trapezeartist

So not everything is bigger in America, then.

I don't understand this either. Clearly there is a lot of pumping going on in the crankcase of a single cyclinder 4 stroke. A volume equivalent to the swept volume needs to be pumped in and out of the breather every stroke. If the breather isn't big enough there will be a fluctuating pressure in the crankcase. Adding a one-way valve simply means that the breather flow in one direction is enhanced. I can see this being a benefit for stopping the engine pumping oily fumes out through the breather, but I don't see what it does for engine braking.

Buck is slang for a dollar. A quart is an archaic measure of liquid quantity, along the lines of furlongs, firkins, poles and perches.

Any good?

If you suspect the tapers are not as good as they should be, lap them together before finally re-assembling. Leave out the key, smear som grinding paste on the shaft taper and then oscillate the flywheel on the shaft. After a few seconds of that you can wipe the paste off and inspect both tapers. If they're a nice even grey, the job is done so just get on and assemble. If not, put more grinding paste and work away until you have got to near 100% contact between the two tapers.

Is the 4x4 on the short wheelbase or long one?

Countyist! Drifting off the subject slightly, but if world-class or even national results could show us the hierarchy of the "best for an expert" trials bikes, I still suspect that the hierarchy of the "best for a clubman" trials bikes might be very different.

Citroen Berlingo or Peugeot Partner seem to be the obvious choices for a bike-carrying van. However a lot of the older/cheaper ones are in an awful state as they seem to appeal to builders. I've noticed a few nice Renault Kangoos advertised which look to be in much cleaner condition. Perhaps they appeal more to flower shops and the like. Has anyone used a Kangoo? Does a bike (just one) fit in OK?

That may or may not be true. But if Tony Bou won a trial this weekend with a banana stuck in his left ear, we'd all have a banana in our ear next week.

What's the engine?

Wakka, it's just a wild guess but I think he might be in Dumfries.

Purchase valve cores? I thought you just had to pick them up off the floor at the local tyre fitters.

I'm pretty much a newbie too, and I've yet to buy my first bike. Some people advised a 125 to start out and others advised a 250. The one consistent piece of advice was to avoid anything over 250. I rode a 200 Beta at a trials experience day and it was entirely manageable. I could imagine that with a few more goes I might occasionally be wanting a bit more oomph, so I will be buying a 250 almost certainly. If the right 200 came along I would be happy with that, but it seems unlikely because they're up on the same shelf with hen's teeth and rocking-horse s**t.

The double gearlever looks a bit unnecessary. And the humungous rear sprocket might be vulnerable. Surely there's another way to achieve suitable gearing.

This is something that has really surprised on me return to trials: the obsession with bling. Sticker kits, wheelrim stickers, colour-anodised bits and pieces, fork protectors, frame protectors......... For god's sake! It's going to get covered in mud and thrown in amongst rocks.

Mud, mud, glorious mud! There's nothing like mud for cooling the blood.

I thought Kickstart was recorded at Easton Neston (Lord Hesketh's estate).

I recently fired up a little petrol genny that had been lying under the bench for several years. First pull, and a large and very surprised spider flew out of the exhaust.

Yes, that is a description I could happily live with. Fortunately I think my daughter has thought of me that way ever since she was about 5.

Really I think we're both on the same wavelength. It may work, it may not. It's just that your glass is half-empty and mine is half-full.

I raced karts from 1976 to 1980 and again 1996 to 2003. In this country I think the classes for industrial engines were dropped around the late 60s. (Honda 4.5hp industrial engines are used for arrive-and-drive commercial circuits.)

Breakheart have a system of self-observing when there are no observers available. Each rider has a punchcard; there's a punch-gun at the end of each section and riders mark themselves. Yes, they could cheat of course, but they'd be only be kidding themselves. Seems a good system to me for a low-key evening trial.

It looks like there was plenty of thought given to combustion chamber design in the 50s and 60s (http://myweb.tiscali.co.uk/speedex/index_files/Page2476.htm) but this is all backyard development of a pre-war design. Direct injection and stratified charge would open up all sorts of possibilities, though the development costs might be somewhat beyond a company like Gasgas or Beta. It would take Honda to have the resources to play with this stuff, and they wouldn't do it just for trials.

Agreed, jonnyc21, but side-valve development ended in about 1939. Since then fuels, materials, lubricants and design ideas in general have moved on a long way. I do think there's enough potential in the idea for someone to give it a go. I'd give it a 90% chance of being a success.

Brilliant piece of lateral thinking. Modern instinct would naturally think of OHC, yet the side-valve is ideal for trials: light valve train, low engine height, low C of G, revability will be adequate, ditto compression ratio. What's not to like?