trialsrfun

The bridge & dam riding was just breathtaking, hope they owned the VW Golf though ???

I watched the excellent display of extreme trials riding given by martin & Dan at the recent Hillhead 07 event at Buxton and it was stunning. On the Case stand they had several big screens showing the stunts with the machinery in Gerrmany but Dan Clarke told me the HSE (killjoys) had prevented them from providing this show at Hillhead despite showing them the video and explaining that this is what they do. I particularly liked the bit where they are riding on the tracks of the excavator while it travels along. Brilliant show lads.

All the Villiers 250s were 66mm bore x 72mm stroke the 1/4 longer rod was to enable a stronger barrel flange to be added (rermember the iron barrel is secured by studs and nuts around the base flange) no capacity difference or anything else it is simply a matter of everything happening a 1/4 further off the floor. I have owned one of the bigger motors mentioned they were the Moto-X-Motors conversion made by John Burns & Maurice Brayford Maurice uses one to this day, I cannot recall the bore size or exact capacity but it was around 350cc. They do give a much greater power output but are very much heavier than a Greeves or similar top half and still restrricted by the transfer port area. Pete Carson has one as well as someone in the Midland Centre in a Sprite. The original Greeves square barrels had a chrome on alloy bore finish with no steel liner as well as detachable outer covers over the transfer ports but the chances of ever getting one of these are about the same as winning the Lotto

Probably worth mentioning that the real purpose of the aftermarket alloy cylinders was to give increased power which came at higher rpm the bottom end power was / is no better or even as good as the std iron barrel. While an alloy top half is very desirable why not build the bike with a cheaper iron/alloy cylinder & head and wait until an alloy one appears, simple swap as only the exhaust might need changing.

The DMW head/barrel is one of the best because it has an extra port above the inlet port at the rear of the liner this helps the incoming charge to push the burnt gases out of the exhaust port, the disadvantage of this barrel is that you need to have the 5 1/2 con rod. Villiers engines have two con rod lengths 5 1/2 for the 197cc engines and 5 3/4 for the 250cc use the wrong combination and the piston will either stick out the top or stop 1/4 low. The biggest single difference between a modern two stroke motor and any of the Villiers barrels is the size of the transfer ports and this single factor limits the performance more than anything else as there is simply not enough capacity or space around the crankcases or cylinder to create the port sizes you see on a moderm motor. I have picures of these barrels etc but I do not know how to add pictures to these pages.

The last time I saw Mick Andrews bike it was fitted with a Greeves TES type cylinder & head as is Mike Gallaghers James that was featured in the magazine article, having ridden quite a few Villiers/square barrel bikes I have never ceased to be surprised at the performance difference with no two being similar. Much of this could be due to set up and exhaust but whatever you go for have a good ignition. A heavy flywheel is very important as well the std Villiers trials flywheel weighed in at 7 & 3/4 ibs for the one with the screwed on weight but if you can find one the all brass wheel as fitted to the earlier 32a motors is 8 & 3/4 ibs so whether you run with bob weights or full circle crank you still need a heavy flywheel to prevent it from stalling. I would not know how much they are changing hands for at the moment but they are about and while not plentiful I think you will find something.

Hello Subira what is this then as I move from Villiers to Cub are you doing the opposite ? and by the way it is not a dumb question at all but it is one that has no easy answer. The 210 karts had to retain the outward appearance of the Villiers original hence the rounded shape but these are ported way different than a trials engine. Greeves made the square barrel and head as well as the tapered (front to back) Challenger type and both were available in trials as well as scrambles spec, in itself this does not mean much as a head spacer can be fitted to lower the comp ratio or sometimes a thin spacer between barrel and c/cases this helps to maximise the transfer port openings. Sometimes it just boils down to what you can get hold of and then try different settings etc but the biggest difference on a Villiers comes from a good electronic ignition, well set up carb and as long an exhaust pipe as is possible to fit. Many people Richard Thorpe included use the iron barrel/alloy head that Villiers made. Hope this helps.

We have one of the Easyclutch devices on ours, it does work but they are a fiddle to set up.

Hi Westyfield was it you riding the Cheetah who had a spot of chain bother on Cheeks Hill if so it was me who helped you with it.

At Hawkstone can we have Martins comments to Dougie sent down the PA ??? three inches back, half a tyre right, perfect, big effort now no radio, no instructions, no minders and no stopping that has got to be the way trials must go to help the sport grow.

Thank you all for the pictures & info, I could not make it to the trial so it is good to see the bikes that won, the Cub appears to have a very special oil tank/air box assembly and maybe the subframe has been lowered by curving down the horizontal top tubes to give a lower seat height ? in contrast the Bantam looks very std but as ever it is the rider that counts.

Is anyone able to post any picures of the Triumph Cub that Tony Calvert rode to win the recent P65 Scottish.

Bloody well kept secret

Come on then any news who is doing the business, any pics as well>

Thank you all for your ideas it sounds as though the crankcase breather is definitely the way to go.

My initial choice of breather was the one on the top of the crankcases but I am concerned that the pumping effect from the underside of the piston might send oil up the pipe and out to atmosphere a sort of total loss system if you follow me, Is there any likelyhood of this occuring.

Has this topic had the biggest ever response here on T/C, I cannot remember anything with more pages/views etc.

Which is the best type of crankcase breather for a Trials Cub, some people leave the original with the small hole inside the r/h engine case. Another method blocks this off and then a pipe is fitted from the screw in bung on top of the crankcases, I am told that one can also be fitted on to the head but I have yet to see this type. So which method works the best.

Amal Concentric carbs are different for 2-stroke & 4-stroke though they can be easily changed. The needle you have with the two rings around the top is definitely for a 2-stroke, the tapers differ on 4-stroke needles. It is widely accepted that 199cc Cubs do not run well on the Amal carb & this is why many clubs Yorks Classic etc do not insist on them being used. When a Cub is overbored 230cc/250cc etc then they seem to run well on the Concentric carb. Contact Surrey Cycles or Hitchcocks for advice on carb parts either one will be really helpful.

Thank you for the help guys but I am still not sure what the correct length of TY 175 shocks really was, some lists say 12.5 others 13.4. Does any one have what they KNOW are original TY 175 shocks to measure please. ScottT I think you are right at 12.5 centre to centre do you know for sure if the shocks you have were the originals, The 13.4s make the back of the bike very high and the fork angle then looks all wrong.

It has been suggested to me that the rear-shocks originally fitted to this bike were taken fron the TY175. Doesd any one know the correct length of original TY175 shocks please.

Does any one know the correct length (centre to centre) for the rear shocks on a 175 Mini-Majesty the one with the chrome Godden frame.

I understand what Andy means but adding pictures still sounds b####y complicated. Is there not a simple explanation as to how it is done.

Can any one please tell me just how do you get pictures onto trials central. Keep it simple though with a full explanation at every step.

Amal pancake air filter is the only one to use in my opinion. Centre hole type screws straight onto the inlet of your carb, offset type is fastened with a hose clip and requires a screw on bush (Amal part) on to the Amal carb. the adavantage with this is you can rotate the filter to best fit. Two types of filter element are available paper (chuck it when dirty) & washable gauze which requires spraying with a filter oil.