www.b50.org

hwan

Interesting article on the blown B25 - theres one running in the UK - very very loud (+120 dB !!!!) and quick - sometimes ! I was going to blow my Norton with an AMR500 (a supercharged 350/500 run sin the 350/500 hill-climb and sprint classes, here in the UK), but backed off when i realized thats th...

hwan

Stew & Minty -

My comments about De-magnetising a rotor are from a LUCAS publication, not something i thought up myself - specifically regarding the LUCAS Alternator fitted to the typical Britbike.
If i can be arsed, i'll work out how to publish the work-sheet for you all to peruse.

hwan

Maybe unrelated but, while looking through some official LUCAS data, for something else i came across an interesting comment; "If the stator is energized (faulty rectifier, etc.) and the rotor is turned, it can DEMAGNETISE the rotor" Now, I'm not certain how a standard wiring system can cause a stat...

hwan

if it was water-cooled - a blown head gasket.
Could be water/condensation or something ?

Has it stopped smoking, or does it keep doing it, or do you give up before you are suffocated ?

hwan

On my own flow-bench, the flow velocity on the floor of the port was very low, using various blobs on wire, i think its indicating that the cylinder wall is seriously compromising flow around the valve head. My bored out (75mm bore) cylinder more or less confirmed this, with much better velocity/flo...

hwan

till cannot post bloody pix! C15 is pulling 8500 rpm using MX cam - supposed to be limit for the roller bearing/long rod crank, but so far .................. Oh yes, its got a KH250 clutch fitted to a machined C15 chain-wheel, simple lever type Clutch push-rod activation (common UK grass-track mod) ...

hwan

106 mph through the IOM speed trap on a C15 this spring. I say C15 - it has a B25 top end on it, and i say IOM, it was actually the Southern 100 course which doesn't have the big long straights and hills. Was lieing 7th behind a few Aeromacchi/Ducati's before an oil leak stopped him - 65 years old, ...

hwan

Push bikes, particularly Tandems have had drums for years - they often were used for drag bikes in the 60/70's (along with Raleigh-Wisp wheels/brakes and D3 forks ..... at +150 mph?) Its the beautiful little discs they fit now, which are SOOO nice - perfect for the back - and the master cylinders - ...

hwan

As ever i beg to differ; The vast majority of aircraft engines historically, were for commercial flight - I.C. commercial engines requirements are, and always been basically power/weight/fuel consumption/serviceability. As for " Try working out primary rocking couples with a slide rule let alone sec...

hwan

Canberra - you mentioned 'backing down a trailer ramp' ............... :grin: Many 'readers' dont realise that a twin leading shoe front brake has sod all braking in reverse!! Not really relevant on a bike until an MOT in the 1980's ....... Around this period (and it may still apply) an MOT station ...

hwan

Thank you M&M, i do try :grin: As for disc'ed 21" front end ????? They are absolutely wonderful, little finger braking on the KDX200 - lovely. It always surprises people how hard you can brake on grass/mud - could lift the conversation by going on about weight transfer, turn in, etc. but wont :shock...

hwan

Its always interesting to place designs (and idea's) in context of time/attitudes/technology/etc. The classic is the 'long stroke' design philosophy of British engineers - initially, IC engines were based on steam engine design - because of the low rate of expansion of super-heated steam, a long str...

hwan

The problem with virtually all Brit-bike brakes over a very long period is one of 'mechanical advantage' to use the formal term - levers, basically. They all suffer from over large operating cams and too short lever (at the back-plate) giving a low increase in operating force at the brake-shoe, comp...

hwan

Scott You are correct, the arm length has nothing to do the with the 'servo' effect. Lengthening the arms is used extensively for road and race in the UK, and was used by the Meriden production racer team when they (successfully) campaigned the T140 in endurance racing (???) After you fit better lin...

hwan

lengthen the cam levers by ~2" and it will actually work then

hwan

I've started to place magnets into a plastic bag and the place the whole lot in the oil tank (away from the suction) - so i can remove after running. Always frightening what sticks on the outside, i dont use a proper full flow filter and it seems as good a method as any. But as i say - frightening!!!!

hwan

if in doubt measure piston distance down from TDC - before TDC of course 11/32" (8.5mm ish) according to Rupert. Use an electrical screwdriver or if you use a bit of wire - make sure you put a bent in it to stop it dropping in :shock: Feel for TDC on compression mark your measuring 'stick' the turn ...

hwan

she is too retarded on ignition if it blues at not much over tick-over. Retard it enough and you get it glowing red, back in the day as a callow yoof, a mate used to light his fag by retarding his tiger cub 9distributor model) at tick-over until the exhaust glowed. Yes the blueing is permanent. :lol:

hwan

As you will read, the B50 needs to be 'just right' to be a reliable starter - new carb, the knack, etc. The running hot may be the give away - some rebore artists do not give enough clearance for old stock or cheap repro pistons - thinking they are reboring a water-cooled car engine or something. So...

hwan

always an idea to go back to the beginning, new plug, etc. For what its worth the Wassel turns off after a few seconds on none-use, so its unlikely you have fried the coil. The yellow, then blue spark is worrying - not much to go wrong really with a charged battery - have you checked earths and loos...

hwan

Warm coil with a Wassel - check the resistance of your coil - cannot remember what it should be, but its in the instructions. I'm firing a twin output coil with mine, i had to use what is rated as a 6V coil to get the correct ohmage - bear in mind that there's no such thing as a 6/12/24V coil - its ...

hwan

The Wassel/VAPe ignition also switch's off after a short period of time - no idea how many pulses are required to retrigger, as I've never noticed any problems at all when starting my B25 which is fitted with the system. Very handy when running constant loss as my illuminated switch (so i know i've ...

hwan

Confirming Andy's statement - 'Official' report on the subject is available on; https://www.gov.uk/government/consultations/roadworthiness-testing-for-vehicles-of-historic-interest If you have any questions or feedback about it please contact <roadworthinesstesting@dft.gsi.gov.uk.> If you can be bot...

hwan

BEAT - sounds as if you had a good drive around and found some nice places. The difference between summer and winter is the reason why wifey could not cope with Cornwall - traffic on roads and beaches in summer - driving rain, mist/fog and a generally depressing place in winter. Its an area of real ...

hwan

My first trip to Cornwall on my own - on a BSA C11G - my tent was a ground sheet, tied to the bike as a Bivi.
We were trying to do Lands End to John o Groats .................... And yes it did rain ..............

hwan

Did you go and have a look @ Eden project ... i literally remember it when it was a hole in the ground :grin: Always good for a warm up (in the tropical zone). I married a Cornish lass, until recently had a house in St Austell, had a boat in the river Fowey for years and did a great deal of business...

hwan

Yep, will do. Am waiting on the blower arriving, already I've realized it may be too big for a 350 :???: Hmmmm suck through carbs and explosions in manifolds seem to be a common problem on highly tuned drag bikes - hence all the rubber hosing and worm-drive clips i suspect !!! Also a reason many use...

hwan

You picked the right pub in Looe ......

I worked summer holidays in the Double-Decker bar on the sea front, sex drugs and sticky carpets ...........

How come LOOE ????

hwan

Jack - that what i'm planning - under driving it - hence my request for info really...... I presume, a lobed compressor will have some leakage at lower RPM - hit a 'sweet' operating spot somewhere around mid rpm, then go inefficient again at higher rpm. Talking to an old boy racing a ALLARD (lobed b...

hwan

international jet-setter Mark.

No wonder you cannot get anything out of him ............... hows the Norton Crank-pin going Mark

hwan

You may guess i'm trying supercharging for the first time - something to try before i die. Spurred on by a supercharged B25 i was watching the last weekend - boy was it LOUD (+128 dB) - suggesting either the cam overlap or general timing is very wrong as it was way louder than HOBBIT (twin 750 comma...

hwan

No Mark is not in the IOM this week.... Could be Italy if i remember correctly. Top-hats are an option as, no the frame mounts dont clamp very well onto the engine. Alternative option is some filing and washer/shims to take up the side clearance between frame and engine - you will find, neither are ...

hwan

So the explosion was in the cylinder and not in the Blower/Inlet ... I would imagine that unlike centrifugal blowers, the peak pressures in the inlet system of a p/d supercharger can reach high values, even in normal running - hence the blow-off/safety-valve requirement. Without a positive method of...

hwan

Fascinated by the valve seats coming loose - bad fit, or something to do with the cylinder pressures? Wots up with CO2 in the extinguisher - just as effective in a closed space - and just as lethal if you happen to be in the closed space :grin: Ask the Texan's if they believe in global warming ? At ...

hwan

No reason not to (other than expense) - you will simply have a long rodded engine. The B40 and B44 pistons also have different compression heights (wrist-pin to top edge of piston dimension) - that are a number of other pistons out there that may/will have a bigger comp-height. Cutting the barrel do...

hwan

I always use the extended nose versions if i can - seems to give better starting and low speed running.

Watch out on B25's though - you can have the piston hitting the electrode, with certain plug/piston/head-gasket set-ups

hwan

My sympathies ......... An ENDURO acquaintance asked me to rebuild his newly purchased T150 engine - a 'bargain' from America - the pistons were so seized into the bores, he had already broken bits off the cylinder before he asked me. I then pointed out the cracks in the sump ........ thrown rod typ...

hwan

You do need patience and persistence with brit bikes.

Character building - i think thats what they call it

hwan

MIKE - the unit BSA's are frustrating little buggers, but because they are basically an oversize 250, have very good power/weight/size ratio. I've raced triumphs and will do again, i'm currently building a Norton single for hill-climb/sprinting and had forgotten just how big and heavy these pre-unit...

hwan

Listen to what KK is saying - its a clearer version of what i was 'sort of saying'. You do need to tighten up the cam float, so the followers run betwixt cam-wheel and crank-case, without twisting. Then check the cam timing.... As for how did they ever run ...... The problem is not really the design...

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