Trials Australia Forums

Hi all new to this site. Bought an early 80''s Montesa Cota 123, I think 82, Engine/Frame No starts with 28M. about 3 years ago, road it a couple of times and then life kind of got in the road so it has lived in the garage ever since. Anyway pulled it out of the garage today to have a fiddle. Replaced spark plug, new fuel line and filter, and that's as about as far as I got as I spent the next 3 hours trolling the Internet trying to get information, not easy so I am hoping someone here can help;

Oil to fuel mix ratio, advice so far is either 40/50 : 1
Gearbox Oil Quantity, conflicting results between 600 or 900ml
Where can I get new Air filter, have the original cage still, local Moto shop says bring it in and see what fits.
Would like to change the Carb to Mikuni, any info size/type would be great, Currently Amal.

Anyway look forward to any help anyone can offer, would like to get this little fella running again and then work our where to go with it from there, not looking at a trophy piece as I like the idea of riding it.

Will post pics in coming days

BR
Geoff

Hi Mate

Lots of Montesa guru's will be along in a bit but most common cause of non start after a lay up is the carb jets blocked.

Take the carb off, give it a good dose of card cleaner - you can get it at most good bike stores - blow the jets out with compressed air, reset the floats to the correct height or just make sure they open and close the valve if you don't know the height, then give it another go.

Good luck

Paul MAc

you can buy sheets of air filter foam from motor bike shops and make your own. That's what most people do for extremely rare model bikes. Yours may be the same filter element as one of the more popular 1980s model Montesas in which case you might be able to get a pre-made filter element. Is it this one? https://www.inmotiontrials.com/product/ ... ite-model/
Looks like they sell Mikuni carbies for them too

Thanks for that!
Air Filter looked different to mine, mine has a circular cage which the filter fits around.
I have dropped them a line about the Mikuni though.
Cheers

Try Dave Renham at inmotiontrials.com - twinshock trials specialist.

Have found some PDF Manual downloads for older Cota123's red tanks and they all state 600ml of oil.
Does anyone know if latter 80's model white tank, 28M would be the same?

Also mentions a Fuel Ratio of about 4 to 5%

If you post your question on Trials Centrals site a fellow called King Scorpian will most likely respond, I haven't caught him in error yet, he's pretty good on Montesa specs for any model & anything.

If the gears/clutch is all one cavity, I'm betting 900mls but thats a guess.

Have included some pics, I can only locate one Oil Fill Point, but I am an Electrician not a Mechanic.

Will try and track down King Scorpion.

Pics of the bike as promised