motovintage Posted July 23, 2010 Report Share Posted July 23, 2010 noticed this was my 200'th post..and have been thinking of adding a 200 top end to my 123, I heard back in the day that you could put the 200 top end on a 123 bottom end and there was no difference in the 123 and 200 bottom ends, is this true? has anyone done this? my bike is a '82 model I think, (white tank, red frame) is the 200 actually a 173cc? Quote Link to comment Share on other sites More sharing options...
copemech Posted July 30, 2010 Report Share Posted July 30, 2010 noticed this was my 200'th post..and have been thinking of adding a 200 top end to my 123, I heard back in the day that you could put the 200 top end on a 123 bottom end and there was no difference in the 123 and 200 bottom ends, is this true? has anyone done this? my bike is a '82 model I think, (white tank, red frame) is the 200 actually a 173cc? Well, since noone has comenteted on this, I thought I would at least throw in my basic recallection that what you stated was indeed true in the earlier years, say mid 70's. Just how all that relates to your year model? Totally unsure! Might make a sweet little runner, though, If you can find the stuff! Gene T. had a 123, did you get it? I looked at it, for a looooooong time! MC Quote Link to comment Share on other sites More sharing options...
motovintage Posted July 30, 2010 Author Report Share Posted July 30, 2010 I bought the bike new, have had it for 28 years, doing a semi restoration on it and was going to give the vintage expert line a try this winter, every thing I can find on the bike says it's a 1981 model, I have the orriginal bill of sale somewhere, 28M's are hard to date since all 125's have the 28M frame # prefix, I have been looking a long time for a 200 parts bike and basicly gave up, I figured I would just keep watching feebay and hope a cylinder & head would come up. here is a pic of it when it was new back in '83 Quote Link to comment Share on other sites More sharing options...
ikb Posted August 26, 2010 Report Share Posted August 26, 2010 Hi, I am rebuilding a Cota 200 and have just bought another for spares, now Ive got it home I see its a 123!!! 28M. I will be stripping it down soon so I will look to see if the barrels are interchangeable Ian Quote Link to comment Share on other sites More sharing options...
motovintage Posted August 26, 2010 Author Report Share Posted August 26, 2010 Hi,I am rebuilding a Cota 200 and have just bought another for spares, now Ive got it home I see its a 123!!! 28M. I will be stripping it down soon so I will look to see if the barrels are interchangeable Ian cool thanks! Quote Link to comment Share on other sites More sharing options...
ikb Posted August 28, 2010 Report Share Posted August 28, 2010 I have now stipped down my "new" Cota, the crankcase is stamped 28 H (it must be the Honda version) but it has a 200 barrell fitted 64.25mm bore! the frame is also a 29H so it looks like some one has fitted a 123 bottom end into a 200. So it looks like a 200 top end willl go on a 123. So I do have a spare 200 barrell, piston and head I could let you have for a fee!!! its 0.25 oversize but I think it realy needs a re bore, jarred at SW Montesa has 0.5 pistons but they are quite expensive! Ian Quote Link to comment Share on other sites More sharing options...
motovintage Posted September 2, 2010 Author Report Share Posted September 2, 2010 (edited) hmm, so the 200's have a boreable cylinder? My 125 has a chrome liner (not boreable), I need to research this a bit more, not even sure what my piston size is. Do you have a price in mind? I would like to see pictures of what you have? Edited September 2, 2010 by MotoVintage Quote Link to comment Share on other sites More sharing options...
chorleytrialsclub Posted May 6, 2011 Report Share Posted May 6, 2011 Hello i am just attempting restoring a 1981 cota 200 29m. i have two of most parts but wont give them up in case i have problems i will be riding this bike and they are fragile so i am told, i need a few things myself. on my second bike i have a complete 200 engine in good condition apart from kickstart gears does anyone know were i can get 2665.001 and 6265.001, and 2665.140. it also needs a std pistion+rings bore is good and standard size. i also need tank stickers, fuel filler cap,forkseals. oh why did i start could i not just be happy riding my new bike...hehe:) just love the old 200's my first proper trials bike even though it used to jump out of gear and throw me down big hills. hmm, so the 200's have a boreable cylinder? My 125 has a chrome liner (not boreable), I need to research this a bit more, not even sure what my piston size is. Do you have a price in mind? I would like to see pictures of what you have? Quote Link to comment Share on other sites More sharing options...
motovintage Posted May 10, 2011 Author Report Share Posted May 10, 2011 (edited) Hello i am just attempting restoring a 1981 cota 200 29m. i have two of most parts but wont give them up in case i have problems i will be riding this bike and they are fragile so i am told, i need a few things myself. on my second bike i have a complete 200 engine in good condition apart from kickstart gears does anyone know were i can get 2665.001 and 6265.001, and 2665.140. it also needs a std pistion+rings bore is good and standard size. i also need tank stickers, fuel filler cap,forkseals. oh why did i start could i not just be happy riding my new bike...hehe:) just love the old 200's my first proper trials bike even though it used to jump out of gear and throw me down big hills. got my forkseals from Jared he has a few NOS parts for these, gaskets seals etc. watch feebay for odd pieces and parts, I decided to stay with the 123 cylinder since in has the nicosil plating, kinda rare I think, and makes enough power to handle milder twinshock sections with the Keihn carb on it. the keihn made a huge difference in power over the Amal, did pretty well on it at my last event (2nd place) http://www.southwestmontesa.com/ Edited May 10, 2011 by MotoVintage Quote Link to comment Share on other sites More sharing options...
jsd Posted June 10, 2011 Report Share Posted June 10, 2011 got my forkseals from Jared he has a few NOS parts for these, gaskets seals etc. watch feebay for odd pieces and parts, I decided to stay with the 123 cylinder since in has the nicosil plating, kinda rare I think, and makes enough power to handle milder twinshock sections with the Keihn carb on it. the keihn made a huge difference in power over the Amal, did pretty well on it at my last event (2nd place) http://www.southwestmontesa.com/ Just purchased a 1980 29M 123 Cota for my son. Hoping to get it fully functional so he can ride with me(my bike is a 348 Cota). It came with a spare 123 Enduro Engine. I too am considering swapping to a 200 piston, barrel and head. Looking for a barrel, head and Piston. Have some parts to swap. Any help appreciated. Jeff in Northern California Quote Link to comment Share on other sites More sharing options...
motovintage Posted June 20, 2011 Author Report Share Posted June 20, 2011 here is a recent pic at Austin, going to stay with the 123 top end and keep looking for a 349 Quote Link to comment Share on other sites More sharing options...
monty_jon Posted June 20, 2011 Report Share Posted June 20, 2011 Did the 123 have odd size wheels? Quote Link to comment Share on other sites More sharing options...
motovintage Posted June 20, 2011 Author Report Share Posted June 20, 2011 Did the 123 have odd size wheels? the early red tank ones do have odd size wheels, the white tank ones have 18 & 21, I think europe had a later model like the white tank ones except a red tank >>normal size tires on it also Quote Link to comment Share on other sites More sharing options...
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