Search found 4260 matches

by Mark Cook
Fri Feb 26, 2021 10:04 am
Forum: Project bikes
Topic: LOBE 2 20-21
Replies: 134
Views: 13034

Re: LOBE 2 20-21

I did wonder if you were purging the tubes, it makes the welds so much stronger. Food grade frame?
by Mark Cook
Sat Feb 20, 2021 3:43 pm
Forum: Frame
Topic: B50 Frame CAD files
Replies: 14
Views: 3554

Re: B50 Frame CAD files

it doesn't calculate the welds , '' no one knows '' , It's not that hard to calculate the tensile strength of a weld, it used to be first year stuff for welding students. But rather than use maths, destructive testing is the best way. I bet most of these so called frame makers have never done a des...
by Mark Cook
Fri Feb 19, 2021 7:41 pm
Forum: Tech
Topic: Maximum bore of a 441
Replies: 11
Views: 560

Re: Maximum bore of a 441

Replacement liner for the B44. You can't get fresher than this ;)
IMG_0353.JPG
Sorry it flipped 90 degrees!
by Mark Cook
Fri Feb 19, 2021 7:09 pm
Forum: Tech
Topic: Best Ball Bearing Brands?
Replies: 8
Views: 237

Re: Best Ball Bearing Brands?

We've found to our expense that a bearing manufacturer we used chose to metrify the main roller bearings. Using smaller rollers reduced the capacity of the bearings. We sourced some very good Japanese ones, but the supply was unreliable. We now use a European manufacturer. Also we were finding probl...
by Mark Cook
Thu Feb 18, 2021 10:06 am
Forum: Tech
Topic: B50 camshaft end float
Replies: 7
Views: 259

Re: B50 camshaft end float

The bush must be flush with the crankcase or the cam follower will hit the edge.
by Mark Cook
Fri Feb 12, 2021 5:19 pm
Forum: Tech
Topic: New oil pump
Replies: 5
Views: 315

Re: New oil pump

I'll need to do a bit more research, I'm hoping a new top will make a C25 - B44 version. The gears with some tweaking will make M20 / Gold star. Pump was started years ago, but no demand. I think the A10/A65 have a different diameter gears, but not the end of the world. Ornaments at the moment, cast...
by Mark Cook
Fri Feb 12, 2021 1:28 pm
Forum: P92 Tech
Topic: Not sure If this is relevant P55?
Replies: 10
Views: 3726

Re: Not sure If this is relevant P55?

No pictures of it, but around 1981 1982 I started making a two cylinder water cooled DOHC engine based on the Cosworth BDX Where I worked I had access to destroyed race and rally engines. I'd collected enough parts that still had good front cylinders. A 180 degree crank was made for it and a capping...
by Mark Cook
Fri Feb 12, 2021 1:10 pm
Forum: Project bikes
Topic: Plum Crazy E35 Fury Project
Replies: 266
Views: 133219

Re: Plum Crazy E35 Fury Project

Final managed to allocate a day to the Main-shaft project. First stage is to produce a solid model that's easy to convert to metric. Yes I can program the lathe in imperial and change it to diameter mode, but that's just asking for a disaster. From the new model I can extract dimensions in a form th...
by Mark Cook
Thu Feb 11, 2021 6:09 pm
Forum: Tech
Topic: Foot Brake Lever Lubrication B50 / B25 oif
Replies: 1
Views: 151

Re: Foot Brake Lever Lubrication B50 / B25 oif

Just use a waterproof grease, surprisingly most greases are not.
by Mark Cook
Thu Feb 11, 2021 4:24 pm
Forum: Tech
Topic: New oil pump
Replies: 5
Views: 315

New oil pump

I'm sure I mentioned this many years ago, and possibly even posted pictures of the internals. Well we've sold all the internals! But the body castings have turned up. When completed this should solve many draining back problems because of a worn spindle/housing. The housing will have a seal also. IM...
by Mark Cook
Thu Feb 11, 2021 4:18 pm
Forum: Tech
Topic: First Start Up ?'s
Replies: 9
Views: 396

Re: First Start Up ?'s

You have to have oil in the sump before it can return it. Then with a dry pump they don't like sucking air. It will take a while.
by Mark Cook
Wed Feb 10, 2021 1:05 pm
Forum: Tech
Topic: B25 con rod B44 piston
Replies: 4
Views: 332

Re: B25 con rod B44 piston

It's not the roller bearing as such that fails as such, it's the design of the roller bearing that is at fault. This style of big end bearing is used in many BSA's all with the same problem if you over rev them for long periods. We started with the B50 and a better quality cage in the bearing, that ...
by Mark Cook
Wed Feb 10, 2021 12:48 pm
Forum: Tech
Topic: Layshaft loose in bearing 441 - Resolved
Replies: 5
Views: 418

Re: Layshaft Troubles 441 Layshaft bearings - Why so loose?

The bearings shrink when pressed into the housing. measure the housings.
Also don't trust Vernier's, the jaws wear more than you'd expect. We replace our expensive ones every 4 to 6 months. Measure further up the jaws for better accuracy. Better still use a micrometer.
by Mark Cook
Mon Feb 08, 2021 10:00 am
Forum: Tech
Topic: Points pillar bolts 2ba?
Replies: 2
Views: 202

Re: Points pillar bolts 2ba?

I use 2ba for them.
by Mark Cook
Sat Feb 06, 2021 2:30 pm
Forum: Tech
Topic: Help Please.
Replies: 1
Views: 273

Help Please.

Dose someone have a BSA drawing of Clutch operating pinion 57-2700 40-3283 and or Clutch release rack 57-2699 40-3282? Over the years I've never been happy with these and they can even be the reason why the feel of your clutch can be rough and heavy. Now that supplies of these are drying up it looks...
by Mark Cook
Sat Feb 06, 2021 2:17 pm
Forum: Tech
Topic: Maximum bore of a 441
Replies: 11
Views: 560

Re: Maximum bore of a 441

Even though we make and supply a 84mm piston for the B44 we still don't recommend it. It's NOT a B50 piston. The crown is designed for a B44 head and so is the compression height. (Deck height in American) Round barrel liners get thin after a 0.5mm bore. Square barrels will take more. 1mm O/S is saf...
by Mark Cook
Fri Feb 05, 2021 12:19 pm
Forum: Tech
Topic: woodruff keys
Replies: 13
Views: 998

Re: woodruff keys

41-0560 is the correct key if you haven't swapped bags.

Please let some one else build your engine. Also let them buy the parts too.
by Mark Cook
Thu Feb 04, 2021 7:43 pm
Forum: Tech
Topic: woodruff keys
Replies: 13
Views: 998

Re: woodruff keys

You have put the wrong key in. Timing side is a smaller radius.
by Mark Cook
Thu Feb 04, 2021 2:30 pm
Forum: Tech
Topic: B50 hydraulic drum brake
Replies: 53
Views: 2920

Re: B50 hydraulic drum brake

Engine braking with a bigger four stroke or with a big two stroke single, sometimes is not enough when racing. Trying to stop that crank spinning can be hard work. If road conditions allow you to glide around you nearly don't need brakes. Now experiencing bigger towns and cities I see that all newer...
by Mark Cook
Thu Feb 04, 2021 11:15 am
Forum: Off topic
Topic: Reducing Condensation in Garage
Replies: 30
Views: 21007

Re: Reducing Condensation in Garage

Your a bit late to the Party with this one Rickard, but very good anyways.
by Mark Cook
Thu Jan 21, 2021 10:36 am
Forum: Tech
Topic: Gearbox main shaft thread size
Replies: 3
Views: 363

Re: Gearbox main shaft thread size

Later ones being 1/2" unf, also 20 tpi !!
by Mark Cook
Thu Jan 21, 2021 10:32 am
Forum: Project bikes
Topic: LOBE 2 20-21
Replies: 134
Views: 13034

Re: LOBE 2 20-21

Well done Beat.
by Mark Cook
Wed Jan 20, 2021 11:23 am
Forum: Tech
Topic: Kickstart stop pin.
Replies: 0
Views: 297

Kickstart stop pin.

I have 3 kickstart stop pins.

B50 57-4342 wire clip fitted.
B44 40-3276 wire clip not the same position as above
C15 ?? No wire clip.

Does anyone know the part number of this stop pin with no clip?
by Mark Cook
Wed Jan 20, 2021 11:18 am
Forum: Tech
Topic: b40g mainshaft/sprocket seal too small ?
Replies: 4
Views: 353

Re: b40g mainshaft/sprocket seal too small ?

The B50 output seal is marked 52.38mm O.D.
by Mark Cook
Wed Jan 20, 2021 11:12 am
Forum: Tech
Topic: kickstart cotter pin
Replies: 9
Views: 636

Re: kickstart cotter pin

The best answer to the kickstart cotter pin can be found here. https://www.ccm-britain.co.uk/searchfor ... %2057-4357
by Mark Cook
Mon Jan 18, 2021 10:41 am
Forum: Tech
Topic: woodruff keys
Replies: 13
Views: 998

Re: woodruff keys

Two new keys being sent to you Francois
by Mark Cook
Fri Jan 15, 2021 10:37 am
Forum: Tech
Topic: Gearbox part numbers and suppliers
Replies: 12
Views: 843

Re: Gearbox part numbers and suppliers

Nice work Kommando, did you do it to the drive spindle housing too. Or was this based on Paul Jennings cavitation experiments?
by Mark Cook
Thu Jan 14, 2021 6:35 pm
Forum: Tech
Topic: B50 hydraulic drum brake
Replies: 53
Views: 2920

Re: B50 hydraulic drum brake

Ah ha, I see the little devils now :)
by Mark Cook
Thu Jan 14, 2021 4:47 pm
Forum: Tech
Topic: B50 hydraulic drum brake
Replies: 53
Views: 2920

Re: B50 hydraulic drum brake

I'm sure you have mentioned it, but what are you doing about "slack adjusters"?
by Mark Cook
Thu Jan 14, 2021 10:52 am
Forum: Tech
Topic: B50 hydraulic drum brake
Replies: 53
Views: 2920

Re: B50 hydraulic drum brake

A couple of simple cnc programs would sort the brake plate Gerry, as long as BasilF didn't mind.
by Mark Cook
Thu Jan 14, 2021 10:41 am
Forum: Tech
Topic: Gearbox part numbers and suppliers
Replies: 12
Views: 843

Re: Gearbox part numbers and suppliers

Remember even on a good engine or an engine with a good oil pump, oil will still find it's way up the spindle when left for long periods. I have a new oil pump in production that should cure this.
by Mark Cook
Wed Jan 13, 2021 4:40 pm
Forum: Tech
Topic: Gearbox part numbers and suppliers
Replies: 12
Views: 843

Re: Gearbox part numbers and suppliers

Thanks Kommando, our gears are really fresh. I think we are out of one of the sliding gears as Anita mentioned we have to make more. They won't be long though.
by Mark Cook
Wed Jan 13, 2021 4:37 pm
Forum: Tech
Topic: B50 hydraulic drum brake
Replies: 53
Views: 2920

Re: B50 hydraulic drum brake

Nice to see some creativity, well done. Stan would have liked this.
by Mark Cook
Sat Jan 02, 2021 2:23 pm
Forum: Tech
Topic: auto decompressor/valve lifter ???
Replies: 25
Views: 1676

Re: auto decompressor/valve lifter ???

Years ago I looked at making one for the B50 like the Husaberg, but very small parts required.
by Mark Cook
Thu Dec 31, 2020 12:51 pm
Forum: Tech
Topic: Flow bench Testing in South West England
Replies: 4
Views: 668

Re: Flow bench Testing in South West England

The profile around the seat will make the biggest difference at small openings. As you know, ports are subjected to pulses rather than static flow and as such I don't think conventual flow benches are much use for fine tuning. Where they are really handy is measuring the restrictions with air filter...
by Mark Cook
Thu Dec 31, 2020 10:50 am
Forum: Tech
Topic: Flow bench Testing in South West England
Replies: 4
Views: 668

Re: Flow bench Testing in South West England

You'd be better off looking for someone with a bigger flow bench, you won't get any meaning full results from a small one unless your working with tiny ports.

Janspeed or Swindon racing engines should have some good kit.
by Mark Cook
Wed Dec 23, 2020 5:43 pm
Forum: Tech
Topic: race tuning 250 and 350
Replies: 15
Views: 1514

Re: race tuning 250 and 350

We put bigger seats in them.
by Mark Cook
Wed Dec 23, 2020 12:47 pm
Forum: Frame
Topic: B50 Frame CAD files
Replies: 14
Views: 3554

Re: B50 Frame CAD files

I tried opening both files in solidworks 2021 and they looked the same Francois. I know there is lots of options on how you can open them. It was much better when we all worked in 2D IGES seemed to work with most cad systems. I think with the info it did open with, it would be easy to skin it again....
by Mark Cook
Tue Dec 22, 2020 11:51 am
Forum: Frame
Topic: B50 Frame CAD files
Replies: 14
Views: 3554

Re: B50 Frame CAD files

BSA_B50_frame_stp2.JPG
by Mark Cook
Sun Dec 20, 2020 3:25 pm
Forum: Tech
Topic: race tuning 250 and 350
Replies: 15
Views: 1514

Re: race tuning 250 and 350

The limiting factor on the early roller bearing big ends is the aluminium bearing cage. I have made a new B40 crank with an improved conrod and big end. No real would test figures as yet, but it should work beyond the limits of the valve train. I have a small flywheel version too, but struggling to ...