Britbike forum Forums Thread Like Summary - BSA C15 Scrambler project .....

So, in preparation for playing in the woods and running Moto Giro events, I've got a 1961 C15 Scrambler. Two-owner, fairly complete, rolls, has some compression, brakes engage, shift through gears, all the switches and levers move. Needs a a complete going-through, of course. I'll have the appropriate manuals and parts lists for this year, and will search thoroughly through past posts on this and other sites before asking any potentially dumb questions.







Just straddling it and going "Vroom Vroom", it feels like it has plenty of room for me, so that part will work.

I'll be looking at photos to see what the "battery box" area should look like - it looks a bit "homemade" as it is. The numbers match on the frame and the engine at "C15S3692". The original title has a notarized date of 5/20/61 for when it was first titled for the road in Pennsylvania, so I'm going with it's a 1961 unless someone changes my mind by showing that 1962 BSAs were sold in the USA in May of 1961..

I don't know if the alternator or charging system works. I had thought I read that the Scramblers of this era had an Energy Transfer system and no battery, but this one has a "distributor", although what it could possibly be "distributing" to I don't know, since there's only one place to send a spark.

I'll be doing a compression and leak-down test before I take the top end apart, and assessing whether the bottom end needs to be replaced. There's quite a bit of "patina" on the wheels, so I'll be looking to see whether to wire-brush them and go on, or whether a nice set of period-correct aluminum rims would be good. I can see that the rear tire is too big, so I'll look up the modern equivalent of the old sizes, and find some 50/50 road/trail pattern tires.

I'm going to order a 500-pound hanging scale and work on getting this thing down as light as I can. Not for speed, since the best way to do that would be to get some of the lard from off the top of the seat, but for ease of handling and picking up off the ground.

I'll have to count teeth on the sprockets and figure out how to gear it - it has a manhole-cover-sized rear sprocket which looks like good fun on a trials bike, or a fire-road bike at 35 MPH, but I need it to go 50 - 55 MPH without throwing the rod to get me over the back roads from home to the state and national forests and game lands.

Looking at some of the wiring, I'll either buy a wiring harness for it, or make my own, it looks simple enough.

I don't want to take this apart and scatter it all over the shop ... I'll probably start at the front and the back and R&R the wheels, forks, brakes, shocks, wheel bearings, etc a bit at a time, and finish up with the motor so as to have a minimum apart at a time ....

Lannis

Attached Images

Just teasing us unit single guys heh????????

1964 C15 Star America w/ the number 1 engine number for the model.

Gordon

Oh no, and here I was just going to go with the "patina'ed" look, and you had to show me this!!!

All I can hear now is "ka - CHING!!" in my head, as I contemplate a speedometer, new kicker, a stock-looking seat, a new taillight, a proper front fender (although I may use the one I have), and possibly a chainguard which the BSA brochure shows, but the restored-bike picture does not and it looks OK.

Since I'll be riding it in the National Forest, I'll need to have a proper silencer on it, not the straight pipe in the brochure, and figure out an air-cleaner for the Monobloc ....

The fun begins soon .... Got to get the Firebird Scrambler off the lift ASAP!

Lannis

Yep......Gordon

I have some previous experience with one of these in a field, wonderful bike, it had ET ignition , liked a bump start, IIRC the bottom end has better bearings than the stock ceefers, scrambles cam, bumpy piston and big ish carb. A modern front end would shed a lot of weight, this model got the "heavy weight " forks. Get Rupert Ratios books they will be invaluable. Nice find.

Yes.

No guarantee that it's running its first distributor
but the distributor will have a month and year date stamp

This thread is going to bring back memories, some good, others not quite so warm and fuzzy. My first "real" bike was a 1961 C15S, frame #C15S3417, engine #C15S2540. It's amazing that I still remember those numbers. It was actually a pretty good bike and withstood most of the serious abuse I sent its way and when it didn't, it was simple enough that I could dive right in to the deep repairs when needed.
Bacon's singles book lists the 1961

Engine: C15S 2112 through C15S 3100 (1962 beginning production number minus 1)

Frame: C15S 2701 through C15S 3600 (1962 beginning production number minus 1)

So your 3692 frame number does appear to be 1962 number.
I think matching numbers would have been a coincidence in these years.

Rupert Ratio's Unit Single book will be a big help to you.

I currently have a 1965 side points C16FSR that I rode the crap out of for years. It's basically stock but with lightened and balanced flywheels and a 69mm Triumph T100 twin piston in it. This piston trick is super handy if you have a rusty or worn cylinder that would clean up at .080" over. I've even heard of using a 71mm T120 piston in these iron cylinders. Apparently they are thick enough though I haven't tried it myself.

So anyway, thanks for starting this thread. Best of luck with the old thing.

Sez "6/60" on the distributor body...?

Gordon - Thanks for the continuing research.

It certainly sounds funny that my bike has a "frame number" matching the engine number. Here's a photo of the frame number C15S.3692 just below the headstock on the near side. Experienced folks may be able to tell whether this is a factory stamping, or someone was satisfying an overly officious Motor Vehicles jobsworth by making the number match ... ?

Attached Images

Both the UK BSA Club and the VMCC have a machine dating service. The VMCC will do 2 bikes/year free for members, otherwise 10 or 15 quid. I think the BSA Club is similar, but don't know if affiliated BSA clubs count.

They were all rather stretched over the last couple of years, but seem to be getting back to normal.

It's certainly worth checking up on rare and unusual machines, and I reckon this one counts.

Ain't that the truth, and it's exactly how in the early nineties I got my 1965 model. It was a rusty, beaten on chopper!! Struts, peanut tank, slugged front end and cobra seat. It was truly pathetic.

Gordon - You can never overdo passing on information, opinions, suggestions, and/or parts, I'll take all the talking you can do.

I don't think anyone's been playing shell games with the engine numbers... They and the surface they're stamped on look clean and original, nothing dodgy or over stamped or ground-away looking about it.

Besides, it would likely have happened the last time the title was transferred in 1983,when you could buy a truckload of these bikes for the favor of hauling them away.... wouldn't have been worth the time to meddle with it.

One thing I'll do is measure the cam lift once I have the barrel off, that'll be a good data point.

Lannis

Learning all sorts of little things about mine .....

'62 Scrambler had the pipe going to the outside of the frame, necessitating the loopy kickstarter ... '63 had the pipe going inside the frame like a Victor. I'm either going to source a '63 pipe or buy a pipe shield for my '62 one ... I'm not having a red-hot exhaust pipe 1/2" from my leg!

The '62 Scrambler DID in fact have a 4.00 x 18 tire on the rear ... I said it looked too big, and the picture of the Mecum-auction one you showed me had a 3.00 x 18, but I'll keep the right size on it. My one has a 19" wheel on the front, but it looks like the specs call for a 3.00 x 20. My front rim is a little warped from an impact, not unrideable but I wont leave it like that. I'll lace up whatever rim is The Hot Ticket for the well dressed dirt racer of 1962, since apparently people were using both kinds.

I'll probably use Dunlop Trials Universals on it, unless there's a period dirt tire that people would have switched to. I use TT100 tires on my Norton for that very reason, even though the hot-shoes use Avons or something else.

"Period Correct" is my motto, not "Concours Matching"!

Lannis

Stuart, you should start a thread on this, don't want to steal from this thread, but your cases may warrant some exploration. Interesting...

So this is my next step, as you and Shane suggested. The information on the BSAOC web site is very much UK-registration and Member oriented (I was a BSAOC Member once but now an OVBSAOC member), so I've sent a query via the BSAOC "Contact Form" ... I have Steve Foden's mailing address, but no idea what to send or how to send money and how much (I read the 2014 thread on the subject but suspect that it is out-of-date by now).

So we'll see what I get back from that.

Lannis

I'm the last guy to ever complain about "Thread Drift", since I've always thought that "One idea leads to another" is a strength of these forums, not a bug.

But sometimes, separating subjects with separate threads helps avoid having to read through a lot of posts that don't apply to your subject. Rule 1 of forums, though, is that you don't get a deed and a title to threads you start!

Lannis

Lannis,
Whether the bike is restored original or made into an off-road rider, it makes no difference to me. That old bike has always been one of my favorites along with the Victor Special and the Goldstar. Motorcycling (to me) has always been about lightweight machines that could cruise the backroads or take a spin in the dirt. If I had seen that bike, it would have been hard to resist buying it even as I try to reduce the complexity in my life.
Keep us informed on the fate of this jewel.
Mr Mike

Mike - I don't think there's any danger of not being informed...we're on the third page of the thread and just now got it identified!

Just wait till I start turning wrenches... !

Lannis

FWIW
I have found that when using that tool it is very hard to keep sufficient downward pressure on it to prevent it jumping out of the slots damaging either the slots or the tool
However if you invert the whole shebang ( drain the oil first or it gets very messy ) , stand on the arms of the tool an use either the actual axel or a dummy bar through the axel hole it works a whole lot better

Don't use a strap wrench. It is too easy to crush the thin part of the seal holder. I've done it myself.

This is true. Old BSA forks take a special tool. Best to make, borrow or buy one.

Gordon, and anyone else that's interested, I think I just learned why that tool of yours might not always fit.

I'm piecing together a set of forks for an A10 basket case I never should have bought and just had a good look at my selection of various seal holders including a reproduction one. It turns out the ID of the spring end on the repop is quite a bit smaller and my home made tool from years ago won't fit in it. The other odd thing is the seal housing measures larger than an oem one even though it screws on the slider nicely.

SO that may be an answer but also, for anyone rebuilding these forks, you might be better off with original seal holders if at all possible. But then, we probably already knew that.

Right on. I'm not sure how one would assemble a BSA front end with oem headlight ears if he didn't have those tools.

Methinks I have a dim memory of my dear old mom once promising to "beat the whaley" out of me for something I may or may not have done. Not sure if this applies or why I even mention it.

But I suppose trying a judicious tap on each end with a HEAVY copper hammer would be a good start. It might move more easily in one direction than the other. Not much else you can do without a big press. Maybe heat up the brake drum side of the hub first?

And "Whaley away."

Stuart……that’s a tough one. There are folks on here that have a lot more experience with the GIROS than me but since you didn’t get answer yet I thought I’d try to help.

As far as I know there isn’t an actual web site but they have a presence on Facebook. It’s put on by one of the vintage racing groups. Find them on Facebook and you can find some contact information if you want to ask questions.

Seems like they limit attendance to around 100 riders but lately from what I can tell they haven’t been turning people away.

I think they used to hold some out West…..but I haven’t heard of any of those happening the last few years

I’ve been to 4……all held in absolutely beautiful parts of the country. I did those by myself and I won’t do that again. If there’s a group of BritBike folks I’ll gladly join them.

Thank you. Thanks for taking the trouble to post these.

Those drawings showing that BSA actually moved the engine to the left 3/8" on the competition models are the best answer possible and cleared up the question in the back of my mind. All but one of my C15's have been competition models and I have often noticed how the engine was noticeably offset to the left but it never occurred to me that the road model would be different on something like that. Go BSA!!

That worked. It just had a hex-head bolt and a spacer under there, I can't make out how the PO got it on in the first place. My son pulled up hard on the tank while I put the rattler on it, and it was off in three seconds. The frame fitting is intact, so just need a new bolt and rubber bushing....

Lannis

There are a number of different length tank bolts, spacers and rubber bushings which can be a minefield, tanks differ too so pick the replacements carefully.

"Never know until you try" is correct; I couldn't tell if the ones you sent were the right size or not until I actually "offered them up" to the forks, then found that both the ears and seal holders were just a LITTLE bit too large for the C15S forks.

The seal holder tool, however, turned the fork seal installation from a bodge with a pipe wrench into a leak-free proper job. I used PTFE yellow thread sealer on the threads and gap, and predict no leaks. Thanks! I'll get it all back to you at TSMR, or send it if you need it sooner.

Into gas tanks, wiring, seat and rear end .... the spec calls for a "1/2" x .335"" rear chain. I assume that this is "520" chain in modern parlance? I know that O-ring chains won't fit an A65; will they fit (in case I decide to try it) on the C15?

Lannis

With my early rear hub from a B40 I used 428 chain, plenty of clearance so its X ring.