Jump to content

Montesa Cota 247


stevewarden0
 Share

Recommended Posts

More research tells me this little follower thing should be brass, although some mentioned steel. Mine was steel and what's left of it isn't much good except for the part that locates on the lever. I looked on inmotion site and they have the brass ones in stock, but more importantly (for me) is they have pictures. The parts list shows several different part numbers for this item and all are different lengths, suggesting you change it out for different clutch packs or to allow for clutch/linkage wear. Anyway it's enough information for me to make a new one, just have to work out what length I need. Might have to get a replacement for the 3 leg pusher as well, will see what happens.

Found a nice size piece of brass and made a new follower - made it 15mm overall with a 6mm deep slot for the lever. Set the 3 leg pusher up and machined the contact face, then polished it. Set the side cover back on and without a gasket, the lever is about 15mm off the side cover join when everything contacts. Added a piece of gasket material and the lever to cable angle is almost exactly 90 degrees, so I reckon it should be about right. Contact and operation is as smooth as you would want, so fingers crossed. The screw on cable end is the right length on the screw side, but only 2mm long on the other side, so looks like I'll have to find or make another longer one. Will get the side cover crack welded while it's off, then I can probably put that side back together. Need to confirm the drive shaft taper will match the new sprocket and cut a keyway in the sprocket - hoping the taper and bearing is OK, but will check it out. 

 

Edited by oldaz
More information added
  • Like 3
Link to comment
Share on other sites

 
  • 2 weeks later...

Been a bit quiet for the last week, too much farm work and wife in hospital, but life goes on. As mentioned above I've started on the power unit and got the clutch side pretty much sorted - still have to get the cover welded at the front lower edge. No cracks in the timing (right) side cover, but where the chain has come off the front sprocket the seal and side of the case is pretty chewed up - also a fair amount of play in the drive bearing on that side, so looks like I'll have to split the engine after all. Still don't have the wheels back, discovered the drive side bearing in the rear wheel has been loose at some time and partly chewed out the hub, so getting the hub machined to take a larger bearing on that side, then re-spoke it. The more I find the more I'm convinced this poor bike wasn't looked after very well in it's former life. Will order more gaskets today and look into getting the cylinder and head hydro-blasted to remove external corrosion. Now to salvage the right side case where the seal and drive bearing goes.

Finished sorting sheep this morning, but it's about 44C in workshop already today, so think I'll stay inside and give it all a miss - maybe a couple of Coopers dark for lunch??

  • Like 1
Link to comment
Share on other sites

 

Hi Oldaz

Been following with interest your refurbishment of your UKR. I have a mk4b the version before yours and have found similar problems to what you have come across. Your timing cover might have been damaged by the chain but pay particular attention to the inner case around the Kickstarter shaft, in a lot of cases the Kickstarter itself has been positioned to far forward on the splined shaft in the miss belief it would give a longer throw to the kick, unfortunately all it does is allow the stop on the shaft to punch a hole through the inner casing allowing water/moisture into ignition.

The correct position of the kickstart should be the ' one o clock ' or 30 degrees, or looking side on parallel to the frame down tube.

Hope this helps, here's mine.image.jpg

Edited by pro sport
  • Like 3
Link to comment
Share on other sites

 
50 minutes ago, pro sport said:

Hi Oldaz

Been following with interest your refurbishment of your UKR. I have a mk4b the version before yours and have found similar problems to what you have come across. Your timing cover might have been damaged by the chain but pay particular attention to the inner case around the Kickstarter shaft, in a lot of cases the Kickstarter itself has been positioned to far forward on the splined shaft in the miss belief it would give a longer throw to the kick, unfortunately all it does is allow the stop on the shaft to punch a hole through the inner casing allowing water/moisture into ignition.

The correct position of the kickstart should be the ' one o clock ' or 30 degrees, or looking side on parallel to the frame down tube.

Hope this helps, here's mine.image.jpg

They're a great looking bike when complete, thanks for sharing. I already know what you mean about the kick-start lever - I've already found the big wad of silicone in the hole. I'll do a better repair than just silicone when I get into the case repairs. The timing cover doesn't appear to be damaged from the chain, it's the side of the engine case where the main drive seal is - still some of the seal retaining boss left there so that's a bonus - just hoping the main drive bearing isn't loose in the case, guess I'll find out soon enough.

  • Like 3
Link to comment
Share on other sites

 
 
 
1 hour ago, turbofurball said:

The kickstart hole on my 349 is patched with silicone now, I didn't want to risk getting anything hard catching on the flywheel!

I understand, any welding repair requires removing or shielding the flywheel, possibly removing the kickstart shaft and ideally removing and stripping the right side engine case. Once welded any excess metal can be dressed back with a rotary tool and it should be good as new again. Be aware it's also possible to put a suitably shaped steel (or stainless steel) piece over the hole, seal with silicone or gasket cement and rivet or screw in place. Yes it's fiddly, but possible and doesn't require a complete engine strip down. I've also had great success using Devcon F aluminium putty to repair VW crankcases.

A shaped piece of copper to protect the flywheel will also prevent any excess welding material getting in the way and there's still room to get a rotary burr in beside the kickstart shaft, only downsides I can see with this approach is potential heat damage to the kickstart seal and how good the welding operator is.

I already have to strip the engine case to see if the main drive bearing is loose in the case, worn out, or loose on the main drive shaft, so will repair the kickstart damage while it's apart.

Link to comment
Share on other sites

 

Well, the engine is in bits for new mains, silicone just seemed like a common sense fix as it'll last as well as anything else I could plug the hole with (in other words till the engine comes apart again, and if I get it vapour blasted I'll get it fixed properly.  If not, fresh silicone)

  • Like 2
Link to comment
Share on other sites

 
 
 
  • 2 weeks later...

Finally starting to get into the power unit - the further I go, the worse things look. As I said above somewhere, the clutch case is cracked and needs welding, the kick-start stop has punched a hole through to the magneto, chain has come off at some time and chewed up the right side engine case, most of the material that locates the secondary shaft seal is torn off, the drive sprocket has slipped on the secondary shaft at some time and damaged the tapered section, there's excess play in the drive end of the secondary shaft and seal is damaged, cylinder head has been drilled out to accommodate 2 over-size cap screws (other 2 head studs OK), piston is 0.25mm over-size and looks OK in the bore, but can be twisted a bit as though the pin is loose (haven't pulled the barrel yet), both the head and barrel fins have surface corrosion that will have to be treated (maybe hydro-blast) and the exhaust clamp thread is chewed up. I removed and repaired the magneto nut, it had been hammered on a lot, but thread is still OK so that's one positive.

Will pull the barrel next, then split the cases before I decide what to do with it all. Will order a flywheel puller this evening, don't have anything with the right thread to make one from.

Not impressed with the PO's ideas on maintenance.

Link to comment
Share on other sites

 
 
 
6 hours ago, brewtus said:

Always fun to discover your new purchase was once owned by a butcher, and even more fun reversing the damage done by said butcher.  :angry:  Got my fingers crossed that you have discovered the worst of it. 

I always look for the positives and one thing I can be positive about is this has turned into a bigger challenge than I imagined.

After cleaning up the threads, I got the exhaust flange nut to work last night, seems there's enough good thread deep in the barrel that will allow it to work (fingers crossed) and after some measuring I believe I can make some stepped head studs to replace the over-size cap screws. Decided to get the barrel and head hydro-blasted to remove the corrosion and left-over paint, same shop can also weld the clutch case - again, not cheap but I believe necessary. Think this is going to take a while to get it sorted - I did tell myself it would be a summer project :-) 

  • Like 2
Link to comment
Share on other sites

 
  • 2 weeks later...

A little more progress, finally got the wheels back, they did a great job, hydro-blasted all the alloy, new gal spokes with phosphor-bronze nipples and the rear hub machined and new bearings fitted. I completed the modifications to allow the after-market brake shoes to fit, made new spacer for front wheel now there's no speedo, fitted the new tyres, tubes, bands, rim locks and got the wheels mounted in the frame. It's starting to look like a bike again.

Got the barrel and head are away for hydro-blasting, made a start on the new head studs to replace the M12 cap screws PO put in there, new gaskets and flywheel puller on the way from Inmotion, should get here in a week or two, meantime I can finish off the brake connections and other detail bits, then get back into the power unit.

DSC_0106.JPG

  • Like 2
Link to comment
Share on other sites

 

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
  • Create New...