Search found 227 matches

by mlb50
Tue Dec 01, 2020 3:32 am
Forum: Parts & Bikes wanted
Topic: B50 Tank & Side panels
Replies: 2
Views: 58

Re: B50 Tank & Side panels

Looks like the small capacity tank (2 gallon). I got a new one from India, it was OK....but while B25 and B50 tanks are identical except that the fuel taps on the B25 are vertical on the bottom, the B50 tank needs the fuel taps on the corner at an angle so as to clear the rocker box. My replica 2 ga...
by mlb50
Sat Nov 28, 2020 9:04 am
Forum: Tech
Topic: Brake master cylinder.
Replies: 7
Views: 190

Re: Brake master cylinder.

In my experience - Yes it will match the switch body from a 71 onward conical hub brake. Note there are 2 long screws and 2 shorter ones.
by mlb50
Mon Nov 16, 2020 6:06 am
Forum: Tech
Topic: Setting Valve Clearance
Replies: 8
Views: 359

Re: Setting Valve Clearance

There's a couple of ways you can do this. In simple terms, the cams have a base circle - around about half of the circular motion where the tappet is relaxed. When the piston comes up on the compression stroke, the inlet cam is coming off the lift lobe and down to the base circle. The exhaust cam is...
by mlb50
Fri Oct 23, 2020 12:40 am
Forum: Tech
Topic: Ok..now its got me mad..spark plug
Replies: 11
Views: 733

Re: Ok..now its got me mad..spark plug

Guessing there is no choke on this? Do you know the size of the Pilot Jet? It could be 17, 19, 21 or 23. Bigger is richer, this makes a real difference to idle and slow speed running. Float level should be checked - this must be between 1.5mm to 2mm from the upper edge of the float to the rim of the...
by mlb50
Wed Oct 07, 2020 3:30 am
Forum: Tech
Topic: Web Cam tr5mx
Replies: 1
Views: 341

Re: Web Cam tr5mx

In the jargon of the day...that's a hot cam. I think it will go ape shit over 4,000rpm. Don't forget to adjust carburetion and exhaust to tune it all in.
by mlb50
Fri Oct 02, 2020 8:27 am
Forum: Tales Of Woe
Topic: When you're at your Wits End ..it could be worse
Replies: 5
Views: 922

Re: When you're at your Wits End ..it could be worse

Ha! Similar experience in 1980. Horsham, East Sussex. I was older then than the local lads and had a A65 Thunderbolt. Young lad Manky Al had just got a B25 Starfire and was very pleased with it and himself. He picked me up after work (King & Barnes Real Ales) on the bike and sitting on the back we s...
by mlb50
Wed Sep 30, 2020 6:20 am
Forum: Tech
Topic: TR5mx Fork/Steering Stem
Replies: 16
Views: 1090

Re: TR5mx Fork/Steering Stem

That can be straightened. Take to an engineering shop and ask that they cold work it. No heat. Should be able to press that true in 5 minutes.
by mlb50
Wed Sep 23, 2020 4:43 am
Forum: Tech
Topic: Chinese Carburetor
Replies: 4
Views: 497

Re: Chinese Carburetor

There are dozens of varieties of "Chinese" carburetors. Most are copies of Mikuni and Keihin and there are licensed versions of both. Ebay has lots of cheap versions. The risk is that copy models do not necessarily conform to a large single cylinder 4 stroke. Most 2 wheelers in Asia are sub-250cc. T...
by mlb50
Sun Aug 16, 2020 2:52 am
Forum: Tech
Topic: 1974 Fork Rebuild For MX
Replies: 3
Views: 429

Re: 1974 Fork Rebuild For MX

Does the fork still have the 2 studs on the upper end (mudguard mount)? If so you may be able to fabricate a tension arm to the front of the brake plate which would need a welded lug with a through stud, unless the one already there could work?
by mlb50
Fri Aug 14, 2020 5:32 am
Forum: Tech
Topic: 1974 Fork Rebuild For MX
Replies: 3
Views: 429

Re: 1974 Fork Rebuild For MX

Without spending a ton of money re-engineering them, you can fit progressive springs and synthetic fork oil. Weight of oil depends on bike loaded mass and how much damping you want.
by mlb50
Mon Aug 10, 2020 3:53 am
Forum: Tech
Topic: encapsulated crank bearing
Replies: 3
Views: 616

Re: encapsulated crank bearing

For suppliers, often it only what is available now for modern machinery. Bearings types from 50 years ago may no longer be relevant so they can only offer what is the nearest equivalent. Fully sealed wheel bearings are a big improvement to the originals. I fit one side sealed bearing to the gearbox ...
by mlb50
Sun Aug 09, 2020 3:19 am
Forum: Tech
Topic: encapsulated crank bearing
Replies: 3
Views: 616

Re: encapsulated crank bearing

If your motor is B50, none of the main bearings should have integrated seals. They need oil flow.
by mlb50
Sun Aug 09, 2020 3:17 am
Forum: Tech
Topic: LED Headlight/Zener Diode Question
Replies: 3
Views: 545

Re: LED Headlight/Zener Diode Question

With a good battery, good wiring, earths and the correct heat sink, the stock zener will be fine. PS - did you get negative polarity LEDs?
by mlb50
Mon Aug 03, 2020 8:02 am
Forum: Tech
Topic: Off-throttle hanging revs
Replies: 25
Views: 2171

Re: Off-throttle hanging revs

Is the needle bent? I had this "hanging high idle" on a Trident and it drove me nuts until I found the culprit. Slide goes down, needle stays up a wee bit and totally messes with the mixture.
by mlb50
Sat Jul 04, 2020 2:36 am
Forum: Project bikes
Topic: 74 TR5 MX Project For Ken
Replies: 102
Views: 11261

Re: 74 TR5 MX Project For Ken

I think the points cover screws are 2BA.
by mlb50
Fri Jun 19, 2020 2:24 am
Forum: Tech
Topic: Engine Builder
Replies: 7
Views: 1288

Re: Engine Builder

Try Raber's in San Jose. Lots of good British experience, parts and service.

www.rabers.com
by mlb50
Thu Jun 04, 2020 2:04 am
Forum: Tech
Topic: Rear Hub?
Replies: 2
Views: 600

Re: Rear Hub?

Yes, there should be a threaded collar. Its job is to retain the bearing and keep grease on the inside. Its a ring with peg holes to tighten it up.
by mlb50
Mon May 04, 2020 1:39 am
Forum: Tech
Topic: B50MX cam in a B25 and Big bore ideas.
Replies: 10
Views: 1624

Re: B50MX cam in a B25 and Big bore ideas.

The B50 crankcases are significantly different to the B25 in that the driveside cases are duplex roller bearings and have breather ports. Converting B25 to a B50 would as you mentioned require a significant amount of work with doubtful longevity.
by mlb50
Mon Apr 20, 2020 1:39 am
Forum: Tech
Topic: B25ss fork damper unit retaing bolt washers
Replies: 9
Views: 1262

Re: B25ss fork damper unit retaing bolt washers

Its a Dowty. Measure the diameter of the damper end and take the fixing bolt to a seal supplier. They should have them, probably 50P or a quid each.
by mlb50
Fri Apr 10, 2020 4:45 am
Forum: Tech
Topic: TRUING b25 FLYWHEEL
Replies: 4
Views: 902

Re: TRUING b25 FLYWHEEL

I haven't done a B25 flywheel but B50 yes and a few others. If the crank seperates into drive side and timing side then its important to set these as close to zero run out as possible. If its a one piece crank with removable flywheel then its just refit it and bolt it up - use new high tensile bolts...
by mlb50
Thu Apr 09, 2020 6:26 am
Forum: Project bikes
Topic: Little BSS cafe racer
Replies: 57
Views: 9312

Re: Little BSS cafe racer

The Wassel was OK to start and run the motor, but after 1 minute the coil was getting very hot. This is a bad sign and can cause unreliability or complete breakdown. The TriSpark is very nice, easy to install and time the ignition. I recommend you only use the factory 34 degree BTDC setting - more a...
by mlb50
Wed Apr 08, 2020 1:25 am
Forum: Project bikes
Topic: Little BSS cafe racer
Replies: 57
Views: 9312

Re: Little BSS cafe racer

Thanks MLB50 did you have problem to start ? my previous owner put a mark with a larger advance than 34° , i think may be to start easily with the wassel. No problem to start with the TriSpark. It is very important that your battery is good +12V and the spark plug clean. Also the carburettor must b...
by mlb50
Wed Apr 08, 2020 1:07 am
Forum: Project bikes
Topic: Converting a B50 to wet sump. (aka Boris Johnson)
Replies: 102
Views: 12203

Re: Converting a B50 to wet sump.

I'm struggling to see how this idea is going to simply engine installation.
I suggest try making up a stiff cardboard replica of the sump and see how that fits under the motor, what clearances etc''. For a dirt bike I think this is going to be more of hinderance than a benefit.
by mlb50
Tue Apr 07, 2020 2:07 am
Forum: Project bikes
Topic: Little BSS cafe racer
Replies: 57
Views: 9312

Re: Little BSS cafe racer

Yes - I had a new Wassel ignition and found it made the coil very hot. I put the original points back in and the coil only got warm. I then fitted a TriSpark and it has been perfect. I also sent the Wassel to TriSpark for testing and they reported it had a very long "on" time that is too much for th...
by mlb50
Tue Mar 31, 2020 4:59 am
Forum: Tech
Topic: Firing Up tr5 For First Time In Years
Replies: 19
Views: 2588

Re: Firing Up tr5 For First Time In Years

Good idea is to remove the fuel tank and petcocks. A lot of fine rust can acrue over time and has a bad habit of clogging the carb. Block the petcock holes, put a handfull of small screws n nuts inside and pour 2 pints of metholated spirit or kerosine inside and shake it about for a 5 or 10 minutes....
by mlb50
Tue Mar 24, 2020 3:52 am
Forum: Project bikes
Topic: My 1971 B25 VT
Replies: 24
Views: 3856

Re: My 1971 B25 VT

Breather off the tach cover is very effective. I run the hose straight up to under the tank alongside the frame and then rearwards to exit just past the right shock top mount. The primary breather exits opposite on the left. You can readily feel the pressure pulses when its idling. I used 5/16" allo...
by mlb50
Thu Mar 19, 2020 1:49 am
Forum: Tech
Topic: B25 to B50 conversion?
Replies: 8
Views: 1487

Re: B25 to B50 conversion?

If the proposed B50 conversion gets problematic, back in the day TriCor released a hop up kit for the 250. This was a 290cc conversion with bore, piston and new gaskets. The test reports at the time raved about the improvement. I think Cycle World did a full cover article on it, certainly in good de...
by mlb50
Thu Mar 19, 2020 1:43 am
Forum: Tech
Topic: B25 Oil circulation mod, why wouldn't this work?
Replies: 8
Views: 1648

Re: B25 Oil circulation mod, why wouldn't this work?

I think your scheme is trying to solve it the long way round. To use all of the frame oil capacity, its far easier and effective to do this - 1. Plumb an outlet at the rear, run the hose down to the underside of the motor to a T fitting. 2. Run the front oil hose to the T fitting now combining all o...
by mlb50
Tue Mar 03, 2020 1:22 am
Forum: Tech
Topic: Rocker Box contents - interchangeability?
Replies: 6
Views: 1439

Re: Rocker Box contents - interchangeability?

At a pinch I think the B44 was identical, but when the B50 was started production, the parts numbering was somewhat haphazard but it may well be worthwhile to check the B44 p/n and the B50 p/n.
You could also do the same with B40 etc' but I really doubt any of the 250 models would even come close.
by mlb50
Fri Feb 28, 2020 1:13 am
Forum: Tech
Topic: Spark Plugs
Replies: 3
Views: 1097

Re: Spark Plugs

I've recently switched from NGK B8ES to the Iridium version B8EIRX. I'd like to go to a 7 rating but theyre n/a but still the B50 starts well and runs good.
Using a Trispark and alway keep the Amal clean on the inside, use 98 Octane petrol.
by mlb50
Thu Feb 27, 2020 5:53 am
Forum: Project bikes
Topic: Electric Start - Broken Knees
Replies: 28
Views: 4291

Re: Electric Start - Broken Knees

While I sympathise with your situation its likely to happen to all of us in due course. The electric start conversion thing, i.e. like the way Doug Frazer did his B50, of which I have had 1st hand experience of is not an easy thing to do. Doug was hoping to engineer a conversion kit but decided it w...
by mlb50
Mon Feb 17, 2020 8:05 am
Forum: Tech
Topic: Mystery problem and BP is to blame!
Replies: 12
Views: 2599

Re: Mystery problem and BP is to blame!

It definelty was shit ''petrol''. I drained both BSA and Commando tanks into a white enamel bowl. The fuel was a orange colour and strange smell . The replacement fuel was Shell 95 - this was very pale lime green, and sure smelled like petrol. I know different fuels have different colours, but I've ...
by mlb50
Mon Feb 03, 2020 10:32 am
Forum: Tech
Topic: Mystery problem and BP is to blame!
Replies: 12
Views: 2599

Mystery problem and BP is to blame!

One fine Sunday I started up the trusty B50, it was very low on petrol so off to the local BP servo. Filled it up, started and suddenly went all fluffy and puff stopped. Tried kicking over and over, then tickled it to flooding and it started but as soon as I put a bit of throttle on....puff puff sto...
by mlb50
Thu Dec 12, 2019 12:36 pm
Forum: Tech
Topic: Fitting Allen screws to rocker box on B50.
Replies: 35
Views: 5228

Re: Fitting Allen screws to rocker box on B50.

That's a very interestingg drawing. Do you know the history of it and how did you get it?
by mlb50
Sun Dec 08, 2019 1:57 am
Forum: Tech
Topic: Fitting Allen screws to rocker box on B50.
Replies: 35
Views: 5228

Re: Fitting Allen screws to rocker box on B50.

Skippy - using bolts instead of studs allows the head to be removed in the frame. I once dropped a TDC probe down the spark plug hole. I had the head off in 35 minutes. Hex head bolts are better in this as you can get the spanner in sideways whereas Allen key is a bit tight under the main frame memb...
by mlb50
Thu Oct 10, 2019 2:40 am
Forum: Tech
Topic: Oil use by date
Replies: 13
Views: 3196

Re: Oil use by date

The only thing to note is if moisture has gotten in to the motor. Good idea to plug the holes when putting a bike away. Anyway get it hot enough to see if the "mayonnaise" appears i.e. breather hose end return feed. If it is frothy and scummy, acid can develop very quickly that eats away at certain ...
by mlb50
Fri Jul 19, 2019 5:31 am
Forum: Tech
Topic: Final Drive Sprocket
Replies: 21
Views: 5034

Re: Final Drive Sprocket

For a number of British bikes, I have a big 3/4" socket that fits over the gear sprocket nut, but as you mentioned the mainshaft is too long to allow a extension bar. So what I did was to cut 2 flats on the socket end so that I can fit an open ended spanner and tighten it.
by mlb50
Sun Jul 07, 2019 2:54 am
Forum: Tech
Topic: B40 and B44 motor in OIF chassis
Replies: 7
Views: 3041

Re: B40 and B44 motor in OIF chassis

Measure the height of the motor from bottom mounting hole to top of the rocker box and determine how much clearance you get between the underside of the top frame tube to the top of the head. Then see if that clearance will permit removal of the rocker box and the head in-situ. Otherwise you have to...
by mlb50
Wed Mar 13, 2019 7:00 am
Forum: Project bikes
Topic: Starfire 441
Replies: 91
Views: 19287

Re: Starfire 441

Regarding your query on Indian made tanks - I had fair success with a B25 replica fitted to my B50. The shape was OK, the frame diameter tunnel a tad to narrow so I had to cut down the side rubber buffers. The exterior needed sanding back a lot and surface filler to eliminate the score and scratch m...
by mlb50
Wed Mar 13, 2019 6:47 am
Forum: Tech
Topic: Low compression problem
Replies: 3
Views: 1633

Re: Low compression problem

Knackered piston rings take a while to wear down and start to smoke badly.
Sudden loss of compression can be due to a chip off a valve face or eroded seat. Doesn't take much to bleed off PSI. Pull the head and have a good look, best also to remove the valves and either replace or recut.