a defence against seizures on the A65, which ended up being from the 4CA double point bounce giving a stray advanced spark and nothing to do with oil or lack of oil.

See where the finger points, it does not need to be at an angle, straight up, wider but shallower will do.

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Re: Unit Single goodies from the Autojumble.

Post by Michael Moore » Sat Mar 11, 2017 4:56 pm

I've also seen oiling holes for the pin drilled from the oil ring groove.

http://www.venolia.com/technical.html

I've also seen small diameter holes drilled through the rod from the big end bore to the little end.

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Re: Unit Single goodies from the Autojumble.

Post by HPbyStan » Sat Mar 11, 2017 5:12 pm

If one lives long enough one can see / hear all kinds of stuff imo.

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Re: Unit Single goodies from the Autojumble.

Post by skippy » Sun Mar 12, 2017 2:26 am

HPbyStan wrote:If one lives long enough one can see / hear all kinds of stuff imo.
Well keep up the good work your doing a good job at it so far. (living that is) :thumb :grin: :lol:
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Re: Unit Single goodies from the Autojumble.

Post by minetymenace » Sun Mar 12, 2017 9:57 pm

Yep, hope you have some matches ready on Wednesday Stan
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