Pampera frame malarkey.

Mechanical failures are relatively rare on the AdventureRide fleet of Gas Gas Pamperas, testimony to the inherent simplicity and strength of the original Gas Gas design and hopefully an indication they are maintained properly by yours truly. For sure they consume wheel bearings and rear suspension linkage bearings at an alarming rate but other than that, the Pampera reliability record has been commendable, especially when you consider the amount of use they are put to.

To give an idea of how tough a Pampera is consider this: each bike on the fleet is identified by the name of the county from where it came and ‘Cornwall’ has been been on the fleet since I started AdventureRide ten years ago. This particular bike has probably participated in over 900 trail rides. I purchased the bike in 2012, collecting it en route because I had an entry in Land’s End trial. I rode a MK2 Pampera in the event that year and that bike suffered a rare DNF due to a head gasket failure (a common problem with the MK2s) In hindsight I should have ridden the freshly-acquired Cornwall and I reckon it would have come away with a medal straight out of the box..

Cornwall was pressed into service with AdventureRide the following week and has been on duty on almost every AdventureRide outing since then. During its tenure on the fleet it’s consumed a host of consumables (obviously) such as tyres, chains, fork seals,sprockets and wheel and linkage bearings but the non service-related parts are confined to one piston, a set of clutch plates, and a fan. And that’s it. Most of the other bikes have a similar tale to tell and this is why I’ve stayed faithful to the Pamperas and haven’t been tempted to replace them with newer bikes. There is simply nothing like them on the market, everything else is either too heavy, too tall, too expensive or too focussed on either trials or enduro to be a good all round trail bike for then typical kind of trail riding we have here in Shropshire.

However, what I want to talk about in this blog is a frame problem which has recently manifested itself on a couple of bikes. Two bikes have suffered catastrophic failures of the rear linkage mounts although surprise to say, on each occasion both machines made it back to base. The damage on both machines was virtually identical and whilst I had my theories as to the cause I decided to consult my local frame guru, Malcolm Shepherdson of Metal Malarkey in Bishop’s Castle.

One of Malcolm’s frames with a Triumph engine installed. Simple, elegant and beautifully constructed.

Malcolm is a first class engineer and his past experience includes working at MRD Metisse overseeing the production of their famous Rickman style race frames. Since starting his own business Malcolm has become an established frame builder/designer in his own right and his artistry is frequently featured in the motorcycle press. In short, Malcolm knows his way around a bike frame

After pondering the damage Malcolm expressed concern that the Pampera frames might have an inherent weak spot. When I explained the level of use (and sometimes abuse) the bikes were subjected to we both agreed that after almost twenty years service, the frame failures could reasonably be put down to fair wear and tear! As previously mentioned, some of the bikes have been ridden by almost nine hundred different people…

The problem seems to have occurred due to excessive stresses being channelled through the frame-mounted rear linkage bracket, possibly as a result of a seized linkage bearing caused by water ingress following repeated river crossings.

It would have been simple enough to repair the frames back to original spec but on the basis of ‘whilst we’re at it’ I asked Malcolm to look at improving the original design. Space is tight around the area of the bracket but Malcolm came up with the idea of four strengthening gussets welded in place to brace the linkage mounts and also the outer frame rails. Before bracing anything it’s essential everything is correctly aligned, particularly in a design like the Pampera where the location of the engine, the swing arm and the linkage mounts are all inter-related. Malcolm devised a very neat but effective jig which replicates the engine mounting bosses and ensures that once the frame is repaired , the engine will fit back onto it’s original mounting points.

Neat jig designed by Malcolm which replicates the position of the Pampera engine mounts.

Broken engine mount welded back in place with strengthening gussets to combat stress.
Malcolm with a brace of modified Pampera frames.

The modified frames will enter service during the next few weeks, just in time for autumn and winter season season which is often my busiest time of the year. This often surprises people but the reason for the increase in bookings is a lot of road riders like to keep their eye in over winter by doing a bit of a bit of trail riding. With eight Pamperas on the fleet I’ve adopted a policy of restoring one or two bikes at a time and re-introducing them into service when other bikes become due for a major overhaul. One of these modified bikes is going to be rebuilt into a sort of Pampera Evo1 incorporating a number of technical modifications based on the experience I’ve gained over the past ten years but I’ll cover all that in a separate blog.

Malcolm and Metal Malarkey can be found at http://www.malarkeyengineering.co.uk

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