hughandjen Posted June 18, 2014 Report Share Posted June 18, 2014 Hi guys Help please. Got my old 1973 cota 247 running and ticking over, but it sounds like a bag of nails. Took head and barrel off and there is some play on big and little ends so strip down and rebuild required. Is there an information guide how to do this as I have no manual. Also can I still get the gaskets and bearings.? Thanks Quote Link to comment Share on other sites More sharing options...
pro sport Posted June 18, 2014 Report Share Posted June 18, 2014 For parts try Inmotion, great service. Old Cota's were always a bit rattley, I will try to find a link to the manual that I copied off from this site. Dave Quote Link to comment Share on other sites More sharing options...
hughandjen Posted June 18, 2014 Author Report Share Posted June 18, 2014 Thanks Dave that link would be great. Looked for the bearing from inmotion, they sell con rod and bearings complete on their website so have asked if they sell bearings separately. Quote Link to comment Share on other sites More sharing options...
pro sport Posted June 18, 2014 Report Share Posted June 18, 2014 (edited) Found it http://pilgrim.co.nr/ Under useful stuff Montesa service/repair manual 1965/1975 Edited June 18, 2014 by pro sport Quote Link to comment Share on other sites More sharing options...
hughandjen Posted June 18, 2014 Author Report Share Posted June 18, 2014 Thanks for that Quote Link to comment Share on other sites More sharing options...
hughandjen Posted June 18, 2014 Author Report Share Posted June 18, 2014 Dave I clicked on that link and it wouldnt work any ideas Thanks Quote Link to comment Share on other sites More sharing options...
pro sport Posted June 18, 2014 Report Share Posted June 18, 2014 (edited) My Friend Ben posted a link previously to his website where he is hosting a download link for the manual. I am sure he will not mind me reposting? http://bpilgrim.co.nr/ Try this, don't know why the other takes you nowhere ! ! ! Edited June 18, 2014 by pro sport Quote Link to comment Share on other sites More sharing options...
hughandjen Posted June 18, 2014 Author Report Share Posted June 18, 2014 Got it thats great thanks Quote Link to comment Share on other sites More sharing options...
baldilocks Posted June 19, 2014 Report Share Posted June 19, 2014 HughandJen if the big end has play there will often be wear on the pin and conrod itself. Best practice is to change the rod pin and bearing 1 Quote Link to comment Share on other sites More sharing options...
hughandjen Posted June 19, 2014 Author Report Share Posted June 19, 2014 Thanks Baldilocks. Is any verticle play in the big end acceptable? as i can only feel a bit of movement. Quote Link to comment Share on other sites More sharing options...
hughandjen Posted June 27, 2014 Author Report Share Posted June 27, 2014 Hi Ive found that its the main bearings that are knackered so have ordered the bearings and gaskets to repair. A friend of mine who has had Montesas says you can change the mains without splitting the cases with heat and pulling them out. Has anyone tried this??? Advive would be great Thanks Hugh Quote Link to comment Share on other sites More sharing options...
feetupfun Posted June 28, 2014 Report Share Posted June 28, 2014 I'm sure it is possible. I tried it on a Bultaco M49 engine which is similar in the design of the main bearing fits to the 247. I was pulling the motor apart anyway, so it was just an experiment I did because people said they had done it. I found it was difficult to get enough strength in the weld. I welded a steel tube to the bearing inner and pulled on that. If your 247 has the original conrod/big end bearing, and it has been parked up for a while, I would say it is false economy just changing the main bearings at this point, because even if it currently has no measurable play in the big end, it is likely to fail unexpectedly which may wreck your cylinder bore, piston and rings Also consider that many motors with main bearing setups like the 247 develop a problem where a main bearing outer turns within the casing, or the inner turns on the crankshaft. It's common to require the casings to be sleeved and/or for the crank to be built up. Quote Link to comment Share on other sites More sharing options...
hughandjen Posted July 6, 2014 Author Report Share Posted July 6, 2014 Thanks for that feetupfan. may give it a go. I only want to use the bike very occassionally, bit of green lane stuff nothing strenuous. Quote Link to comment Share on other sites More sharing options...
kingscorpion Posted July 14, 2014 Report Share Posted July 14, 2014 You'd better strip the whole engine and perform a careful rebuild. Take into account that the bearings were mounted after being heated, to have and adequate fit with both sides of the crankshaft. If you simply extract them by heating the whole engine and after that try to set up the new bearings by pressing them against the crankshaft, the result can be a damaged crankshaft or even an unbalanced one. These engines are not difficult to repair, if you know how to do it. Quote Link to comment Share on other sites More sharing options...
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