feetupfun

Don't throw away the standard fork yokes. You may decide to revert to them after trying alternatives.

Have you got a photo of what you are after? I'm a bit lost by the description

One 348 I bought in about 2000 still had visible cross-hatching on the fork tube chrome and in the cylinder bore and it still had the original sprockets, handlebars, levers, cables etc. It had been ridden in trials but very little. I have a suspicion that some people bought them new and found that they were not as easy to ride as they had thought and just parked them up

Yes you can normally operate a clutch actuation arm like the one on your bike with a suitable tool to increase the leverage but you might have to make something due to the space being a bit tight on that motor. I have previously operated a clutch arm on other bikes using an 12" shifting spanner to provide the leverage. It's a very common thing on those motors to bend and sometimes crack that arm next to the weld

What ignition system? What plug gap? What fuel? What premix oil? What does the spark look like? Are there any whiskers on the used plugs? Did the fuel type get changed recently?

Corroded yokes is a common thing with 348s but there are usually some being broken down for parts in the UK. Be aware that the yokes from a 247 look very similar and will fit, but have slightly different geometry. Both 247 and 348 yokes were made from rolled aluminium plate which lends them to that sort of failure. I saw some NOS 348 yokes advertised a while back in the US. Sorry not allowed to mention suppliers on here. As for water getting inside things, one of my 348s came with collapsed forks and I found they were full of water. Lots of corrosion on the insides of the tubes.

That sure looks great. I'm intrigued with the black shields/guards inboard of the footpegs

Wow we had one of those CZ scooters too! I also remember our CZ scooter was 12v electrics when most bikes were 6V

If you still have doubt, why not just check out someone else's trials bike

Yes it is a floating disc

My wife chose her trials bike (Beta 200) based on the relative ease of starting it

That video of Albert on the electric Gasser didn't excite me. The visuals are nice but if the bike could be made to sound interesting it could be appealing. I don't know why but the Yamaha e-bike had a more interesting sound

They are a fabulous reliable and well-made bike with very few weak points but here is what I know: The bashplate is not flat underneath so the bike leans over if rested on a horizontal log (only important to learners) "relatively" heavy (compared with a 200 Beta). Very light compared with a twinshock. More flywheel effect would assist the 143cc motor for novices. The clutch engagement is "relatively" sudden but can be fixed with mods. The gearbox is TTR125 so second gear is further from first than on a dedicated trials motor.

There you go - original folding tip pedals and original crappy footpegs

I think some of us need to post some photos of our original 348s with folding pedal tips

8000 feet ? get ready for a big drop in power. Even 3000 feet which is as high as I go makes a difference to the power. Yes bikes usually benefit from being re-jetted for riding at high altitude. Without knowing how yours is jetted though it is hard to suggest how much to change it for this weekend. I used to go about 3 sizes smaller on the main jet for 3000 feet on a standard TY175 and didn't need to change anything else. Turning the air screw out makes it leaner at idle. Dropping the needle makes it leaner between 1/4 and 3/4 throttle.

I haven't tried vinylester so can't comment

That's why I line my tanks with epoxy resin

from Cota 348 service manual

I would say that the reason it bogs down without the "choke" is because you haven't fully cleaned out the pilot jet circuit

The design changed through the production run as perce says. Brake pedal design, shift lever design, air caps on forks and casing protection loops on the frame. My ride 348 is 51M 10476 motor and frame and has the original style (folding) brake pedal tip, (folding) shift lever tip and no case protectors. Mine does not have the signature on the fibreglass under the seat. It also doesn't have the slotted line along the tank. My memory of the sequence was 76 has the MRR signature, 77 has a fairly plain tank and 78 has a gold/black slotted line along the sides of the tank. I'm thinking that this probably means my ride 348 is 1977 but I'm happy to hear of other opinions.

Degreasing using kero inside and out then hot water with dishwashing detergent then dry it out then quick rinse with acetone and dry it out quickly

Most of the 1970s spanish bike fibreglass tanks that have come into my possession have had extremely poor condition internals with bare glass visible in many areas. You could see areas of thin resin in the dark using a strong torch shone inside the filler hole and can see the exposed glass using a torch and a small mirror. There is no way that I was going to paint a tank in that condition. I have found that after a thorough degrease process then an internal coating of brushing epoxy resin binds perfectly to the old polyester resin and the exposed glass and the epoxy is also highly resistant to the weird stuff they put in petrol nowadays. It adds a couple of hundred grams to the tank and great peace-of-mind to me. The oldest one of mine is an Alpina tank done in the early 2000s and it has had petrol sitting in it since then. The colour of the epoxy inside has gone from light brown to mid brown in that time but otherwise looks unchanged. I've done 5 or 6 old spanish fibreglass tanks so far like this and they are all still going very well and they all have petrol left in them between rides.

If you have a Cota 200 and a 247 frame you are in the perfect position to find your own answer about swapping front ends. I would suggest that you can compare the lengths of both steering tubes and look at how the steering stop from the 200 will work on the 247 frame. If the steering tubes are the same length then it is worth taking the triple clamps out of the 200 and comparing the internal diameters of the steering tubes. Both bikes have leading axle fork bottoms so there probably wont be any issues with clearance between the fork tubes and the fuel tank. If it was me I would much prefer to fit a more reliable motor in the 200. Honda motors are pretty tall. A TY175 motor would be about the right length and height.

If it was me I'd fix the top part and put it back together