I've spent much of my time here reading through other members bike projects, I've decided to strip down my little 1970 cafe racer and get to the bottom of some gremlins. I will be documenting as much as possible, as well as asking for a lot of help, as I will be in over my head multiple, multiple times over the coming winter. List of things I need to do,
Inspect motor for wear, and just a general tidy up.
I know this is just another small BSA project but rather than document it on paper, I wanted to do this for myself. I've always been rather terrified of mechanics and having owned the bigger for over a year, it's high time I get going on it! Will be doing it mainly on weekends, but will be finding time during the week to update at least once or twice!!
Carb is off, and it needs some love. Will be starting that this evening. I will post some pictures up tonight, and you can see the appalling condition of the electrics. The wiring is horendous, and will be a project!!! Will be making a new harness for it over the long Canadian winter.
Ps pictures coming. Just need to get them onto a Hosting site.
got a lot of pitting I would like to get rid of. Especially on the case cover/timing cover
Mmmm ... possibly difficult - polishing would need to remove a lot of metal around the pits, filling with ally weld and then polishing could mean the filler is highlighted as a different shade to the existing ally? It's a near-fifty-year-old bike, how about just regarding them as the scars of its life?
Turning to the electrics, two methods I've evolved dealing with a bike I haven't worked on before. Both involve using a scalpel-type knife - one you can hold like a pen or pencil - so you can control it to cut through the tape but avoid cutting the insulation of the underlying wires. Then:-
. If you've a place you can leave the bike partially-dismantled without needing to move it, and under something just above head height(?) - my first rewire, I was able to connect the wires to the handlebar switch clusters and hang the other ends from a garage roof rafter; the black lines and colour codes of the wiring diagram are then in full 3D colour, easy to pick off one at a time and replace and/or reconnect to the component at the other end.
. If you need to be able to move the bike around, leave both ends of each wire attached but, once the black tape's stripped off, hook the wires temporarily around convenient frame tubes with releasable cable ties - I use these:-
... although I buy 'em at local swapmeets for about one pound for ten ... Btw, I never retape a finished harness - during that first rewire, it was so useful being able to access the wires simply attached to frame tubes, I left it like that when the harness was finished. Makes for easier upgrades (and repairs) later.
When rewiring, given certain conditions, I don't have any problem reusing an original wire. My first rewire was one of my T160's, over the winter of '82/'83; I reused some original wires and they're still in use. The conditions for reuse are:-
. No measurable resistance end-to-end (you either already have or are planning to buy at least one multimeter?).
. Not intending to attach a bullet terminal to either end of the wire. Reason for this is any standard-looking (3/16" o.d. but also known as "4.7 mm." and sometimes even "5 mm.") bullets stay on the wire conductor purely by friction from the crimp, any modern wire is metric (avoid any debate over AWG (American Wire Gauge); any you buy from Europe will be metric and e.g. British Wiring in the US sells metric wire with the Lucas insulation colours) whereas original wire was Imperial SWG, slightly smaller than the 'equivalent' metric so crimped bullets tend to slide off 'em.
Suppliers British Wiring doesn't sell as many components and tools as are available from British suppliers and some things from BW can be ouch! expensive. I've used both Autosparks and Vehicle Wiring Products for decades; given the current weakness of the British pound, one or two large orders from British suppliers might be cost-effective, just using US or Canadian suppliers for top-ups?
Wire You'll find it with both modern 'thinwall' PVC insulation and 'normal' PVC insulation. I use 'normal' in the smaller sizes (9/0.30, 0.65 sq.mm., 5.75 Amp and 14/0.30, 1 sq.mm., 8.75 Amp) and 'thinwall' in the larger sizes (28/0.30, 2 sq.mm., 25 Amp and 44/0.30, 3 sq.mm., 33 Amp) simply because: bullet terminals that work are available to fit all those conductors, whereas ime they don't work on 'thinwall' smaller than 2 sq.mm.; the bigger 'thinwall' and is easier to manipulate in tighter spaces than the equivalent 'normal PVC-insulated', and it has a higher Amp rating.
I use 25A (28/0.30, 2 sq.mm.) thinwall for wires that are common to several circuits - Brown/Blue (and Brown/White?) between battery, rectifier, Zener and ignition switch, White or White/Blue from the ignition switch to the junction of the individual component White wires. Not sure what was original on a '69 TR25 but ime of larger pre-'71 Triumphs, Lucas supplied (Imperial-sized) 23.5A for Brown/Blue, Brown/White and main Red, 17.5A for main White or White/Blue.
I have used the 33A (44/0.30, 3 sq.mm.) thinwall for the main Red return wire between headlamp, engine and battery but that's probably overkill.
Btw, talking of Red wires, when you strip the old harness, you'll likely find wa-aa-ay more than is sensible:-
. I make up one thick (25A or 33A) Red wire to run from the headlamp area to under the seat, with an 8-way snap connector at each end, then I connect individual components' Red wires - including battery +ve - to the nearest 8-way,
. I either split the thick Red wire above the engine and attach the two ends to a ring terminal on a rocker-box/head bolt/stud, or fit a 4-way snap connector between the ends and run a short thinner wire to the aforementioned ring terminal on a rocker-box/head bolt/stud; either way, electrical components on the engine have a good return to battery +ve.
. On a '69, you'll likely find the rear lamp has only two wires - Brown/Green to the bulb tail filament and Brown to the Brake filament; the return to battery +ve was/is supposed to be through various bare metal-to-metal connections in the cycle parts; in practice, nearly half a century on, whether the bike's restored or un-, this is crap.
. I run a Red wire alongside the other two, between the lamp and the 8-way snap connector under the seat. If I can thread the Red wire alongside the other two into the lamp unit itself, I solder the end to the outside of the bulb holder; if I can't, I attach the Red wire to to a 3/16" i.d. ring terminal and attach the ring terminal to one of the studs that mount the lamp unit to the ally mounting casting.
. For any wires that aren't covered when tank, seat and sidepanel's replaced (e.g. between headlamp and frame under the front of the tank), I use lengths of what's known by the British suppliers as either Split Convoluted Conduit or Slit Convoluted Tubing; the Split/Slit is lengthways so it can be fitted or removed without disconnecting the wires inside.
. When routing wires between headlamp and frame under the front of the tank, don't forget to turn the forks fully to the opposite side before cutting any wire to length ...
Thank you so much for all that information! I will be back working on the bike probably Thursday, which is when I will begin removing the tape and seeing what I have to work with. I like the idea of keeping the wires loose on the bike, to keep everything together. I am planning on going out and buying a multimeter before then, and then learning it. I've got a lot of time to look at wiring, and I'm not planning on rewiring the bugger till probably march, but it's never too early to plan! First I need to get the engine rebuilt!
Thanks again mate! Really appreciate you taking the time to respond!
Ok so tomorrow, will get pics of electrical system sans tape, and also pulling the head off, and inspecting condition of valves, guides, etc. I'm super excited, as I've never done anything like this before!!! Like I said above, I will probably need more sets of eyes on the head than just me to tell me if what I'm looking at is normal, or if anything needs replacing!! Will post all these pics up tomorrow night!!!
Thanks again to every one on this forum for help, support, and giving me the confidence to dive in!!!
Your wiring harness actually doesn't look so bad. Perhaps a bit of investigating where is was rubbed between the coil and gas tank to check the wires. Perhaps very little will need replacement. You can also buy a whole new wiring harness for your bike. That would save you both time and money if you decide to start tearing it all apart. I happen to stock wiring harnesses for the unit singles along with just about any part that you will ever need for your B25 project. I have rewired a number of BSAs from scratch but that is because I have re-arranged many items in the electrical system. When I am keeping all the components in basically the same place they came from the factory in it is easier to just put in a new harness. If you happen to do a sensible upgrade like tossing the zener diode and finned rectifier and replacing with a new solid state regulator/rectifier, the new regulator/rectifier will be in one place rather than two places far apart. A wire or two might have to be added or relocated to accomplish this.
Stuarts comments on the poor tail light wiring and on red ground wires are ones to remember! Of course so are the other things he says also
I am looking to toss the diode and upgrade. I'm also relocating the battery from the frame into the seat jump of my cafe racer seat. So it would have to be a custom harness... I also have all connections for signals, but don't have them on the bike so those can go as well! I have a friend who teaches electrical physics at the university here, and he's going to design me a harness which is much more streamlined. This harness feels clunky, and honestly, cheap. I'm looking forward to getting it re done, and much more streamlined, to go along with the cleaner lines I'm looking for with my project!!
Thanks tons for your comment, this is all info that I need to take into consideration!
Without wishing to do Peter out of any sales, helping other people get started, generally only the first harness is about the same cost whether home-made or bought off-the-shelf, because of the cost of the tools. Once you have the tools, wire, terminals and connectors are cheap as chips.
One potential tip I missed out of my previous post is I choose the battery early in the project, but obviously connecting wires to an actual battery isn't a brilliant idea when other ends are waving about and could touch any part of the bike ... So I make up a block of wood to the same dimensions as the intended battery; I fit the steel inserts for wood so I can use battery terminal screws to secure the wires' terminals, but obvs you can just use self-tappers.
Imho, the block's also useful when I come to the first test of the complete harness. Rather than actually connecting the battery to discover a bit of bubbling and smoking insulation (not happened yet ... ), I leave the block in place and connect a battery with jump leads. Then, if the worst does happen, it's just a matter of yanking off one of the jump leads.
Originally Posted by Alexp
I also have all connections for signals,
Minor point but you're seeing only the Green/White and Green/Red wires between the headlamp area and the rear of the bike? These'd connect handlebar switch and front signals to rear signals but what isn't present is the Light Green/Brown wire between relay and handlebar switch, and the White wire from the harness to the relay?
Another component missing from the '69 250's, that you might want to consider and Peter might comment on, is the oil pressure switch. Unlike other ranges, the 250's didn't get the switch and warning lamp 'til '70, but '69's have a suitably-threaded hole and plug in the crankcase?
Originally Posted by Alexp
I have a friend who teaches electrical physics at the university here, and he's going to design me a harness which is much more streamlined. This harness feels clunky,
I'd be very interested to see the design? Over the years, I've known many people say they'd like something 'better' than a standard Britbike harness but, when Lucas harnesses are analysed and replicated, there really wasn't much unnecessary, apart from a lot of Red wire. Lucas was screwed to the floor on price by all the bike makers, so they had to design carefully to make any sort of profit.
One thing to bear in mind, especially if your friend isn't a biker, is any electronics on a Britbike live in a very vibratory and damp environment. The likes of, say, motogadget do some funky electronics but, at 269 Euros just for the m.unit basic ... ye-ea-ah ... Makers of electronic ignition and reg./rec. for Britbikes have been refining vibration resistance and water-proofing for decades; I've used both for the thick end of forty years with only a few problems. Then ime an inherent part of speedy diagnosis is substitution testing, for which the substitute has to be cheap enough it doesn't matter if it isn't the solution ...
Got tape off and wiring actually seems to be possibly original, although wiser eyes than mine can tell for sure!!!
One thing I did notice is that on some parts of the wiring, near the front wheel, and above the rear wheel, there is some sort of rubberized shield that's been out over the wiring loom. I'm wondering is this original or was it an afterthought by a PO? Either way, it's a rather good idea.
Also these hard opaque yellow plastic sleeves are in a couple sections as well. Only about 2 inches long, and I don't really understand the point of them, but again, no idea if it's original or not.
Sorry you can't really see the yellow in that pic.
Also today got the head removed. Didn't have time to pull valve springs out and measure against factory spec or check for cracks but will do that on Sunday. Head looks like it's in need of a clean up, but after a VERY quick check, everything seems in order. Will get a proper look at everything Sunday when I remove valve springs, guides and valves. Interested in seeing the condition of the piston as well....
Interested in the stamping PBM-2 and then 40-930. Are these parts or serial numbers?
All in all a great day, and I'm looking forward to spending a full day in the garage Sunday.
Hi Alex, PBM-2 is probably a mold number, and 40-0930 (add a 0 to make a standard 6 digit part number) is the casting number. The BSA part number is usually one number higher or lower. I can't remember which. Regards Adam
some parts of the wiring, near the front wheel, and above the rear wheel, there is some sort of rubberized shield that's been out over the wiring loom. I'm wondering is this original or was it an afterthought by a PO?
If you mean the piece on the harness by the ignition switch in the second picture down, not seen it before so might well have been added by a p.o. to prevent chafing of the harness.
Originally Posted by Alexp
hard opaque yellow plastic sleeves I don't really understand the point of them, but again, no idea if it's original or not.
The one in your third picture down appears to be insulation over a connector? Can I see the brass connector inside? Also, the harness braided covering is frayed and the wire running off the bottom of the pic appears to be Black(?); if so, again, Black wire not standard, never seen that type of insulation over a standard connection so likely added by a p.o.
Originally Posted by Alexp
head PBM-2 and then 40-930.
Originally Posted by AML
40-0930 (add a 0 to make a standard 6 digit part number) is the casting number. The BSA part number is usually one number higher or lower.
Bare but finished BSA cylinder head part number is 40-929.
I would have taken a compression test before taking the head off. It would give you a better idea of the state of the engine so that you are not throwing parts at it that it doesn't need. If the compression was low, you can then do a leakdown test to determine where the problem is. At this point though, that is academic. What you can do however, before you take the valves out, is test how the current valves are sealing. With the head upside down, fill the combustion chamber with gas and let it sit for a few hours. If no gas leaks into the intake or exhaust ports, the valves are sealing well.
Ed- that's a fantastic test and definitely something I will be doing this weekend!
Stuart - thanks again for your reply, I was hoping you would see those pictures and get me pointed in the right direction electrically. Will get a picture of the connector for you Sunday. If that's indeed what it is, it tells me the guy wiring the bike didn't have a clue what he was doing. In all fairness, neither do I at this point but am learning as much as I can as fast as possible!
Aml- thanks for clearing that up!! Was definitely curious about it!!
I was hoping you would see those pictures and get me pointed in the right direction electrically.
I thought you knew what you wanted - a custom harness and your friend's designing one for you?
Is the existing harness original? Probably, but we're talking about a near-half-century-old bike; a harness replaced 25 years ago would likely look equally tatty.
If you're wondering how much of the existing wire might be reusable, 'fraid that's a "how long is a piece of string" question, certainly 'til you strip the harness and we see your friend's design. Even then, reusing isn't a big deal; as I posted earlier, new wire and terminals are so cheap.
Originally Posted by Alexp
Will get a picture of the connector for you Sunday. If that's indeed what it is, it tells me the guy wiring the bike didn't have a clue what he was doing.
Mmmm ... even in the early 1980's when I did my first rewire, original terminals weren't available at any common auto-parts chain store, I had to mail-order from specialist suppliers or buy large quantities from the local Lucas branch, when we had such things in GB. And I was lucky there was a proper auto. electrician there, and old boy who was willing to share his knowledge.
You and p.o. are several thousand miles from where the bike was made; as a couple of threads current elsewhere on the Forum have revealed, interest in these 250's is only very recent; when a p.o. made those repairs, likely he (or she) just went with what was obtainable locally and fixed the problem?
I definitely know what I want! But comments and opinions from people wiser than me are always helpful! That's what I meant by that comment!! Didn't make it out to the garage today as it was a typical Canada autumn day... 9 degrees and raining! Bought a kerosene heater though so winters will be manageable!!