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Montesa Cota 349 1980


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Small lever opens a valve next to the spark plug which stops any compression in the cylinder. This allows you to turn the engine over past TDC when starting. I wondered if that was stuck open. TBH I'm pretty new to these myself and also in South West. Is there compression when you put it into gear and try to push it with clutch released?

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43 minutes ago, turbofurball said:

Note that on Montesas if you pull the clutch in it disconnects the kickstart ...

The 248 is a cracking bike - I wish I could find some nice trials bikes in sheds, lol

Aghhh thank you for that, I just had the clutch in and it was getting no compression. When it was in 1st gear I could feel it had compression.

I was just a bit worried about it going into gear and taking off somehow, oops!

I will try it with clutch out just to see if that resolves that problem.  I am also glad to know that pipe is not disconnected from anything and is just a breather pipe (the one in the picture)

What is the chances that the spark plug would need to be replaced? Do they usually degrade overtime or are they normally pretty good?

Edited by Sparky1001
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Ok got it,

another novice question, are there only 2 oils I need to change? One on the left hand side of the bike is a screw plug that I can take out, im guessing that is the engine oil? And it drains from underneath the bash plate?

What oil should I buy to put in there?

Where do I replace the transmission oil? Again what oil should I buy for that?

What oil goes with the petrol & at what ratio? 

Sorry if these have been asked a million times, I have researched on here but there are lots of different oil types, ratios etc and it’s quite confusing ?. 

Thank you :-)

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You need to change gearbox oil which is the plug under the bash plate and fills above in the middle of the engine. Also the transmission oil which drains from below the gear lever and fills from above it to the left of the clutch arm.

Did you see the link to the manual Sparky? I can send a pdf if you would like. It's in Spanish with English as well. Oils are listed as Gearbox SAE 90 and transmission SAE 10w30


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Got it ta, page 20 - I must of missed it the first time round, oops!

god I know this is basic work for you guys, but attempting all this seems a bit overwelming! But be great once it’s done as I know how to do it in the future then :-)

I would never be able to clean the carb as it’s to advanced for me, so I’m going to replace the trans oil and engine oil, put fresh petrol and mix in the tank and give it a kick over!

thanks all

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I would suggest using the decompressor lever (by the clutch) if trying to start it or you can get a very sore leg/shin if it kicks back. It lets you move the piston just past top dead centre to a position where you can have a swing at it.

Slowly push the kickstarter down until it won't move then pull the decompressor lever in until the kickstarter will move slowly and it has gone over TDC. You should be able to kick it all the way down then. Wear sturdy boots and try it a couple of times with fuel off first to practice.

Everyone starts somewhere and there is a wealth of knowledge here and I'm no expert at all so I'm always asking advice.

Keep us posted.


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