Hello. Ref my early C25 engine No C25-317. I've owned the bike for nearly 50 years, but have only recently reactivated it.

The workshop manual and the excellent RR book show that adjustment of valve clearance is achieved by turning the eccentric rocker spindles outwards.  Later engines from engine No C25-2050 onwards had revised spindles and rockers and adjustment was achieved by rotation the spindles inwards.

However, on my bike the spindles have to be turned inwards to set the valve clearances when according to the above they should be turned outwards. The engine starts, runs and idles nicely.

A BSA Service sheet from July 1967 shows the modified rocker arrangements and states that the new arrangement is interchangeable as a complete rocker box assembly, but individual components are not.

Would anyone know if the later rocker spindles would in fact fit into my earlier rocker box. The rocker box does seem to be original as it includes the internal rib that the Service Sheet shows as being removed for the later arrangement. If so and a previous owner had done this it might explain why the valve setting procedure is apparently reversed.   

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Hello.  This is maybe a daft question, but does anyone know if incorrect valve timing could be responsible for the exhaust header changing colour?

I have only run my newly rebuilt C25 for a few minutes whilst trying to set up the carb. Initially the bike was reluctant to start or idle once started. I noticed the exhaust header becoming golden in appearance. Presuming that this was due to weak mixture I stripped the rebuilt carb again to ensure that all was as it should be. This carb was the original Concentric 928/1 with the pilot jet at the base of the carb body. I found nothing obviously wrong and also checked the carb flange and inlet manifold for leakage with nothing found.

I then double checked the ignition timing and found this to be about right at 35 degrees BTDC. After this work I found that nothing had changed and starting and idling was still poor and the exhaust header was changing colour.

Presuming this to be a carb issue I then fitted a 928/8 concentric as fitted to later B25's, this carb has the later idle bush pressed into the carb body opposite the pilot air screw. The engine now starts and idles as it should, but the exhaust is still changing colour!

As the carb seems to be set up correctly and I cant find an induction leak and the ignition timing seems to be ok, I'm now wondering if incorrect valve timing could cause the exhaust to change colour? If not, does anyone have any suggestions for other things for me to check?

             

Wishing to protect the rebuilt engine of my 1967 C25, I've bought a remote oil filter kit, this seems to be of the Norton Commando type with 3/8" hose spigots on the filter head.

Whilst mounting the bracket and filter onto the rear engine mounting stud is straightforward, I'm struggling to work out suitable hose routings.  One concern is that it looks like I will have to shorten the inlet pipe of the engine oil manifold 40-1035 to allow the hose to pass between the rear of the crankcase and the filter mounting bracket on its way up to the oil tank.  The other concern is that as well as having to force the supplied 5/16" return line hose onto the 3/8" hose spigots, the orientation of the filter head means that I have to bend the hose well beyond its intended minimum bend radius to get it onto both hose spigots.

I might well have missed the obvious.  Does anyone have any photos showing how they have installed such a kit or any advice?  Thanks in advance for any help.

I'm finally getting around to getting my 1967 C25 back on the road after 40 years. The original gearbox sprocket had 16 teeth, but the new one that I bought at a classic bike show has 17 teeth.  I was assured that this is the sprocket that most people now fit. Does anyone know if the standard 100 link chain can still be used with the bigger sprocket?  I need to buy a new chain so need to make sure that I get the correct chain length. Thanks for any advice.

Hello again. I wonder if anyone would know the paint codes for my 1967 BSA Barracuda.  The fuel tank is orange and white/cream and the side panels are orange.  The frame is of course a gloss black, but I'm aware that there are different shades of black. I would be grateful if anyone could help with this information. 

Hello.  I'm carrying out a total restoration of my C25 which has sat unused in our garage for 40 years.  The frame is completely dismantled ready to go to local paint strippers.  I Have not removed the swinging arm Silent Block bushes as they seem to be ok. I guess that this means that the swinging arm will have to be shot blasted rather than acid dipped to avoid damage to the bushes.

What do others think about me not replacing the original bushes? Are others still using original bushes which are now 48 years old?

Hello. Hopefully someone can help me with this.  I am still rebuilding the 1967 C25 engine that I stripped down many years ago. I have reassembled the clutch using a new clutch drum, plates and rollers.  There are however a couple of issues:

1. I cannot fit the new clutch springs that I also ordered. The original springs were approximately 35mm long and the new ones are 42mm. The spring cups are 7/8" deep and it is not possible to compress the new springs into these cups without the springs becoming coil bound!  The clutch was working ok when I last rode the bike. Checking the Draganfly website, they list the spring cups that I have 40-3218 as 7/8" long for production years 1967-1969. They also show 57-3951 Spring Cup at 1+1/16" long.  They only list one spring though, 40-3231, 1.75" (44mm) in length for use in all years of production. This doesn't seem to make sense to me.

2.  Only one clutch hub is listed for all years of production, 40-3207.  With the clutch fully assembled with the original shorter springs and the spring nuts incorrectly screwed in fully as far as they will go, the ends of the studs are still 5mm below the face of the spring nuts.  This means that I can use a normal screwdriver rather than the special forked tool to tighten these nuts.

Does anyone have any thoughts about what might be wrong?  Like I said, the clutch was working OK before I stripped the engine.  I guess that I could just rebuild it as it was!

Hello. I'm using a 1971 inner timing cover on my 1967 C25 engine.  The cover came with a crude 3/8" UNC bolt to secure the non return valve ball and spring into the case. The earlier cases used a flush fitting grub screw.

I'm not convinced that the fitted bolt is correct as at 1/2" in length it is quite a bit longer than the equivalent earlier grub screw.  The Draganfly website shows this bolt as being part number 21-2044 with a description of 3/8"UNC x 3/8", but also states that they supply a different bolt which has to be shortened.  Can anyone confirm that 3/8" is the correct length?

Does anyone know what the flange thickness of the inner camshaft bush of my early C25 should be? the part number is 40-0955.

The recess in the crankcase into which the flange fits seems to be 0.0625" deep. I have 2 new bushes from different suppliers, one has a flange thickness of 0.072" and the other 0.0675".  If I fit either of these, I am then unable to fit the inner cam follower as it fouls on the protruding flange.  I have lost the original bush that I removed when I stripped the engine 17 years ago!

I am trying to use a 1970/71 inner timing cover on my 1967 C25. With only a new camshaft and new camshaft bushes fitted to the crankcase half and timing cover the camshaft rotates freely until the cover screws are gently tightened at which point it locks up. I'm considering skimming the flange face of one of the bushes to create end float. Has anyone else dealt with this issue?

If I refit the original timing cover/bushes/camshaft, the camshaft does start to nip up but doesn't lock when the screws are tightened.

When I stripped the engine of my early C25 (Engine and frame No C25-317) there were no shims fitted anywhere on the crankshaft.  The manual states that shims to adjust end float should be fitted between the timing side main bearing and crankshaft web.

The crankshaft web is stamped with "52" and the crankcase is stamped "56" below the front engine mounting lug. When I rebuilt my A50, the crankshaft and crankcase were stamped in a similar manner and the manual states that these stamped numbers show the crankshaft end float when the engine was initially assembled by subtracting the number on the crankshaft from the number on the crankcase.  I can see no mention of this being the same in the C25 manual or the excellent Rupert Ratio book. Does anyone know if this does apply to the C25? If it is, then this would explain why there were no shims fitted as 0.004" is within the tolerance for end float.

A second question. I want to use the plate glass and grinding paste method to attend to the timing side crankcase sealing surface where it mates with the inner timing cover. Can the two solid steel dowels be removed by heating the crankcase in the same way as the hollow dowels can be removed?

Thanks for reading this.

Hello.  Ref my 1962 A50.

The routing of the speedo cable on my bike just doesn't look right. The gearbox drive directs the cable straight to the off side exhaust down pipe mounting bracket. This causes the cable outer to be damaged by heat and abrasion. The cable was originally routed over the bracket but I have rerouted it below the bracket as it looks as though this is where it should go. I have wound some exhaust wrap around the cable where it fouls the exhaust bracket but this looks untidy.

Does anyone have an illustration to confirm the correct cable routing? I'm thinking of getting a new cable and running it through a length of Firesleeve where it rubs against the exhaust bracket.

Hello.  I'm finally getting around to rebuilding the engine of my 1967 C25 which I stripped down 15 years ago.  Engine and frame No C25-317, these early bikes had no provision to monitor oil pressure. I would like to keep an eye on oil pressure in future.  Amongst the many used spares that I have is a later inner timing cover with oil pressure switch. This later cover will bolt straight onto the crankcase, and I also have the matching outer cover.

The later inner cover has the wider cast web that includes an O ring to seal the oil supply from the pump.  The matching web on the crankcase half is however much narrower and will not provide a surface for the O ring to seal on. Does anyone know if the gasket for the inner cover as made for the earlier engines will seal against the later inner cover.  This gasket is missing from the set that I bought all those years ago.  I have the excellent RR book, and this suggests maybe machining an O ring groove around the oil outlet in the crankcase half. I don't think that this will work if I use the later inner cover due to there being insufficient space between the inner cover O ring groove and its port to allow an O ring around the crankcase port to seal.

Apart from the above issue, is anyone aware of other reasons why I could not use the later inner cover? I see that the machined slot for the gearbox cam plate is longer in the later cover.  If I cannot use the later cover, has anyone come up with another method to monitor oil pressure?

Thanks in advance.

I wonder if anyone can help with an issue ref the rear brake on my 1962 A50.  The workshop manual and the parts book appear to show the brake shoes fitted differently. Both shoes have the friction lining fitted for about 3/4 of the way around the shoe circumference.
The workshop manual shows the trailing shoe fitted with the lining starting nearest to the cam and the leading shoe fitted with the lining starting about 1/4 of the way from the cam.  This suggests that the trailing shoe will contact the drum first.  The parts book seems to show the shoes fitted the other way around and this is what I would expect to see.

On dismantling the brake I found that it had been assembled wrongly with two of the same shoe! If someone could confirm which of the two scenarios above is correct, I can then decide if I have two leading or two trailing shoes. Thanks.

Hello. I'm finally getting around to restoring my 1967 Barracuda. I rebuilt the engine 45 years ago and had intended to replace the conrod.  I bought a new conrod from the ex BSA dealer in Taunton who told me that it was an improved part for a later model to help prevent conrod failure. They told me that some machining would be required and I presume that this would have referred to the crankshaft flywheels. I didn't use the new rod and rebuilt the engine with the original part.

I now want to rebuild the engine using the new conrod.  I believe that my original item is part no 40-0908 and the new part is 70-9911. Does anyone know of any information available showing what work needs to be done so that I can use the new rod?

Hello.  Can anyone help me with the correct clutch cable routing on my 1962 registered A50? The bike is completely standard. I am replacing a life expired home made cable and ordered part number 68-8500 as shown in the parts book for 1963. This was superseded and the cable received is part  number 68-8593. The new cable inner length is 56" and seems to be about 8 or 9 inches too long.  I just cannot seem to come up with a sensible routing to loose this extra length.

The frame number is A50 5090 and engine number A50 1457.  Is there any way that I can confirm date of manufacture?

Thanks

Hello. I am replacing the alternator stator on my 1962 A50. The cable has to route through a tube threaded into the left side crankcase. The original stator had 3 wires which easily passed through this tube and these were sealed onto the tube with a rubber sleeve. The new RM21 stator has only 2 wires but these are enclosed in a pvc sleeve which is secured with heat shrink tubing at the terminal ends of the wires.  This arrangement has too great an O/D to pass through the tube in the crankcase. What have others done to overcome this? I'm considering carefully removing the pvc sleeve, what do others think?

Hello. I am hoping to improve the "Designed in" oil leak on my 1962 A50.  I have tapped the breather outlet to 1/8" BSP, and intend running a pipe or hose from there over the gearbox mainshaft boss and out through the rear engine mounting plates.  The only decent hose that I can get to fit is 1/4" R6 oil hose.  My concern with this is that this could be too small a bore size that might create excessive back pressure.  Does anyone have a view on this?  My preferred option is to use a copper or "Bundy" pipe.  I've tried to fit 8mm O/D tube without success as I cannot get an 8mm compression fitting into the limited space available.  Again, I wonder if this size of tube would create excessive back pressure, so would not want to try to fit smaller tubing.  Am I being over cautious and over thinking this?

Hello.  I really would like to finally get my 1962 A50 sorted so that I am happy with it.  It is in standard trim with the 17 tooth gearbox sprocket and the bike just feels uncomfortably busy at anything over 50 mph.  I live in flat North Wiltshire and will only ever ride solo.  I am quite happy to cruise at 50, particularly as it only has the 7" front brake, but I would like to reduce engine RPM at that speed.  Does anyone have experience of using a larger gearbox sprocket?  I see that there are 18 and 19 tooth sprockets available as well as the standard 20 tooth sprocket for the A65. I guess that if I did increase the sprocket size I would also need a longer chain.

Hello. I have recently converted my 1962 A50 from 6 volt positive earth to 12 volt negative earth. I fitted 12 volt coils, a solid state regulator/rectifier, an AGM battery, new HT leads, new spark plugs and I made a new loom to suit.  The bike has slowly developed a persistent misfire.  It starts easily and idles nicely but misfires under load.  I am convinced that it is an ignition fault. 

If I flick the points open with the ignition on I get a weak yellow spark across both sets of points.  With the engine running I get a strong blue spark across both sets of points. To me this suggests a problem with the condensers, but they are fairly new and have only run for about 300 miles. How likely is it to have both condensers fail? Are condensers sensitive to polarity?  If so, I should have fitted new condensers suitable for negative earth.

Any advice would be much appreciated.