Monty 348

[yam175]

Hi , just got myself a 348 , what oil should I be using in the gearbox, clutch etc thanks

[section swept]

There is a whole raft of info on the Cotas and the 348 especially. Do a search through the Montesa area of Trials Central. I use automatic transmission fluid in the alclutch ( Actually a Mercedes Benz fluid) but most ATF fluids will do. In the gearbox EP 80 will be ok. There is no level plug so its an overnight drain down and then fill with the correct amount. The amount you will find on this site, I cant remember the exact quantities but 300cc and 600cc might be ok but CHECK as too much oil will cause the breather to pass oil out. The gearbox is a ‘dog box’ so you can change gear with out the clutch (as are nearly all bike gearboxes) so a strong oil is best. ATF in the clutch will help prevent clutch sticking and dragging. Mont 348’s with a proper set up on the clutch are very reliable. Do not rely on the old sealing washers on the drain plugs fit new if you can, otherwise they ‘will leak’! If not already done it is a good policy to turn the clutch filler into a breather, also the gearbox filler. Or purchase ready made. Either way allowing the clutch case and the gearbox to ‘breathe’ allows any gas pressure build up due to the oils getting heated and creating vapour (gas) which will need to get out. This usually means the oil seals or a gasket weak area. The Montesa 348 has a breather hole in the gearbox casing but it is well hidden and can get blocked....not good! I have tried to show these in some pics....hope you enjoy your ‘tractor’ an endearment for the lugging ability of that motor.??

[nh014]

Original factory recommendation is 200 cc (6-3/4 fl oz) of 10w-30 engine oil in the clutch and 300 cc (10 fl oz) of SAE 90 gear oil in the gear box. I use Maxima MTL-XL 75wt transmission oil in the clutch and any good 80w90 gear oil in the gear box. Never been a fan of ATF for the clutch.

[peterb]

Section swept, what a very good post. I also tend to use ATF in clutches, Bultaco's too for well over 30 years now. Never had any problem with ATF in the clutch on any bike. Bye, Peter B.

[feetupfun]

I use car manual gearbox oil in my 348 clutch and it works beautifully. I was using ATF in the clutch previously but it squealed during engagement.

Edited December 16, 2019 by feetupfun

[yam175]

Thanks guys , by turning the filler plugs into breathers do you mean drilling a small hole in them.

[yam175]

Ah right I can see now , on my phone reading the replies, on my tablet now , good idea on the breathers , will do thanks again guys

[section swept]

Yes you can drill a small hole centrally into the filler plug. I then inserted a plastic tube with superglue. Measure the plastic tube for drill size, try for a really snug fit. Then attach a clear plastic tube and run this to where ever you think fit, my breathers are routed up to the top frame tube and are then held inside the open end of the top frame tube with cable ties.

[yam175]

Ok will do any other mods