feetupfun

Yes the TY250 has a 26mm Mikuni as standard equipment and they work fine. A 26mm to 28mm mm carby of whatever brand is a good size for two-stroke trials motors from 200cc to 350cc

I will take photos and post dimensions later on today when I clean some air filters. Are you telling me that Uniflow Australia will not sell to you?

To use the DT360 piston, you make a new, bigger sleeve to fit into the TY250 barrel. If you use a DT360 barrel, the port timing will be wrong because it the DT360 has a longer stroke than a TY250. 26mm VM Mikuni carby is good for a 320cc TY250 motor

Options 1 Buy some 12mm threaded rod from the hardware/building supply shop 2 Theres a person making stainless steel replicas of many old Bultaco screws, plugs, axles, nuts etc and advertises on eBay 3 Any machining business could thread the ends of a piece of 12mm steel rod for you

My 1977 TY250D air cleaner uses the same type of filter and cage as my TY250A and TY250B. The air box is different though in that it breathes through a slot in the lid on the D model and breathes through two holes in the side of the airbox on the TY250A and TY250B. When you say the 1976/77 model does not have a cage, what supports the filter foam?

Last time I bought a TY250 element from www.uniflow.com.au it came with a new cage in the same bag as the foam element. If you still want to make your own cage, I can measure one up and post details later on today.

Neo it certainly is true for pneumatic-tyred tractors. I know that because I helped my Dad add the water after changing a tyre on our tractor when I was a kid. There was even a special valve nozzle that was in two parts. The outer nozzle section screwed off so you could add the water from a garden hose, then you screwed the outer nozzle on and added the air through a standard schraeder valve. It was useful for tractors because it lowered the C of G. I don't think it would help a trials bike that has rear suspension, but may be of use on a rigid-rear-end trials bike.

They would probably fit your model 125 but it is impossible to say for sure from those weird angle photos on the eBay listing. The listing reads be like they are NOS from a model 199B. The price sound too cheap to me so am a bit suspicious about exactly what they are. The caps are different to what came on the model 125 and all the aluminium bits on the model 125 forks were polished rather than painted black. If it was me buying them I would ask the seller a few questions.

Have a good look at the Honda rims before you get too excited. Some alloy rims from that era have suffered quite badly from corrosion inside the well. Some TLR200 models had gold coloured rims made of steel. Another thing is that the TLR rims would have to be very cheap to compete financially with new rims from asia (in many colours) I have started seeing on twinshock trials bikes around here this year. As far as lacing the two together, if the Honda rims are 36 hole and same lacing pattern as the TY then the only issue would be slight differences in the angles of the nipple holes (caused by the difference in hub flange diameters and the flange spacings), and this can be overcome with patience and a small round file.

Yes there are many standard Yamaha TY175 colour schemes from different parts of the world but I think the USA market C model was the same as our C model (orange and white). Have a look at this. Not all are standard TY175 colour schemes but most of them are: http://www.bikepics.com/yamaha/ty175/

This is what the Aussie 1976 C model looked like when new http://www.bikepics.com/pictures/763083/

Inside the carby is a device that controls the level of fuel in the bowl. It consists of a float and a valve. The float pushes the valve shut when the fuel is deep enough in the bowl. As fuel is used, the float goes down and lets more fuel in from the tank to the bowl, restoring the level. For some reason that valve in your bike is not stopping the fuel from overfilling the bowl. You will need to pull it apart and work out why that is happening. It might be as simple as the valve being stuck open, or it might be something else.

Your footpeg mounts are standard TY175 but the footpegs are from something else 525 - 00..... is B model 1975 525 - 10...... is C model 1976 Standard fork tube protrusion for TY175 is 22mm.

As far as viscosity goes, SAE 10W40 will be OK in the gearbox. The important thing with gearbox oil in wet clutch bikes is to avoid oils that contain friction modifiers or extreme pressure additives because they will cause the clutch to slip.

There were plenty of the red coloured first model Shercos sold here and one of them is still being ridden in our local trials. I will be able to get high quality photos but it will be a while as our riding season has just finished. I am pretty sure I have magazine photos of that model and I think there might be a close-up of the thumbs up graphic in that. I'll have a look later today. When they were advertised they were referred to as the "Bultaco Sherco" which was very hard for some of us to pronounce after thirty years of saying something very similar but different.

Rev 3 is the model series that followed the Techno series ie Beta Techno, Beta Rev 3, Beta Evo

1968 Sherpa T (model 49) triple clamps are different to model 125 triple clamps in many ways, if they are indeed the originals on the model 49 or even on your model 125. It has been so many years since new that your bike or the one that the 1968 clamps came off may not have the original triple clamps. The model 125 Sherpa T does share triple clamp type with many other model Sherpa Ts so you stand a good chance of being able to get some to replace yours. I hope you have considered straightening them because it may be possible and easier. Sherpa T triple clamps are unique amongst Bultacos so you can rule out triple clamps from Alpinas, Matadors, Fronteras and Pursangs. For a model 125, you should be seeking triple clamps from a Sherpa T from about 1974 onwards (model 124/125 onwards) Eariler fork tubes and triple clamps were different to what should be on yours.

It only takes a tiny amount of water in the oil to make it go grey. There is no reason for the gearbox oil to go whire/pale/grey other than water ingress - the water is either getting in from riding in water with poorly sealed gearbox or getting in from the coolant circuit.

The bronze bushes are normally a light push fit in the swingarm tube

Brian I would love to see it too. You should be able to post photos on Trials Australia www.trials.com.au Alternatively you could email me photos and I will post them up David

yes its a byproduct of sugar manufacture. I have no idea how it works but it is commonly used for cleaning up rusty steel for automotive restorations. Have a look on google if you really want to know how it works.

Dunlop rears are not available as tubed type and their tubeless rears are incredibly difficult to keep on the rim of tube type rims at trials pressures. No idea about Vee Rubber tyres I ride only twinshocks with tube type rear rims and happily use IRC tube rears and fronts and Michelin fronts. All three are readily available and work fine. If Michelin made decent tube type rear tyres I would use them too. The front tyre brand does not have to match the rear tyre brand for the bike to work well, but on a twinshock the performance of the front tyre is important for the steering to work well. I reckon Pirellis MT43s are woeful compared with modern tyres for trials competition use. Of course if I was riding a trials bike on the road much it would have Pirelli or MITAS tyres as they wear out more slowly than proper competition tyres.

Important things to do if there has been water in there Remove all rust from all the steel bits - especially the whole way though the ID of the fork tubes. Pitting is not important but getting rid of any particles that might come loose in service is important. Remember that the springs can rub loose anything not part of the parent metal. I have recovered a set of severely rusted (internally) forks from a 348 Cota by cleaning all traces of oil out of the tubes and then plugging one end and filling the with molasses and leaving for a few weeks. This dissolves the rust and leaves the steel alone. Similar molasses treatment was used for the other steel parts like damper rods and springs. I haven't used molasses on any aluminium parts and suspect it may damage them. I usually use a specialised aluminium corrosion treatment for those parts. You should not need to polish anything except the outside of the sliders (for visual appeal). The sliding surfaces (ie damper piston to ID of fork tube and the anti-bottoming devices) do not need polishing. After you get the bike rideable, use it for a few hours then change the fork oil to remove the fine particles generated by the running-in process. The only remedy for pitting of the chromed surface of the tubes is to have them re (hard) chromed or to buy new tubes. This is commonly required on old bikes.

The cap pulls the tapers together. Make sure the bottom clamp is fully free, loosen the cap a bit, spray some penetrating stuff around, load the forks so there is a pull on the taper and then use some persuasion techniques (tap cap downwards/tap on OD of clamp/apply heating etc. Another way is to let all the oil out, take the spring out, leave the cap off and use the slider like a slide hammer to shock the taper free. The stuck side may have a rusty fork tube bore or maybe the fork tube is bent or maybe the slider has a dent. Maybe the fork leg is completely full of oil or water.

Thanks Manuel. I don't need photos because your description is perfect. I went out to the shed and pulled a 348 cover off and found that the 348 flywheel slot is long enough for my two-pin tool to work fine similar to having two holes. Mystery solved. David