247 Cota - Lost cause ??

[Colin Jay]

I have spent the best part of the day stipping down the 79(?) 247 Cota that I bought a couple of weeks ago.



When I got the bike home, after a I cleaned out the carbie and checked the points, the engine fired up easliy and ran ok, so I though that I might be on to a good think.

The swingarm pivot was seized, and had flogged out the swingarm mounting points on the frame. I have seen my friendly local machinist and the plan was to take the frame in for him to have a look at on Monday so we could come up with a plan of attack for fixing it.

While cleaning up the engine I descided to drain the gearbox and primary oils. The gearbox oil was good, but as the primary drive oil was milk I removed the cover to clean it out properly.

This is what I found;




Now, this is the first Montesa that I have played with, but I take it that there should be a flywheel mounted onto the end of the crank. None of the missing bits were inside the engine, so I must presume that this happened some time ago in the bikes pasted and the previous owned had just put it back together and continued to ride it.

The big question is: Am I fighting a lost cause here?

Is it going to be a "Grail Quest" to find a replacement crank and flywheel?

My plan was to get the bike going for use in Post Classic / twin shock trials, without going overboard and doing a full on restoration. So should I persist with the Monty or just get my 199A Sherpa going again and ride it?

CJ

[David Lahey]

The standard flywheel effect on a 247 (both external flywheels in place) is very pronounced. I have not seen inside a 247 clutch case but suspect they are the same as a 348 which has a weight on that side. Some people prefer to ride their 348s without the drive side flywheel so it probably would be fine on the 247 as well.
Judging by the number of people who have reported finding that failure on their 247s and 348s on internet forums over the years, I suspect that sort of failure is relatively common on 247s and 348s. It wouldn't be a show stopper because the crankshaft can be cleaned up and threaded and used without a weight on that side.
I also think you would be able to get a S/H, NOS or custom-made crank half without too much drama.

[David Lahey]

While you are in there, have a good look at the clutch spider. Its a three-fingered thing that pushes on the pressure plate and they seem to be a problem area with 247s, causing clutch drag when bending/misalignment happens

[cappra]

It's rare to see this happen to the 247. It happens more often on the 348 and 349.
In 82' they increased the size of the crank on the left side because of this problem.
It should be pretty easy to find a 247 crank halve or crank assembly and aux flywheel.
Very hard to find for the 348/349. The retaining nut get's a little loose, the aux flywheel
starts moving and there goes the shaft! It's hard to ride a 247 without the flywheel, really changes
the power delivery.

[cappra]

You could ride it the way it is. I doubt if the primary gear will come off if
it hasn't already. It's on a tapered shaft and is very hard to remove anyway.

[Colin Jay]

Thanks for the info guys, I think I might keep going with it and see how it goes.

CJ