woody

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/

Ah, ok, I thought he'd only ever tested one, didn't realise he'd ridden a trial on one. Interesting though as I thought the Ossa would have suited his riding style as from what Martin Lampkin has said, Rathmell preferred to ride a more measure style and pick his way up sections which the Ossa was better suited to than a Bultaco

As far as I recall, he was under contract to Bultaco and tried to sign for Ossa following a disagreement. Bultaco stopped it. He finished the year on the Bultaco and won the world championship for them, or European, whatever you want to call it, same difference. He never rode the Ossa in competition. He moved to Montesa the following season

I'd use Yamabond (or threebond from Rex Caunt) It's designed for jointing metal surfaces with no gasket but I've used it successfully with a gasket as well. It's better than Blue Hylomar and seems to fill imperfections better As for welding, I've had Bultaco and Ossa barrel fins, heads, clutch, crank and timing cases all welded with no problems at all

This is my old one which had an original 1959 frame and '62 engine. Also considered a special and not allowed back to Scotland after I rode the 2 day on it some years back. Quite how they considered it inelligible when at the time it was parked next to a couple of brand new Cubs using all new parts was lost on me. The term and meaning of replica was also lost on the organiser... 'tis a funny old world we live in

This is the bike. It's in solitary at the back of the shed at the moment as I'm having real trouble getting it to ride as I want.

Yes, tubeless rear rim, bought a used GasGas wheel for about £45 and prayed the rim wasn't rotten. With the exception of the engine, which is a scratch built long stroke 340, the bike was built using mainly stuff from the shed I already had. The frame is a Faber MK3 which was £580, not the best frame available but for that price a pretty reasonable compromise. It is a light frame. Rear hub I had relined £45, rebuilt into the rim with new spokes, about £80. Front wheel is Grimeca and I machined off the fins and rebuilt with new spokes, again about £80. Forks are spare set of Ossa I had. I chose not to run oil in frame and had a mate build the oil tank and the airbox. If I'd run oil in frame and used a foam filter the oil tank and airbox costs wouldn't have been incurred. Originally I used a spare set of Marzocchi yokes I have but wasn't sure about the offset so bought a pair of Alan Whitton's which have some rake built in rather than the usual parallel option The cost of that to get a rolling chassis, no engine, was about £1500. If I'd used the Marzocchi yokes and not had the oil tank and airbox built I could knock £4 - 500 off that. If I'd then used a normal C15 motor, like the type I had in my old bike instead of the long stroke, I could have rebuilt it for around £600, using normal road gears and cam, standard head, iron barrel. Add on ancilliary costs such as tyres, tubes, bars levers (new bars, expensive domino levers) So by using the Faber frame and as many parts as possible from spares in the shed, the bike could actually have been built for under £2000. That's saved over £2000 by not using new hubs, brake plates, rims, fiddle forks And that exercise in economics and practicality makes it a special in some quarters Takes all sorts... As for yours, like I said, I don't think you need worry about anyone picking flies where you'll be using it. 98% of clubs take a more pragmatic view than the odd couple.

Yes, the model 27 was known as the San Antonio and they are a rare bike as they were only produced for a short time before being replaced with the model 49. Rarer than the model 10 thay have the lowest production run apart from the 198b, so a nice find. Has the frame been modified around the footrest area or is it just the angle of the shot that makes it look different

When I said no-one would bat an eyelid I should have maybe qualified it as no-one in his part of the country or from the Midlands southwards which is where he'd most likely be riding it

That should hopefully account for it. I had an engine bolt come loose on my Sherpa once on the road and the rumble was bad enough for me to think the clutch flywheel weight had come loose - or worse. Rumble disappeared when we tightened the bolt.... Also had the same affect on another Sherpa when a badly mis-shaped bashplate was touching the underneath of the engine. The rumble disappeared when the bashplate was removed

I have a Sherpa rear wheel in my BSA which has a Faber frame. I'm assuming the width of the swingarm on that is going to be very much the same as a BSA and Drayton item. The problem you'll face id getting the wheel far enough over to the left for the chain run. With the boss on the Sherpa brake plate it will push the wheel too far to the right and the sprocket will be way off line with the engine sprocket. I machined the boss right down, even taking a bit off the face of the brake plate itself in order to get the sprockets to line up. This meant countersinking the bolt holes in the sprocket to use countersunk bolts as it runs so close to the swingarm normal bolts will foul it. The rim offset had to be moved about 10mm to the right from standard Sherpa offset if I remember correctly due to the wheel sitting closer to the left hand side of the arm than it does in a Sherpa. Next problem was the brake arm as this now fouled the rear of the swingarm if the wheel was forward by a certain amount. In the Sherpa, it sits slightly inboard of the swingarm due to the boss on the brake plate so it's not an issue, but with that machined off it became a problem on the BSA. As the spline exits the brake plate at around 2 o'clock (due to the position of the torque arm stud in the plate) it sits just on the upper rear point of the arm. My solution was to take some metal from the top of the arm above the spindle, angling it down towards the rear to stop the brake arm fouling. Not much room to play with but you have to ensure you can move the wheel forward in the spindle slots and not have an issue. I guess if you're able you could reposition the torque arm stud in the plate to allow the brake arm to be position elsewhere but that was beyond what I can do. You then need to make a torque arm to fit. As there is no spacer on the sprocket side it just needs a spacer made for the other side and that was it. I had thought about fitting a spacer behind the sprocket, moving the sprocket over, not the entire hub which would mean the brake plate wouldn't need shaving down and the brake arm may not be an issue. But I thought it would look odd as there would be a distinct step from sprocket to brake plate, so I never tried that. I have a Grimeca wheel in the front as opposed to a Sherpa but that was a doddle to do compared to the rear, just needed to make spacers and to sleeve the brake plate and bearings for the 12mm spindle as I have Ossa forks. As to whether it's acceptable or whether you'd offend anyone, I doubt anyone would bat an eyelid. Like me you've done it out of practicality and cost and used stuff you already have. There is no real difference in doing what your doing from using new billet machined parts and anyone who thinks there is because they aren't British hubs must have their head stuck far enough up their backside that they've lost touch with reality This is the only picture I have of my back wheel, none of the other side unfortunately. Is it really so different from a billet hub?