telboy1969 Posted October 23, 2014 Report Share Posted October 23, 2014 Have recently bought a cota 348 which was originally for me to do up for the kids, it was an amazing barn find for £100 so couldn't complain. A week later I get offered a TY80 for £200 so that is now the kids toy as it didnt need much TLC before it was revving freely and racing down the fields. Anyhow this montesa has got me hooked, used to have a bultaco sherpa in my youth so I think I'm going through a mid-age crisis here trying to relive my younger days. Took a long look at it before I started then a couple of hours later I was down to the bare frame ( hand painted white!!), have stripped that back to bare metal, along with the swinging arm and the central engine mount bit, applied some red oxide primer and just going to spray it with black hammerite smooth to gibe it some more protection. Forks were seized ( that was a learning curve) managed to knock them out with an improvised piece of wood screwed in the bottom of the damper and carefully sand back the pistons, working nice now though with fresh seals and oil (can alloy really swell?) . There was a spark on the bike but no clutch, got one off fleabay but after taking the cover off though the push pin looked worn so got another , worn??? tsk the new one is about 5 mm taller and there was no oil in it either. Got new gaskets for electrics and clutch, new tapered head bearing, wheel bearings and swinging arm bush kit (ouch!!) and am just going to piece it all back together. Exhaust was a tin can end, on a butchered front pipe, after 2 fleabay purchases I think I've got enough exhausts to kit three bikes out as each one had been cut at some point so missed the bracket hole. I like it to be right.... hate things amiss. So in the next few weeks I'm going to put it back together, I'm not after concours, just something that rides nicely, and I can have fun on, it'll be smart but usable, not to bang in a garage on paddock stands (have an R1 that does that) BUT after all that dialogue I do have one query, don't know how to date it, The engine number and frame numbers are different (might be nicked!!) the frame has no bashplate or mesh, just tubes and is earlyish as is stamped 87**, the engine may have been replaced at some point as this is 129**. Anything I should be aware of when putting this all back together now just in case I start buying short exhausts(as I have done) as it may be a bit of a hybrid!!! Quote Link to comment Share on other sites More sharing options...
feetupfun Posted October 24, 2014 Report Share Posted October 24, 2014 suggest you post photos of (at least) frame and motor 1 Quote Link to comment Share on other sites More sharing options...
kingscorpion Posted October 24, 2014 Report Share Posted October 24, 2014 Both numbers should begin with 51M. That was the factory code for 348's to 349's and 350. 1 Quote Link to comment Share on other sites More sharing options...
telboy1969 Posted October 24, 2014 Author Report Share Posted October 24, 2014 Sorry both numbers do indeed begin with 51M, Will post some photos of them both shortly 2 Quote Link to comment Share on other sites More sharing options...
telboy1969 Posted October 26, 2014 Author Report Share Posted October 26, 2014 this is the frame stripped of paint ready for primer... Quote Link to comment Share on other sites More sharing options...
telboy1969 Posted October 26, 2014 Author Report Share Posted October 26, 2014 this was the bike halfway through stripping it.... Quote Link to comment Share on other sites More sharing options...
feetupfun Posted October 26, 2014 Report Share Posted October 26, 2014 Brake pedal looks like 1977 or 1978 348 Someone has removed the drilled steel bash plate that is normally welded between the frame tubes under the motor Looks like the ignition flywheel cover has been cut away, probably to allow easy cleaning around the sprocket Can't see much in the photos but from what can be seen, the rest looks like normal 348 to me Have a good look at the frame while the paint is off, looking for cracks and bends One of my 348 frames has tubular ears/loops welded to the frame tubes under the front of the engine as a protective measure, but I don't know which year it is. My other 348 frames don't have those ears Quote Link to comment Share on other sites More sharing options...
telboy1969 Posted October 26, 2014 Author Report Share Posted October 26, 2014 Thanks for that, guessed it was late 70's, got another complete flywheel cover to go on instead of the cut one, as for the bash plate, they've done a very good job of cutting it out and grinding back as there are no visible remains of welds or bobbles on the frame where it may have been so thats a mystery as to why someone would do that or did some just not have them? Frame is pretty solid, few little dings but no cracks or bends, actually in very good shape for something that old!! I don't know the complete history of the bike but will ask the previous owner (who I know wouldn't have the tools to do that ) and see if I can trace the background. Another query is the front wheel bearings got a new set and fitted them today but they are not tight as I expected, still quite a bit of play - could it be that the bearing housings has worn? On the main hub side it was tight to hammer in then once through the gap seemed jts to pop into place too easily, on the shoe side the bearing just pushes in and out using fingers? Definitely the right bearings as got them off inmotion with some other bits and pieces.... Quote Link to comment Share on other sites More sharing options...
feetupfun Posted October 27, 2014 Report Share Posted October 27, 2014 yes the bearing seats lose metal when people replace the bearings without heating the hub. What you have is quite common on old motorbikes with aluminium hubs. If there is no radial play, you can fit them with a retaining compound to prevent them from moving and making the fit even worse. If there is radial play, the hub can be sleeved. If there is radial play and you use a retaining compound, the brake drum surface may not run true Cota 348 trials bikes were sold in 1976, 77 and 78. There were trail versions (348T) sold later on (probably to use up the unsold 348 frames after the 349 frame was released) The piece of perforated plate may have been removed from your frame to allow easy cleaning of the underside of the motor. Another possible reason was that one brand of aftermarket bashplate made for 348s fitted between the motor and the frame tubes, so they might have taken the mesh section out to prevent debris building up above the mesh plate Quote Link to comment Share on other sites More sharing options...
kingscorpion Posted October 27, 2014 Report Share Posted October 27, 2014 The frames with tubular loops welded under the front of the engine correspond to the "second series" 348. Those bikes also had another improvements like an optimised shifter for the gearbox, the air assisted fork, and many other details. 1 Quote Link to comment Share on other sites More sharing options...
telboy1969 Posted October 27, 2014 Author Report Share Posted October 27, 2014 Hmm this bike has air assisted forks so am beginning to wonder if it a bitsa from two bikes due to the different engine and frame numbers and from the info you kind people have given me.. Gonna rebuild it anyway so may be asking other questions too Many thanks for your help much appreciated!!! 2 Quote Link to comment Share on other sites More sharing options...
telboy1969 Posted October 28, 2014 Author Report Share Posted October 28, 2014 Been thinking, If I want to use this properly I would like a bashplate of some kind, scoured the internet for one but no joy, does anyone know where I can get a decent aftermarket one to u-clamp on or something?? Also think the back wheel has the same problem so gonna try the retaining compound method - will let you know how it goes... I will get there eventually... Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.