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You don’t say if your bike is standard or comp model. There are differences to needle height position, 2 is for standard position 3 is the comp version. Are you following the Beta hot start procedure fully? Fuel tap operation is a part of hot start process. Have you got owners/workshop manual? Beta web site has plenty of info for you.

An awful lot will depend upon the overall condition of each bike. At these years you may find them to be either in serious need of rebuilding or totally immaculate. The Sherco will have the stronger, possibly more reliable engine, but again condition and maintenance is very important. Have you considered a 250 Beta as you already know your sons bike. I was looking at the classifieds last evening and there were quite a few good bikes at reasonable money. Either way give which ever you chose a real good testing, ensure the engine ticks over (idles) evenly and no stalling. Clutch may be grabby but not unusual. Look for cracks in the frame especially around engine mounting points. Service records or invoices of parts fitted are a good indicator as to the way a bikes been looked after. Check out the owner/rider too, how long have they been riding and owned the bike. If you can ride the bike go through all the gears accelerating and decelerating. If a stand is available spin each wheel and listen for rumbling noises and look for wheel rim truth. Hope you get a nice bike and enjoy it??

Bit like owning a modern..ish car or van then!

Ah...now then where’s that screwdriver thingy.

What’s a screwdriver?

The detent plunger holds the selected gear in place, this component can sometimes make gear selection feel very stiff. With the detent removed you could possibly have selected one gear and caught another which would lock the gearbox. I am assume here that the piston in the cylinder is free and not seized. Alternatively you could try a role reversal and let your wife with her logical thinking take over the restoration. This would leave you to do the cooking, dusting and hoovering, but you would be able to use your 4rt for the shopping??

Yes and if you should happen to fall off with the bike on top of you, the slope of the bank can make extracting yourself dammed difficult. Some railway banks can be very interesting and challenging, what with overgrown bushes, tree stumps, railway detritus and of course rubbish. ??

Toni Bou could probably win on a rigid framed Bantam! As for your bike, you obviously love it! What about some top end engine work; polishing and porting with some appropriate mods to enhance low end torque and throttle response. What fuel are you using, pump gas or other? You don’t mention tyres, which to some riders is most important. Have you had the suspension (current) set up by someone who knows what they are doing, you may have already done this yourself perfectly well, what suits one does not always suit another??I know of one rider who spent most of his time just getting the wheel bearings as friction free as possible, alignment in the hubs, selective bearings etc, worth at least 3-4 hp he would say.

You’ll hate this, CDI sends a much faster and powerful charge to the ignition coil. The CDI unit is triggered by the Hall effect sensor or trigger as some call it (little black or grey unit close to crankshaft where the points would have been on older engines) this is the component that electronically sees the timing/ignition point. The Hall sender/sensor can work quite well even when its starting to break down in performance. Did you send the Hall sender to be checked at the same time as the stator. I’ve replaced no end of these senders, they can perform just like a human with toothache, it’s hurting like hell but there’s no sign of pain when the dentists approaches??I bet the previous owner went through the same checks you are now involved with. Hall senders can become unstable in that one moment they work and then the next nothing. Many ignition systems get pruned down in design so that the coil sits directly on top of the spark plug and there is no HT lead just a cap to connect to the plug, again one coil per plug produces more efficient ignition. What was wrong with the stator? Hope you sort the problem out, please keep us posted?Your CDI unit may contain the Ignition coil, on some systems it’s a separate item. Testing the ignition coil is the same procedure as for seperate coil, but you need to know the electrical specs for your particular unit.

Just another thought, you aren’t confusing the drive chain rattling against the frame etc. ??

I used to practice on a disused railway line, the track was gone but the banking and the fact it was right out in the country meant that no one could see me or hear me. Make sure if you go ahead that no planning consent is needed to use the land.

Original bikes one day will be acknowledged as such. Bring it on, just look how much value they command in totally original condition! That may be a bad or a good thing but either way they have character, history and presence; bit like a film star or Royalty.

Was this noise evident before changing base gasket? Have you had bike long? What oil/fuel mix ratio are you using? Its best on a two stroke to not close the throttle fully on ‘run down’ as this could cause the piston to nip up due to lack of oil, momentarily is ok but on downhill you should keep the throttle slightly open. What you may be hearing is the piston slapping the cylinder bore as there is no stabilising power stroke, so rather than the piston doing work it is being driven by the transmission. All this is fine and dandy but without hearing the engine my advise is purely based on conjecture. ??

Ditch the pump and the oil tank, that’s two less things to go wrong. Throttle cable only pulling on the carb slide means easier action and less effort from rider. Don’t forget to remove oil pipes and unions, plug oil in holes otherwise you have an air leak. Space now freed up by oil tank removal allows for better access to air box etc.

Ignition coil may have a defective primary or secondary winding, in other words a broken wire. Hence your stated ‘power to ht lead but no spark’. The engine running for a while and then stopping is indicative of the coil wire being broken internally. Double check the coil earthing to frame before removing. Also easily missed, but have you changed/checked the spark plug cap? The CDI unit as the name states contains the capacitor which may have gone open circuit. Can you borrow (rather than buy) from another bike the suspect parts to eliminate before spending out? Are you using a multi meter to check electrical items etc. Ignition coil should have a range of between 0.5 to 3 ohms between wiring connector tabs on coil body. From neg terminal to ht lead 7+ thousand ohms, you will need exact specs from w/shop manual. £130 for a CDI unit sounds a lot, most are not repairable unless you burn out the resinous sealing and can get at the pcb and find the faulty component. The time and frustration in doing this plus possible health issue due to burning the resinous sealant out needs to be taken into account. Maybe another CDI unit from a breakers might be worth considering. Bet after this little lot you find it to be something simple and obvious, but then we have all been there at some stage or other, good luck. Oh, I don’t recommend sticking your CDI unit in the oven either, not good for other half relations or the CDI unit. You might try a hot air gun to warm the body of the unit but I doubt it will have any effect. If moisture has got in the unit the damage will have been done.??

Could be a supply error, sounds like you have received 4-stroke piston rings (XT 250) and the expander(50 pence shape-ish) ring is supposed to go behind oil control ring. I could well be wrong ?. GDT and TY OE rings must butt up against the ring locator pegs in the grooves.

And it’ll be even longer than ‘in a while’ after having performed that little lot. Maybe just ensure it’s safe to start the engine, then work out from oni nous extensive list what you need to do. Cotton buds...cotton buds for reaching all those little places that need cleaning?Like the list and especially the energy drink ?

Kawasaki, Suzuki, Honda and Yamaha have all used similar types to the ones you show in your first picture. It was a novel way of getting more suspension travel without raising the height of the bike at the front end. The design was first seen on MX bikes and then migrated to Enduro and Trail bikes. You might find that the extended lower part of the leg may foul on rocks and other trials type going, which would be a disadvantage. They probably weigh a bit more than the normal forks.

If the engine has been allowed to overheat then the thermostat will suffer. Usually the high heat causes the wax in the stat capsule to escape and then the stat will no longer open causing overheating. My advice is to 1) lift the head and inspect the cylinder bore for excess scoring and signs of seizure. 2) check the temp sensor switch for the cooling fan. Do this with a multi meter set to continuity, meter lead on each terminal of the sensor. Hot air gun played onto sensor tip. Continuity should be made when temp hot. No continuity then sensor shot! 3)The cooling fan housing may be distorting with heat and jamming the blade, or the motor is worn. 4) The coolant should have anti freeze in it. Anti freeze raises the boiling point of water as well as protecting from freezing, if the mix is too weak or non existent then this will not help with the cooling. 5) Water pump impeller may be slipping on the drive spindle. 6) Thermostat needs changing, you would have already looked at this, to test it use a piece of wire and lower into a pan of water that is warm and turn up the heat. When the water reaches approx. 75 degreesC you see the thermostat start to open and be fully open by 86degrees C. Hope you don’t find anything nasty wrong with bike? With the clutch drag, put that on the back boiler and sort the engine out first. Most trials bikes have clutch drag and owners have different ways and means of reducing or eliminating it! Start with the external operating mechanism parts clutch lever pivot first then adjustment check. Lube all items that you can, find out what oil the previous owner used, it may be wrong spec. You might end up striping the clutch down to do the job properly, cleaning burrs off of plate edges and clutch drum. I’m fairly certain there is a good amount of info in the GasGas section on this forum.

If the ignition timing has altered you need to find the reason why. If the stator plate has not moved, and the woodruff key is good and there is no excess play in the key way...you don’t say if the key way is good. Why did the engine run away, was the throttle slide stuck? Not sure if your electronic ignition unit has an advance map or not, still if it was faulty I doubt it would retard the ignition enough to cause reverse running.?

Hope you get to the route cause of the problem. Lube the oil crankshaft seal lips with either two stroke oil or a smear of silicon grease. Good luck, let us know how you get on??

You can experiment with richening and weakening the mixture by adjusting the carb needle. This may also be very worn as will the main jet allowing too much fuel in and hence the engine trying use up the excess fuel. This would also cause the engine 4- stroke and try to bog down. Are you using a manual? I ask as it appears to me that by asking how to alter the mixture you are not that experienced. Please take that comment with the good intentions meant by it, we all learn something new each day and this forum and it’s members have a wealth of experience to share and to learn from???

It’s not the air before the carb that influences engine run down from acceleration, its the air that can be drawn in from other areas including the throttle slide. So as suggested by others, crankshaft oil seals, crankcase drain bungs, cylinder base gasket, carb air leak after throttle slide( engine side), breather pipes blocked, kinked and incorrectly routed. Popping at the exhaust could be ignition incorrectly set, possibly crankcase containing excess fuel residue, the list goes on.?

Sorry that wasn’t helpful?

Suppose really it depends on how far round you twist it?