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Bultaco Sherpa 340 sidecases


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I have a Sherpa 340, which I'am rebuilding, the bike is in a let's call it good condition beside of some parts.

One of the main issues are the side cases where some alumium of the embelms are broken off, (can be fixed with

fluid / kned metal). My concerns are the impacts that are visible and caused cracks on both side cases.

I searched already E-Bay, dealers worldwide for gettimg replacement cases, but did not found any.

Here are some pic's of the cases outside:



Now the problem inner sides, (the cracks to the clutch side are not so good visible (only one of three!):



As visible the case structure on both sides is weakend a lot.

I could by a second bike as a sparepart would work with a 199a to 199b, but this is not my first intention.

I have sent both cases to a manufactory that do metalcsatings and have also a machining center, (they do gearbox castings for VW here in Germany), to give me an offer.

The casting will be a sand castings, no die csating because than they have to make forms which should be extreme expensive.

To remanufacture only two for both sides will be expensive too, if there is a smaller production run the costs will be go down,

anyone interested? (I don't want to make any bargain, you would get them for the money the manufactor will have + shipping.

If the remanufacturing will be to expensive, (I'am afraid it will be), do you have any good hints to get the side cases repaired?

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As cases go i wish i could find most as good as yours. As for casting well i tried with OSSA cases but i would have had to have 200 made to make it financially viable and lets face it trials riders are the last people on earth to part with their money so that was a financial black hole also and i have made too many of those recently.

Your best bet is to get yours welded and ride the bike.

Moto crossers and racers will part with their cash but Trials riders would sooner bung up the hole with blu tack than part with cash so if you had some recast you would be definately out of pocket.

Have you tried some of the Spanish suppliers? Expensive but cheaper than getting them remanufactured :thumbup:

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For dents with internal cracking, push dents out from inside then weld repair on the inside

@feetupfun: Thank You for the hint, one question:

If I will do so (pushing the dents out, the cracked parts will probably brake off, this is no problem? :unsure:

weld a repair and machine back.. they 'll be as good as new.

@feetupfun, @totalshell, Thank You for the hint, one question:

The side cases are die-casts so welding is difficult are there any hints which kind of weldingmaterial I should use, welding should be done with WIG? :unsure:

As You see in my reply:

I do feel a little bit unconfortabele doing so because these are the only one I have, If I would have spare a try out is no problem, (I like to do some experimental stuff if it is reversible or there exist a second plan. :)

Edited by PSchrauber
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Clutch cases are always available on ebay, the one on the 340 is no different from other models, any Sherpa since 1975 has that clutch case as well as Alpina and Pursang. The ignition cover would be harder to find.

However, any competent welder can easily repair them with a TIG welder.

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About pushing the dents out before welding on the inside - the dents in your photos should move back into position without further cracking and the reason you would do this is to preserve the external detail (logos and lines). If you are worried about the process, either do nothing or just weld the inside without pushing the dents out. It's your choice. I've got a clutch cover with bigger dents than yours on my M49 and it still holds the oil in and looks OK. I will not be doing anything unless it starts to leak.

The material in those Bultaco casings is very good to work with compared with many other engine casings so if you give the casings to someone who is experienced at this sort of work you will have no problems.

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I suppose another alternative which i have used succesfully in the past is a product that is sold over here called Lumiweld. Basically a low melting temp alloy rod. You heat up the alloy casing after cleaning with a stainless steel wire brush and melt the alloy rod into the dent or crack and let cool. You can then machine or file as alloy and repair is permanent and almost indistinguishable. Have to be careful abot heat temp but on a large casing which has good heat soak it's fairly easy. Worth a consideration :rolleyes:

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I suppose another alternative which i have used succesfully in the past is a product that is sold over here called Lumiweld. ...

Haven't heard about that brand or that possibility yet, I will give it a try. I just have ordered a set with 10 sticks, (hope this is enough). Will keep you informed how it worked out at the end.

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Just got the reply from the factory,

it is not possible to take the original sidecases as a model for sandcasting because the new cast will shrink during cooling down - around 4% of the original dimension - this will not work because of the rods for the clutch, the gear and the kick starter ...

Their solution would be a 3D scan of the cases, then they would crop the electronical model to the calculated bigger dimensions that are necessary to compansate the shrinking while cooling down. They would then milling a castingmodel of the 3D data. This model will then be used for the casting process.

The costs: 4000

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Its the mould/die that costs not what its made of, magneto cover side is structural anyway on a 340, and both struggle to hold oil as ally.

I'd heard that Bulto had problems with porosity of their castings and had overcome it by impregnating with resin.

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