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Re: Little BSS cafe racer

Posted: Thu Jun 04, 2020 8:51 pm
by beat
FGF wrote:
Sat May 30, 2020 9:31 am
was sold in south africa in 1971.
in this country BSA sold it 's bikes with speedometer in miles ?
yeas, I think so.
FGF wrote:
Thu Jun 04, 2020 10:59 am
Looking for a new conrod
the original conrod do not have a good name,- means, - some of them break with no " excuse moi "

PES ore other new types are the way....

beat <212

Re: Little BSS cafe racer

Posted: Wed Jun 17, 2020 3:22 pm
by FGF
on the two sleeve gear bushes , we can see a slight groove where the seal scrub :
i don't see it on the pictures showed by the part suppliers.
are the bushes made with a rolled sheet of metal ? it 's not broken ...?

Re: Little BSS cafe racer

Posted: Wed Jun 17, 2020 3:27 pm
by minetymenace
Original ones were a rolled sheet (there is a topic on this somewhere). PES who make these from new use a solid bush, I think they will sell you the bush on its own (if they have one) but it will probably be unfinished so you may need to fettle it into the gear and then ream it to fit your mainshaft. They also do one with a needle roller, I guess (I don't know) that the bush just becomes a stub on the end of the sleeve gear that runs in the bearing....

Re: Little BSS cafe racer

Posted: Mon Jun 22, 2020 5:16 pm
by FGF
Hello ,
now the oil pump :
the case was fitted with gasket sealant and the scavenge hole nearly clogged...

surprise : no feed gear thrust washer on this B50-1971 .
the main case has the S mark and the upper one the V mark.

someone gave me a blue print of the 2 studs oil pump but there is no note about the axial clearance in the gears ,
do you know the maximum gap ?

Re: Little BSS cafe racer

Posted: Wed Jul 01, 2020 10:30 am
by FGF

the pump faces are covered with very old '' bond gasket '' .
How to remove it ?

i 've tried brake cleaner , white spirit , gas oil , white vinegar , acetone real result .


Re: Little BSS cafe racer

Posted: Thu Jul 02, 2020 8:07 pm
by beat
using a knife as a scrapper.
working carefully, - should go.


Re: Little BSS cafe racer

Posted: Fri Jul 03, 2020 1:09 am
by skippy
I have used gasket remover from a spray can.

Re: Little BSS cafe racer

Posted: Fri Jul 03, 2020 3:35 pm
by FGF
Thanks riders ,

3 hours bathing in unleaded gasoline and 3 hours with a cutter slowly and then acetone with a brush .

this B50SS will be ready to fire in a few weeks ...many weeks maybe, but it will !

Re: Little BSS cafe racer

Posted: Wed Jul 15, 2020 1:23 pm
by FGF
Hello ,

'' Re-building '' the oil pump , i see two little problems to solve :

- no gasket : just oiling the plates and fully tightening the screws ?

- worn screws ; the screw 's round cylinder head has been chewed by the screwdriver .
I only find one at Draganfly store but they supersede it with the breather cover screw which has a different thread :

70-8100 : 3/16 BSC 32 TPI OD 4.34 mm

40-0309 : 2 BA 31.4 TPI OD 4.7 mm

i 've tried carefully my breather screw , it 's more difficult to screw it to the end of the thread ...

Has someone use this solution ? Thanks

Re: Little BSS cafe racer

Posted: Thu Jul 16, 2020 8:01 pm
by beat
hi Francoise

the BSA B50 concords do not have a good name.
some of them go out of the case whilst they should be on work !
PES or Carillo doing better Rods....

beat :ok

Re: Little BSS cafe racer

Posted: Wed Sep 16, 2020 3:28 pm
by FGF

the work progress slowly : big end conrod and piston changed by a French machinist ( philippe Huron , goldstar French specialist ..)
carillo , alpha B28 , PES bearings
34 mm inlet , new PES valves
waiting for it : frame tank petrol cleaned and new paint for all the frame.
now beginning the engine rebuilding : a little problem with the oil pump ...
little wear on the plates
Rupert says something like '' lapp the step made by the gear with a grindstone ''
I tried it a little with a valve grinding paste but the case is made with cast iron.
It 's hard and i would'nt want to have the plane not perpendicular to the spindle bore ...

If this work is not made , is the ''wellseal'' a good solution to prevent the leaks here ?

Re: Little BSS cafe racer

Posted: Fri Sep 18, 2020 11:02 pm
by minetymenace
I wouldn't put gunge anywhere near the oil pump, it is too close to the important bearings and is probably the one essential organ in the engine that needs to be right, fix it properly or get a new one (better one) or pay the price of a complete rebuild in a few miles.

Re: Little BSS cafe racer

Posted: Sat Sep 19, 2020 3:22 pm
by Momus
Use a sheet of 120 grit wet and dry paper wetted with soapy water on a flat surface to fix those pump parts.

When you have a true surface put the gears in the housing and run the lot over the paper and you will get the assembly down to zero clearance.

Take a bit more off the gears so you have .002" clearance and it will be good.

Re: Little BSS cafe racer

Posted: Sun Sep 20, 2020 10:03 am
by FGF
Thanks for your help , Gerry , Momus ,

Gerry , i understand and my big end is a new one .
I do want to fix my oil pump cases and it 's not very easy to find a 3 studs B50 oil pump now.

My pump is not worn out , there is a little wear of course : i can see a little step on the upper plate but don't feel it when i slip a finger
on it .
the gears in the main case are nearly fitted with zero clearance , so i 've not lapped this main case for instance.
i think like momus says i 've to try a little on it anyway to clean the plane.

but , the final question : BSA put a thin coat of shellac ( it was difficult for me to remove it ) so what substitute coat to day ?
really nothing or wellseal ?

Re: Little BSS cafe racer

Posted: Fri Sep 25, 2020 6:28 pm
by Momus
A little of your favourite sealant is what I suggest; but not a silicone.

I use Loctite 515 or Permatex No 4 hard setting.

I'm doing a B25 pump right now and surfaced the steel end plate.
It had some witnesses so I surfaced it. It only took a couple of rubs and it was good.
It was soft and I was surprised as I expected a case hardened part.

Re: Little BSS cafe racer

Posted: Thu Oct 22, 2020 2:21 pm
by FGF
Hello ,

After a few advises, i 've tightened the head stud nuts with oiled threads , torque wrench 40 Nm .
Obviously all seem to be OK .
i 'll try to start like that
i wait for my oil pump sent to PES for two weeks .
Bushes seemed to be necessary .