02-apr

As the hose at work is out of action I haven't been able to wash the bike today so am working from memory a bit. I think all the screws on the casing can be removed but, as I want to renew the pump bearings, has anyone managed to remove the casing without dropping the sump guard - can it be wiggled past the rubber protection sandwiched between crankcase and sumpguard? As the guard is now a lot more bent than it was when I last removed it I anticipate even more of a battle to get it back in position. Thanks

I hope they've registered that under the Scottish Register of Tartans Act(2008).

From the discussion on the other topic I assume that by fitting Cub hubs you hope to increase your chances of "getting in" next year Ross!

This is one of those rare occasions when the oft used mechanic's phrase "They all do that Sir" is actually true.

Most likely the Woodruff key positioning the flywheel on the ignition side has sheared resulting in the timing having slipped. With your racing experience I won't insult you by explaining further as you'll be easily able to cope with such a repair.

I can't help but think that the mineral, but particularly the semi or fully synthetic, oils now available will be far superior to what was available to the guy who wrote the manual for the 349 back in the day so it may be possible to run leaner oil ratios with no ill effect on engine life. Of course this would result in a slightly richer mixture as far as combustion is concerned and, as the 349 never seemed to be the crispest running of bikes, some rejetting could be required.

Can't say I agree with you Zippy. My 200 Beta has at least as much bottom end as the 250 Yam that preceeded it and will pull high gears if required (I've used 5th in a slippy section before now) and seems to be a grip manufacturing machine over the moors. It would be hard to imagine a better bike for a beginner. The 200s are after all derived specifically for the sector of the market that wants this type of performance as the target audience does not want the zippiness of a 125 but does want the perceived lighter weight of the small motor. But let's not get involved in a discussion about rotating mass.

It's been a decade or two but I seem to recall starting with the system facing backwards and threading the pipe through the downtubes then twisting it round, or vice versa.

As far as I can tell (from having them round me at trials) all the "modern" 80s are horrendously noisy - it's really just a massive (compared to adult bikes) expansion chamber with not a lot on the end to quieten it. The TY may be equally loud on a meter but it is certainly far less piercing to the ear, perhaps it does not rev quite so highly. In short I think you're stuck with it as is.

Michael you sound as if you are as fussy as I am about these things but I long ago gave up worrying about this with trials bikes because I have never found one where everything lined up properly and the other forces (rocks, camber etc) trying to put the bike off line are, at trials speeds, greater than a wheel being slightly misaligned. Tyre wear isn't really a factor at these speeds. A twisted swing arm was very common in the old days and most folk didn't feel the effect of the off-vertical wheel. I usually just try and get the chainline right by sighting along the chain - nobody actually believes the swingarm or snail cam marks do they? - and live with the resulting wheel alignment (unless it is really bad when I might go half and half) as the wear on the chain is probably the biggest effect of misalignment. Even Japanese production tolerances aren't that great. I wasn't happy with the tyre wear on my then new SV 650 and knew that the chain line was not perfect. I never had satisfactory results using string but when I finally found a good reliable straight edge (fluorescent light tubes, advice courtesy of Kevin Cameron who will not be unknown to you) I discovered that with the wheels correctly aligned (and sharing a common centreline) the sprockets were parallel but offset by 8mm. Measuring the shoulder on the outside of the rear sprocket showed it to be 4mm so reversing the sprocket such that it was on "the wrong way round" cured the chainline problem. Given that the motor really had to be in correct relation to the frame and the chance of the rear hub being "too narrow" was nil then the real cause was a mystery. Interestingly later batches of the SV had no shoulder on the rear sprocket - so presumably only run 4mm offset with no means of correction (I haven't had the chance to measure one to see).

"Did you ever see any clarification from SM on why he thought that? I can't think of any reason why having the wheels out of line could be of a benefit, unless maybe you were doing flattrack/speedway and wanted to bias things in the only direction the bike ever turned." Michael, out of line was not mentioned. Out of line means pointing in different directions whereas offset means running parallel but on different centre lines. The article (and I'm not going to go through the pile of period publications in the attic to check) said, if I remember (and it has been the topic of conversation over the years so hasn't faded too far from memory), essentially that having the wheels offset gave a wider base on which to balance. I'm not saying I necessarily agree with this or that the small measurements involved in this context would make an appreciable difference but SM was probably better placed to appreciate the subleties. He must have had something right in his ideas as I recall him saying in the last few years that the wheelbase and steering head angle of a modern Gas Gas were the same as the original SHS on which he rode his first SSDT. Only forty years or so of development to go full circle.

"Never manufactured nor was the KTM. Both developed by Scottish regular and mate of Big Johns Walter Luft." OK then I'll be cheeky and see your "never manufactured" and raise you an "Edgar Brothers", an Edinburgh dealership who converted an M125 Puch road bike to trials spec(I wonder where it is now), or is one too small scale?

Leaving aside any production quality problems you refer to, the Sherpa was designed by Sammy Miller who expressed the opinion at the time that a trials bike was easier to balance if the wheels were slightly offet. That being the case it was designed such that the offset needed to accommodate the chainline was not seen as a problem and the wheels do not share a common centreline.

Well you are the right weight for a 125 but I would suggest that the power characteristics won't be appealing to you (I'm from essentially the same era as far as riding style goes)with a 200 being much better, much like an old fashioned 250 in my experience. I doubt whether you'll find one though as they are British market only as far as I am aware.

"ACU Approval" is not required for trials, merely of a standard to meet the rules; which means approved for road use (regardless of whether the trial takes place on road or not) so you have a compliant helmet.

As far as I can tell from riding, observing and spectating a fair few riders still seem to expect to be allowed to stop under no stop rules, I suppose the stop habit is so well ingrained in them. I know how it feels as I never really got to grips with stopping - if I got in to trouble my instinctive reaction was to keep the thing moving rather than stop and compose myself. From spectating at major "stop" trials I would dearly love to know if anyone ever gets a five. No matter how bad the performance, unless bike and rider actually part company, they seem to get a three at worst. I'm sure I would become unpopular pretty quickly if I was observing at these events.

I understood, from articles on here a while back, that Spain had undergone a complete changearound and that it was now illegal to ride a bike more than a very short distance from a public highway. Can anyone confirm that?

Judging by the number of Betas advertised with newer model plastics I would say that mudguard colour is not a reliable way to identify year.

I imagine the bigger tank on the Rev 3 might be advantageous in certain events. Also there's no rear linkage to wear out.

Thanks for the info hrc, they don't publicise them well enough.

I have found over many years that the best way is to put some masking tape on the bar to give a grippier surface and to increase diameter to suit the particular grip. Lubricate grip with electrical cleaner or similar that will evaporate and not leave any residue. I've never wired grips on having seen too many cut thumbs in the old days when we rode gloveless and folk left the end a bit untidy. It beats me why we still have this problem as the mountain bike guys sorted it years ago with grips that clamp on. I'm surprised nobody has done this as it has to be a way to make money by selling different colour clamps to the sort of people who bother about such things - which seems to be a fair proportion of riders judging by the "bling" that appears to be in demand.

It needs a bit of care. Long ago two pals tried the air pressure method and ended up with a pair of wings instead of a tank.

The last time this came up in conversation with an ACU club secretary the document ran for a year from the applicant's birthday - a very sensible idea which both gave the competitor good value and, just as importantly, spread the load and avoided the situation some other licence issuing authorities experience when the entire cadre applies at one time close to the festive period.

Well I've checked and, interestingly enough, the only definitions of helmets in the ACU rules pertain to speed sports. For trials the requirement is, as said above, a completely undefined "motorcycle helmet". If someone sells me a bicycle helmet with a "motorcycle helmet" label on it does that make it a motorcyle helmet as far as the ACU is concerned? Cue argument with scrutineer. It looks like the SACU has been farseeing and has nailed things down to prevent any legal problems.

I will check the formal publications when I get home but I run under SACU rules (they send us the ACU rules as they have adopted them) and the SACU website says with reference to trials "Helmets, which must be in compliance with the Road Traffic Act, must be worn by riders at all times when riding the machine". I can't see why they would meddle with ACU rules on this point.