2stroke4stroke

Can we have that one on a postcard instead of on the stamp?

Blocked exhaust perhaps?

Well Dad, after the stick you've had on here (some of which amounts to personal abuse and would have seen the perpetrator barred from at least one other forum I read), you must be having a wee smile to yourself when your opinion on gearboxes seems to have been vindicated in GasGas 249's latest interview.

Thanks Martin - no switch gubbins on mine, though it would have had, so I'll proceed on the basis of the diagram.

You're right Baldilocks, t'ain't a Honda. Thanks ourian, I know the principles, I've done enough of them over the years. There's usually a bullet connector or other means of getting the cut out wire in to the system. The standard electronic ignition on the SWM has several wires coming up from the generator bound together in a sealed outer which enters the back of a multipin plug which has a well sealed joint to the coil with no obvious access. I had hoped to get the SWM specifics from someone as I'm sure they must have had a cut out when new and I certainly don't want to have to use destructive access, even if I could tell which was the right wire. Being electronic there's no way of taking a wire in at the points.

Does anyone know how to wire a cut out button on the TL 125? The wires to the coil end in a multipin connector with no obvious way of introducing a wire. Any advice appreciated as, apart from the stuck throttle scenario, I'm getting fed up stalling it every time I want to walk a section.

As Rolls Royce would say, "adequate". But I assume you're wondering in the context of 31 bhp claimed for the Vertigo. I imagine if the Ossa differed significantly from the low twenties quoted for a Gas Gas the last time I saw a published figure for a modern bike then they'd have shouted about it. For what it's worth, the original Sherpa claimed 18 bhp if I remember correctly. There's a good reason why bhp figures have not (until Vertigo) risen much and it's to do with rideability, though with World sections now bhp may be more important than the old days when it was torque that counted more in a trials bike. I can't recall a posting asking how to increase the power of a bike but there have been plenty along the lines of "how can I detune my XYZ?". Which makes one wonder how much of a sales point a comparatively large bhp for a new bike will be in the mass market.

The original Mk2 exhaust was a primitive expansion chamber with a steel bomb shaped tail silencer with a bayonet QD fitting and was very quiet for its day. Try running without the tail silencer, as per the Mk1, and you'll find out what a noisy bike is really like. I assume it's just the Miller tail silencer you have so an original tail silencer would fit but the chances of getting one are slim though I daresay there are a few lying under workbenches.

Of course you could just put the motor in a Bantam frame. With the right exhaust it even sounds like a Bantam. The one I've seen does anyway.

Presumably Bultaco wanted to keep the thing quiet (and it certainly was) hence the weight. Back in the day one of the guys wanted to make a silencer for a special he was making and used the work facilities to x-ray a clubfoot. Seems there's a lot in there.

Petrol tank breather may be blocked. Take cap off next time and see if it restarts.

Try dragging the brake to get it hot then spray water on it. Easier than fitting new pads. May need to repeat.

Ah, "woods". Take heart, I'd suggest that an easy woods section is probably harder for the beginner than an equivalently easy rocky section. As well as all the balance and use of controls you probably also have to find grip whereas that's usually less of a problem on the right kind of rock section. Thirty-odd years ago, during the Bath Two Day (regrettably no more), we were trying to persuade a Centre champion from the south west area that he should be doing the Scottish, so impressed were we with his ability to find grip, but he thought rocks would be too hard. Our opinion was that if you can find grip in "English" mud and woods then rocks are easy to adapt to compared to going the other way. Stick at it.

That looks like an early 125 (the hubs are the giveaway but there could be any mix and match at this age) with a later tank. Try, gently, using kitchen cream cleaner, which is midly abrasive, to clean the tank. I used it with good results to clean trials bikes when they had proper plastic components on them unlike the painted ones of today. I think the paint is put on to give an extra layer for strength :-)

If you think that one's erratic you obviously haven't tried an original one :-) A normal 700c cycle wheel is close to a 21 inch front I think so the scale does go that far up. If you measure how far the wheel goes in one revolution using the valve as a reference point you can plug that in to the computer. Most instructions detail how to do this.

It's interesting how opinions/preferences can vary. I had a KT at the time and the really soft suspension was a good point, to me, and, as you say, the brakes. However I couldn't get on with the lack of flywheel weight (compared to what we were used to with Bultos etc). Also they didn't really run too well at higher revs, suffering detonation etc (this mattered in those days as most trials had roadwork), and the Alec Wright suggested remedy of removing the outer electrode of the spark plug had no effect beyond demonstrating what a powerful spark the system produced. It would not be fair to comment on performance in the sections as it had the Japanese tyres and I wasn't keen to spend on proper rubber given the other problems and didn't keep it long. Kawasaki UK commissioned Napier College in Edinburgh to do some work and I rode an early version of that without knowing the mods, other than an Amal carb, and don't recall much difference. I think the bike ended up somewhere over 300cc but I suppose the demise of the KT prevented adoption of any improvements. That bike still exists in a shed up here. I always thought that all Kawasaki had to do at design stage was copy the porting etc from one of the Spanish bikes but, hey, that approach didn't work for Italjet :-)

There is a less conventional way to remove a flywheel:=) In the day one of the guys messed up fitting a throttle cable and when the revs soared the ignition flywheel disintegrated and took part of the crankcase with it on its way through the wing of his dad's van.

I wouldn't worry too much, it is Spain we're talking about after all. It was the same when I was waiting for an Ossa in 1974. Manjana rules!

Apex, I've been trying to PM you without success - could you please PM me?

I remember that well. It was the first time I observed at the Scottish but I struck lucky that day as I drove the back marker's car up for him and so avoided the worst effects of the snow.

That's because it is "Beeta". You'll be telling me next you didn't know the ancient Greeks had trials bikes

Do I foresee a Wobblers time and observation event Allan? It's been forty years since we had one in Scotland as far as I can recall.

I suspect you've got access to good chemical stuff we can't get nowadays. The best degreaser spray I ever had was of South African manufacture, Spanjaard if i recall, but I'm sure it would kill small mammals if they got a breath of it.

You really are a glutton for punishment Allan. Or are you just trying to mask your considerable riding ability.

Unless the dish is so far out that you are having to put the wheel in squint to avoid the tyre rubbing the swingarm then the offset is not the problem. Trials bikes, unlike road bikes, are not necessarily designed to have the wheels running on a common centreline. No matter what the offset the wheels would run parallel when so set. That said, build quality being what it is, it can be necessary to have differing "clicks" but usually only by one or two. If you sight along the chain then you can tell when the sprockets are in line which should mean the wheels are in line, but not necessarily. For trials I'd say the chain alignment is more important than a small difference in wheel alignment (how often do you have the wheels in line in a section?). You may need to find a compromise position between chain and wheel alignment.