jon v8

The only thing I would add to this thread is about Aspen fuel, I use it in my chainsaws because it does not wreck my at least 30 year old kit. But mostly because the fumes from it are much less toxic than from ordinary pump fuel. I used to get terrible headaches from chainsaw fumes after as little as 20 minutes sawing in still conditions. Since using Aspen I don't get them at all. I still have a couple of tree surgeon customers who use it because they have a duty of care to their employees. They are worried about asbestos type comebacks on their insurance, plus they don't want headaches either. I understand that the HSE have approved its use for petrol engined wacker plates in railway tunnels. Which helped Network rail and their contractors no end because previously they had banned them.

Sorry, but you are wrong, the ethanol in the petrol is destroying fuel pipes, the worst case I have seen is 6 month old "Ethanol resistant" fuel hose that became porus and leaked like a sieve. Plenty of diaphram type carbs on strimmers and chainsaws etc, have been wrecked. It is a pain in the a***.

I use a BTH electronic unit on my rigid AJS, it is reliable and more accurate than the Lucas racing mag it had before. Go to the Talmag and you will see loads of them there. Not cheap, but worthwhile if you want a good spark at the right time,every time. I have nothing against mags, I'm going to a VMCC meet on my ex WD G3l tomorrow,happily running on an N1 Lucas. But for trials its a new BTH.

A promise not to post 4 hrs ago, and already 3 more... I enjoy a healthy debate, but this has gone beyond it. Woody, all the way through this thread has made honest,sensible and very well thought out responses, which TT Spud refuses to accept, he seems to be living in a different world of, (Very) occasional trials.

TT Spud, twice I have asked you who is going to do this scrutineering and how should they be qualified ? It is hard enough trying to get enough observers, without trying to find extra staff. many clubs offer money to observers, but they still struggle to find enough, or in some cases apparently people have taken the money and disappeared. So who is going to be the scrutineer ? I for one would not want to stand in a field on a Sunday morning trying to tell a rider that this petrol tank or front hub is not acceptable - So you need to go in a specials class. You need to start your own club and see how many riders you get.

TT Spud, I think you would soon put an end to many events if you put your rules in place. Firstly as I asked before who is going to do the scrutineering, and more importantly what would qualify them to do it ? They are not going to be popular are they ? And if the riders were forced to ride in a specials class they would still be there on the same bike. And the reson a large proportion of those "cheat" bikes like Drayton Bantams are being ridden every weekend is because the riders can no longer manage a big pre unit bike. I would rather see all of the more senior riders out on a lightweight or cheat bike than not at all - Which is what would happen with your rules. I can think of plenty of West Country riders in their seventies and eighties who are out most weekends riding, I would hate to see them excluded by forcing them back onto bikes they are no longer comfortable or confident to ride.

TT Spud, I think you need to be more realistic about your dreams or ideas of what Pre65 trials is or should be like. I'd like to point out a couple of things to you; 1, Nothing good lasts forever. 2, Many of the riders who have original Pre65 trials bikes are simply too old to ride them or are scared of hurting themselves.( Or their partners have forbidden them ) 3, The Talmag as a trial is a great spectacle,a lovely collection of bikes and well known faces in the trials world. But many of those bikes will go back in the shed and not be ridden until the next Talmag. I have almost begged riders there to come and ride our Ashwicke Classic trials which are set out to cater for rigids and with older riders in mind. None will come and join us, they are happy to ride one trial a year. And its not distance, look in the Talmag entry list and people drive from all over the country to it. 4, You make a big point about cheating with trick bikes, ANY rider who is honest will admit it is the rider, not the bike that wins the trial. Study the results of any trial where you know the individuals and you will see this is true. An alloy tank full of fuel can easily weigh more than a steel one with just enough fuel to finish the trial... 5, If you make the "rules" of entry too rigid then someone needs to ensure they are enforced - Who is going to do this ? And what qualification would they need and be able to prove ? I don't mind my bike having looked at as per the Talmag,checking if the brakes might work etc. But every time I have ridden it, no mention was made of it having a modern BTH electronic mag on it. Point is 80% or more of the bikes would have failed scrutineering for this reason. The late Len Hutty was using exactly the same mag as me each time he won - Was he cheating ? He would have won with a Lucas racing mag anyway. 6, A few years back there seemed to be a big argument / discussion on the Trials Australia forum about using square barrels on Tiger Cubs, I think the Aussy rules banned them. This and similar issues, (From what I was told by a friend living there) has contributed to Classic trials of almost any kind being dead in Australia. Be too fussy and people simply won't bother. 7, Over here in the West Country I ride most weekends, the trials usually have A and B routes plus a Gentlefolk route where you go in the start cards and take any path you choose to the ends cards. It works. Entry is usually between 50 and 100 riders. Few of the events have prizes and those that do are good natured fun. We run a couple of charity trials a year to put back into the sport, and it seems well received. 8, If you are confident that there are people who would like to ride in events with entry requirements as you suggest, why not set up a club like I did. It cost me about £700 in kit and we pay the AMCA an annual fee. Its a bit of work, but well worth it. (Especially if you donate all the proceeds to charity)

Foot and mouth, then Covid = No trials. Anything else is just whinging - Get on and ride while you can.

I think you can still order them from a Yamaha dealer.

I don't think you should give up, people here complain about there being no trials where original pre unit bikes can be ridden. That may be true in some areas of the UK, but here in the West Country we are luckily spoilt for choice, my rigid J9 James is my choice this weekend, rigid AJS for the Golden Valley road trial next weekend. I remember reading about some issues in Oz with eligibility for Pre65 bikes, maybe they could be relaxed if its still a problem. Again people complain here, but the truth is many old bikes,original or not are still being ridden regularly - That is what matters.

Good luck with that David, last time I was over my brother and I tried to find a supplier, even Stihl dealers didn't have or even know about their version of it. My brother is a small engine dealer in Perth and none of his connections either knew of it or who could get it...

Its a very clean fuel and won't harm any equipment its used in. I use it now mainly in my elderly Stihl chainsaws that would die quickly on E10. I also use use it in my AJS,C15 and J9 James. The best thing for me about it is that I don't get headaches from the chainsaw fumes anymore. Its brilliant stuff, only the cost puts me off ! But like you I don't use much so its not a big problem.

I had a couple of early Cota 247's a few years back, yours looks like an early Mk3. They didn't have tailpipes and are quite noisy... Mk 1's look quite different and are rare, the Mk2 is very similar to yours and had much larger hubs, this is the main difference to the Mk3, the small hubs borrowed from their little road bikes.I think the works riders used to retro fit the bigger front hub where higher speed road was involved. The pic shows the Mk3 I started restoring, but sold early on...

Pair of Levi's with some knee pads underneath did the job for me yesterday. Boots and helmet way more important.

I've just fitted a 2mm O/S Wossner piston and ring kit into my old banger of a TY... It was the only size I could get, but not bothered because I have spare barrels. Pleased to report it runs very nicely, I did remove some unnecessary weight from the inside of the piston with a Dremel drill. The wrist pin is shorter than the old one and was a fair bit lighter. The assembly was just over 1.5 Oz lighter than the old one. It has certainly made the motor much more zappy, and the big bonus is the lack of rattling ! Just need to get used to riding a 2 smoke again...

Use the clutch more, keep the revs up. Back in the 80's I used to be always stalling my TLR and RTL 250's, they just don't plonk at low revs. Or put a BSA C15 engine in it if you want a proper trials engine, they are luverly...

I've been using WD40 for years, there is no problem with it at all.

This is the kit; https://www.venhill.co.uk/universal-2-stroke-decompressor-kit-vdec.html Works very well with the lever setup on the left bar underneath the clutch, just the same as all my 4 stroke bikes. I use it to prime the engine with fuel via 2 or 3 kicks, then release it halfway down the next kick. The engine fires up straightaway then. It also makes life easier for the kickstart gears etc, maybe not important on a Yam, but it makes a big difference on a unit BSA engine.

If its kicking back the timing is too advanced. They are not the easiest bike to start because the kickstart shaft is so high up. I'm only 56 but my right knee is not too good, fitting a decompressor into the cylinder head has helped me starting mine mine a great deal.

The time you are spending researching and pontificating over which way to go with this situation, you could easily strip down,set up and enjoy reliable service from what you already have. Its not that hard,and decent quality service parts like points and condensors are easily available at very little cost.Even if you bought 2 or 3 of everything you would have enough parts to keep it running for another 20 years of trail or trials use...

Just to add to the advice given, the standard ignition on all Yamaha TY's with points is very good quality and extremely reliable when set up properly. For the little effort it is to make it work properly I don't think the cost of electronic ignition is worth it. Yes, the 175's may benefit from the extra power available at the top end, but 250's make enough power for the bulk of riders. Personal choice and only my opinion. Only once in the last 15 years of using Ty250's have I had a problem with the ignition, my fault for using a dirty old set of points that I didn't bother to check when I built an engine out of 3 boxes of bits, using only a couple of new gaskets and circlips. The moving point was tight on the pivot and tightened up when the engine got warm. Cleaned out and greased, its not missed a beat since.

I would also be suspicious of the spark itself, as already said modern plugs don't work very well when fouled. My 350 AJS when running on a Lucas racing mag,(Which was in good condition) would go through a couple of plugs a year, I could always tell when the performance was dropping off. When I changed it to a BTH electronic mag I could run the same plug all year without even cleaning it. The BTH mag clearly had a stronger spark which could cope with a dirty plug. I proved it using an inductive pick up and viewing the spark trace on a laptop based oscilloscope. The Lucas spark was less accurate and weaker. Then when the condensor started to fail I could make the spark trace disappear by applying 100psi of workshop air to the plug. If you have access to this kind of kit it would be good to compare the HT trace of your bike to a similar one that doesn't eat plugs.

Money spent on the mag and carb will be the two areas I'd go for first. The Amal Premier carbs are great, a decent carb and spark then the rest is fiddling. Do you know if its got trials ratio's in the gearbox ? A set of Mick Ash gears in the box also is a huge benefit if its still on a road cluster.

I can't be sure, but the frame looks very like the one I had a few years back. That one was made by the late Alan Brown from Bristol. Having a Monobloc carb on it shows it as being a good few years old too. Thats going to be a big heavy handfull... I gave up on mine and sold it,my little,(By comparison) rigid 350 AJS is much easier to ride,steers better,has softer,more controllable power. Just more difficult on big rocks or steps etc. HT5's are nice bikes, but in most cases the 500 engine is too much,and unless they are very trick they can be heavy and hard work.

I think mine is on 12/53 too, but its at work so I can't check till tomorrow. The one I'm using at the moment is a D model, but the engine is more than overdue a rebore and piston. (The A model is more snappy from memory) Saying that it still goes very well and does not hesitate in picking up the front wheel in second, although third does take a bit more of a pull on the bars... I run a slow throttle too. This bike is currently only used for club trials and playing in the woods, but I never get the feeling that it needs more power. What I do like about it is its ability to run down to absolutely nothing then pick back up again without complaint. At the trial I rode on Sunday I made it do this several times where slipping the clutch would have been very risky in terms of losing traction. It just did what I asked of it and found grip on slippery mud and tree roots,not even a finger hovering over the clutch...