woody

Early 250 Sherpas had the double weight, then they went to the single weight but not sure when, maybe '75. The 250 198B uses the lighter Pusrang weight on a single row cog, really picks up quickly.

You may have the best of intentions Spud but your rules can be easily exploited. In addition they do nothing to keep a level playing field of bikes in original Pre65 trim, which I believe, was the intention? Modified forks in the original class??? So if you have the money to pay someone (£500) or the machining skills to do it yourself, you can have a set of roadholder bottoms with modern internals, or even machine or cast your own new replica bottoms to take modern internals. Meanwhile, Joe Average with little money, no machining skills, is stuck with the original and utterly ineffective forks. You say it's for practicality but I see nothing practical about it. Surely it's the very thing you're criticising? And, it's where it all started back in the late 80s as forks were the first things to be modified (and disguised) You're allowing the people that can, to create modern exhausts, airboxes etc. If they are fitting alloy rims then whilst they're at it they'll fit replica alloy Cub hubs to lace them to and pain them black - that's running to £1000 a pair of wheels. Practical or just favouring the man with money or engineering skills? I can't see the difference between that and what's already happening. Joe average ends up in his original bike, someone with means and the desire to do so ends up with a modernised machine, superior in many respects, at a hefty price. Unless you have a scrutineer that is able to virtually dismantle certain components, there is no way your rules will stop modern parts being used. This is why they are now accepted. Because back in the 80s, when the modifications first began with the advent of the Sebac series and the increasing popularity of the Scottish, there were some very good riders (ex champions and world round and national trial winners) taking part - far removed from the disgruntled band of average club riders who formed Pre65 10 years earlier. They were still very good riders and just as when they were factory or supported riders they had a very strong will to win. Many had ridden genuine Pre65 bikes in that era but had experienced much better machinery in the intervening years. Better components were now available but obviously not allowed - yes, there were rules back then, just the same as yours are now in terms of what components could be used. These riders wanted the best machinery, just as they had benefitted from in earlier times. They had modern internals slipped into their forks. The forks looked standard but anyone with a bit of nouse could see they actually worked up rocky sections as opposed to the pogo action of the standard items. Then they wanted the engines better, so internal mods began on those. Then exhausts. Then the clutches and ignitions. All disguised in standard casings The bikes back then, late 80s, early 90s, still looked pretty well standard. How would any club official prove that illegal internal mods were being made using modern materials without taking components apart. Who would have time to do this and which rider would sit there and let someone dismantle a bike before the start of a trial - or at all... Then the quest for lightening the bikes began with replica frames. The frames were then modified to give better geometry but that's not exactly easy to spot. 'Ordinary' riders with money to spare or machining skills of their own began modifying their own bikes, or bikes of friends. And so it went on. So how can you blame any club or organisation for this? How can they be responsible? The rules were there, it was riders who bent them and there was little a club could do about it. The same would apply to your proposed rules and the rules originally drafted by Deryk. So what do you do? Follow what happens in other motorsports and have all competitors report for scrutineering the day before the trial in order that a team of expert scrutineers can thoroughly examine every bike, including removing components where necessary (a condition of taking part) and then where appropriate, move any bike they deem ineligible to the specials class? Unworkable with people having to stay overnight in accomodation for the event the next day, meaning two days away, increased costs and where does every club get this team of expert scrutineers? The 'problem', if there is one in Pre65, is that there are very few riders left now who rode these bikes in their era, that aren't below their late 60s in age. As has been mentioned before they can't or don't want to struggle with a big heavy bike any more, They want to go out and enjoy riding a modified bike. Hence the popularity of lightweight Bantams now. The remaining (most of) Pre65 competitors now have streamed through from late 60s and the 70s which was a different style of riding with harder sections (although some of the video I've seen of some earlier trials from 60s, I wouldn't call them easy) These riders don't really want a section that is akin to riding up a green lane. Neither do they want British Champs style severity sections. They want something that provides a challenge and that's why it has evolved like it has. It's just evolution. If the riders are still out there who want to ride a standard big thumper over traditional sections, then why doesn't someone put a series together and make it clear what it is for - Completely unmodified bikes. It's been done for twinshocks this past year so why can't someone do the same for Brit thumpers and create a series for unmodified bikes if the demand is there? Leave the rest alone, whether you or anyone else agrees with it or not, what's done is done and can't be reversed, the bottom line being being more people seem to prefer riding the modified bikes than the standard version - So did Sammy... I was watching a video of the Ilkley grand national recently, from sometime in the late 50s I think, and it was very difficult. Big rigids stuck up to their engines in mud with their fit young riders struggling like hell to free them. Riders, again fit young men, being bounced all over the place up rocky tracks which were just lanes. These were what are now referred to as traditional rather than modern sections, but show me many 60 to 70+ year olds who who are the riders from that era, who would want to ride a big bike like that at their age.Many? There is more than one reason they've been modernised

This is an M92 weight This is from an M49 Looking at the M92 weight, it has a more square edge than I remember but without seeing the weight from a later bike I can't remember how different they may be now. All I can remember is that when I tried to fit a casing with to an engine it fouled on the weight - but I can't remember which combination of case / weight it was now... not much help unfortunately.

Reason I mentioned it being a 91/92 is because it has a couple of features introduced on that frame. The frame is recessed where the spindle nuts locate, M49 is flat for the bolt on plates. It has the oiler in the swingarm and the headstock gusset is different from the M49 Not picking holes in it, just an observation

If it is the big double weight it will be the same as the 325 Sherpa, or 250 models from around '68 to '70 The thing to watch out for is the profile of the outer edge of the outer weight. There are two types, one has a flat, sharp edge, the other is rounded off. If I remember correctly, the weight with the sharper edge will foul the inside of the earlier clutch case - ie: the one fitted prior to 1975 that was up to the M150/151 which had the later style case.

Mentioned in my earlier post but essentially, observer at last double sub in second group (I think, where we rode down a track with a new wall on the right hand side and sections were the other side of the wall) blew his stack at me after I replaced a log that was being used as a section boundary. A sidecar had run over it and moved it so I was putting it back, observer thought I was moving it to my advantage probably, and was yelling his head off at me which got me a bit riled so went to explain. He was ok about it but was pretty well steaming with riders trying to go beyond the section boundary at the bottom turn before the last climb out, basically out of the section to get a better run up the climb. It was pretty obvious where the section was intended to go and the tyre marks also gave it away, but there were no blue markers on the trees which formed the boundary, just the log which had got dislodged by the sidecar. I thought it was strange there were no markers as all sections were marked pretty clearly, but not this one. He then explained that there were markers originally but they had been removed by a rider or riders. He put the log across as a makeshift boundary. He was bloody fuming and to his credit was taking no crap from anyone. Anyone that went too wide was getting a 5 and they got no change out of him if they contested it. Could do with more like him, good lad. So, either the markers fell off all by themselves or someone took them down. They were there when the observer arrived and were there when my mate rode it early on, but there were none when I got there.

Yes, can see the yokes clearly now, I thought the bar mounts were missing in the original photo but can see what they are now. The bottom yoke is very similar to the mid 70s 250 Sherpas Now I can see more of it, your white frame looks more like a model 49, maybe a 27 but never seen a 27 frame, most likely 49. Rear shock top mounts match positioning of series 1 49 but picture not clear in that area so can't tell if modified or not. I think probably original. The rear sidepanel mounts aren't original, they've been added to take the slimline tank/seat unit mounts. Rear mudguard mount matches 49 type. Bolt on footrests are 49 type (also fitted to 80 but the frame headstock gusset is 49 as it has the mount for the rubber top hats either side. Your 49 model in the background is an M91/92 series 1 frame, not 49.... (not that it matters)

In respect of different weights and crank balance, I can't answer from an engineering aspect as I don't know. I've not had any issues swapping them from one bike to another, that's about all I can comment on that one As for the weight suitable for your bike, I don't know as the Alpina 350 is a longer stroke and bigger capacity than the big Sherpa, and I've never ridden one. I've no idea what the power delivery is like, whether they have any similarity to the 325 Sherpa, so I can't even make a guess as to the effect of different flywheels. The Alpina is a trail bike, different gearing from the trials bike, so not sure what it would be like in trials sections, especially more nadgery ones.

I wondered if it had been machined down but the holes threw me. Never thought they might be to balance it. I tried machining a Sherpa one down recently. Nothing came off it and I just got a squealing noise... Pays to know what you're doing I guess before trying to machine what is probably case hardened (what ever that means) metal...

Can't tell you if that's the right weight for an Alpina as never had one, but on the Sherpa double weight, the inside weight is welded on. I have one that the weld has broken on and it's in two pieces like yours. Can't see any trace of weld in your pictures but maybe that's what's happened. If the inside weight was loose then it could have caused vibrating which may cause a problem with your crank and may give an air leak through the ignition side seal? A 250 Sherpa weight looks as though it would be about the same weight as yours, they are often on ebay, you could try one of those, or a 325 Sherpa weight (not sure what a 350 Alpina is supposed t perform like but obviously, the lighter the weight, the quicker the engine picks up) I'd replace the crank seals, sort the weight and try it again. You'll soon know if you have to strip and replace mains.

Much better. I know the starting method has been done for MSA reasons, but I wonder if it really achieves anything in that respect. The sheer volume of mud dragged onto the A419 from the two (very good) sections just off it was more likely to attract the wrong kind of attention than a conventional start and route markers.... Route marking was very good. Perhaps also for next year, 'no nails' to fix the section markers to trees... Maybe in this year's results, add a note of thanks to the riders who helped the organisers clear up by taking down section markers in section 6(?), even though a little prematurely...

Yes, great event, great day out and well done to all who made it happen. A pity though that one or more riders removed some blue markers from the trees in the second group in an attempt to gain advantage by opening the section up to get a better run up the final climb out. The observer knew they'd been removed as they were there when he got to the section and they were there when other riders I know rode it early on. The lengths some people will got to to get a result. Not keen on the mass start in several random groups though. I know why he does it but it's a national championship and the start order should be correct with riders in the same class going off in roughly the same time frame. As it is you can have some riders in the same class starting right at the front whilst others are right at the back where it's a completely different trial. It also causes massive queuing at the first 2 or 3 groups with about 40 riders arriving at once. If we must start in groups, make them groups consisting of riders from the same class and tick them off to make sure they start at the correct time. The other issue is that as individual riders aren't 'ticked off' as they leave, it allows them to not even report to the 'starter'. So if an early number is an advantage they can just set off themselves whenever they like and before the first officially started group has even left. Not really the way it should be done as it's unfair (as usual) to those chasing the championship who play it by the book. Great day though. Not sure what was hardest, some of those very slippery sections towards the end or finding the pub from where the trial started...

Original carb was a 627 Amal, yes 6 for 600 series and 27 for 27mm. They run just fine with these if the carb is in good order, plus you have the benefit of knowing the correct jetting etc as it was an original spec carb. Yes you can fit Mikuni or Delorto or whatever but if you don't know what jetting etc to use you're in a sea of **** trying to figure it out, plus you'll need an adaptor to take the push on type carb if you can't get a correct fit bolt on Mikuni, the adaptor is £30 - £40. You don't want to be cutting existin inlet manifolds off, there's no need when the adaptor is available. Mikunis are a real pain to jet properly as the combination and sheer number of needle jet / needle combinations is bewildering. Didn't know that Burlen now do the 627 carb but I think their jetting spec may be out as I'm sure the main is about 150, but been a long time since I ran an Amal, so memory not so good. Pilot was normally 25, not 30. Good luck buying anything from Burlen as from my experience they rarely have a carb built up and you have to wait weeks for them to do it. Surrey Cycles are usually a better bet for Amal stuff. Amal also do the premier carb now with an improved pilot circuit with externally fitted pilot jet although they wouldn't have that as a 27mm, only 26mm but it would work fine.

Model 80 or series 1 model 91/92. The frame side plates by footrests/swingarm mount would determine which but can't see it. Bultaco frame number went from top to bottom and were on the right hand side of the head stock. That one goes bottom to top and is in the wrong place and as you say, not a Bultaco number Yokes are from a mid 70s 250.

I had a rear hub lose what was left of the chrome lining in the rear hub during a trial a few years ago. You would not believe how quickly the mud and silt wore into the exposed alloy. Quickly enough to cause retirement from the trial. Cost of having steel liners in the UK is about £40 - £50 average, per hub

Last frames were red due to Yamaha's request that they reflect the corporate colour / image which was red and white at the time I had both Godden and Yam framed bikes, I preferred the Yamaha frame out of the two, it felt more flickable and was lighter on the front. The Godden framed bike felt very front heavy

I don't think there is any difference in offset / rake between any year of Bultaco yokes and if so, changing them won't alter anything with the steering. With your Miller frame, it would be hard to know whether it had '71 parts originally and had a '74 engine fitted or other way around. It could have had anything in reality I've never heard of Miller doing a yoke set, his frames just used the standard Bultaco parts. He used to do a top yoke to replace the earlier original Bultaco item that was considered weak, but no full set as far as I know I've never ridden a Miller frame but heard people say they're an acquired taste. I could never understand why, having declared a Bultaco steering to be the optimum for trials, he produced his own frame with a different head angle... Your front end problem is more likely due to 40 year old springs not being up to the job any more. With correct rate springs and damping working properly, the forks shouldn't dive and cause the problems you're having. If you fit yokes with less offset the chances are the front mudguard will foul the exhaust on compression as they come pretty close as standard. The other problem with older Betor foks is that the piston on the damper rod is just plain alloy and doesn't have the fibre ring that acts as a seal like later forks do. If the piston wears oil can just bypass it and travel between the piston and inner wall of the stanchion instead of being forced up the damper rod and through the valve. Your M150 forks may have the fibre ring, not sure when it was first fitted. If so you can replace this by cutting new strips from the correct thickness PTFE card available on ebay. This will improve damping effect. You can judge the effectiveness of the piston by placing the damper rod in the top of the stanchion and just letting it go into the tube. If it falls freely to the bottom you can be pretty sure there is room for oil to pass between the bush and the inner wall of the stanchion and that damping effect is being lost. With new seals fitted you have to p[hysically push them down the tube, the difference is marked. If your pistons don't have the fibre ring you could get new ones machined with a groove in them to take a seal. Easy job for someone with a lathe. Picture below shos two damper rods, one with, one without fibre seal on piston

Never had much success with the grease gun, it just seemed to ooze out of the nipple joint itself so didn't give me much confidence that it's spreading through. Could well be a user issue though... Mentioned about the outer bush not being drilled as in every bike I've removed bushes from, I've yet to see a drilled outer bush, so no idea where the grease is supposed to go from the nipple

Better to just take the swingarm out, remove inner bushes and regrease bushes and spindle? On the 124 or any bike with one piece tube for the spindle, if the nipple is in the centre I can never imagine getting enough power through the gun to force grease right up inside the bushes inbetween the bushes and spindle as well as between the inner and outer bushes - both sides If the nipple is in a part of the swingarm that houses the outer bush then the grease is going nowhere as it's blocked by the outer bush, unless the outer bush is also drilled through to the inner. Even then, can you really force grease where it needs to go. I just take it apart and regrease the parts

Looks as though someone has moved wheels, forks, engine from M92 and fitted into M159/182/191 chassis - is number not on headstock? Tank isn't a Commerfords as wrong shape

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175cc frame is the same as model 158, 181 and 190. The forks were shorter yes, to with the smaller frame. When the 198/199 came out the 250 reverted to the bigger frame and forks.

250 / 280 / 300. Why? Why don't any of them make the bike that would suit 90% of riders - a 200

There are some tips here about starting the Sherpas and avoiding clutch slip http://www.trialscentral.com/forums/topic/46574-clutch-slip-since-oil-change-is-it-the-right-oil/