section swept

Thank you for showing the photos.?

Not Cadwell is it....this is the potential future of trials if H&S get their way, fences, inflated barriers, tyre walls (debatable) and run off areas plus all that nasty slippery green grass stuff. Beta 300 on slicks anyone, you could opt for wets but in any case the mandatory neck brace, seat restraint and airbag rider protection system is going to slightly affect anyone’s chance of sweeping through the sections.....did you see what I did there....did you? ? That’s not grey sky oni nou, it’s a dastardly H&S newly developed method of shielding your eyes from the brightness....a mere £60,000 to pop an airship up and burst it scattering a cloud of talcum powder in front of that bright thing in the sky. You are going to need the CE spec safety glasses to for when the talcum powder starts to settle???

LOL

Good point, also leaving the bike standing unused for a time would allow the water to go bad and attack the rim quicker. Although the same problem occurs with race bikes (read track day that don’t get tyres swapped every five minutes)and road bikes the heat generated riding at speeds much higher than a trials iron would travel at usually dries off any moisture so the issue takes longer to become a problem. Leaving the tyres at a relatively low pressure ie 4 psi may also allow the water trapped between tyre, tube and rim to puddle and work more effectively. Maybe inflating the tyres back up to 15-20 psi might squash the water and spread it into smaller droplets that might not be able to do so much damage. The only other alternative is to pop the tyre off and dry inside?although this might make getting down the pub a bit later than usual?

Would that be beer, wine and spirits?

By the way these posts are coming thick and fast is no one working, or are you looking as though you are working? I’m staring at a pile of washing that has yet to reach the washing machine, but it’s no good I just feel too static to be bothered?

Glad it wasn’t spelling?

Agree but the placebo affect worked, static charge is on the conductive surfaces of the object usually discharged when the first person out of the car touches both object and ground. Don’t try refuelling a helicopter without first discharging the static build up otherwise kaboom! I can never read anything like a map or book in a car front or rear as it makes me nauseous. Agree nothing to do with static, but those straps still exist. I find that excess alcohol prevents travel sickness in trains boats and planes, cars too but it tends to get messy when the inbibers brain works out what’s going on.

Does it matter, the threads mushed. Most decompressor valves are the same thread as the spark plug, it will need helicoiling or a thread insert boss fitting. All of these can be got on that website that has the same name as a dam great river begins with Am, and not too dear either. The insert boss will look good but most people would opt for a helicoil, from an access point of view you should be able to do the repair in situ. I may be wrong but it looks like you have an insert in there already. If the hole is too big you will need a thread boss insert, these are totally different to a helicoil and I suggest you do a search on google before spending out on an unsuitable repair. If you are going to fit a decompressor valve a kit is available from the usual dealers at approx£40 with cable, lever etc. If just blanking off then it is important to completely fill the hole down to the roof of the combustion chamber. The current bodge up has reduced your compression ratio slightly.

1985 was a reasonable year for me too and I suspect many others, but I too prefer not to say why. But Joni nouy (your description) doesn’t deserve your comment about ‘knowing it all’ just because he responded to another members post. In your experienced time on this and the forerunner site I would have thought you to be a little more understanding. My posts are few compared to you commendable contribution, but you too have information time issues when you reply “what was it 14 years ago”. So perhaps “fact check that” was uncalled for.?

Who cares it was hilarious save for the young lad who wasn’t too badly hurt. He was looking quite confident to. I bet there would be some riders today that would baulk at this type of obstacle. H&S wouldn’t allow that on tv now, mores the pity.

Thank you to everyone who has taken the time and trouble to post pictures and provide information. I would seriously like to own any of the bikes shown, almost want to put my arms around some of them! They all seem to stir up emotions in me of the past when each bike was full of character and more importantly then were available to be bought for a small outlay. ??? Thanks guys.

In the first three shots that petrol tank looks like a Bultaco plastic item. Fits very close and looks good. Both bikes look to have fairly steep steering head angles. Thanks for setting my appetite even more. Just spotted a WW11 Zundapp sidecar outfit.....a mere £58,985 and the smaller road bikes are comparably priced at £3,000+ I’m going to have to save a lot more earnestly if I’m to get a trials version.

Like to be entertaining, but informative too! Serious about the travel sickness, that’s why you can still obtain earth discharge straps that hang down off the rear of the chassis/body. What with nylon seat material, nylon content in tyres, etc etc the static that can build up is noticed by some people. You even get some car owners getting a static shock when they get out of their car and touch the door handle. Manufacturers either use non conducting materials for door handles or trust to the paint to provide insulation, but the first scratch on the handle and zap. Also serious about rim issues, anything that helps an owner to understand a problem or reason for something happening and hopefully provide a solution or remedy is what I’m about. I like to keep things light hearted to as this is a sport to be enjoyed?

Not a boat owner are you, having to change anodes for different water conditions, ie aluminium for brackish water...river and sea mix or estuary. Zinc for sea water and magnesium for river water. All of these anodes have to be earthed and clean of antifouling and other applications before they can act as sacrificial anodes to protect props, rudders, steel hills etc. Zinc needs moisture to protect steel and aluminium not just on boats but for electricity pilons and other constructions that are on the ground. Cathco based in Chesterfield is one of the largest companies specialising in catholic protection for all aspects of metal constructions through to ship building. In Lorenzo picture it looks as though the spoke nipples are unaffected by the corrosion and it is the alloy rim that has acted as an anode sacrificing itself as opposed to the nipples rotting away. There by hands a theory that you should consider the material from which the rim, spokes and nipples are made from including the valve assembly. In the case of the valve assembly for a tubeless tyre ensure that the fixing is NOT earthed by overtightening or not using sealing washers correctly, stainless spokes and stainless nipples is to some wheel builders a no no, preferring to use brass nipples instead. Had Lorenzos rim been painted on the inside the corrosion might have been far less, but he wouldn’t have known until taking the tyre off.

Yes but through the spring, and unless it is attached at the top it is a free component. It drops down into the fork stanchion tube and sits on the bottom of the fork slider, with the weight of the machine and rider pressing down through the springs at the front end. At the rear we have a dichotomy as the damper carries the spring and the damper(s) are attached both top and bottom, there the top half is sprung and the bottom half is unsprung, a reason why some units are fitted upside down and not just for looks or clearance issues. Years of working on race cars doing corner weights and calculations to achieve the impossible ie make the driver better has helped me set up bikes that respond in almost the same mode. USD front forks is another way of reducing unsprung weight giving the damper less to do when controlling wheel movement on compression and rebound. If you put your bike onto a stand with the wheels free of the ground, anything that drops down or moves down is going to be unsprung weight. Anything that is attached to the frame is sprung weight. The drive chain it could be argued is both as it hangs down on the underside and is pulled across the top but it is carried by the rear wheel sprocket so the portion that is closest to the gearbox sprocket could be said to be sprung weight. The side stand if attached to the swing arm is unsprung weight but if attached to the frame tubes it is sprung weight, that’s why many bikes have the stand on the swinging arm. There in lies another reasonable case for stating that some of the swing arm is sprung weight and some is unsprung as it is carried by the wheel but also carried by the pivot point. There is also the issue of the rider dabbing, this can unsettle the suspension and the second the riders weight is transferred to the ground the suspension can unload slightly and upset the riders balance. Those who bunny hop and bounce about like they are on a pogo stick have developed a better sense of balance and machine control, sime do it violently some do it as a performance control and smoothness trying to plan with the reaction of the suspension. End of sermon, enjoy your bike ( ? theres no unsprung weight on an old bicycle save for a tiny amount of absorption through the tyre walls) stay away from suet puddings to reduce sprung weight⚖️?️‍♂️?????

Stay away from the Christmas pudding?

I have sealed the spoke nipples on the inside of the rear rim to keep water out...with a bit of luck...my rims are original Arkront and show no real signs of corrosion on the inside. Might be down to the silicon mix when the aluminium was cast, or possibly the rolling process to form the rim could have something to do with it. I won’t hold my breath as I can feel some comments coming my way saying that Arkront are rubbish and dissolve in water etc??⛲️?????

Nah don’t believe in all of them Ologies, but had to teach Science to some learned individuals??‍??‍???‍???‍♂️?‍♀️

Luckily the product you mention does eventually dry up, but at least you won’t have the worry about suffectants attacking the rim. I use a bar of soap that’s going soft, acts just like proper tyre fitting soap.

Stupid place for a water pump anyway. Poor design.

That’s alright until you hit someone! Hope it never happens but even spectators can and will sue, never mind the warnings about sport being dangerous. At a trial open day my partsman decided he could ride up a bank next to the car park, he lost control and managed to crash into an innocent bystanders car, luckily it was just the car damaged and the partsmans ears from my rollicking that I gave him. I can’t advertise but google competition insurance, there is firm that covers Trials bikes on road and during competition for reasonable money ie £95 annually.

As all of the spring is carried in the fork tube pressing down on the bottom of the fork slider all of the spring is unsprung weight. The fork slidertube is unsprung weight to. It’s fun working out what is and isn’t sprung and unsprung weight! I never did trust Newton’s Law preferring instead to follow the writings of Bart Simpson, his diagrams on which part of a progressive spring compresses first are a joy to the eye. The calculations as to which part of the progressive spring rebounds first are a positive cure for insomnia. Girder fork discussion anyone.....anyone???

You will know if it’s tubless as the valve will be a sealed fit to the rim. Fit a tube and the problem goes away! Or as oni nou suggests seal everything up but you can get a tyre sealant that you paint on to the tyre bead or/ and rim. This product is used by the car trade when an alloy rim and tyre bead leak air out, the tyre is deflated and the bead pushed away from the rim and the sealant is applied by brush. The tyre is then forced back onto the rim by compressed air and the sealant goes off after a few minutes sealing the bead to the rim. The main reason your tubeless tyre loses air is the pressure is too low to maintain enough force to keep the bead against the rim. When not in use pump the tyre up to 30 psi and leave overnight, re check pressure in the morning and see if it’s lost any pressure,this should all be done with cold tyres. Now you simply have to remember to let the pressure out to your favoured riding pressure. The whole reason for going tubeless apart from a marginal weight saving ( the tube) is to prevent the tube from being trapped or pinched when the tyre is pushed against the wheel rim and puncturing, tubeless prevents this but presents other issues namely one talked about above. Tubeless also allows for quicker puncture repair but that’s about it. Nasty rumour going around that 2020 bikes will have marvel of marvels....tubed tyres or even no air in the tyre at all just a type of indestructible compressible mousse.?

Go with the progressive springs, you get smoother and predictable action. In any case all suspension springs will eventually sag, collapse or break due to the life they have to lead. If the manufacturer used better quality material in the first place you would still end up with the springs becoming weakened and softening to a lesser extent. Secretly some works riders will ditch the springs after a few rounds and fit new or different rated springs. A main reason for poor handling on any bike be it road, track or whatever is the springs going off song....weakening...that’s both ends.