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Messages - om15

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Twins / Re: Battery flat after riding with lights on
« on: 27 August, 2017, 20:57:51 »
Go for the easy fixes first, change the battery and see how you go

Singles / Re: Torque wrench
« on: 23 August, 2017, 19:31:20 »
Best advice I can give is buy the best quality tools you can afford, less chance of damage to the bike and will be easier to use, - spanners and sockets will be slender and give better access.
If you are unfamiliar with using tools then a torque wrench is advisable rather than using your own "feel", not too expensive and will help to prevent overtightening (stripped threads) and under tightening (leaks).
I have a set of old BSF spanners (used on RR Merlins), but still find odd threads on my C15, you might find that a set of metric and BSF/Whitworth spanners will get you started.

Singles / Re: First classic
« on: 06 August, 2017, 15:33:21 »
Phil, rather than go for a bike that requires a rebuild, perhaps look at a runner that you can tinker with and fix as you go along. The BSA twins are rather expensive, I have a C15 that I potter about with, but if going for a bigger bike you might like to look at the AJS/Matchless twins that are available, comparatively cheap to buy, spares are ok to source and the manuals, wiring diagrams are available.

You might pick up a good AJS runner for 3K, but an A65 might be double that, which ever way you go I'm sure you will get enthusiastic help on here.


Singles / Re: B31 help
« on: 29 July, 2017, 17:39:54 »
I can recommend this place.

Jed overhauls and repairs classic bike engines, I had a small job done there on my C15 head and he showed me his various jobs in hand, nice bloke, sensible price and top quality.
If you go into the estate, Three Cross Triumph is on your right, take the next right and he is on the right hand side of the lane.

Edit, if you are at the other end of Dorset you could speak to Andy in Bridport, he carried out a tricky repair on my Adventurer a few years ago, did a good job

Singles / Re: Internal Incontinece
« on: 28 July, 2017, 19:51:12 »
Here is a better view of an oil shut off valve, fitted to a Matchless to prevent wet sumping. As mentioned the results of failing to select to flow can be expensive.
I only switch off for a prolonged lay up, over winter for example.

Singles / Re: C15 oil feed problem
« on: 28 July, 2017, 17:47:04 »
Yes I was an RAF rigger (1968 to 1977), still doing it - until November when I thankfully retire. :)

Singles / Re: C15 oil feed problem
« on: 28 July, 2017, 09:49:42 »
I think that the answer may lie with the actual return tube in the oil tank, if you look at the return oil flow with the engine idling it indicates that the hole in the tube is much smaller than the internal bore of the oil line, if this is the case it will create a back pressure, and the oil will take the line of least resistance and flow up the line to the rocker feed.

Which BSA do you ride? / Re: Hello, new arrival
« on: 26 July, 2017, 18:29:54 »
Here it is, good inventory of parts and interesting bikes for sale.

Here is another link, I have bought a couple of bikes here with no problems, always has a good selection, and is nice bloke

Which BSA do you ride? / Re: Hello, new arrival
« on: 23 July, 2017, 19:57:58 »
I used Bugad as well, recently bought a front brake cable and exhaust from there, they seem to have everything on site. They also have the odd C15 for sale, they have one requiring finishing for sale at the moment.  Not only a good inventory, nice bends on the way there as well.

Singles / Re: B31 Cush Drive Nut
« on: 23 July, 2017, 16:03:39 »
It's not a left hand thread by any chance? 

If it is seized you could try heat, if you have good access use a socket rather than stilson's for better grip, heat the assembly using a hot air gun, (the sort electricians use to shrink plastic heat shrink) then shock the socket bar with a hammer. Applying heat to the nut expands it more than the threads it is screwed onto.

Which BSA do you ride? / Re: Hello, new arrival
« on: 23 July, 2017, 15:54:47 »
I bought the bike 5 years ago, it had just been overhauled, loads of teething problems, all of which introduced me to the bike, usual stuff, gear shift fell off in cruise, clutch failed because the little grub screw came out of the clutch operating rod, bits of electrical failures, spark plug threads were shot, took the head off for an insert repair and pleased to see the piston and bore in as new condition. Slowly tidied her up with little mods and improvements, now is an easy starter, I was thinking of uprating to 12 volts and electronic ignition, but she is running ok as she is.
I have had five Hinckley Triumphs, Trident 900, Bonneville ( 2), Adventurer, and now Street Twin.

Singles / Re: Compression Test
« on: 23 July, 2017, 12:10:41 »
My service notes give the C15 compression ration of 8:1, (the C15S is 10:1), no mention of acceptable psi measurement, however I found this on wiki

Measuring the compression pressure of an engine, with a pressure gauge connected to the spark plug opening, gives an indication of the engine's state and quality. There is, however, no formula to calculate compression ratio based on cylinder pressure.

If the nominal compression ratio of an engine is given, the pre-ignition cylinder pressure can be estimated using the following relationship:
p = p 0    CR  γ     {\displaystyle p=p_{0}\times {\text{CR}}^{\gamma }}  p=p_{0}\times {\text{CR}}^{\gamma }
where p 0      {\displaystyle p_{0}\;}  p_{0}\; is the cylinder pressure at bottom dead center which is usually at 1 atm, CR    {\displaystyle {\text{CR}}}  {\text{CR}} is the compression ratio, and γ    {\displaystyle \gamma \;}  \gamma \; is the specific heat ratio for the working fluid, which is about 1.4 for air, and 1.3 for methane-air mixture.

For example, if an engine running on gasoline has a compression ratio of 10:1, the cylinder pressure at top dead center is
p TDC   = 1  bar  10 1.4   = 25.1  bar    {\displaystyle p_{\text{TDC}}=1{\text{ bar}}\times 10^{1.4}=25.1{\text{ bar}}}  p_{\text{TDC}}=1{\text{ bar}}\times 10^{1.4}=25.1{\text{ bar}}
This figure, however, will also depend on cam (i.e. valve) timing. Generally, cylinder pressure for common automotive designs should at least equal 10 bar, or, roughly estimated in pounds per square inch (psi) as between 15 and 20 times the compression ratio, or in this case between 150 psi and 200 psi, depending on cam timing. Purpose-built racing engines, stationary engines etc. will return figures outside this range.

Which BSA do you ride? / Hello, new arrival
« on: 23 July, 2017, 11:48:39 »
Hi all,
just found your forum, I learnt to ride in 1971 on a C15, and have had this C15 for the last 5 years, bought it as a runner and just kept improving/mending as I went along.
My other bike is a Hinckley Triumph Street Twin, (is that the wrong thing to say on this forum?)

Here is my 1964 C15.

cheers om

Singles / Re: Internal Incontinece
« on: 23 July, 2017, 11:28:22 »
Here it is

Singles / Re: Internal Incontinece
« on: 23 July, 2017, 11:04:57 »
I had the same problem with my 1964 C15, I thought that I would do more harm than good by splitting the engine, so I bought a small brass gas tap with an internal bore of 3/16" and fitted directly below the oil tank in the feed line, when ever it is parked up I shut it off to prevent wet sumping.

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