feetupfun

Next time when you put it into 1st gear from neutral with the motor running, while your foot is still holding the shifter down, let the clutch out a little bit and you will probably find that the shift lever drops a little bit further (and there is a clunk). That is signalling that it is fully engaged in that gear. The clunk you have described with your 349 is the bike finally going fully into gear and is a fairly normal thing with 348 and 349 Cotas. If you can select all the gears and it stays in a gear once fully in gear, your mechanic has done a great job.

Those extra washers on the outside of the frame plates are unusual. Possible reasons are: Your swingarm pivot axle may be a bit too long. The trail riding kit for TY250s may have included a longer bolt to suit the trail riding footpeg mounts being attached at the swingarm pivot, and your bike may have one of those axles. Previous owner thought it would be a good idea to spread the forces. Is there damage at the holes in the frame plates? Shims: Shims are used if the width of the swingarm is less than the distance between the frame plates. Some bikes match without shims and some bikes need shims. Holes in the inner tube: Yes, original inner bushes have holes and if you loosen the swingarm bolt before using the grease nipple then you may get some grease to flow into the space between the inner bush and the axle. However, because you can slide the axle out to grease it or to apply anti-seize, the holes are not necessary. They also serve to lighten the inner bush. If you are serious about lightening your bike, you can buy ready-made aluminium inner bush and aluminium axle.

Yes all TY250 twinshocks have the same heat shield, just decorated differently. The flat section is 122 mm x 19.5 mm

https://trials.com.au/forum/viewtopic.php?t=5545

https://www.inmotiontrials.com/product/bultaco-red-tank-frame-paint/

https://www.ebay.com/itm/Montesa-cota-349-white-fuel-tank-and-new-seat-/292556986104

If this is the bike you bought and it has a fuel level pipe in the side of the tank, then it's not a White Wonder tank

Throttle cable port side of headstock and inside the gusset plate. Clutch cable starboard side of headstock and not inside the gusset plate. I run mine above the front tank mounting to give it a nicer radius for the curve down to the clutch casing It's fairly standard on any bike to run the throttle and clutch cables around the headstock. This is especially important on a trials bike because of the extreme steering lock. Running them around the headstock provides bigger radius bends.

Do you want a modern-looking one or a 1970s looking one? 1970s OSSA kickstart is a direct replacement and swivels at the bottom. Just beware there are two spline sizes on OSSAs and only one is the same as the Bultaco spline.

Speedway solos and sidecars, MX sidecars and probably others I don't know about. There is no rule against fitting a second kill switch of any type you like.

Those clutch plates are meant to be rust-coloured. If you want to do some useful maintenance on your bike, the things to fix on an old TY250 that has not seen much use are usually the steering head bearings (rust), the steel inner bush in the swingarm pivot (rust) and the magneto side crank seal (gone hard)

Bultaco Betor mid 1970s probably Alpina

They aren't the same as TY. Photo of Betor damper rod assembly coming

If the nikasil is applied to an all-aluminium cylinder, then heat transfer is better and it is lighter than with a cast iron sleeve design. In your case however, you would be applying the nikasil to the cast iron sleeve, so you would not get those benefits that nikisil can provide. If your cylinder was worn beyond the size of the biggest oversize piston you can get, then nikasil would be a good option compared with resleeving.

Unless I ride beyond my endurance limit, I don't crash in trials at all. I've been riding a very long time and at 59 years old seem to be much more fragile than I was young so I'm both conservative and a very good judge of what I can do without crashing. I generally don't do stuff that pushes my limits, just riding for the pure pleasure of it. However for some reason if in a trial I keep riding after I get knackered, sometimes I misjudge things and crash. Because I only very rarely crash, I very rarely break anything on the bike. Usually it's only a small thing like tearing the end of a handlebar grip. Maybe one broken mudguard per year. Overall I would say I would only break something about once in 10 trials and the practice sessions between the trials. When I was first riding trials I used to smash things every time I rode including broken frames, bent handlebars, dented exhausts, tanks etc Yes I've done a bit of body damage riding trials but only a small fraction of the body damage I've done in off-road racing and trail riding. The worst injuries at trials were once getting knocked out by the handlebars hitting me under the chin and once breaking my ACL when I landed on my feet the wrong way after jumping off. I think trials is way safer than the other forms of off road motorcycling. Improving rider safety would best be achieved by good training for beginners who often have no concept of what they are capable of doing safely. Modern trials bikes are pretty good for safety. They are much lighter than the old bikes I ride and their controls like brakes give much better feedback than old bikes. Recent improvements like shrouding of the brake discs and the rear sprocket look good but the type of incident that they protect the rider from are vanishingly rare. I suspect cut-out lanyards have made a more significant improvement in injury rates. Exposed exhaust headers still burn people. I've had two fairly bad leg burns from trials bike headers in 44 years. Helmets are very good nowadays. If there was shin/knee PPE and forearm/elbow PPE that didn't affect your riding I would use it.

Looks good to me

This mod does not stop slipping. It is to stop the kickstart lever clamp screw head hitting the casing on return. If this is your first TY175 it may be that you are just not accustomed to the kickstart engaging at a low position. Normal engagement is with the lever just below the level of the footpeg

The brake pedal in the photo is not tweaked, it is from the "trail" kit and the tip is too far forwards for use in conjunction with the "trials" footpeg location

That's a standard TY250A brake pedal. The pegs are standard TY250A in the standard position. There was a trail-riding kit available from Yamaha that had a different footpeg location and a different brake pedal and a bigger seat

What model Ducati is it based on?

Yes you can squirt oil inside or any other way to get oil in there. Yes you can heat the outside, but the idea is to burn the gunk that is on the inside, so you need a fire happening inside. If you direct a torch inside, you can accomplish this easier. If you only heat the outside it will take longer and you will need a way to create a draft through it to provide oxygen for the fire. If you have big and small LPG torches you could heat up the shell with the big one, then aim the small one into the pipe so that air gets sucked into the pipe with the small flame and is carried through. I usually use a big oxy-acetylene welding tip and direct the flame inside the pipe until the gooey carbon starts to burn (lots of dark smoke comes out the other end and the pipe wall starts glowing dull red in a ring at the closest end to the torch). I then turn the acetylene off and blow pure oxygen in with the welding tip which pulls in air with it. I control the flow of the oxygen to control how fast things are happening inside. The glowing ring slowly moves through the pipe until it gets to the other end. Be prepared for a big bang if the conditions are right inside the pipe. Think about what is happening inside there - especially if you decide to use oxygen. No problems hanging the pipe up to do it, but if you want to move it around while it is hot, I find it easier to do it with the pipe on the ground.

It's the first 349 model and sold in 1979 and 1980. The following 349 model was the White Wonder. The standard swingarm on this model is longer than other 349s. They are not easiest trials bike to ride in tight sections, due to the motor and the wheelbase. They are awesomely good for riding up mountains.

Sounds like you are having fun. I don't know what will happen the way you are suggesting but it sounds fairly explosive. I never put any solvent inside and they burn out fine. If you have washed out the gunky oil with a solvent you may have made the job more difficult that it would have been. If you can't get it going with a torch you can always put the whole thing in a wood fire. I usually have to maintain a draft through the pipe to keep the fire going in there. Oxygen is good but you have to be careful to avoid melting the steel (and glass). Fresh air draft takes too much heat out unless it is slow velocity. A gas flame directed into one end works well to start it up

The nuts are not obvious and are 7mm internal hex drive

I put the flame through the inside with the direction of flow the same as the exhaust gases. The pipe is lying flat on the ground. After it is cooked and cooled you can tap it and shake it to remove any loose stuff. If you want to try and get the glass to flow out while it is liquid it would be best to get it to flow towards the inlet end because it will get trapped inside at the outlet end. Don't leave it sit around for long after the burn out or the insides will rust out pretty fast. Refitting it and going for a ride does a good job of coating it.