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As usual, click any image to zoom in.

Luigi convinced me that it would be a good idea for him^H^H^Hme to set up this blog so that we would have a record of the work we have done on our bikes for our future reference.

Seven months in and the blog has had hits from a fair part of the globe - I hope they aren't all because of those "VIAGRA" meta-tags I've been sneaking into the pages.

Torque settings

Mark saw something yesterday on a web site along the lines of "When you replace the cylinder head, it is necessary to tighten the bolts to a predetermined torque. For the C15 it is 28 ft/lbs"  which I am sure is very true. In fact, how could it be more than merely true? But I digress.

You can read yourself silly worrying, but I can remember in my day, when the world was in black and white, nobody used a torque wrench.  They probably never heard of one and certainly couldn't spell it.  

If you under-tightened the bolts the engine leaked and as long as you weren't a total moron you didn't over-tighten the bolts and strip the threads.  Everybody's bike worked... Simples.

Having said that, I know someone who claims he rode his bike with a loose dizzy and noticed his exhaust pipe actually glowing one Winter's night and ended up blowing more big-ends than he cares to remember...

New head gasket

As usual, click any image to zoom in.

It’s been sunny for weeks and today it decides to rain. At least we were able to work in Mark’s garage while we replaced the head gasket on his C15 to try to cure the oil leak.

It seems a little better now in that the top of the crankcase and the vertical part of the exhaust pipe are now dry, but there is still a leak from somewhere putting a light film of clean oil on the front of the gearchange rubber, the bottom half of the crankcase (below the gearchange lever) and the vertical downpipe of the frame on that side.

RTS engine quote

The bill for my engine rebuild will be £850-900 ish. That includes new alpha big end, main bearings, rebore, new piston and rings, valves and springs etc, plus cams and larger inlet valve.  I'd hoped it would be around £750:00 but I suppose the cam and inlet valve modification are worth the extra.  I see no point in doing so much work on the engine, knowing that the head needed sorting out, and not completing the job properly for the sake of £150:00. 

At least the bike will be up to spec apart from the front forks and indicators. We can then fit the indicators and put some oil in the forks and see if any oil leaks and, depending on how fast any leak might be, that will help me decide whether to just keep topping the forks up, or consider having the forks repaired!

Speedo bracket

As usual, click any image to zoom in.

Mark has managed to find a speedo bracket for his Smith's speedo so that will have to go in soon to replace the myriad cable ties!

Engine rebuild

As usual, click any image to zoom in.

After a few people taking a look at my bike and saying it sounded OK to ride, I could still hear a knock so we took the engine out and the head off. Lo - the conrod was waggling about when you tried lifting it.

Not fancying trying to repair it ourselves, we found Roger Taylor of RTS Racing while searching on ebay for some spare parts. We dropped the engine off with him today in Gloucester and he reckons that even though he's really busy at the moment, he can turn it round in 2 or 3 weeks.

On another note, Roger explained that the oil return on my other engine sounds fine because the return flow rate is higher than the inbound flow - this is why the initial return rate after starting the bike is excellent but then settles down to a slower rate, even with the odd bubble.

BSA C15 lubrication

As usual, click any image to zoom in.

If I start my bike up then the oil return is healthy for a few seconds but then reduces to the odd spurt, blowing big oil bubbles. If you turn the engine off, wait a minute and try again, then the same behaviour occurs. This would seem to point to the oil pump being OK, especially given that it is not wet sumping.

At first we thought it might be a problem with the return flow of oil but we're now beginning to suspect that it might be that the oil isn't flowing into the system quickly enough. Hopefully it is not the feed non-return valve as that means splitting the crank cases and replacing it.

There is a good description of the lubrication system on the Classic Bikes web site: