ask greeves

building sidecars isn't an exact science. If you cheat...make the width say one inch under the minimum ACU regulation, then you have a distinct advantage, as most sections are 'tight' with regard to fitting the outfit through. As for sidecar wheel lead ( the amount of inches the side car leads the back wheel) less lead the sidecar turns left easier, but more likely to tip over on left hand cambers. (talking here about sidecar on left english)........is that Robin our famous Robin..35 times Brit champ and Brucey, how's our little Tracy

201 crankcases are not in anyway interchangeable with either 240-241-300-301.

These photos really are outstanding, a real slice of history, in the development of motorcycle trials, thank you for sharing them. I would even go as far as saying 'could make viagra redundant' (only joking). KTM had a similar project with Walter Luft, wonder how trials could have evolved, had Maico and KTM put trials bikes into production.

How about this.....PRE 72 Class (British Twinshock). Motorcycles (manufactured upto 31st December 1971)any manufacturer generally available up to this date. Should not be visually 'forward engineered' with exception to Controls, Mudguards, Seats and Tanks, any alterations/improvements to these parts should be within the 'spirit of the class'. No Hydralics. The scrutineers decision is final. I've tried to include everything , from everybody, with the minimum amount of words. The only thing it doesn't include (as far as I can see) is grimacea hubs, but is that such a terrible thing !

Bob and Me thought you had died (from eating toooo much meow meow)..Slip

In a previous post you showed 3 yokes, which of those 3 did you personally find was the most pleasing to look at, would you agree that the aluminium facsimily of the steel yoke was the most esthetic. This is one of the many reasons I like pre 65, the bikes are very pleasing to look at, both from an engineering perspective and esthetic looks. I would rather look at 25 attractive women, than look at 100 ugly women. If i have the desire to look at a pre 65, in a condition as it was manufactured, I go to Sammy Millers museum. If I want to see pre 65's competing, I go to a pre 65 trial and those bikes are the accumilation of maybe 20 years of competition, within a set of ever changing rules and personal modifications within those rules. In another post there was a Tiger Cub, correct me if I'm wrong, but it looked as if it had steel sliders and cub front hub, your argument that to be legal within pre 65 cost's fortunes doesn't really hold up, wouldn't heavyweight BSA forks and cub hubs do the job, at a fraction of the prices, you have lead us to believe. Pre 65 Trials is still a gentlemans sport and the gentleman that has to scrutineer the bikes can only do this visually with regard to a set of written rules. With reference to yokes, I think you'll find, it's the forward facing clamp bolts of a Montesa Yoke that is the main stumbling block, visually they look 100% wrong. Don't hold me to this, but with little work, a helicoil here, an aluminium plug there. I personally think Montesa Yokes could be altered to pass the scrutineer. Why build a bike which is only eligible for some trials, when for little or no extra effort, you could build a bike which is eligible for all.

I must respond, there is no hidden agenda. Everything we do is completely above board, we've made no secret, that we are trying to purchase the free worlds over supply of magnesium and titanium. From our underground factory in the 'black country' our 6 station cnc's are going 24hrs a day, trying to forfill the order from 'the Sultan of Ranipoor' for magnesium tiger cub hubs, magnesium heads and barrels and titanium stanchions and associated nuts and bolts. The Ranipoor royal signal display team are updating thier fleet of rather old and tatty HT5's for use around the middle east. I must confess, we do have agents throughout the UK, looking for and purchasing the right Norton Roadholder sliders, and possible that is why only the wrong side is sometimes available on e-bay. These sort of export orders create for us Petro Dollars, which can then be used to 'grease the palms' of the 'right people' so that we can develop our next generation of HT5's. We are looking for staff, so if you have a genuine interest in pre 65 Trials Ariels, and if you've had experience working for a formula one team, especially 5th tier digital electronic ignitions or nano technology pre-preg carbon composites, we would look forward to hearing from you.

I wonder what Neil Gaunts thinking ! Maybe it's....I know i'm under weight, wish I had those valenced rims, cos they don't weigh it until after the trial. An they'd all be filled up with mud.

After trying to digest all the input to this disscussion, it seems the class would consist of bikes to old to be considered 'pre 65' and to young to be a competitive 'twin shock'. Would you agree that a suitable name would be MTB Twinshock...MISSED THE BOAT

I personally think that in all classes upto but not including Twinshock that all rims should be as the era, meaning either Valanced aluminuim or Steel non valanced with coresponding spokes ie if your machine was manufactured with 40 hole then the wheels should be laced with 40 or 36 as the case maybe. This still leaves the (i've got more supertrick bits than you brigade) option to run aftermarket hubs (that look standard)and titanium spokes. The wheel situation with regard to what can be done, is in my opinion becoming stupid, there will soon be 28 spoke rims, with aftermarket magnesium tiger cub hubs, titanium spokes etc etc.

Almost every 'hardcore' pre 65 owner that I know, thier yearly ambition is to ride the pre 65 Scottish 2 day. therefore it follows, that throughout the length and breadth of the UK, these pre 65 bikes are being fettled as to pass the SACU regulations. Only a moron would build a pre 65 that isn't elegible for the Scottish, as and when you wanted to sell it, you'd be greatly limiting your selling market, as most buyers would want to purchase a 'scottish legal' machine. So indirectly the SACU regulations have already been accepted.

Maybe the vendors didn't like your attitude.

I consider that at last, a sensible solution has been found regarding the 'twin shock' class. Let's hope that everybody, clubs/individuals take on board this sensible resolution. Also with regard to Pre 65, i'd like to see the regulations employed at the Pre 65 Scottish, as the standard set of rules throughout the UK, with regard to Pre 65.

On a rebuild all bearings must be within limits. To check a bigend assembly, there must be no up and down play, sometimes sideways play can be confused for the up and down play, so check very carefully, any up and down play whatsoever is suspect. Sometimes the bigend assembly can be saved, by just changing the pin and roller bearings, as the pin has to work twice as hard as the rod itself. Rods can sometimes be reconditioned if a replacement isn't available, by firms such as Alpha. But i'm sure Bultaco Uk would probably have a rod assembly.

It would seem he(kickstart196343) has recently bought on e-bay a LDV Maxus Van (white) reg no BU05 KAK

you really need to disassemble the clutch, as the drive plates and driven plates, could move as your saying, but stuck together. I personally would have driven the bike (in a high gear ) with the clutch lever pulled in with lots of throttle and your foot on the footbrake (put some torque through the clutch). This is always my 1st thing to try, to free a clutch, before taking it to bits.

The engine number is a plate fixed to the inside primary chaincase, which is detachable from the crankcases, so in the bikes 50 years lifetime, its likely this has been changed, these engine number plates are available (blank) A siba dynastart crankshaft wouldn't work with the magneto type side cover that you have, so the crank would be a 9e thru 36a type (could even have full flywheels and oval rod fitted)with conventional magneto. The gearbox is the important part, wether yours is the wide ratio trials box. As for the barrell, as far as I remember, marcel had the cutout on the fins, to stop heat transfer to the transfer ports.

Interesting information from Hewson, i think you might have to consider that the cylinder head and barrell could be from different manufacturers. Will be interesting to know your final conclusions, to what exactly you've got.

Hello, I would agree with Trickymicky, looks like Parkinson Conversion. Don't know about the 'upright 9e' Engine, could it be a Chinese copy ! What interests me is the middle silencer, looks very much like a 1968 Vauxhall Victor middle exhaust box.

It would be interesting to know, what you consider the benefits are of fitting later forks, with increased diameter stautions. Will it make you ride the bike more expertly. Is there something inherently wrong with the 35mm forks, something that FanticMotor were not aware of, when they designed the 300. Have you considered, that fitting these forks, could be interperated as NOT BEING IN THE SPIRIT OF THE CLASS. Your peers may have a little giggle and your elders might have a little tutt, but to my mind, seems a really fine way to spoil a fine bike. Don't forget there are other mods, which are allowed in the UK, hydralic clutch comes to mind, allowed here, but not on the continent, yes it's your bike and you can do whatever you want to it, but as you've just found out, all these parts are becoming hard to find.

Really you should have 2 security bolts in a rear rim, drilled at 90 degrees to the valve. Unless of course somebody knows better ! also a tubeless rim has an inner lip which in fact holds the tyre in place.

Sorry about my 'vague' reply, regarding centre hole, I was refering to the hole in the middle of the backplate, where the spindle goes through. Enlarging the hole by 20thou or more, this allows the brake shoes to centralise themselves in the brake drum, allowing maximum contact area. Assemble front wheel assembly into forks, leaving front wheel spindle loose, apply front brake, then tighten front wheel spindle, this centres the shoes in the drum..It's just the inherent design of drum brakes, trying to expand a smaller diameter into a larger diameter, engineers tried to overcome the problems by 'twin' leading shoes, and even quad leading shoe. There's probably room for improvement, by using modern materials, that could deform to accept the diameter of the drum and still retain friction properties, therefore utilising the full swept area (spongy kevlar maybe !). All developement ceased with the introduction of disc brakes.

Both 240 and 300 have exactly the same amount of brake shoe contact area. The trouble is centralising the shoes to use the maximum amount of brake area, the 'works' Fantic riders had a 'trick' of enlarging the centre hole , centralising the shoes. The 300 backplate, was a progression of this modification, loosen the small nut, apply brake, to centralise shoes, and retighten. It just goes to prove what a progressive company Fantic were, no other manufacturer, using gremacia hubs had this update. 1985 saw the introduction of disc brakes, so ending the development of drums. 240 and 300 brakeshoes are different, and should not be interchanged, always order and make sure you've got the appropriate shoes for the correct backplate. Works 300's seemed to prefer the 240 backplate, probably because it was lighter and more tucked away, with regard to the brake anchor point.

I'm so pleased that you tried my advise, it seems so simple, that simple that in fact, people dismiss it. The same can be achieved with the front brake also, this type of hydralics, uses mushroom type seals, leaving them under pressure pushes the seal onto the cylinder wall, creating better feel. Do it to both clutch and front brake, the evening before the trial, you'll be amazed !