Devon TRF Group Forum

Next up were the forks, fortunately the forks the bike came with had new stanchions so it was straightforward rebuild with new seals and some progressive fork springs that are readily available.

This bike was launched in 1971 and the frame had a very good pedigree as it was based on the Mkiv BSA works MX frame so it came with what were advanced features for its day with taper roller steering head bearings and needle rollers in the swinging arm with eccentric adjusters for chain tension on the swinging arm pivot.

I drilled and fitted a grease nipple to the swinging arm as the later bikes had this, it's important that the seals are fitted with the lip facing out as this allows the old grease an escape route otherwise the seals get pressurised and the old grease can't get out.

New steering bearings fitted.

Hi John,

I've got a 1961 BSA trials bike that I've just finished a minor restoration on; nothing like as in-depth as yours though.

Mine is a C15T engine (bored out to 290cc) in a B40 frame. It was common at the time to build them this way as it was the most competitive set up.

We'll have to get them together sometime - an Exmoor LAF meeting on the bikes maybe??

cheers
Colin B

-- Edited by cee-b on Monday 9th of October 2017 07:27:29 PM

-- Edited by cee-b on Monday 9th of October 2017 08:24:17 PM

Somewhat jealous of your facilities John! I've fitted an austenitic exhaust valve in the Norton too, they tend to glow red apparently when the engine works hard! 

-- Edited by devondan on Tuesday 10th of October 2017 07:38:59 AM

Nicely done John

I thought I'd post up some pictures of what this bike is supposed to look like for those not familiar with these Birmingham built trail bikes.

Here's a picture of a restored 1971 BSA B25T in original condition.These BSA & Triumph 250's for 1971 were unfortunately to be the last ever mass produced 250's to be made here in the UK.

For a number of reasons BSA got into financial trouble in 1972 and one casualty of this was that the 250's were dropped. For 1972 the B50T were restyled with chrome mudguards and a similar tank stripe paint scheme but used a Candy style of paint that came from the hot rod scene in America. It consisted of a base coat, normally white or silver then a top coat that was a lacquer with a colour mixed the result was a colour that has a depth of gloss to it that looks different in different light...all very 1970's

Here's a couple of examples of the 1972 B50T model

You can see a clear influence on the later XT and TT Yamahas that came along a few years later and especially so as they copied the oil in frame system BSA used on these bikes.

I've never been keen on the grey frame colour so decided to build my B25T in the style of the 1972 B50T with a black frame, chrome guards and a candy paint finish.

-- Edited by John Harvey on Tuesday 17th of October 2017 10:29:51 PM

TTR wrote:

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I was looking at a Triumph Trailblazer the other day and your BSA seems to have taken some styling cues from it - or vice versa 

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 Good ol badge engineering Brian, they are the same as each other apart from the paint scheme, fuel tank shape and of course the badges  I guess a similar scenario with Husky & KTM today?

Here's a couple of pics of the Triumph T25T version and you can see they are very similar.

 

The crankshaft arrangement on these bikes is unusual in that it has a 1 piece forged steel crank with a plain big end bearing with bolt on cast iron flywheels and a high tensile duraluminium con rod with steel end cap.

 

This was a known weak area on the original B25 model so for this 1971 model were fitted with a stronger conrod a new oil pump and a better pressure relief valve. It must have helped as this particular engine with 27K miles was standard with a small amount of wear on the crank.

Reassembling the crankshaft.

Quick check of the oil pump and all ready for reassembly of the engine.

 

Best read I've had in a long while John, sterling stuff !!

Excellent work John and a very good, detailed thread.
You will certainly enjoy riding it now that you know it's been done O.K.
The number of times I've done the same to my T100 since buying it as a wreck in 1966 is legion - and I still love it.
I'm sure yours will give ytou good service as well.

Martyn

Hi Martyn, I'm certainly building this one to use and for keeps, really good to hear about your T100 inspiring stuff. Hi Mike, you are right about the similarity with the C15 as this bike is the final development of the C15, same bore and stroke but I don't think there's a single engine part that's common between them.

My interest in this model of BSA goes all the way back to that glorious summer of 76, a guy who lived just up the road had just bought one and as he worked nights it would conveniently sit outside his house in the daytime meaning I got to feast my eyes on it twice a day as I made my way to and from school. I think I could have burnt the image of that bike onto the back of my eyes, I really liked seeing that bike 10 times a week, I was mad about bikes back then and as a thirteen year old I saved enough money from a part time job to buy a BSA C12 I couldn't ride it anywhere though... that just seemed like a mere detail back then 

At that time my older sister's boyfriend had a nearly new T140V Triumph Bonnevilles that seemed to go wrong now and then, unfortunately he knew even less about bikes than I did, so he used to let me work on it. He didn't have a workshop manual for it, so when we hit problems and were unable to fix it I'd wait until the next day after I'd had a chance to refer to my font of all motorcycle mechanical knowledge and fix it the next day, I will tell you  this secret below, its been a while now so I'm less embarrassed to admit this  

Back to the bike rebuild, things are coming along really well now. With British bikes of this age there are many parts that are common with other models, things like most of the electrics, carbs and instruments. You may recall from earlier how many miles this engine had done, unfortunately I had "borrowed" a few parts from this bike over the years it was apart and one of them was the speedometer. I managed to source a replacement Smiths speedometer and although it had a different ratio and a different dial face it's not a problem as they are all essentially the same, so I was able to get this wrong one rebuilt as the right one.

Earlier Speedometer core for rebuild to later style.

If you have ever done anything up you will know that some parts that didn't look too bad when you started may look worse when sat next to something freshly painted. For me this meant a number of steel parts that were once zinc plated were looking a bit rusty. I thought I'd give one of the home zinc plating kits a go and have to say that I was really pleased with the results, if you look at the earlier picture of the painted wheel hubs you can see the front wheel spindle I plated.

Here's a small seat clip I did first that shows really well the before and after of the zinc plated finish.

-- Edited by John Harvey on Thursday 2nd of November 2017 11:47:31 PM

John Harvey wrote:

If you have ever done anything up you will know that some parts that didn't look too bad when you started may look worse when sat next to something freshly painted. For me this meant a number of steel parts that were once zinc plated were looking a bit rusty. I thought I'd give one of the home zinc plating kits a go and have to say that I was really pleased with the results, if you look at the earlier picture of the painted wheel hubs you can see the front wheel spindle I plated.

Here's a small seat clip I did first that shows really well the before and after of the zinc plated finish.

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What plating kit did you use John? The results look impressive  

Brian, I used one from here www.classic-plating.co.uk/ rather than use a battery I managed to borrow a DC power source which gave some fine control, it was still a bit hit or miss at times. I also found a wire wheel mounted on a bench grinder the quickest and easiest way of preparing parts. It's a bit of a flaff doing this and you obviously have to follow all of the H&S side of things but I think the results are impressive.

I got bored and watched it!!!!
You are wasting my time Mr Sussex.
Nice job though, Tiger needs an awful lot of "Passivating".
Or is that Passify? ;)

You might of noticed in some of the previous pictures an aluminium box with some side reflectors that sits just below the petrol tank. It's an item unique to these models and is a classic case of a solution looking for a problem.

The thinking was to put all of the major electrical items into a one box so in there is the charging control, ignition coil,  flasher unit etc there is also a plug & socket that goes to the headlight so you can simply unplug and remove the headlight assembly? Useful... not really and in the event of an electrical problem a pain in the ass as access is poor, it does house a large capacitor that allows the bike to be kick started with either a flat battery or no battery at all. There is also the issue that the bike has three separate (small) wiring looms, there's one inside the electrical box linking everything together, another that goes to the headlight and then the main loom itself. The fact that this idea was never copied says it all really.

I managed to get hold of an original new old stock braided wiring loom as the original was a mess and some of the mounting brackets I found online from the states. 

 

-- Edited by John Harvey on Sunday 5th of November 2017 10:20:25 PM

Cheers Ian, looking forward to hearing about your rebuild mate 

It's a landmark to get the tyres and wheels fitted...because

...for the first time, in a very long time, it can finally start to look more like a (motor?)bike 

Cheers Steve, yes it would be a shame to get it dirty, but a bigger one not too  If you doing your Air Ambulance Santa charity run this year give me a shout & I'll try and get along on.

Next up is fitting the engine.

Da daa..it still fits 

I needed a new exhaust down pipe and the only ones that are guaranteed to fit really well are the original BSA ones. BSA had a deserved reputation for some quality control issues towards the end  but one thing they rarely got wrong was parts that were fitted whilst on the assembly line (they just fall off later). The exhaust pipe follows the shape of the engine really well and then neatly tucks in behind the frame, it looks like a complex shape to get right a poor fitting pattern down pipes can be found for around £50 yet a good original one, like the one I found below, cost £80 and yes it did fit perfectly 

 

 

-- Edited by John Harvey on Wednesday 8th of November 2017 01:26:49 PM

Yes, but yours has a CCM part number so that will double its price  

The paint is a high temperature metallic black paint for a woodburner?

An odd thing about these oil in frame bikes from this era is that there's probably more of them here in the UK now than when they were new! Back when this bike was new BSA/Triumph used to export 80% of everything they made to the USA, since from around the mid 1980's there has been a steady stream of these bikes being brought back that is still going on! Back in the early eighties I went along with a friend to look at a BSA Starfire for someone he knew, low and behold the seller also happened to have a non-running B25T in his garage which my friend ended up buying. By then I had passed my test and had my very own Triumph T140V...living the dream at last  Forward a year and with my Bonny in need of a rebore and no other transport my friend offered me the loan of his B25T. For a bike mad teenager going backwards from a 750 to a 250 was on the face of it a step in the wrong direction, it wasn't. For some reason this bike ended up running really really well and the few weeks I spent riding this bike I have really fond memories of, it was just a nice bike to ride.

Many years later and having sold my main bike to start a business and a few more years later on I spot an incomplete Victor 250 for sale and is the bike you see here.

Nearly there! tank painted and on, side panels about to be fitted

Overhauled clocks fitted.

Finally ready to get it started!

-- Edited by John Harvey on Thursday 9th of November 2017 09:58:38 PM

Brilliant, John - it really looks "the dog's danglies" and very attractive.

I spy the tradional Brit Bike drop of oil too. 

Martyn

Well spotted Martyn, they all like to mark their territory 

Mike, I'm hoping it will be an all year bike, there are people using far more valuable cars on race tracks and hill climbs and after all, I know how to repair this one 

Some outdoor shots before the MOT...it did pass 

 

Saw one at the NEC Classic Motor Show today John but it was nowhere near as well restored as yours. Also a rough-looking Triumph version with bits missing for sale at £1,750....

Brian

For anyone interested here in these final BSA models I can highly recommend this book called 'BSA Motorcycles The Final Evolution' written by Brad Jones HERE not a bad xmas pressy if you're into Brit bikes & stuck for ideas