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Bultaco 350 Clutch Troubles


trialsrfun
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Has anyone else tried the Barnett plates?

Yes the Barnett fibre plates work great in Bultaco Sherpas. The takeup becomes silky smooth and the clutch spring preload can be backed off to provide a lighter pull yet retain the required resistance to slipping (they have a higher coefficient of friction than steel on steel).

I just wish Barnett made them for Montesas as the sudden and jerky takeup is the main weakness with my 348 Cota in competition.

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re clutch snatch.

If you look at the clutch basket where the clutch plate ears fit you will probably find that the slots have troughs where the cluch plate ears have been sitting. The same will apply to the hub where the plates will again have worn the surface.

You can file both these areas smooth so that the plates can move easily (they only move a small amount).

This will cure the snatching problem completely.

If the clutch basket is aluminium then this problem occurs more frequently beause of the softer material.

This process can only be carried out a few times because if you enlarge the slots too much clutch rattle will result.

Also make sure the plates are the correct way around ie where they have been stamped out

You can fit persang plates which can reduce the snatching as there are more plates and thse will sit in the basket at slightly different positions to the sherpa plates.

Sae 30 oil was always recommended and i have had no problems with using this oil for 30 years.

Clutch drag is much more of a problem especially if you have a longer clutch arm fitted but with careful balancing of the clutch via the spring retaining nuts you can reduce drag to a minimum.

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Nigel,

Yep i know most of it has been covered.

But unless the clutch basket and centre hub (which i didn't think was mentioned) are new then there WILL be wear and even a small amount can stop the plates moving freely resulting in snatch.

One of my sherpas a 1978 model has a very light clutch indeed (as light as the gas gas pro) When i took it apart to find out why i found that it had one extra plate fitted. The springs seem to be standardard and adjusted like my others and there is no slip at all so i'm puzzled as to why but i wont change it as it really is easy to use with one finger.

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Nigel how do the Frontera clutch plates differ from those of the Sherpa 199a.

I seem to recall seeing on these pages a list of Bulto works mods but cannot find them, does anyone have the list available or know where it can be found.

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Nigel,

The clutch plates are standard sherpa plates and not the thinner persang plates.It just has one extra centre plate which makes the whole basket thicker.The large plastic screw in the caseing has a few fibre washers under it to stop the adjusting nut fouling. The clutch springs seem to be the same strength as standard ones which I have plenty of.

As far as I know the pursang/frontera plates are the same and are thinner than the sherpa ones but there are more of them.

There are a number of works mods. In 1979 Reg May was featured in TMX news where he outlined all the works mods of the day. I have a copy if anyone is interested

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"There are a number of works mods. In 1979 Reg May was featured in TMX news where he outlined all the works mods of the day. I have a copy if anyone is interested "

Yes please would be most interested. I'm sure a lot of them could be applicable to the 199b i've got.

Thanks for the offer. <_<

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