www.b50.org

midgie

SteveS wrote: ↑Sun Nov 01, 2020 3:59 pm Hi Johnu

I admire you putting the engine back together without a manual or parts book. Remember you have access to the following info on the site:

B50 Parts and handbooks

Ball - clutch push rod, Part number 60-2363, 3/32"

Ball dia is 7/32"

midgie

Momus wrote: ↑Thu Jul 02, 2020 4:43 am How does one contact this 'midgie', Minty?

This Midgie sent you his phone no. Neil!

midgie

Or genuine BSA new old stock from midgie.

midgie

Looks a great little project, correct with the date code Nov 70.

midgie

minetymenace wrote: ↑Tue Jun 02, 2020 8:58 am I know that midgie, but this is the Unit Singles forum....

I just figured you need all the help you can get

midgie

minetymenace wrote: ↑Mon Jun 01, 2020 12:35 pm All '71 and later OIF bikes had Aluminium fork yokes.

Apart from the 71 oif twins of course.

midgie

I have a fleetstar motor on the bench now, rebuilding it for a friend.NG 02830 OCT 71 date code, this one has seen some action!

midgie

I have spent some time today looking through the box of bits that came with the machine. I notice that the fork stanchions are slightly pitted. Is a re-chrome and grind economically feasible when there seems to be new items readily available for about £80/pair?? The only usable thing left of the se...

midgie

I have b50 cranks here that are 5/8 x 20 tpi and 5/8 x 18 tpi . The parts book list's the nut as 5/8 unf but not all are!

midgie

minetymenace wrote: ↑Tue Apr 07, 2020 2:07 pm Thanks for putting us straight midgie, what took you so long?

I was enjoying it!

midgie

Its a later bsa/tri slider for the models that only used the 8" conical front hub.

midgie

I would strip the motor now, and clean the frame out then you know for sure that all is well. Firing it up without doing this could be costly.

midgie

The tr5mx is a bsa all but tank badge, and made at bsa, so no problem.

midgie

Yes the long footrest bolt is 7/16" dia on the 73 mx/tr5mx/tr5t, up to 72 models they are 3/8".

midgie

I think I have a spare l/h switch .

midgie

The 73 mx frame has beefed up seat mounting and rear mudguard mounting brackets, and no electric box brackets the same as the 71/72 mx version. As well as 3/8" bolt holes for the rear engine plates as opposed to the rest which are 5/16".

midgie

The adjuster screw did change, these are longer on b50 than others, Steve is correct, part number did not change on the exhaust rocker arm.

midgie

Exhaust rocker arm is the only difference on the B50, shafts and inlet arm are the same from c15/b40/b44. The only difference on the B50 arm is the pad which contacts the valve lifter spindle is larger.

midgie

Remove the oil pump drive gear also, this will give more room.

midgie

You wont get the puller legs behind the worm gear, the legs need to be thin enough to go between the worm teeth. Then put a jubilee clip across the legs to stop them pulling apart.

midgie

71-2026 is the correct type to use, as for the std 10 plate clutch. I thought you might have had a b25 or victor item, I have noticed many people use the trailblazer type chaincase, might be worth offering one up just to see. I have fitted neb clutches and have never had a problem with the late case...

midgie

What is the casting number on the primary cover you are using Jean Paul?

midgie

I have one, pm me cheers.

midgie

kommando wrote: ↑Wed Jan 22, 2020 5:25 pm The 20 TPI is the pre OIF rotor nut, so either dropped into the wrong box or a supplier assuming they were the same.

No the thread on the crank is 20tpi.

midgie

Be sure that the thread on the crank is 5/8" x 18 TPI as it says in the parts book, as some I have found are 5/8" x 20 cycle thread, just a heads up before you try to wind on the wrong nut!

midgie

Typical std b50 rod trick, breaks there every time, you were very lucky not to destroy the cases.

midgie

The b50 crankshaft nut is the plain type Steve, its possible to put a 5/8" cycle tap through a 5/8" unf nut, this works a treat.

midgie

A problem I have seen many times, is owners mix up the normal inspection plug and the vented type that has no internal clearance, which then fouls the clutch pushrod adjuster screw.

midgie

Genuine new old stock b50mx engine with factory labels from late 1971.

midgie

Genuine new old stock b50 crankcases for sale, complete with all studs and bearings condition perfect, still has the factory part no. tag. Pm me if interested.

midgie

The offset measured across the brake drum to the edge of the rim for a std wm3 rim is 1. 7/8".

midgie

None of the 250 or 500cc oil in frame singles ever left the factory with a chain oiler, it was blocked off with a fibre washer and a 1/4" unc x 5/8" setscrew. The bsa badged oif 250cc machines also had qty1 screwed breather plug fitted as std. The b50 of course didn't need it with the breather alrea...

midgie

B50 stud centre's are approx 80mm.

midgie

Spot on JB.

midgie

You need the lobe on the cam facing the gearchange quadrant, the slot will be upright. Dab a bit of paint on the top of the adjuster screw to show you its in the correct position and not 180 degrees out,adjustment should then be no more than 90 degrees either way from the vertical position.

midgie

Nice work Gene, looks super.

midgie

The oif 250, and early b50ss/t machines had a hook type spring anchor on the prop stand, this changed to the barrel type on the later ones, both had the cross hatch on the foot.

midgie

minetymenace wrote: ↑Thu Dec 20, 2018 6:26 pm Early oif B25 Chris, my is on the left and B50 type gearbox mainshaft and kick start mech..

Yes I agree that's all correct for the b25fs.

midgie

minetymenace wrote: ↑Thu Dec 20, 2018 6:26 pm Early oif B25 Chris, my is on the left and B50 type gearbox mainshaft and kick start mech..

Yes I agree that's all correct for the b25fs.

midgie

Bracket shown in shot is the oif b25 item, mounted on the r/h side. Hence not for the b50.

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