2stroke4stroke

Or just whip the front pipe off and measure through the port - accurate enough for your purposes.

"Changing the gas flow out" as you put it usually weakens the mixture. There may be undesirable long term effects - worth checking for this, how does the plug look?

Quite possibly, and I would drain mine if there was an easy way to drain the 4RT - I don't want to remove everything after a trial to be able to upend the tank.

I'd hate to see this develop in to the thin end of a wedge that saw full face helmets becoming compulsory. Protection from injury by use of a helmet is a complex subject that used to get an airing in the days when the motorcycle press carried intelligent articles rather than encouraging people to get the knee down on the public highway. I recall Scandinavian research using a helmet (deliberately open face) with a shell having a low coefficient of friction in order to reduce rotation of the helmet. This would be my concern if using a full face in trials (but the choice is down to the individual) and was the reason why the ACU used to forbid the wearing of full face helmets by children in motocross. My assessment is that the chance of hitting my face is less than that of catching the chin bar on something and wrenching my neck. I might reassess my needs if I was riding World sections. Being a mountain bike rider as well, I have seen these full face helmets worn and the thing that struck me was that not only did the extension of the chin bar lower down increase the likelihood of leverage but it left a gap plenty big enough not to offer protection if landing face first on the typical trials rock. Last time I looked the ACU required a trials helmet to comply with the same standards as for road use.

I had spotted the Dalesman tank but jc2's comment about the chain adjustment makes me think AJS for the frame. I seem to recall they had such a system for tensioning the chain.

During your many hours of practice do you put down section markers or just run as wide as necessary to get round? You need the discipline of going where you have to go, not where you find it easiest.

You might still find some CO2 inflators at Aldi I think it was. Much cheaper than branded MTB stuff.

That's basically it. I'll just have to keep saving and hope to find a Mont wheel? But if my info on the Sherco dimensions is wrong I'd be delighted.

We could have chatted about this tomorrow at Belford Baldilocks but as there is now a trial half an hour away from the house I won't be venturing south after all. Your experience shows that the Sherco wheel can be fitted to several bikes thus answering the OP's question and you suggested, quite reasonably, that it might also fit the Montesa. The only reason I said anything was to avoid any Montesa owners obtaining a Sherco wheel then finding it was not a straightforward fit, not to hijack a thread or start a disagreement. The guy with the Sherco wheel told me that the distance between sprocket and disc on the Sherco was 145mm; I can't confirm that distance. The same measurement on the 4RT is 140mm. The defining factor on wheel spacing is that the caliper, which is on the right hand side of the bike, has to be hard against the swingarm in order to locate on the anchor tab, which also determines where the disc has to be. If I fitted the Sherco wheel then the sprocket would be 5mm too far to the left, which can't be sorted with spacers. The only solution would be, assuming there was enough meat to do so (there definitely won't be on the sprocket side of the hub), to machine 5mm from the face the disc sits on which probably means it won't be a cheap wheel for anyone after all. Who knows why Montesa use a different width of hub from the others but it is a problem for owners who just want a reasonably priced spare wheel. I hope that explains things it not being feasible to put a sketch on here.

I know computer guys who have used fan motors from IT equipment on various vehicle cooling applications. Apparently the (entirely unnecessary in the UK) Mini oil cooler motor is very badly placed and gets a lot of dirt thrown at it.

The spacer wasn't the issue but the width of the hub (ie distance between mounting faces of disc and sprocket). The sprocket would have been 5mm out of line.

If you get the sizes then you want to be going to a bearing supplier, not a bike shop. Good quality bearings can be obtained at a reasonable price from suppliers through the net. Names have been mentioned on here in the past so a search might bring them up.

I e-mailed them when the trousers first came out and got a prompt reply and they indicated they might be looking for a UK importer. Trousers seemed good but too dear to be shuttling them across the Atlantic to establish the right size/fit.

I considered a Sherco wheel for the 4RT but the distance 'twixt disc and sprocket was 5mm too great.

Approximately once per revolution, in effect.

Personally, if I were doing this I would use the trials ratios as a means of being able to raise the overall gearing to give a more sensible top gear which seems to be what the 4 Ride lacks. I understand it is the same as the 4RT.

I have a pair of wheels less brake plates if he can use those Murray.

100:1 is actually richer not leaner "in jets" ie you are putting less petrol at 50:1 into the motor than designed but how it would equate to jet sizes as you are trying to compensate for I don't know.

As far as I was aware, Derek Elwell Products had no connection with Walker Exhaust Silencers.

I'm assuming you are in the UK. If the dealer won't comply with the rules (and I'm not sure of the detail about paying for sending back) then contact your credit card company if you used such.

Aye, and are you taking their advice to change the piston every year? I think there's room for intelligent judgement on oil changes - does the 4 Ride manual call for an oil and filter change every two days I wonder. Which could equate to the 4RT requirement.

I believe there's one the first week in May somewhere in Lochaber ☺

As above there's barely any oil in there but it seems to do the job. Whilst it looks clear as it comes out, if you collect it in a transparent container then it looks much dirtier. Part of that is because you leave a quarter of the total oil in there and it immediately starts contaminating your fresh oil.

The multilap thing came in with a vengeance when the ACU barred events using more than one piece of ground during the foot and mouth epidemic of 1967. The remaining road events were, if I recall correctly, pretty well killed off by the oil crisis of the early 70s when road use for motorsport was effectively barred by the government. Once they discovered that they didn't have to tax their bikes for these pocket handkerchief trials, as they were referred to, after the ACU relaxed the requirement to do so then trials riders were happy not to register them at all which destroyed entry levels for the few road trials left.

Well it always worked for Doug Domokos.