I've always used between 180 - 200cc 10 grade per leg in the Betor forks as fitted to Ossas and Bults. Lower amount to achieve softer action, higher for stiffer. I used 200cc 10 grade in my 74 slimline and they worked very well.
In my opinion 30 grade is way to thick for forks and with good quality modern fork oil available these days I don't know why anyone would want to use the Auto trans fluid. Ultimately though it's down to personal preference and experimenting with volume and grade but the above spec. is good starting point.
Blissy photo was from Lower Norcott Farm group I think, only used by South Birmingham in the Mansell and the odd Midland Centre trial.
Agree that the 4t Majesty is a nice looking bike - apart from the rear mudguard - prefer a better shaped one myself but other than that they look, sound and go like the dogs doodies. They are quite pricey but I imagine it will run forever with minimum maintainance so if it is your only bike it balances out over a period of time.
Jon hasn't got a website. He'll be at the next round at Bootle though and all of the rest I believe. He had an ad in TMX very recently with a contact number.
Correct Dabster - and they are still a passion even after its crap brakes and duff clutch cost me 6 soft marks on 2 soft sections at the Mansell on Sunday. The frustration which finally burst forth in verbal form at the penultimate section was probably heard echoing around Wenlock Edge for hours afterwards.
Wish I could help with where to get an airbox for a Gripper but I had the same problem when I rebuilt a 250 and 350 couple of years ago. Both were mashed but couldn't source one anywhere, even from the states, new or used so had to improvise with them and patch them up. Chances are though any used example you locate will be next to useless as they aren't the best construction. They can break apart at the mounting points and crack open here and there. I daresay that Spain would provide one (I never tried as I can't speak Spanish) and there are several specialists on Mats Nyberg's Ossa site that you could try.
There is a story that somewhere in Barcelona there is a lock-up or such where there is an Alladin's cave of Ossa stuff, spirited away from the factory in the dark days before closure but no-one seems to know where it is. One day I will make the pilgrimage to find this Holy Grail of Ossaland.
If I were doing a Gripper again I'd get an airbox made from alloy and re-position the mounting lugs so that it can be removed from the bike sideways through the frame tubes - from memory it has to come out the back which means back wheel out. Memory not so good though as I've tried to erase my time working on the Gripper..... Depends whether you're bothered about originality, personally I wouldn't be as I'd rather have an airbox that I can remove easily and that won't break again. It can also be designed to take a top loaded filter such as TY/TYZ Yam or Scorpa SY which are available and make servicing easier. As I recall getting Gripper airfilters was also a problem when I had one.
If you're busy modifying it, moving the footrest position down and back and replacing them with modern pegs improves the riding position a lot too in order that you stand in it a bit more rather than be tipped over the front. Depends how tall you are and whether it bothers you I guess, but I've done all my Ossas and it makes a worthwhile difference to riding position/comfort.
Try speaking to Steve Goode 01938 850544. He may not have parts but may know a contact, who the original importers/dealers were etc.
I remember a mate of mine bought one of the first when they came out and it was a seriously pokey bike.
I've also noticed there are some being ridden in Spanish twinshock championship trials when I've been looking on TODO Trial Classic website so there may be some spares back-up there if things get desperate. They're badged as Merlins there I think.
Norwich Union will insure up to 4 bikes on one policy. They have most off-road bikes listed on their bike portfolio. As long as the bike is registered you just insure them fully comp or Third Party fire and theft. If unregistered they will insure them on the chassis number whilst you get it registered as yuou need insurance to register it.
Although only one policy, each bike has it's own certificate which means for payment of one premium all bikes are insured, unlike their old rider policy where it was just the bike in use at the time that was insured. The premium is generally based on the highest rated bike. For example, if you have a bike insured with them which is say group 15, other bikes in lower groups can be added up to a total of 4 with no increase in premium, just an admin fee maybe. If one of the bikes added is a higher group, then the premium is revised and based on that bike etc. I've got my road bike, 2 trials and an enduro insured for Third Party fire and theft for about
As previously posted, Craig Mawlam bought up the remaining Majesty stock from John Shirt. Depends on how much you want to spend on this project but you can buy a brand new 200 Majesty frame from Craig as well as other bits and pieces. I have a brochure with his contact details somewhere, as soon as I find it I'll post them. Otherwise you could look at the twinshock site run by John Cane (who also runs trail and trials UK, specialising in parts for old Yams - advertises in Vintage section of TMX) There is a picture gallery of twinshocks with quite a few Majesties. Craig also posts on there as MajestyMoto so you could try contacting him from that - might be quicker than me finding the details. It is a Yahoo site and you'll need to sign up to view the contents but it doesn't cost anything. Address below.
The only problem in trying to identify Ossas without seeing them is that as the bikes were so similar between 74 and 79, if previous owners have repainted or modified them in any way it is almost impossible to tell which model it is from a description.
71 - 73 bikes, the MK1, would have had fibreglass tanks with broad green stripe as Big John said, bolt on carb, flat fork bottoms and a short wheelbase due to a shorter swing arm. You can tell the short swing arm as the shock mounts are virtually right over the spindle.
Mk2 74 - 75 had the alloy tank, rubber hose fitted carb larger diameter crankshaft assembly, the toolbox built into the left hand sidepanel and a 1" and a bit longer swing arm (spindle sited rearwards of the shock mounts) Different forks were fitted with bit where the spindle passes through now shaped and rounded. Thinner green tank stripe came down from the filler cap and swept back along bottom of tank to rear - very different from MK1. Detachable rear 'cherry bomb' shape silencer added. 310 model also introduced with red / green stripes.
MK3 76ish was a MK2 with longer front forks and the shocks canted over at more of an angle, the rear shock mount is down by the bottom rear sidepanel screw. They were then fitted with a longer front pipe followed by an hideous, longer rear silencer which was now welded to the middle box.
77 - 78 model was green tank and sidepanels, black frame, white / tranlucent (and very breakable) mudguards. New style fork yolks painted black. Around this time they moved the rear top shock mounts up the frame a bit, shortened the swingarm again and slightly changed the shape of the tank and sidepanels. The barrel fins also had cut outs in them making them look different from earlier models.
79 model got a green frame and mudguards and somewhere along the way got different porting (so I'm told but that may also apply to 77 - 78 model)
80 Then came the Gripper......
Anyway, enough of this waffle, there is a good site for Ossas with loads of info run by a Swedish guy called Mats Nyberg, link below. If you have the engine and frame numbers - they are identical 6 figure numbers except engine is prefixed M, frame prefixed B - there is a link on the site to a reference sheet by a Giovanni Dughera where you can check the model type against the frame number. As engine / frame number on a bike always matched, you can date both the frame and the engine from this chart. The early bikes are listed as MARs but the later bikes are refered to as model type TR, ie; 250 TR77 would be a trials 1977 model etc.
One thing to be aware of though is that parts for Ossas are becoming harder to source in the UK although via the web you can get virtually anything from the USA.
Hope you found something useful in all this waffle, I'm not an expert on Ossas, just that the MAR is my favourite trials bike (most of the time..) As someone else said, Keith Horsman who lives accross the road from John Lamkin's place also knows a fair bit about them and used to modify them for Ossa UK.
Who made the best drum brakes and what made them better than the others?
I'd say most of the 80s bikes had decent drum brakes. Yams, T/S or mono are good, ditto Hondas and most of the European bikes had Grimeca I think, which also work well. They had better feel to them and generally worked when wet, unlike 70s bikes. I guess a lot can also depend on the material used for the lining, of which there is probably a lot more choice nowadays.
I've fitted a TY T/S front wheel to my Ossa and it went straight in with just a new spacer made to fit. It works much better than the Ossa brake, although the bike itself isn't really suited to clutch / brake style riding.
I am in the process of mating a yamaha ty mono hub to a tubless rim to give the 340 an edge, I hope.
Does this mean a return to the Classic series on the 340 is on the cards for 04? Having ridden the Phil King last year and used virtually every body part against very hard and oh so solid trees as some form of braking device for the Ossa down some of those big slippery drops, I'd suggest you look to finding a mono front wheel for it as well....... Good trial though.
Looks like they have some good events scheduled next year to hopefully get the series back on its feet.
Which Fork Oil Sherpa 190b
in Twinshock
Posted
I've always used between 180 - 200cc 10 grade per leg in the Betor forks as fitted to Ossas and Bults. Lower amount to achieve softer action, higher for stiffer. I used 200cc 10 grade in my 74 slimline and they worked very well.
In my opinion 30 grade is way to thick for forks and with good quality modern fork oil available these days I don't know why anyone would want to use the Auto trans fluid. Ultimately though it's down to personal preference and experimenting with volume and grade but the above spec. is good starting point.