Montesa Cota123 Early 80's

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36Cycles
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Re: Montesa Cota123 Early 80's

Postby 36Cycles » Sun Aug 23, 2015 11:14 am

Thanks to the heaps of awesome people out there offering heaps of great information, still trying to get the bottom of this Oil Quantity issue with some certainty.

I have learnt that some Montesa Cota's had two seperate places for oil, and some have a combined, I am reasonably comfortable that mine is a combined as I can only find one fill point as in photos. So I am assuming if you have two places to put oil then the quantity required would be 600ml which seems like the Older Red tank Cota123. If you have latter model Cota123 White tank like Cota200 then you should be using combined quantity of 900ml.

Ahhhhh.... The joys of owning an uncommon bike make the answers so much more rewarding.



Brigalow
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Re: Montesa Cota123 Early 80's

Postby Brigalow » Sun Aug 23, 2015 3:16 pm

Had the same sort of issue a bit with my 172, 900ml seems to work fine in it.



36Cycles
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Re: Montesa Cota123 Early 80's

Postby 36Cycles » Sun Aug 23, 2015 8:32 pm

Information from 29MarkT on Trials Central;

Oil Quantity
900ml's 1982 Cota123/200 share same bottom ends.

Air Filter
Same as 200, which now have a European Link for.

Fuel Ratio
3-4%

Next Jobs;
Oil Change, and fit Genuine Montesa Bash Plate, scored 3 of these in an eBay Auction
Clean out Carby
Repair some bad electrical wiring

Next challenges;
Chain Tensioner
Mikuni Carb

Will post Specs page next



36Cycles
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Re: Montesa Cota123 Early 80's

Postby 36Cycles » Sun Aug 23, 2015 8:46 pm

1982 COTA123/200 Quantities
Attachments
image.jpg
image.jpg (167.5 KiB) Viewed 5294 times



36Cycles
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Re: Montesa Cota123 Early 80's

Postby 36Cycles » Mon Aug 24, 2015 3:10 pm

I have just had additional confirmation from Jared Bates from South West Montesa;
The correct amount is 900 cc. (30.5 ounces) clutch and gearbox are combined on this model.



36Cycles
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Re: Montesa Cota123 Early 80's

Postby 36Cycles » Mon Aug 24, 2015 8:22 pm

Oil Quantity sorted, now I'm getting my head around what is the best Spark Plug to use!

Bike came with NGK B9ES
Manual States Champion N4, NGK equivalent is B7ES

Would there be a reason that someone would change the type of Spark Plug to reflect a different climate, Australian or maybe changed for different riding style than Trials.

I have broken down the NGK Spark Plug code below,

B: Thread Diameter, 14mm
7: Heat Rating, lower is more Hot
E: Thread Reach, 19mm
S: Standard 2.5mm Centre Electrode

What would be the reason you would go down temperature ratings/higher numbers in the NGK code?



David Lahey
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Re: Montesa Cota123 Early 80's

Postby David Lahey » Mon Aug 24, 2015 8:50 pm

36Cycles wrote:Oil Quantity sorted, now I'm getting my head around what is the best Spark Plug to use!

Bike came with NGK B9ES
Manual States Champion N4, NGK equivalent is B7ES

Would there be a reason that someone would change the type of Spark Plug to reflect a different climate, Australian or maybe changed for different riding style than Trials.

I have broken down the NGK Spark Plug code below,

B: Thread Diameter, 14mm
7: Heat Rating, lower is more Hot
E: Thread Reach, 19mm
S: Standard 2.5mm Centre Electrode

What would be the reason you would go down temperature ratings/higher numbers in the NGK code?

If you were going to ride that Cota 123 on the road, you would want to be using a B9ES to reduce the chance of melting a hole in the piston. If you were riding trials or gentle trail riding on it, a B7ES would be suitable.


relax, nothing is under control

36Cycles
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Re: Montesa Cota123 Early 80's

Postby 36Cycles » Mon Aug 24, 2015 9:51 pm

Cheers, thanks for the simple explanation.

Higher Number=Colder Spark Plug type is good for riding on the road or more constant use/longer durations which requires better resistance to temperature. Running long durations on lower value numbers/hot plugs would cause excessive heat.

Not intending to ride on road, most likely to putt around in paddocks or still toying with the idea of joining a trials club and having ago, at nearly 40 I'd be most probably the oldest learner with the least experience.

So I think I'll change plugs to B7ES or B8ES

Thanks for all the help!



36Cycles
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Re: Montesa Cota123 Early 80's

Postby 36Cycles » Mon Aug 24, 2015 10:06 pm

Noticed that my bike doesn't have chain tubes or a tensioner,would like to fit tensioner anyone had experience with a good type or best location for fitment.



29MarkT
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Re: Montesa Cota123 Early 80's

Postby 29MarkT » Wed Aug 26, 2015 9:39 pm

Hi, as regards the chain tensioner, I would advise fitting the original tubes and bracket, which are available from In motion, and prevent the chain jumping the gearbox sprocket and smashing the casing which is a common problem, some people have fitted a universal tensioner and used the long bolt hole on the bottom of the casing. I have fitted the original tubes, they keep the chain in good condition also.

The part numbers if you wish to search the net are as follows,

5120.369 - Bracket
5120.30601 - Tubes

Hope this helps,

Mark Trueman
England :montesa




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