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

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

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.

Found it

http://pilgrim.co.nr/

Under useful stuff

Montesa service/repair manual 1965/1975

Edited June 18, 201412 yr by pro sport

Thanks for that

Dave

I clicked on that link and it wouldnt work any ideas

Thanks

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, 201412 yr by pro sport

Got it thats great thanks

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

Thanks Baldilocks. Is any verticle play in the big end acceptable? as i can only feel a bit of movement.

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

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.

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.

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.