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Interesting, As I said, I couldn't see why it would be anything different but I definitely had to set my tinytach to 720

Umm, maybe, but I don't think that's the case, obviously diesels do but petrol motors don't have to unless they're direct injecion, I think on the 4RT the injector just sprays fuel into the inlet tract at the rate governed by the ecu map for the operating conditions.

Yep, I had to set mine to 1 spark every 2 revolutions or every 720

Dabster gets everywhere!

Like these? Clicky

Excellent idea, and you could recoup a good bit of the cost selling them second hand on ebay if you take them off when you eventually sell the bike. It's worth taking off the thick grips and putting on some thin trials grips too, most of Ted's hands were taken up just wrapping around the grips when he was small. Wish I could find something similar for his Sherco 50, drum brakes and little hands don't offer much stopping power.

You're very quick to condemn. I'm Not so sure. Clearances and bash plate height (2.1/2" higher than standard) look similar to this one http://www.tytrials.co.uk/sitefiles/tytrials/35818/Majesty%20Article%203.pdf Can't get the link to work properly, but it's on www.tytrials.co.uk if you go looking

OK, but it was an easy jibe. I'm obviously going to say they're worth it because I bought one. I think I paid around

Strange, you don't know how much it is but you want a cheaper one. Do you want the cheaper one to be accurate or does that not matter? Cheapest is using your ears, park next to a bike that has been properly set up then set your tickover the same by listening to them both. It's not difficult.

How distorted is it? If it's not much you could try lapping it flat with grinding paste on a piece of glass On a bike of that age and value, I'd be more inclined to try a couple of new o rings and a healthy application of good quality silicone before I paid someone to skim it.

Yep, I use a tinytach, useful as it also records hours run. I use this as a basis for oil and filter changes Get one here Clicky

Think in the Garelli version it was 2.4mm btdc

Oh Dear.....

Loads of potential non-issues here, but maybe problems too. Think about these. Fill the engine with 50% coolant, whilst doing so, you should squeeze the pipes above the pump to 'burp' the air out of that area. Run the engine at idle, from stone cold, with the radiator cap off and look down the tube. If you have bubbles coming up the tube in the first 5 minutes or so, the inner cylinder head O ring has blown, if you don't get bubbles till the water boils, it probably hasn't. Take the wires off the thermo switch and short them together - a short piece of wire or a paper clip and electricians tape works a treat. Start the engine. If the fan is not running then you have a fan problem. If it is running, ride the bike. Half an hour should do it. If you've over filled the cooling system, don't be too surprised to see water and steam, it'll stop after a while. If it doesn't then the inner O ring is leaking under greater working pressures or the water pump isn't working properly, feel the radiator tanks, if the bottom one's not getting warm, the water pump is possibly the problem. If the bike runs fine and settles down with the fan running constantly, remove the short and re connect the thermo switch. Start the bike and leave it idling, keep feeling the radiator top and bottom tanks. They should both get hot. If they don't, the water pump's not working properly. If they do, then when they become too hot to touch, the fan should cut in. If it doesn't and the water boils, you have a thermo switch problem. Check the thermo switch as previously described. It doesn't matter what temp you think it should work at, it just matters that it works at all before the water boils. Make sure you get the radiator cap on properly and tightened down, easy to get it on wonky then you have a totally un-pressurised system Oil in the gearbox. Just because you let some of the oil out and re-filled it, it doesn't mean you got it all out. A friend with a drowned Montesa 4RT recently needed multiple (5?) oil changes to get it clean. Did the level go up when you ran the bike? It would if the water had bypassed the seals and entered the gearbox. Just thoughts....

Thanks.

Unfortunately, re-using a head gasket is normally a waste of time, but on a 2 stroke, why are you going to split the head and barrel? just lift the complete 'jug' off the piston. You can still get your hand in to de-carburize the head if you think it's necessary. If the plated bore is worn past its limits,

Last outbreak of foot and mouth here we didn't get out on our bikes for a year, but, we expected to be out in the next week or two for the whole year so we did nothing. Only problem I had after the year was the first trial I broke the chain (in 2 places) on the first big step I hit, the side plates of the links had corroded on the inside. If you really are bothered, go to your nearest marine chandlers and buy an aerosol can of fogging oil. This is used for 'winterising' 2 stoke outboards. Basically, you run the engine at a fast idle, then start spraying the fogging oil into the carb. It will gradually coat the crankcase internals, main bearings, both con rod bearings, piston, and cylinder surface with an oil that will dry to a protective wax coating. Eventually, it coats the spark plug and the engine stops. Then you don't move the engine at all, everything internally is coated with hydrophobic wax. Tip the bike right onto its side and fill (really fill) the gearbox with diesel. Pump up the tyres up to 25psi Brake fluid is hydrophylic and should be changed every 2 years, though you are unlikely to raise it to boiling point on a trials bike. The water can cause caliper seals to swell. Empty the carb floatbowl of petrol and spray it with fogging oil. Oil the chain (heavily!!) When you are ready to ride again, drain the diesel from the gearbox and re-fill with the correct quantity of your favourite oil, change the brake fluid, put in a new plug and fresh petrol. Off you go.

I want to change the fork oil in the Cerianis fitted to my Cub They have 35mm dia stanchions and are around 31" long spindle to fork tops unloaded What sort of volume and weight oil should I use as a starter. The oil that's in is red so I'm guessing it's ATF.

Whilst the best place for it in terms of the cleanliness of the oil being fed to the engine is on the feed line, the general consensus is to fit on the return line as the effect of no oil reaching the engine due to a blockage or an airlock / airleak doesn't bear thinking about. Wouldn't worry about a bypass valve in the filter element, you'll be changing the filter long before it blocks up with debris.

I presume you also wrote to the manufacturers asking them why they don't produce bikes that conform to the rules? If so, what was their response?

Your profile doesn't mention where you are in the world, but, in the UK for ACU events there are rules. Among other things, these govern the size of bikes youths ride. For example Youth D riders can only ride 50cc mono shock or 80cc twin shock, there are two wheel size based classes, small wheel and medium wheel. There is no point buying him a bike that falls outside of the rules then expecting clubs to allow him to enter. There is an insurance problem in addition to the competitive one. Equally if he's only say 6 months away from being allowed to ride a bigger bike it may be as well financially to keep him on the minitrial, plus a new bike makes a wonderful Christmas present

Regs are on the AMCA site, you just have to look for them Clicky Then click on Kendall (14/08/10)

I had 1999 and 2000 bikes, I have the bearing number 30203 jotted down but don't know which it was off, I'd guess they're both the same. Not exactly difficult though, measure the bearing with a decent rule and phone your local bearing supplier

Hope it's just the seal / shaft, Betas used to have a problem with the magnesium rich alloy eroding in the waterpump, made worse by insufficient antifreeze in the coolant. I'd take the pump cover off and have a look before you order any parts

The nicest repair would be the installation of a pair of rivet nuts