feetupfun

good footage but I think it is in Italy

The speedo drive housing has a flat on it that needs to be positioned against the fork leg. The photo shows that your speedo drive housing is sitting wrongly, which is probably the cause of your problem

but that would be a 100kg rocketship

Photo of DT175A motor to illustrate the mods mentioned by jc2

Here is what the TY175 with DT175E motor looked like

The early series DT175 cylinder will fit to the TY175 bottom end (twinshock DT175 models ABCD sold in 1974/75/76/77) 78 model (E model - first monoshock - radial fin head - plastic flywheel cover) has different cylinder stud layout pattern so would need work to make it fit to a Ty175 bottom end Yes I think you might need to trim the DT head fins to clear the TY175 exhaust pipe The higher top edge for the exhaust port will reduce the low-RPM power compared with the TY175 The higher compression ratio will make it very slightly easier to stall at extreme low RPM If you use a bigger carby than the TY175 carby you will get the full benefit of the exhaust port height difference For a while I rode a TY175 with complete DT175 motor including the 26mm carby from the DT175, but with TY175 flywheel, and it was fine for trials riding, and magic for trail riding. It had a fair bit more power on top and the gears being equally spaced made for very easy trail riding. I didn't mind the slightly less bottom end power but only first gear was any use for trials. Second gear was like third on a TY175. The DT175 motor I used was the E model which looks a lot different externally, but appears to be very similar to a DT175A motor I also have, as far as compression ratio and porting goes. The DT175E motor requires the TY175 frame to be dented in one spot under the motor for clearance, and the standard TY175 exhaust pipe is a very close fit without trimming fins at the front of the cylnder, or over the top of the head. The Ty175 flywheel needs to be trimmed a bit and the inside of the DT175 casing also needs trimming for there to be clearance

Maybe broken fork spring. Should be easy to check without pulling much apart

the ignition stator coil can probably be rewound by someone locally

also check the exhaust system for loose or broken mounts or touching something where it should not

no the clutch does not need to spin to work normally

when the clutch nut is finger tight the pressure plate is not in the same position relative to the spider fingers as it is when it is tightened. There is no point testing the clutch action with the nut finger tight. A common problem with those clutches is the fingers on the spider bend and wear. I would also check the button that pushes on the spider for wear or damage

if Cota 242, then is something like 205cc and made 1984-1987

my guess is Cota 242 depending on what numbers the dots represent after 116 in your number. A picture is worth a thousand words

Is this the wheel you mean for Nigel, lbhbul?

its not air pressure that keeps a tubeless tyre in position on a tubeless rim. The tyre bead stretches as it goes up onto the rim and it grips the rim. Run with as low a pressure as you want with a X11 and if it is seated properly when it is fitted, it won't come off the rim until you force it off deliberately. You do need to make sure any tubeless tyre is fully up on the rim after fitting it, before you let the pressure down to trials pressure. They usually make a pop each side as they seat on the rim. You can use tyre soap or dishwashing liquid to help it slide up onto the rim if it is reluctant to jump into place. It should jump onto the rim somewhere between 30 and 60 psi if it is lubed I suggest you judge how much pressure to ride with by the length of the tyre circumference that touches the ground with your weight on it, rather than a gauge, to start with. Once you have the tyre working how you want it, measure the pressure with YOUR gauge and from then on you can set it to that pressure with your gauge. I usually set my rear pressure to give a contact patch about 200 to 225mm long

bisby is on the money. Montesa, Bultaco and OSSA (and countless British bike) kickstarts drive the motor via the gearbox. Same reason why you have to find neutral to kickstart them (unless you want the bike to take off as you kick it over). The more modern arrangement is for the kickstart to drive the motor via the clutch basket

and this is what it looks like nowadays

I know my series 1 M49 Sherpa T was sold new in Australia and had some bizarre modifications done before I bought it. The rear frame loop had been bent downwards to allow the fitment of a seat that looked like it was from a Bultaco road bike. The footpeg mounting location was used to bolt on some large pieces of steel strip which were mounted horizontally and supported a set of footpegs well forward of the normal spot, and a set of footpegs well to the rear for the pillion passenger. They had fitted Gas Koni shocks with stiff springs (probably to stop the rear tyre hitting the lowered rear frame loop). The super low rise but wide handlebars I had not seen before, but made me think of speedway handlebars The paint scheme was reminiscent of a mid 1970s Pursang, and was applied on top of about 4mm thickness of spray putty, which despite the thickness, was not effective at holding the fuel inside the leaky fuel tank

What use would closed loop control be on a trials bike anyway? Fine on a car or on a road bike, but on a trials bike, the motor would never be at a single condition long enough for it to go into closed loop mode

In OZ that model Cortina was available with the 2 litre SOHC motor which I imagine is what was in Don's car, and they also sold the same model Cortina with the Ford Falcon 4.1 litre cast iron in-line six, which most definitely handled worse

would wear out rear tyre, chain and sprockets pretty fast, and can't reverse car if required

Another thought is that if you want to make the change to right foot braking, you can still use the nice RH shifter. No probs doing both jobs with the same foot and nothing to get in the way of the kickstart. I know of a few people riding late model Sherpa Ts set up like this

Looked in my log and found that I'm running 13/52 and very happy with it

gearing needs to be lower/slower than standard for competition. I use standard rear sprocket whatever that is - probably something like 52T - and 12T or 13T front with 428 chain. I will look in my log tonight for the sprocket sizes. Standard gearing is something like 15T front from memory and is great for highway cruising You should be able to run 520 chain without clearance issues, and it is probably a good idea to go for 520 because 12T or 13 T fronts for 428 chain are hard to find

The standard pipe will come off without having to undo the motor mounting bolts or the cylinder head - however there is a knack The carb to cylinder connector is a common failure I haven't ever touched the rubber swingarm bushes, but if I wanted to take them out I would just burn the rubber and cut the outer sleeve to get them out. There's a bloke from the US called Michael Moore who wrote a great story about his KT that he was fixing up about 10 years ago. Michael didn't like the rubber swingarm bush idea and made a metal to metal setup and explained how and why he did it the way he did. He also experimented with different exhausts and explained how he went about it. From what you say it sounds like you like to have things completely standard so probably wouldn't suit you. In case you are interested, you may find Michael's writings about his KT on Trials Central forums. You won't need a decomp to start it - they are a pussycat to kickstart There's a bloke in Australia was making replica KT taillights a while back. They look like TY taillights but are different in detail. He bought my original light to copy from. haven't heard from him for a while The three position clutch levers are rubbish. A good quality clutch cable is a benefit. Some people use the clutch cover off one of the KX bikes to get a better clutch pull. Getting the fork action sorted and the rear ride height right is important for getting the steering to work well. High rise bars (like they had at the time) are a good idea with the standard footpeg position Good modern shocks have a much better action than the original KT shocks, but if you want to keep it original looking, there is no such thing as a shock that can't be rebuilt Original KT mudguards are moulded plastic, not sure what you mean by "beaters, learning and dumping a lot"