bigshineybike

I have a similar crank shaft in my 348. Not quite as bad. Only one side of the key slot had flaked off.I silver soldered mine back on. Ive only run it for two weekends since. I used loctite bearing fit on reassembly since the shaft is a loose fit in the flywheel and I imgained the damage is because the shaft has somewhere to expand into. I managed to find a replacement half crank on ebay, one day i'll get around to fitting that. There have been stories of people simply doing with out the extra flywheel and I saw one that had the flywheel welded onto the shaft although that makes oil seal changes a bore!

I just saw a movie on you tube part way through theres a clip of someone building a sprite in his shed. hope its of use.

When I first got my 348 the previous own had lost a handful of spacers from all parts of the engine and gearbox. The only excuse i could make up for him was that at some time in the past 40 years the engine had lain in bits for a few years and when it was put back together pre internet there was n way to get hands on a manual. There are racists out there probably thought the bloody Spanish don't know 'owt about engines and they're all rubbish. Nowadays we know better. You may be able to find a bucket of spare spacers eventually but in my case I measured everything and made up new spacers and shims .Do bear in mind there is a requirement to shim endfloat albeit within fairly loose limits. I have a few spare engines in bits but they also are missing all the useful spacers and shims.Sorry this isn't much real help. But be assured many of us share your pain.

when I first got My 348 I found the previous owner has assembled the gearbox without any of the spacer washers at all! I couldn't change gear at all. I have the benefit of access to a machine shop . I have a sketch somewhere with the diameters of the washers. I made up a selection by machining the discs into a pile of brass shim.

The benefit of this method is the alloy tank you make can be quite rough.

It will take some time but I eventually found a used aluminium tank for mine, these fit under the fibreglass cover. The tank currently on my 348 had 349 written on it in felt pen. it wasn't a great fit under my 348 cover but a bit of adjustment and its fine now.

When I first bought my 348 it seemed the internet hadn't heard of such a bike. they built over 10,000 of them. You are not alone and this is as good a place for advice as you'll find. Most of the questions have already been asked.

Plenty turn up on ebay running from £500.There was a mint and unridden one in france went for £3500. most of the crucial restoration bits are easily available but as someone said the costs mount up quickly up so it will never pay for itself.

Do check there's oil in there first. these are metal to metal plate clutches. the clutch and gear oil are separate.

People suggest moving the condenser away from its hiding place in the depths of the engine. Most Montesas have them located behind the flywheel and it was thought to be ok at the time. Some suggest the heat gets to them. I moved mine to under the tank right alongside the coil and it did appear to make a difference.

This has been covered so a search may help. The electric flywheel comes off easily with a screw in puller. the counterweight flywheel is another matter. the big flywheel often comes off easily but a two or three leg puller will get it off easy. The clutch often falls off but if its not been apart before may need a bit of help with a puller or even a pair of tyre levers. Look out for the three little rollers that should drop out at the same time. the drive gear on the crank is the ******* that will not come off with out a fight. its a press fit there is very little room behind the gear teeth to get any simple and cheep puller in. I made a two legged puller based on something like the vauxhall steering wheel puller. it also needs a clamp wrapping around it to prevent it slipping off. then I applied some heat with a blowtorch. it goes with a bang when it lets go so be very careful. http://www.paddockspares.com/steering-wheel-puller-gm.html?gclid=CLrCmIuvmdACFQ4R0wodwvsBKg. when you put it all back together make sure the flywheel is nice and tight on the shaft, and the nut is wired. these do fall off and can damage the very long thin and keyed crankshaft. there have been a few people found they have been welded back on following broken shafts. (me!)

How much would it help if the decompressor was still fitted? My 348 clutch doesn't slip while riding but is sometimes not strong enough to kick over a cold engine. Since riding a royal enfield bullet with a decompressor I'm feeling like that's what the 348 is missing.

My 1978 348 is road registered so I believe the GRP tank is as it left the factory. However I threw that away and replaced with aluminium version. lots of benefits; use any paint you like on the tank cover. run the engine with the seat cover off, just tank in place. less chance of dying due to fire. My road bike, a triumph speed triple is suffering from ethanol in a plastic tank. the tank has swelled up and doesnt fit the frame properly anymore.

it appears to be for sale? Or have you bought it? If you are given it you'll still not make any money from it. Parts are available though. It will need total strip down.

It is only a decorative cover but does hide fasteners you need to get at. The same butcher that mucked up those screws probably didn't over tighten them. If you do not have an impact driver try hammering a screwdriver as you twist it.That should get them out.

Useful to note this post with a few more tips and photos http://www.trialscentral.com/forums/topic/23584-montesa-tapered-primary-gear-removal/page-2

I have an Enfield bullet, it uses the same rubber mount. I use the Enfield more often than the Montesa. The rubber split and I took the rubber from the Mont, that split as well. At the time (two years 3000 miles ago) I cleaned and superglued ( ordinary stuff from a pound shop) the split tube together. The difference now is that I made up a metal bracket to stop the carb wobbling around so much.

Correct its a long bolt. You could be lucky, if the threads are good.Hold the thread with the tip of a flat blade screwdriver, run the nut down with your fingers until the end of the thread is reachable. then hold the end of the thread gently with pliers do the nut up.

Wow, what a great looking bike.

secondary Flywheel and primary pinion gear torque setting. 72 ft lbs or 10 mKg

I use one from a lucas 25d distributor. This is as fitted to most 1275 a series engines minis Mg midgets Morris minor etc. If it helps ask for a condenser for a 1970 Mg midget with 1275 engine. There are lots of alternatives but that worked for me. This type has a suitable tag to screw it to the frame with. rember you need to make good contact with the bare metal of the frame.

The 348 and I believe a lot of other Montesas have a heavy additional flywheel attached to the end of the crankshaft on the clutch primary drive side of the engine. They are keyed to the shaft and if not torqued up properly shake about, split the keyway and snap the crank shafts. They over hang the end of the crank by an inch or so. in hindsight and at 40 years old something of a timebomb.

I had a look in the manual and it maybe worth noting the torque setting for the retaining nut is only 15 ft lbs (or 2m kg). I had a 'shop foreman used to say to me when I asked how tight to do up nuts and bolts. " tights tight and too tights f****d"

http://en.wikipedia.org/wiki/Montesa_Honda maybe?

Google or Ebay search; 5/16" BSF SOCKET HEAD CAP SCREWS 'Allen' is a trademark http://www.aseriesspares.co.uk/imperial-range-of-hardware/socket-head-cap-screws-12-9-self-colour/bsf-socket-head-cap-screws-12-9-self-colour/5/16-bsf-socket-head-cap-screws-grade-12-9-self-coloured/prod_558.html