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Messages - AWJDThumper

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46
Bantam / Re: D7 Restoration
« on: 07 April, 2018, 11:07:29 »
Hope you enjoy restoring your Bantam. Having fun restoring my D14 engine at the moment - I was brought up working on these two strokes but am having to re-learn the art. The main thing I notice is how fragile the die cast engine casings are compared with the normal sand cast 4-strokes ones found in other BSA's.

47
The Star and Garter / Re: A "new" Spitfire at last
« on: 07 April, 2018, 09:34:02 »
I know exactly what you mean about the Spitfire and well done for getting one. I can still vividly remember seeing one perform in deepest Wales 40 years ago and have lusted after one ever since. Haven't got one yet but it is second on my list after a Goldie :)

48
Twins / Re: Clutch slipping ??
« on: 07 April, 2018, 08:49:33 »
You'll need a clutch locking tool in order to tighten the rotor nut, especially if your clutch slips. The best locking tool also has an arm attached which enables you to also stop the clutch from rotating. If not then you'll need to put the engine in gear and lock the drive sprocket using a chain attached. I normally lock the chain by allowing the chain to jam against the engine casing but this is not always ideal.

49
Singles / Re: Running in troubles - engine fade
« on: 07 April, 2018, 07:25:52 »
I would check all the settings again but I would definitely check out the carburation and make sure there are no blockages of the fuel flow from the petrol tank. You mention that you had to play around with the carburation but have you got the standard set up inside the carb and with the air filter?

50
Singles / Re: Rockerbox breathing
« on: 06 April, 2018, 17:53:28 »
The camshaft breather works well on the smaller unit singles provided the exit from the inner cover is not blocked. The engine's going to force out 350cc of air through the breather every time the piston descends.

51
Singles / Re: B40F sump ball valve
« on: 06 April, 2018, 14:46:09 »
Yes - the scavenge pipe is on the LHS built into the oil pump.

All the scavenge valve does is to stop oil draining back into the sump from the return pipe to the tank - 50cc at most? You definitely, don't need to worry about the oil pump gears drying out. Even when dry, it'll still suck up oil from the sump once the engine starts to run.

If there is no ball bearing present in the scavenge pipe, all this means is that you have lost the NRV function which only comes into play when you turn the engine off - it won't affect what happens when the engine is running.

That said, I would be a bit concerned to know what has happened to the ball bearing. It's probably 3/16" in diameter but is it possible for this diameter of ball to have fallen out of the end of the scavenge tube?


52
Twins / Re: '71 A65L valve timing
« on: 06 April, 2018, 14:27:57 »
If you measure both the opening and closing angles for the fitted inlet valve, this should be sufficient to confirm whether the camshaft timing is correct, provided you do it at 0.015" gap. Once confirmed, this should then mean the timing will be correct for the other 3 valves. If there is a problem with valve timing, then this will need to be investigated but doesn't need the other valves to be fitted in the meantime.

53
Twins / Re: '71 A65L valve timing
« on: 05 April, 2018, 21:06:03 »
Do you know which valve hit the piston, originally? For the inlet valve that's in the engine, have you measured the angle at which it closes at 0.015" gap or does this one hit the piston?

54
Twins / Re: '71 A65L valve timing
« on: 05 April, 2018, 18:27:15 »
Have you measured all the valve timings (x4) at the specified 15 thou gap? That way, it's easier to make sense of what's going on. My experience of measuring numerous sets of valve timings in the past is that they have always been inline with the specified settings, at least, within the achievable measurement error.

55
Singles / Re: tips? - fitting tight oil pipe
« on: 05 April, 2018, 17:58:49 »
I measured a set of feed pipes earlier and their nominal diameter is 5/16" showing that the 5/16" ID tubing shouldn't be that tight a fit.

56
Singles / Re: tips? - fitting tight oil pipe
« on: 05 April, 2018, 16:50:26 »
The pipe should be 5/16" ID and will be a moderately tight fit on the pipes emerging from the engine.

57
Singles / Re: tips? - fitting tight oil pipe
« on: 05 April, 2018, 11:07:28 »
Which pipe are you having difficulty with? Normally, with the correct size tubing, it should be a tight fit but not that difficult to push on without the aid of lubrication or heat.

58
Singles / Re: C15 Valve Guide
« on: 05 April, 2018, 06:42:53 »
You can get +5 and +10 thou oversize from Dragonfly but they might need to be ordered. Normally, I take heads to my local engineering firm to get valve guides replaced and seats machined at a reasonable cost.

59
Bantam / Re: D7 Restoration
« on: 04 April, 2018, 15:43:28 »
Fortunately, my wife gave up trying to stop me buying motor bikes a long time ago providing I don't encroach on her garden. :)

60
Singles / Re: Scavenge Valve Replacement
« on: 04 April, 2018, 15:35:53 »
My scavenge valve arrived today. Basically, the bottom half consists of a tube which is smaller in diameter than the ball bearing while the top half consists of a tube which is much wider than the ball bearing. The ball bearing is retained in the wider tube by a ~1mm bar through the top of the valve which can just be seen in the pic. The bore is blocked when the ball bearing falls down under gravity and is opened by the oil flow sucked up from the sump by the oil pump.

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