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Which ever bike you decide to go with here are a few things to consider. 1 If the bike has a fibre glass tank then it will most likely be suffering from the dreaded Ethanol poisoning. 2 If the fuel tank is plastic then Ethanol can affect the plastic by making it soft and other lovely side effects. Ethanol proof tanks are to be found but they cost! 3 Early Bultacos if ridden hard i.e. lots of jumping and hitting bumps really hard such as sudo scrambling can cause the frame to bend. Check down near the swing arm as the frame can crack where the side tubes meet the main down tube. Look for signs of repair. 4 The Bultaco frame tubes under the engine can get distorted and push up against the timing and clutch cases causing them to wear and leak. 5 Spares are available for all the main Spanish makes. Do some research on the internet to compare prices. 6 Such things as crankshaft main bearings, seals and gearbox bearings run at about the same cost be it a Montesa, Bultaco or Ossa. Con-rods and big ends are £100+ then you have the fitting to bear in mind. 7 Some Montesas had an alloy tank under a fibre glass shelter. Some Ossas had an alloy tank. Alloy tanks on Bultaco trials are rare, Sammy Miller did produce an alloy tank and seat unit but the majority of these usually split at the rear of the tank next to the seat panels. There are some really good machines out there you just have to find the right one. I have had 3 Bultacos a 1972 L regd 325, a 1980 350 and a1972 250. The engines are very straight forward to work on and very few special tools are needed, I managed to make mine. The Yamaha TY 250 is not the best at steering in the tight naggery stuff hence the John Shirt Majesty kits which altered pretty much everything and made the TY perform well. Engines are not the easiest to work on and the cases are magnesium as are the brake back plates so look for corrosion as this can render the component scrap. Ossas are finicky and the gearbox has to be shimmed correctly. Probably the best bike in a tight spot and very stable if in good order. Montesas are well thought out machines with grease nipples in abundance, they are relatively tough and usually very reliable if correctly maintained. Value added are things to look for, electronic ignition, replacement carb correctly set up, fancy suspension although it may not suit you, your weight etc being a factor. Modified footrests, ok for some but the purists hate them. Hope this info is helpful and that you get a cracking bike that you can enjoy??

Very nice bikes??

I’d be a little concerned about the a) rust evident on the crankshaft wheels, there might be rusting on the big end crank pin b) the obvious welts on the right hand side wheel, what caused those? On the other hand if you hadn’t taken the engine apart it would probably gone on for years without any trouble what so ever....but now you know??

There have been a number of members looking for various bikes pistons on this website. I find Google comes in really handy and there you will find a few stockists of pistons that might be what you need. Hope you have success.

Not jumped into gear has it? Go with the spark plug removed and turn the engine over slowly. If its water down the bore you need to remove as much as possible before running engine. Check the airbox it may need sealing to prevent further water intrusion.

Thanks guys, just to add some more confusion In Motion reckon it to be a 1977. I’m tending towards the 1976 year as mine has the folding tips on both gear and brake levers. The frame has a welded on bash plate with thousands of tiny holes in it, very similar to a Bultaco although the holes on those were a tad larger. The footrests have been modified with S3 type pedals and a welded plate either side which brings the pegs down and back level with the wheel spindles, neat job by previous owner. Thanks feetupfun for your pics I may well put my bikes pegs back to as factory. But retain the S3 pegs instead of the teeny originals.

The ‘double’ gear lever was in the 60’s/70’s a recognised mod, enabling the ride to prod each the front for up changes and prod the rear for down changes. This stopped the ‘fishing’ effect trying to get the boot under the lever to lift the it up to select a gear. Possibly not as effective on later trials bikes due to space confinement. The Ducati engine may have road gearing ratios in the gearbox and possibly close ratio, so not ideal for trials use. By the looks of the bike in the photo fitting a smaller out put drive gear would cause chain to frame clearance issues. Agreed the rear sprocket might be better suited for cutting logs but its not the only special that has worn quite largish rear sprockets. Nice bike, looks well made and its different and very attractive with the current colour scheme. I hope the owner has a great time campaigning the Ducati, lets have more of these ‘specials’. Have a look out for Ras Sport Kawasaki a well thought out bike.??

The whole fuel system needs checking and making sure pipes and the fuel tap are clear. Tank breather clear, Bogging as you describe may well be incorrect main jet but there are other factors that can bring this issue up. Have you checked the exhaust for excess clogging. Factory jetting may not be what you want as you have a non standard carb fitted. Some one will be along shortly with advice on jet sizes unless you contact a supplier of the carb fitted to your bike.

Yes I’m afraid the stators are fragile and its not just Sherco’s that suffer. Do a search on this sites Sherco area. You can get the stator rewound.

The oil pump blanking plates with gaskets are still available from Chase TY and other good shops. The blanking plates are a piece of cake to fabricate, just make sure the gaskets are well sealed. Crankcase oil seals may be worn which will affect engine running.

With my 348’s frame number as 51M 11** its got to be an early 1976 then, possibly confirming your bike as you describe?

Mine has the folding pedal tips and it does have a stout moulded bash plate that comes up to protect the cases. With such low numbers it is defo a 1976 I am now convinced.

Apparently so did man and then the Romans got carried away, but Montesa stole the lime light.

Makes sense of a non sensical recording system, thanks for the equation nh014?

Do you polish under the mudguards as well? Excellent looking and obviously very well cared for?

You are not the only one that has had issues with the relatively uncomplicated fitting of fork slider seals, especially aftermarket types. The actual tooling used by most bike dealers is like a pair of large collets and quite weighty too! With a little rubber grease on the seal lips and on the fork tubes and using the tool it usually only takes a few strikes sliding the tool to the top of the tube and bringing it down with just hand force. The retainer internal circlip is then installed job done. Your seals were most probably the wrong ones.....close but should not have required all the effort that you put in.

Set the mixture screw for the smoothest and slowest idle speed. A plug chop would help you to identify correct mixture setting has been achieved.

May be that the carb has been fiddled with as its a fairly old 2001 bike, main jet may be too big. There are possibly many reasons but its a starting point. Maybe ensure that the air filter is clear, clean and not restricted, hoses not kinked or crushed.

Its more than likely the oil in the clutch case is not damping the noise of the rattle that is the clutch basket and plates as the oil is quite thin. As tecnowaldo states just get on and enjoy. Fill the clutch case with EP 80 or 90 and there will be no noise but your clutch will be extremely snatchy, grabby and not at all nice.

I have recently (last week) bought a Montesa Cota 348 Malcolm Rathmell Replica. It is alleged to be of 1976 vintage. The frame and engine numbers are matching 51M 1*** yes there are only four numbers after the 51M which denotes a 348. This bike has not been registered for the road. I trolled about on the infernal web but can only find production numbers and type reference designations, but no actual year data. I am assuming that my 348 is one of the first for 1976, any help would be greatly appreciated. I have visited ToDoTrial but no success there, I have not bothered In Motion for info yet hoping some one here can help.

Well its off and it is stamped as a Skywalk Spark Arrestor there are other markings together with a number 2500. If you want it you can have it for the post and packing from UK to USA.

I am about to remove the spark arrestor from my Cota 348 MRR. If its going to help you out I can send you a photo or two. PM me bgeacock.

Well I’ve very much enjoyed Trials Central as both a resource for useful information and expanding my knowledge base. The various banter between like minded individuals and groups has been challenging, heartwarming, hilarious and at times worrying?...say no more! But I need to take a new direction...no I haven’t joined a boy band....my recent and sudden illness of the physical kind ( get in first with that before oni nou touches on brainy stuff)?has made me think about other things rather than the all encompassing world of trials which has been my passion as a bike dealer, rider and enthusiast. So I will sign out for now, concentrating on other influences that need addressing. To the Trials Central Team thank you for providing the best platform available for everyone in the sport both passive and active.??‍??

Just had a quick look on Google and Goetz seem to state that they have a wide selection of piston and rings. As I understand it when you want to manufacture an engine for mass production or a one-off, the designers specify the requirements and the various suppliers look at what they have in terms of manufactured stock. In other words by referencing they tell what to use. So out there somewhere is a supplier that may well be able to match the specs from their stock. As for rings I’ve taken a pattern to a local engine remanufacturer who plopped the ring onto a magnifier and produced a slection of options for me to select. Without being petty about it....if you are determined you will eventually find what you are looking for and don't discount the idea of searching in other areas such as the marine (outboard) industry. Then theres the China and India route.....? In all of this I hope it may be helpful??

Noooo you need to retain some coating for the reeds to seal against and cushioning, no sanding used.... all hand scraped.