Twinshock

I need some help here please. I have a 247 Cota around 74 75 vintage on standard bore (72.58) that has bad rattles in the top end. New rings, pin, bearing have not done much to stop the problem. I bought a new piston and rings advertised for a Cota 250 (72.75) (made in Italy) but have found that under the original packaging they are marked for a Bulty 250 Sherpa. That was crossed out and Cota written in texta. Both pistons are nearly identical. Original Cota has a port on the intake side with oval ends, the new one has a port with rectangular ends. High and low skirts appear to be the same. Ring pegs on the old one are at the front, the new one has them at the rear…

Hi Guys, New to this forum - have posted introduction elsewhere - although glad to see its not compulsory! A couple of quick questions that some of the Montesa experts might be able to answer: I am re-building a Cota 247 bought as non-runner on ebay (will I ever learn!) So far its been fun, havn't rebuilt a bike in 15 years (last bike rebuilt was a Guzzi) Its a right bitsa with frame no 21M16407 and engine no in the 5000s and a tank/seat unit from late 70s version. OK, questions: 1) Would the fact that Frame is 1974, engine 1972 and they don't match make getting a V5 harder if I was to try? 2) When does the vintage no-tax deal start - 1973, 1974, 1975 - would thi…

Hi, anyone got a manual or know the ring gap and piston skirt to liner clearance as i have located an oversized piston (ebay) and its winging its way over to me. I have got the barrel mounted on my old van norman boring bar ready to go as soon as the piston gets here and i can give it a good measure up. The barrel was on its second bore and the piston was standard!!! and it had a fair old rattle to it, its amazing that someone would put an engine together like that. Cheers Dave

Hi there! I have recently completed a rebuild of a 1972 247 Cota. The bike is now running well and I even managed to resurrect my worn out Amal carb by replacing just about everything!! The only problem I have now, is that occasionally the kickstart slips when kicking the bike over. The engine was in good running condition when I got the bike, so apart from the top end, it has not been stripped. Before I start stripping the engine, I would appreciate anyone's thoughts on what causes this and the cure.

Hi - my 247 was a bit reluctant to start on the weekend so I replaced the plug and away we went. However whenever I stopped to open a gate etc it died, which is not normal then after about 20 minutes riding I left it switched off while I explored some new tracks by foot. When I returned no sign of spark and a long push home. I have removed flywheel, cleaned and checked everything but very very week spark. I removed kill switch and condensor from earth and measured voltage from the stator coil but it is less than .5 volts. Can anyone tell me what the output from the stator coil should read - alternatively how many ohms in a healthy coil. Cheers Andrew

I have had chronic tuning problems with my 247T and spent hours on forums and decades (it feels like pulling carbie on and off, changing jets, needles ..... I recently had to replace the woodruff key got it started but it was dying for no reason at low revs and then hard to start. So I decided to pull the carb off for a routine clean and while I was at it I lowered the needle just to see what affect it would have. To my delight the needle adjustment appeared to improve my top end performance - but the cleaned carbie did not fix the dying. The bike is going great - probably best I have ever had it but for example when riding down a cow track leading to a creek cros…

Thought I'd post this here rather than Monty section as most t/s's run drums. Bloody odd this. Front brake creaks when applied when stationary and the lever feels spongy. The drum lining isn't split which was my first thought. Stripped the brake down and still does it...bit of a strange one? When moving the brake works ok but is still spongy. Any ideas welcome no matter how bizzare

Hi there! Does anyone know if Montesa Cota 247 & 348 fork springs are interchangeable, i.e. the same part No.? Cheers

Montesa 247C with Amal mk2 Concentric. Now the bike starts n rides fine but for this odd issue. Even when hot, stop the bike, restart after say a minute and ride off, just off idle and she dies after 10 yards....keep the gas up for say 30 secs longer and ride her on just off idle and she gets thru this and is ok again and will be...until stopped again. It's annoying as it means I either keep her running in the queue for a section or restart her and give her some beans before the section to get over this 'blip'....not good if you have any mechanical sympathy. Now from what I read Amals can be a little quirky. My thoughts are she is running slightly weak…

I have stripped down the bottom end, to replace the main bearings and seals. I am looking for advice in which order to reassemble the crank and main bearings. Do you heat the two halves of the casing and fit the main bearings into the casing first and the fit the crank ? If so how do you know the position the bearings in the casing as there is no lip to push them up against.

I need to repair a small area around the Kick start / Kick start return sping area. Has anyone a photo of a bare crank case, so i can see what it should look like the area i am intested in is the wall to the right of where the kick start shaft goes through the casing. Many thanks John H

Yesterday I found this 10M survivor in Vancouver, BC. The little rascall is 99.5% complete and all original. The only thing I can find missing is the tail light lense. I couldn't wait to fiddle (fettle) with it today, so I drained the old gas, put new gas in, took the carb off and apart, cleaned it, and guess what? It runs! The lights and horn work too! All the chrome needs to be redone, but miraculously the fenders and all the rubber is excellent including the original Pirellis.

Does anyone have a Cota 25 tail light lense they can part with? It's small, about 1-1/4" round, dome shaped and screws onto the light base. It's the only thing I need for my 25 and so, of course, will pay WAY more than it's worth to get one.

Hi fellow Montesa owners. I know this site states Twin shocks, my Montesa is a single shock, I need some help please, I have a Cota 307 and need some info on the ignition electrics. No spark been testing the individual parts , any body got any suggestions where I can go to get the info .

has any one tried any other carb on a 330? the amal carb on mine is well worn and although i know i can get a new replacement amal would somthing more up to date work any better ? eg mikuni or a dellorto, any one have any ideas or sugestions

Hope someone out there can give me some clues about my 348. The bike has always been hard to start from cold. It is running the standard Amal monoblock carb which was recently resleeved etc etc. Once the bike warms up it is fine although the amount of smoke it produces is embarrasing. (exhaust and muffler were hit with an oxy to burn all rubbish out) Fuel consumption is terrible. I went for a short ride today around the property and ran out of fuel coming back home. I put in just over 2 litres of fuel before heading off and would not have done more than 5 kilometres riding. There are no fuel leaks anywhere. It still has plenty of power but the above problems are d…

Anyone here knows the right size of Montesa Cota 348 fork oil seals? Mine worn out seals are 35x47x7 but I'm not sure about the 7 mm. Where to get the new ones?

I was going to replace thirty years old front fork springs. The length of the new ones (which were said to be for 348!) were only 47 cm but my original are 50 cm. What's the right length? So whatever it is, I desided to lathe some nylon spacers (30-40 mm) and try with them.

Could anyone out there please tell me what the following piston size`s are for the 348. Std Bore / 1st oversize and 2nd oversize.

Hello Everybody I need some help to sort out my 348 Cota. I don't ride it that often but when I try to it will just not start unless I take the plug out, pour a bit of two stroke down the plug hole and then it will go revving its dinger off for about 30 seconds and will settle down to normal revs. Once it is warm it will start first kick every time. I suspect that it is sucking air in somewhere but have no idea where. It does not like choke to start and runs fine after it settles down. I replaced crank seals, rings, bearings, ect, ect, recently, points and timing are spot on, had the carb (Amal) reconditioned but just does not like a cold start. Any help much appr…