Jump to content

1981 Montesa cota 248


__tom4
 Share

Recommended Posts

Hi,

I have just acquired a Montesa cota 248.

I’m new to the biking world so I need advice!

Its in fairly good condition and has been stored in a heated garage for the last 20ish years. 
Firstly, the last owner told me the gear shifter turns 180 degrees once put into 1st gear. Is this a common issue? If not, is it easier enough to open the gearbox? I work in engineering so have a good technical background.
 

Secondly, it hasn’t  been started for years so what sort of maintenance should I do before starting it?


 

Link to comment
Share on other sites

 

A 180 degree gear lever change sounds more than weird. Should be a quick 10 degree click. The ‘70’s/early’80’s mechanics are pretty straightforward with a workshop manual but do shout on here for the best oils and spares. Best of luck and enjoy your Montesa!

Link to comment
Share on other sites

 
2 minutes ago, rr62 said:

A 180 degree gear lever change sounds more than weird. Should be a quick 10 degree click. The ‘70’s/early’80’s mechanics are pretty straightforward with a workshop manual but do shout on here for the best oils and spares. Best of luck and enjoy your Montesa!

Yeah when the engine runs, the shifter moves 180 degrees as if it’s caught on something, then it cannot change gear after that. I haven’t started it yet as I want to makes sure the rest of the engine is all okay.

is the manual it came with good enough? I looked for a Haynes manual or something similar and couldn’t find one.

thanks for the reply 

Link to comment
Share on other sites

 

I'm sure you can work out what's going on when you pull the clutch cover off, without a manual. They are very simple machines. From the sound of what you have said the shifter may have had a bit of a hit. My friend's 1981 349 had similar symptoms after the shift lever was bumped on a rock just before a trial and he laid the bike over on its side, took the cover off and fixed the problem and then rode the trial.

If you can't work it out yourself, pull the cover off and post some photos up here and you will get lots of help

Link to comment
Share on other sites

 
29 minutes ago, feetupfun said:

I'm sure you can work out what's going on when you pull the clutch cover off, without a manual. They are very simple machines. From the sound of what you have said the shifter may have had a bit of a hit. My friend's 1981 349 had similar symptoms after the shift lever was bumped on a rock just before a trial and he laid the bike over on its side, took the cover off and fixed the problem and then rode the trial.

If you can't work it out yourself, pull the cover off and post some photos up here and you will get lots of help

I’ve whipped it off. As far as I can see it looks okay. I might have to take the whole engine out and dive deeper into the gearbox 5332718C-7CB3-48DD-8735-2B346A7FC59B.thumb.jpeg.91408b2761523ce1a4266d17eebdf4a7.jpeg37CA18A3-7E3E-486B-B208-867A8ECD69F9.thumb.jpeg.b3e0d8cca909d6ecbb636d8bb5a002f6.jpeg

Link to comment
Share on other sites

 

All looks in place to me, I'd check selector mechanism first by loosing the three screws and the bolt on the right hand side.

You can check the gears are ok by turning over the engine and putting a spanner on the square shaft in the middle of  the star wheel.

 

 

Link to comment
Share on other sites

 

Your gear change problem is the dimpled plate held in place by the M6 nut. Its an eccentric adjuster. Has to be i the right pace to get all the gears.

 

Its a 40 year old bike, laid up for 20 years.

 

I would budget for:

Crankshaft seals (can be replaced without splitting the cases). You need a special puller tool to get the pinion gear off the crankshaft. Dont try to use anything else, you will damage the pinion gear.

Have a look at bore and rings. You might get away with honing the bore.

Flush out the fuel tank (alloy under the f/glass cover).

Clean carb and jets. (Its a mkII concentric)

Ensure float and shut off needle are E10 proof. (Go to Surry Cycles for carb parts.

Replace the fuel pipe tank tap to carb. E10 will eat the old rubber.

Replace air cleaner.

Swinging arm bushes check

Rear shocks - check damping

General lubrication - cables

Check grease in wheel bearings,

Lube chain.

Tyres - Probably perished, replace + tubes

 

Could go on. 

 

Hope this helps.

 

 

 

 

Link to comment
Share on other sites

 
13 hours ago, dr nosh said:

Your gear change problem is the dimpled plate held in place by the M6 nut. Its an eccentric adjuster. Has to be i the right pace to get all the gears.

 

Its a 40 year old bike, laid up for 20 years.

 

I would budget for:

Crankshaft seals (can be replaced without splitting the cases). You need a special puller tool to get the pinion gear off the crankshaft. Dont try to use anything else, you will damage the pinion gear.

Have a look at bore and rings. You might get away with honing the bore.

Flush out the fuel tank (alloy under the f/glass cover).

Clean carb and jets. (Its a mkII concentric)

Ensure float and shut off needle are E10 proof. (Go to Surry Cycles for carb parts.

Replace the fuel pipe tank tap to carb. E10 will eat the old rubber.

Replace air cleaner.

Swinging arm bushes check

Rear shocks - check damping

General lubrication - cables

Check grease in wheel bearings,

Lube chain.

Tyres - Probably perished, replace + tubes

 

Could go on. 

 

Hope this helps.

 

 

 

 

Thanks for the list. Luckily the last owner replace the tyres, chain and rear sprocket before I got it. I took the 3 screws out of the gear selector and took it off. The ‘pawns’!? The slanted blocks of metal with a spring popped out and I looked at the plate you said about. I checked the exploded diagram I have and it doesn’t state where it should sit. 
it sucks there isn’t anything online I can find 😕 

on another note I want to say thanks for all the help! I might be posting a lot…🤣 

Link to comment
Share on other sites

 
  • 2 weeks later...
 
1 minute ago, keychange said:

Is the spring broken?  The spring is locked in place by the pin towards the rear

It isn’t broken but it is very loose and as I understand it should hard to get on and off? At the moment it falls off easily. I’ll order a new one

Link to comment
Share on other sites

 

It isn't hard to get on or off.  But it controls the rebound of the gear lever ie: when you push down for first the lever moves back up to the middle position etc.  I can't see how you can do a 180degree turn if the spring is operating correctly.  I have a 247 and the selector is different but the spring has the same function.

9E2E1BC3-7D25-45F7-97EF-9B53274B450B.jpeg

Link to comment
Share on other sites

 

Ahh thanks for the info. Do you know where I can buy spares? I’ve looked online but most are from America with really high shipping costs 

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...