section swept

Comin me Lord.

You can buy filter foam in sheets and then cut to size. You can double or treble the layers to give finer filtering just be careful you dont cause a restiction to breathing. Experiment on scrap filter foam if you use a glue, some will melt the foam. If you are careful you can end up with a very workman like replica of the original. Foam obviously must be petrol proof.

Get your son to try getting on any of them big or small wheel. These youngsters go through growth bursts, you put them to bed one night and in the morning they dont fit the bed or their clothes anymore?Are you after a Trials or M/X bike, you might be able to find a bike with both sets of wheels just make dure all the relevant bits are there to actually allow the swap from one set to another. Warning....these types of bikes get knackered pretty quickly by not being serviced or even checked over.

Guess I was wrong, glad you found the issue. Nothing like keen maintenace??

Could be a ‘technique’ issue here, what do you reckon??

Torque= Force x Effort. For example the longer the length spanner or lever used ndoing a bolt or nut the easier it is, whereas with a short lever or spanner the more effort you have to exert. Enger the Torque Wrench. Old four stroke and two stroke engines had longer strokes than their modern day counterpart. With longer connecting rods the leverage against the crankshaft will be greater.....allied to this is the larger crank radius from main bearing journal to big end journal which of course adds weight and subsequently mass. With a larger and heavier flywheel this adds to the mass and it therefore takes greater effort to slow this rotating mass allied to the greater crankshaft weight and the greater ‘push’ on the big end journal of the reciprocating piston and con rod. Draw back is that to run the engine at 3,000 rpm the piston has to travel much further than a short stroke engine running at the same rpm. The modern four stroke has such a short stroke that the engine needs to be revved hard to generate sufficient inertia in all of its rotating mass to produce the take off thrust you need when the run up is very short! Anyone thats watched Any form of road racing or dare I say it... race cars will have noticed that to actually pull away an awful lot of revs are needed. The flywheel of a formula 1 engine is no bigger than a tea cup saucer or a sandwich plate, producing so little inertia that the engine won’t pull below 6-8000 rpm. (example) Make the flywheel heavier on the 4T and the mass weight obviously increases but then the engine has to work harder to get that mass spinning, with a short stroke the con rod doesn’t have the leverage on the crank to produce the desired torque. The Mass just makes the engine take longer to decelerate from high revs. The 2T however has a longer stroke and hence more leverage on the crank. If you've ever tried to ride a kiddies bicycle (be nice and ask first) the pedal cranks are very short and your lickle leggies are going to go round at a fair old rate justto travel a short distance. Now jump on an adult size bike ( not one of those stunt things or trick trials cycles but a normal every day one) the pedal cranks are much longer and when you push down on the pedal you exert a much greater force....longer lever....Someone is going to have fun pulling this little lot apart? Race engines have skimmed, lightened or alternative material flywheels and some are reduced in diameter, these mods then allow the engine to rev much more quickly or be more responsive. But they have little inertia and decelerate much more quickly due to less inertia. So thats my engineering doctorate thesis tsken care of......next patient please!? To sum up....remove the 4RT engine, stick in a good Ariel 500 HT engine ( bloody great flywheels, dammed great long stroke generating armfuls of stump pulling torque) and away you gooooooo!?

Its not too much effort if the set up is for road use most of the time, then swapped for more serious off road use at the weekend. Adding or removing a short length assuming all is well shouldn’t take more than a few minutes.

All reet matey boy, ?

You’ll need to remove the exhaust and allow it to drain out too! Check the carb vent pipe routing from the workshop manual to make sure you don’t create problems. If you turn the bike upside down to empty the crankcase be aware that the gearbox oil may leak out through its breather.

Safety Factor, nearly everything thats concerned with carrying weight has to have a Safety Factor included in the design. Just because the nose weight maximum is 70kg that doesnt mean the moment the weight is exceeded the component will fail. Take for example the load exerted just by cornering, braking and sudden acceleration, all will cause extra load to be placed in different areas. Just look at most builders vans and trailers, usually grossly overladen with materials and the vans suspension sitting on the suspension bump stop rubbers? As you have already discovered, things are going to bend before breaking. Is your van not suitsble to have the bike inside? I’d be more concerned about thieving scum bags seeing your bike (hhmmm nice lets av it) and latching on to you, cover or no cover.

£6.00 Asda look for the cycle accessories display Bell products cycle computer, does speed, distance and a few other techie things and has a memory. Its small, light and comes complete with all fixings. You may need to make a mounting for the sensor a fairly easy thing to do, waterproof too!?

TRIALS please its trials...over to you oni nou? I used to moor my boat at Hull Marina....if you speak to the lockie he might let you ride around in the lock entrance when the tides out be good for your mud technique (I jest) ....seriously though welcome to TC

Riding in 6th gear at high rpms is NOT recommended that you shut the throttle and coast, then crack it open again, you will rapidly starve the piston of oil with throttle closed. Even on long downhill sections in trials/practice you should be holding the throttle slightly open to allow fuel and oil mix into the cylinder to lube piston and rings. The black colour is combustion carbon starting to form, on a re-built or new engine after a short run you would expect to see carbon deposits forming as a sooty damp residue....this would just wipe off. However after a long engine run time this residue will fotm into a flakey substance and gain hardness from being continually heated by the combustion flame front. The term de-carbonising didnt come about by luck, it was a d is necessary to allow your engine to run at its best. The carbon does get down into the ring land (grooves) and helps to build up a seal....one of the reasons for running in an engine! Carry out all of the checks that lineaway has suggested, plus drain the crankcase and also clean the radiator matrix, those fins look like there is mud in between them. Your spark plug will appear wet if you start the engine, run it and then shut down as no resl hest will have been transfered to the plug tip area...thats a plug chop exercise...Google it saves me writing?? Then there are the crankshaft oil seals to worry about as if these are worn or damaged they will have an effect upon the way the engine runs overall....the list goes on and not to be disrespectful to you I would hazard a guess that your Enduro mount is a four stroke and your mechanicing skills are still developing. We all learn something new each day so lets hope you get to the bottom of this engine issue ?

Lotus 54, once a TPS has been set correctly, it really shouldnt go out of synch. Not many of us have to ‘tinker’ with the TPS on our cars, unless of course an internal fault develops with the track or contact path. On my BMW 1150GS the TPS is placed by design restriction in fairly easy access, but this renders it liable to external damage....and there was at one stage reams of info and set up procedures on the GS owners club web site. Amazing how many people develop ‘ fiddle syndrome’ with things they have little understanding of...and thats where it all goes wrong. Like with all computers you put rubbish in and rubbish comes out, so adjusting one component throws all the other settings and sensors out. Once set the TPS should not need to be adjusted, if it has to be a part of maintenance and taken off it should go back exactly to very good reference marks. You will find quite a few videos on TPS adjustment, in the majority of cases being adjusted to try and compensate for other issue with the system. Manufacturers specs and set up procedure is the correct way forward, the info must be out there but I do not have the time to search...good hunting??

Named after the USA Astrodome and American only import. 163 was 250 and 164 was 360. No front brake only rear disc brake...light it up and hang on, sideways here we come?

What I said!

Well avas.eduard, have you been treating your trials bike like an enduro machine? Sounds to me like you have nipped the engine up and messed the rings, probably stuck in the ring grooves causing compression loss and subsequent poor starting. Lineaways suggestion is probably close to whats happened. D2w lists some sensible checks that you could carry out while you strip the head and barrel (jug) off and expose ? the piston. From your description its the classic 2T seizure, I just hope its not too badly scored the bore.?

Nearly all bikes now whether road or competition have floating discs. Together with a well maintained caliper there should be little if any noticable brake judder. If your bikes brake disc has been clobbered by hitting a rock or when dropping into a gully etc this may have caused the brake disc to distort and hence the floating disc spacers will be in compression. Oni nou suggests increasing the clearances for either the floating spacers or the locating holes, these should be adequately machined to size at manufacture. However corrosion could be causing the floating to be restricted due to stiff/binding of the bobbins ( the rivet fixings holding the disc to the rotor). Floating disc brakes are really intended for brakes that generate lots of heat, more so than most trials bikes will ever do. Its just another way of making the bike look more technically advanced and also a little lighter due to the alloy rotor ( disc carrier) shaving some weight off the total disc weight. When manufactured the disc should be easily moved sideways to the limit of the bobbins and restriction of the flanging and anti rattle wave washers. My bet is you and gasserguy have distorted discs due to impact as previously described.

Throttle position sensor can be set by very slight movement, get engine warm and slacken to finger tight the TPS securing screws. Now with engine close to idle as possible move TPS and note engine speed change....only move it a tiny amount in stages until you notice a reaction. These things are set with an ohmeter normally but this process I have outlined usually gets a reasonable result. You wont harm anything by moving the TPS through its adjustment range at idle. The factory should have put a reference mark on the lip of the TPS and its housing usually paint. The ECU reads the resistance created in the TPS and wotks out from this how far open or closed the throttle is, very much light a light dimmer in a living room as an example but the TPS is far more accurate.??

75 mins to a tank! Are you saying you get 75 minutes worth of riding around practicing or are you meaning 75 miles? Fuel consumption for a trials bike can be very different due to the way the bike is ridden, the gear selected and the amount of revs employed to tackle each obstacle. I think we can discount the 75 miles as this would not equate with trial gearing and high friction tyres etc. If the bike runs nicely and starts ok and idles well, answers to your throttle hand responsively then all would appear to be well. At a guess I would say you could expect to travel approximately 30-35 miles ridden at a constant road type speed of say 30-40 mph, but you wouldnt want to do it as the tyre wear and chain slap wearing the tensioner and any other associated items. Quickest way to wear a trials bike out is to ride it on the road all the while, Im not talking about on the road between sections in a trial.

Running with a very small gearbox sprocket can cause issues with the chain. Theres stuff about this somewhere on TC and Google, with a larger rear sprocket there is a better reaction from the chain. Basically with a very small eg 9 tooth gearbox sprocket ( for example only) the chain links are at their maximum with regards to following each other around the gearbox sprockets teeth and either a smaller chain ie going from a 520 to a 428 and associated sprockets would alieviate the problem. In the case of a chain fitting around the smallest gearbox sprocket it tends to want to lift off the teeth rather than neatly follow round the sprocket. The torque reaction in the chain, where the tensioner should be placed to mimick the chains centrifugal whip at the highest point of the whip...if you see what I mean. For this reason it is better to use a larger rear wheel sprocket instead of a smaller gearbox sprocket. I know this may sound b@ll*@s to some of you..no disrespect...but Im sure its shown with a diagram on the back of some of the better quality chains. Many bikes are overchained ( too big ) fitted with a 525 that looks good and strong but heavy, its this weight that causes problems for the sprocket teeth. Swapping down to a 428 means less overall chain weight and less weight in the thinner front and rear sprockets. Hope you understand this, Ive left out the math content as its near to Christmas and we have enough to think about???

The airwrench is only for undoing the flywheel nut....its not used to tighten, at least I don’t.

No but there will be 48 ars@*&ls looking for other employment pdq!

Thersa May was their first choice!

May be the top riders are getting fed up of hurting themselves at nearly every outing. When you’re paid and expected to give a good performance at what stage do you back down and say....nope thats too dam dangerous...even with a catcher! The older you get the longer and usually more painful it takes to recover.