Hi, does any body know what size (and thread)the gearbox drain plug is in a 348 Montesa.

I took it out to change the oil and had the thread away with it, iwas wondering if a helicoil would work.

Thanks.

a helicoil would work but you have to drill out the hole and tap it a size bigger first ehich could be a bit dodjy.

ehich could be a bit dodjy.

like your typing !

My 348 has a 14mm with a 1.5mm pitch. It had a plastic plug so I don't know how it could have stripped the case???? I replaced the plastic plug with a magnetic drain plug from a BMW /7 transmission. I don't know what size the clutch/primary plug is.

Edited October 16, 200718 yr by cyclist

I wish mine had been plastic

If you don't feel confident or got the tool's to do it,take it along to your local engineering shop and let them take alook,the place i used to do my fantic engine only charged me a fiver for the job.

Hi, does any body know what size (and thread)the gearbox drain plug is in a 348 Montesa.

I took it out to change the oil and had the thread away with it, iwas wondering if a helicoil would work.

Thanks.

In an aluminium case you will not need to drill out the stripped hole, should tap out directly as the helicoil tap is not much larger than the root diameter of the old thread. If you clean up the drain plug and check it will screw into the helicoil before it is fitted you have the right size.

However the cost of the helicoil kit, including tap and insert tool will be dearer than getting somebody to do it for you provided they have that size available.

Good luck

Hi, does any body know what size (and thread)the gearbox drain plug is in a 348 Montesa.

I took it out to change the oil and had the thread away with it, iwas wondering if a helicoil would work.

Thanks.

In an aluminium case you will not need to drill out the stripped hole, should tap out directly as the helicoil tap is not much larger than the root diameter of the old thread. If you clean up the drain plug and check it will screw into the helicoil before it is fitted you have the right size.

However the cost of the helicoil kit, including tap and insert tool will be dearer than getting somebody to do it for you provided they have that size available.

Good luck

i would suggest drilling it the correct size, if not you will end up with some dodgy thread, it will only take what a minute to do, also you can buy the tap and helicoil and tool all seperate you don't need to buy an expensive tool, also if you were taking it to some one you have to either strip the engine so that you could just give them the casing or take the whole bike in.

ps. my typing is awesome haha

there is a much better product then a helicoil to repair threads, called "time sert" it is a solid steel insert. I've been in the repair business almost thirty years and have done alot of both product and if givin the choice I would never use a helicoil over a time sert. once installed they won't pull out like a helicoil. Bruce

there is a much better product then a helicoil to repair threads, called "time sert" it is a solid steel insert. I've been in the repair business almost thirty years and have done alot of both product and if givin the choice I would never use a helicoil over a time sert. once installed they won't pull out like a helicoil. Bruce

Sounds good, can i buy a kit or do i have to take bike in, can it be done with engine in the frame?. Dont supose your anywhere near cambridge