tony283

Majestyman340, Just to clarify the severity of AHRMA sections, this is what we normally have. 4 lines, 1 being Modern Classic Experts only which = 1960/70 Open to Center, 2 Premier Classes Experts and Modern Classic Ints = 1960 Open to Center, 3 line Modern Classic Novice and Prem Class Ints/Nov, 4 line beginners only and could be ridden by anyone on a dual sport bike. The NORMAL tendency for AHRMA events is to make the sections TOO easy which often means a single dab is enough to put you down the order! Like yourself I have been riding a long, long time and apart from some self inflicted "stupidity of youth" situations don't usually come away with more than a series of cuts from desert plants. In all my experience I have never seen anyone need to be taken away from a trial in an Ambulance. A serious accident on a Vintage Trial is more likely to be a stroke or heart attack!! Tony

Generally speaking why not use the "Trials specific" clothing? Why would anyone, other than cost, choose to use something designed for a different sport? Trials "specific clothing" has come a long way from the traditional peaked cap, barbour suit, and fireman's leather boots with cricket studs in the soles. First there was the helmet law of 73 and all the crap that we wouldn't be able to hear the engine etc, etc. Then we went for the industrial wellie boot and then the lighter riding suits. Since then helmets have come a long, long way and the trials specific helmets offer good protection while being light and comfortable and also cut higher on the neck so that you can look well up the section without any restrictions. Boots have equally been redesigned for solid ankle and shin protection but could still do with some improvements in the waterproofing area. Jeans and shirts are adequatedly padded and also offer the room for extra knee protection and braces if that is your need. Chest protectors are designed for motor cross or enduro where you encounter sharp flying rocks and stones from other rider's back wheels and are not designed to prevent you injuring yourself in a fall! Trials gloves do not offer much in the way of protection other than insect bites as they are made of such thin material. Most expert class riders if we look at past pictures of events like the Scottish are normally seen bare handed as wet gloves never gripped anything! Tony

bo drinker, I guess he saved a couple of lbs by not having the kicker! These frames were made by a friend of Mark Kemp in the UK by the same company that does Valentino's race frames........ the price may not be available to mortals! The forks of course come from "another" Yam but are acceptable under our ITSA rules. Tony

Majestyman, Here are the pics. 2 frames made one for Mark Kemp and this one (still in the raw) for Bob Ginder of BJ Racing. Bob's Frame Mark's bike in finished state 30lbs lighter! Different bash plate and exhaust routing .....and with ITSA rules for Modern Classic Twinshock Drum Brakes TwinShock Air Cooled Engine Tony

majestyman340, I'll post a few shots of Trevors's frame and final build tomorrow. Tony

Logie, Standard set up with a 520 chain is 46 rear 12 front. I use 11 on the front for modern sections. Tony

Now THAT'S what we call a dirty pass Gear Down, Hook Down, Outer Wing UP???? Tony

Our newest Organization here in the USA was formed to cover all the "Twinshocks" that currently are not allowed to compete in the AHRMA Championships which currently cover all bikes up to model year 1979. Crazy as it sounds, especially after Bernie Schrieber's wins all the 79-85 bikes (the last of the Twinshocks) have nowhere to ride! ITSA (International Twin Shock Association) has 3 specific classes which encompass all Twinshocks: MODERN TWINSHOCK Air Cooled Drum Brakes Twin Rear Shocks HISTORIC 1973-1979 PRE-HISTORIC Pre 1973 So basically here is a class which allows the rider to build "whatever" to whatever cost he or she wishes to invest as long as it conforms to those 3 simple rules of Air Cooled, Drum Brakes, and Twinshocks. An early RTL Honda with Twin shocks will be out there soon! All the TY 350's could be in if someone puts twinshocks on them. I know we do have 2 new Majesty "lookalike frames" which will be competing which were made by the same company that makes Valentino Rossi's roadracing frames in the UK.......I dread to think what they cost??? It's only going one way unless YOU guys get the ACU to lay down some firm rules. Tony

Having ridden nearly all of them during the 70's, they all had their pros and cons and seemed to be better at different events. The early Bultacos had the benefit of Lampkins and Rastus riding for them and were a delight on rocks. The early Ossas found grip on muddy hillsides when others ground to a spinning stop. The Honda was getting it right in the hands of Rob Shepard and the other Eddie. The 348 and 349 Montesa is not a bike that I like due to a lot of geometry and engineering flaws. Probably the most robust, and the easiest to rebuild, as parts are available worldwide is the Yamaha TY250 series. Note these machines are nothing like the ones Mick Andrews used but are exceptionally robust and seldom have any engine malfunctions. With their reed valve induction they are "peppy" enough to compete with the best but benefit from coming down one tooth on the engine sprocket. Another worthwhile mod is the bolt on Sammy Miller footrest set and if you go for the Yam get a later model 76-79 which has a slightly smoother response at the bottom end. All the ones you list are good choices. Tony

Majestyman340, Our rules are a lot more lenient see my recent article on my blog "The Pre 65 Debate". With regard to our pre 65 classes then you may use any item up to model year 1974. That means you don't have to go to enormous expense to find a pair of Betors or Ceris to fit your Triumph or old BSA. Rear shocks as Michael said are limited to 4" travel and this is normally done with a little insert around the shaft. Miller framed Cubs are OK with oil in the top tube but Otter or Faber frames are not allowed in the Premier(pre 65) Classes and must be ridden in Modern Classic. Likewise if you wished to put the old Spanish Onion engine in a TY175 frame again you would be in Modern Classic. With regard to AHRMA sections we have 4 lines to cater for the 3 rider levels, (Exp/Int/Nov). Mod Class ride 1,2,3, lines and beginners (all classes ride the 4 line. The Prem Class ride Exp on 2, Int on 3/2 (dependant on severity), and Nov on 3. How do these sections compare ? The 1 line (only used by Mod Class Exp) about = Open to centre Trials of the 1970's The 2 line Prem Exp Classes and Mod Class Int =Open to centre Trials of the 1960's The 3 line Novices =Open to Centre Novice Only Trials 60/70's Hope that helps Tony

Very Very NICE!! How much for the lot ??? Tony

Vaughan, Have you just fitted new points? If you have go back to the start as a lot of the new points come with a "grey" coating which you need to file off. If you haven't fitted new points, maybe a good time to do so and also fit a condenser at the same time. From the Stator plate there should be 3 wires, one black and 2 yellow, the black is the live wire and this can sometimes get burnt and blackened from engine heat at the lower end and you may need to replace that. Then ensure the kill switch wire is disconnected and you should have sparks with a 15 thou gap at the points and 22 thou at the plug NGK B7ES. As you are probably aware the stator is a fixed plate but while you have the flywheel off check that the area between the magnets is free from little bits of metal. Good luck Tony

Majestyman340, The forks on the Cub are from a 1970 BSA B50 and give the same wheelbase. 1974 is our cut off year so I can use them along with the 74 Yam front wheel and as carburation isn't subject to any rulings a Martyn Adams Del Orto. Strangely we can't use the Otter frames in our Premier pre 65 classes but they are OK in the Modern Classic Series. There we go RULES IS RULES! Tony

Michael, Sorry for any confusion. The top picture is a DMW frame and these were made by DMW as their chief engineer was an East Midlands Trials rider. Fraser is a much later frame for the Hondas, and I believe that is your second picture. I rode a fair number of events in the Midlands and I never saw any of these DMW frames during the 60's or 70's. I was also surprized when shortly after having acquired mine a SECOND DMW identical frame came up on e-bay 3 months later! Incidentally Dick Mann also has recently finished a DMW, different design to mine with a Villiers 9E engine. He had it out at Donner last year. This was mine still with the DMW badging This one was on e-bay 3 months later Another action shot see you at Donner Tony

This was the build sequence Sizing the frame to take the Yam engine The first build Shortened Exhaust Back from plating, now the Kreem Final build Complete In action It will be at Donner if you want a test ride Tony

From what you say the "overtightened chain" sounds like the problem right there. Even a "new" chain will have a couple of tight spots which you will be able to see, and feel as you rotate the wheel. Also check the alignment of the tensioner and look at the pad which may have been cut offset by the old chain. I would always change the pad when you change the sprockets and chain. Tony

Michael, The top picture you show is the DMW frame (Dawson Motor Works) and they also owned MP Forks. The other 2 pics are the Frasier for the TL Honda and the unknown for the Bult. You can still find them on Google with all the company history. The DMW frames were built to take the Villiers 32 and 37A engines and came with Hagon gas shocks (Alf Hagon the Britsh Grass Track Champion, Speedway and European Longtrack hero of my childhood) As I said all the build photos and narrative are on my blog, feel free to use any you wish. See Under; "The OSSAMAHA" in the October or November ARCHIVES. There are also some action shots of the bike in "2007 Central Arizona Trials" (2 articles) It handles like a dream and has unlimited steering lock! Tony

As this thread never dies I've written an article on my web with a few personal views on "the problems" and some suggestions as to the way forward. Then a look at the USA Vintage scene and what you can do over here. See "The Pre 65 Debate" Too long to publish on this site. Tony

Michael, I built a special last year using a 60's/70's DMW (UK) frame and all Ossa front end and then grafted a 74 TY250A engine and back wheel into it. The build pictures, problems and solutions, are on my "blog" under "The OSSAMAHA" I was given a Kawasaki to test ride back in 1975 when they first came on the UK trials scene, can't say I liked it but on reflection with some mods I'm sure it would make a very competitive bike on the twinshock circuit. Only problem with building a "Big Banger" is that you are stuck in Modern Classic and might find the lighter 2 strokes have a big advantage, but you can always compare scores against the Prem Heavyweights, might be a lot of fun! Tony

You say you just fitted a new C&S, did you replace BOTH sprockets? If not the new chain is probably tightening up on the worn front sprocket which will stop the rotation when you spin the wheel..... just a thought See my blog on "how to chains and sprockets" Tony

As Woody and I have already suggested this machine has both frame and engine numbers that do NOT relate to anything on known Yamaha records. Clearly the machine you have have has a modified rear end both in top and bottom shock mount positions, the awful air cleaner mod is non standard and really needs some work! The basic forks/frame/engine set up suggest something circa 77/78, the bash plate is standard for the period and I can see no other alterations other than the non standard rear shocks and the Sammy Miller front mudguard stay fitted the wrong way round! Having tried them all when you rebuild it fit the SM "back and down pegs" and you should have a WINNER! See my blog "Building the Glitzmobile" Tony

As Woody says the TY250 A which has the slightly wider flywheel and clutch cases starts with 434 and this will be in the place that you showed in the photo and on the headstock. The later models with the slimmer cases (like yours) and the full width fins on the barrel all started with 493- . All Yamaha engines as fitted to trials TY series machines had 6 figure engine numbers that were duplicated on the headstock. All that having been said I do have one in my showroom that has the 434-005772 on the frame and on the engine -005772 with the 434 designator missing? What is the frame number? I have also seen a TY 250D which DID have an odd ball number but this apparently was a "test" engine Tony

Yes, the question is a little vague..... what are you doing in Lux? what are you doing in NI? Tony

I think some of them came with a little barrel nipple in brass which had a grub screw in it. Tony

Dave, I will be helping wherever possible, and trying to get reports of the events that I attend published in Vintage Views. Ed and Evelyn Peacock will again be doing most of the donkey work and I don't think you could find a more conscientous and hard working couple. Brenda will be taking photographs of all that ride in the events we go to and all of last years are on her site, by event, on www.trialsphoto.com Ahrma has promised we will get a bigger share of Vintage Views, but that's up to the riders to make their voices known and put in their points of view. Should be a Great Year! Tony