billyp Posted October 15, 2007 Report Share Posted October 15, 2007 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. Quote Link to comment Share on other sites More sharing options...
ned1 Posted October 15, 2007 Report Share Posted October 15, 2007 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. Quote Link to comment Share on other sites More sharing options...
paul w Posted October 15, 2007 Report Share Posted October 15, 2007 ehich could be a bit dodjy. like your typing ! Quote Link to comment Share on other sites More sharing options...
cyclist Posted October 16, 2007 Report Share Posted October 16, 2007 (edited) 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, 2007 by cyclist Quote Link to comment Share on other sites More sharing options...
billyp Posted October 16, 2007 Author Report Share Posted October 16, 2007 I wish mine had been plastic Quote Link to comment Share on other sites More sharing options...
bilco Posted October 17, 2007 Report Share Posted October 17, 2007 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. Quote Link to comment Share on other sites More sharing options...
oz thumper Posted October 17, 2007 Report Share Posted October 17, 2007 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 Quote Link to comment Share on other sites More sharing options...
ned1 Posted October 18, 2007 Report Share Posted October 18, 2007 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 Quote Link to comment Share on other sites More sharing options...
autodoc345 Posted October 25, 2007 Report Share Posted October 25, 2007 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 Quote Link to comment Share on other sites More sharing options...
billyp Posted October 25, 2007 Author Report Share Posted October 25, 2007 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 Quote Link to comment Share on other sites More sharing options...
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