feetupfun

There was nothing in place apart from the cable sheath to stop the wires being damaged. A common improvement for reliability was to run the wires along the top side of the mudguard.

It is a modified Yamaha TY175 or TY125 frame.

Another factor in rear tyre clearance is that the rear competition tyres in the 1970s were nowhere near as tall as modern competition rear tyres

So here's a photo of a Spanish Betor trials shock from back then. I have no way of knowing if its actually from a model 92 or not but I do have quite a few and they all have the same length shock shaft. Some have this type of seal retainer and others have a different type of seal retainer.

My memory is saying 3.25". I'll have a look to see if I have one to measure

The ratchet mechanism you can clearly see in the photo should click as the kickstart lever returns towards the stored position. Just before the lever reaches the stored position, there should be a cam or ramp that moves the ratchet teeth apart. If not for the ratchet mechanism, the kickstart shaft would be rotated by the motor when the motor starts.

If you aren't sure, do a test fit both ways in the hub holes and see if they will work OK.

The rubber carby mount piece (between the carby and the reed cage) are known to crack and let air in

Sid to get a photo of the front end of the cable, the bike needs to be on it's side or upside down and my OSSAs are currently packed away. I'm not willing to unpack one of them until I'm convinced that you really need a photo. So here it is in words. Pedal bar end: The pedal bar arm has a receptacle for the end of the cable outer. The nipple on the cable inner fits into a holder on the frame. Wheel end: The brake plate arm attaches to the cable inner. The cable outer is held in a receptacle on the brake backing plate.

I'm assuming you are asking why the mounting holes do not perfectly align with the muffler sitting there. How close does it get to the mounting holes lining up if you lift the muffler? If that's not enough, you could loosen the exhaust mounting bolt near the airbox and loosen the bolts at the cylinder and try moving the exhaust upwards. If that's not enough you could bend the end section of the exhaust upwards.

The Leonelli has a longer red plastic bit that houses the magnet, so is a bit more easily bumped off its seat. They have opposite magnetic polarity. I haven't looked close enough to see it the magnets are held in place differently. Having the magnet pop out of the holder seems to be a fairly common problem, based on how many people have asked to borrow a lanyard after theirs lost its magnet. I didn't notice a difference in price between them.

There will probably be an aftermarket rod kit available because the TY250Z motor is based on the YZ250 motor of the same era (ie probably the same conrod)

when you say 04 TY4, do you mean an SY250R or a SY250F or SY125F or something else?

It sounds like you haven't pulled a motorbike engine apart before. The Cota 348 is far from being an easy one. To get that casing separated on many other bikes is straightforward. The primary drive components are removed, the shifting components are removed, the gearbox output sprocket is removed, the ignition flywheel is removed, the shift drum indexing plunger is removed. All the fasteners holding the halves together are then removed and the crankcase halves are separated. Cota 348s have a few unusual things that can prove to be more challenging than on most other bikes. The drive gear on the crankshaft is on a taper that can be very difficult to release. The sprocket is on a taper that can be very difficult to release. The gearbox components are positioned precisely left/right with shimming that can fall off the shafts during disassembly. The crankshaft seal holders, gasket thicknesses and shimming are what positions the crankshaft in the right spot left/right and provides correct end float.

Oh no!

If the reason you asked this is because it is hard to find B7ES plugs for sale, there are other brand plugs that can be used in place of the NGK B7ES. If you only ever use your TY250 for trials type riding you could probably get away with a BP7ES but if your riding involves sustained riding under load then you are at increased risk of heating up the piston crown compared with a B7ES.

Those nuts are on the ends of bolts that hold the two centre casings together. The other ends (inside the clutch compartment) may need to be held to retighten them. As for the crack, there is a common mode of failure with 348s caused by the kickstart shaft being rotated too far during a kickstart stroke. This usually punches a hole into the magneto compartment and is not a big deal. The marks on your inner casing and the position of the crack does not look typical for the damage to be caused that way. I'll take a guess that someone has attempted to kickstart the bike without the magneto cover in place. Because the kickstart shaft loses it's outer support when that cover is removed, kicking it with no cover in place could cause a crack like that. The crack is fixable by welding and to do it properly, requires disassembly of the motor (removal of the cylinder and separating the left and right inner casings). Rather than welding, you may be able to source a second-hand RH inner casing. Whether it is worth fixing or not depends on many things that you haven't mentioned.

We have run lots of public trials riding displays and static displays at rural shows and swap meets with videos running and this thing about the videos is one of the things we have got down to a fine art. We only ever show videos made at our own trials events. This way people not familiar with trials have a look and think to themselves "wow they are a gumby lot. I could do better than that!" Of course when they do turn up for a ride we make sure we have suitable sections for them to ride as they discover that it actually a fair bit harder to do than how it looks on a video. The big growth in rider numbers for us in the past couple of years has been people wanting to improve their skills in Hard Enduro, which seems to be popular everywhere. It's well known within the Hard Enduro scene that the riders who are at the pointy end of the field are mostly ex or current trials riders. We don't need to do any advertising to get these new people coming along to trials and having a ball. Another story about people doing cross-training on trials bikes is about a middle-aged rider who had obviously done thousands of hours riding dirt bikes and had some amazing bike skills. However it was very entertaining when he had a go at riding trials sections on a borrowed bike and could not, no matter how hard he tried, stay within the boundary tapes. Just thought of another story. This time about arbitrary rules in trials. One local rider convinced his Dad to have a go with him at trials and bought his Dad a trials bike. No matter what we said about the rules, the Dad would not, ever, inspect any sections from outside the section or by walking them. His idea of the right level of challenge was to ride through each section navigating only using the coloured arrows as he could see them while riding along through the section!

DT250 sliders of the same era will probably work apart from the lack of the mudguard mounts that make the TY250 sliders unique. There are two different slider types on the TY250A. The earlier type has the drain screws on the sides and the later TY250A type has the drain screws at the rear of the sliders and are the same as the TY250 BCDE models fork sliders. Which side are you chasing?

Magneto side requires a puller for the magneto flywheel. The magneto flywheel will have ID on it so you will be able to buy the right puller. The drive side seal requires you to take the clutch off and to get to the clutch nut, you may need a clutch spring tool if you have the spring pins that have a cross-pin retainer. If you have threaded clutch spring posts then you wont need any special tool to get to the clutch nut. The clutch nut is 22mm (from memory) and requires a thin-wall socket because the nut is recessed. I machined the OD of a standard 22mm socket down for this. To unto the crankshaft drive sprocket nut it is helpful but not totally necessary to have a clutch holding tool. This sprocket is on a parallel shaft with key drive. It may need a puller to get it off. A standard industrial two leg or three leg puller will do for that. The clutch basket and crankshaft sprocket come off together with the primary chain in place. Bultaco clutch holding tool (helpful if the motor is out of the bike) Bultaco clutch spring tool (unlikely needed on a 199A) Thin wall 22mm socket (definite) Large two or three leg puller (maybe) Bultaco magneto flywheel puller (definite)

I do like how you think outside of the box. Please keep at it. Here is a story that might be of interest. At 64 and with lots of old injuries, I'm not looking to take big risks when riding trials, but for the past 15 years or so have had a thing about improving the setup and performance of my twinshock bikes, mainly to maximise how long I can keep riding trials for, because I get such a kick out of riding trials. Part of this bike improvement thing is that I have a few comp bikes and find that by riding the different bikes in the same sections on the same day, I can better work out how to improve them. Swapping bikes like this is usually detrimental to my score. It's also great fun riding different bikes through the same sections. It's not a big deal though and it wouldn't stop me from riding an event if I wasn't allowed to swap bikes. All I do is ask the event organiser in advance so I know how to approach the event. Sometimes it's no and sometimes it's yes. If they have concerns about fairness to other riders, I suggest that I'm happy to be taken out of the results if I swap bikes. In your case, you may be able to choose events that are more favourable for the sort of riding you want to do. Many clubs I'm familiar with run events where you can continue riding the sections after the event and also, depending on the observer and if there is a queue or not, are happy for you to continue in a section after having fived.

They are mechanically identical to the "Montesa Cota 200". If you search the Montesa forum using "Cota 200" you may find the information you seek.

Good to hear and welcome

Lots of people ride in competition trials events without using a scorecard. They just ride whatever line they want to challenge themselves with. Also lots of people enter the grade they feel comfortable riding and sometimes take a harder route to increase the challenge. I set lots of sections and my goal is to do it so that people can ride higher grade lines without going outside the gates for the grade they entered. Yes gate trials are great fun and they are also a competition. I love the mental aspect of gate trials in that the better you know your riding ability (and act on it when choosing gates), the higher you will place.