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Bike Review - Posted 28th June 2013
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BMW R80/7 - Part 15 - What Happened Next

Or "You don't need to have an adventure bike to have an adventure", in which Mr Gelder returns from parts foreign and restores his classic BMW motorcycle to working order...

If you're a RealClassic magazine subscriber, you'll already have read the two part feature in which myself and my mate Ted rode two wholly unsuitable motorcycles across a Spanish desert and then up a Spanish mountain. You can find the full sorry tale in RealClassic magazine issues 110 and 111. The story finished with my tired old airhead BMW limping home after needing a bump start to escape the bowels of the Santander to Portsmouth ferry.

Who needs whitewall tyres?...

It got me home, 150 non-stop miles, then it stalled and wouldn't restart. The battery was dead flat and wouldn't hold a charge. Fitting a spare (those three words conceal a good view hours of fiddling for a boxer BMW) and probing about with a multi-meter eventually pinpointed the problem. The über-reliable indestructible solid-state voltage regulator was pumping 18 Germanically efficient volts through the bike's wiring; our final day's motorway dash across Spain had been the final straw for a battery that had been having a hard time for a couple of months, something I'd initially put down to a number of other causes. Who knew that reliable solid state regulators could be so unpredictable?

Actually, several people seem to have known, but none of them mentioned it to me. So now I know, and I'm telling you. Keep an eye on the charging voltage if you use a solid-state voltage regulator, and if your battery is boiling dry or your bulbs are popping, you know where you should look first.

When they originally built R series BMWs, they started with the battery... This is the *quick* way to get the battery out of an airhead...

With the bike now startable, it was time to find and fix the misfire that had proved such a pain in Spain. We'd had a poke in the carbs in a hotel car park, but there's only so much I was prepared to do while the bike was still starting and running and we were a long way from home. With no pressure now to keep the wheels turning I could dig all the jets out and see if there was anything obviously wrong.

The symptoms had been very rough running at low engine speeds, particularly coming off a closed throttle, and seemingly only on one cylinder. When the bike was cold it was much better, and at higher engine speeds and larger throttle openings the problem was much less apparent. On the smooth, fast motorway from the Pyrenees to Santander the bike had been fine, but on the rough and loose mountain tracks with precipitous drops shrouded in thick fog we'd been tackling before that, it had been the stuff of nightmares.

That's not meant to be in there... The o-ring on this jet had collapsed, filling the passages with gungy crumbs

Sure enough, the pilot jet o-ring on the on the suspect side was crumbling to rubbery gunge which was clogging the air and fuel passages in the pilot circuit. At this point it's traditional to blame the ethanol in modern petrol but stripping the other carb revealed that the pilot jet on that side had also been fitted with what looked suspiciously like a grommet rather than an o-ring; whatever was in there was nothing like the replacements that came from Motorworks.

Not right... Arrowed is the jet from the carb that was working well. Note the collapsing, grommet-like, o-ring
Reliable BMWs on

I run the BMW on a mix of ordinary unleaded and the expensive super unleaded, and had been doing the same in Spain. The only difference that might have caused a problem was the extreme heat we'd experienced before the bike had started stuttering. Temperatures the day before the problems started had been in the mid to high thirties, and then we'd ridden off-road for about 50 miles, the BMW in second gear for most of the time. While off-road the bike had been faultless and it wasn't 'till the mid-afternoon run back to the hotel that the bike's fuelling deteriorated. The bike was very hot, and I think the heat was probably the final straw.

Back at home and with the carbs buttoned up and refitted, the BMW started easily and settled into a smooth and even tickover the like of which I can't remember it ever having before. Perfect.

Well, almost.

Flushed with success at having diagnosed and fixed not one but two problems, I chose the BMW for the 500 mile round trip to see my parents the following weekend. It was a great ride, along some familiar roads that have become old friends, and the bike ran faultlessly. Until it got home, at which point it began coughing and spluttering like an old man watching a rap video. With a heavy heart I set about cleaning the carbs again, but this time the problem was elsewhere. After swapping every other component of the ignition system I finally tracked down a fault with the condenser; could it also have been weakened or damaged by the heat and the high voltage that the regulator had been letting through?

Touch wood, since then the BMW has been a model of reliability. It's stayed in tune, it starts easily and runs smoothly, the battery's held its charge... and I've been getting on with just riding it, my faith in the quality and durability of airhead BMWs renewed. They really are great bikes.

You could do this...

Where We Went

We used the Portsmouth to Santander ferry, which takes about 24 hours to make the crossing between the UK and Spain. Bilbao would have been more convenient but that ferry was full when we tried to book. We would also have missed the ride through the area to the south of Santander, which was spectacular.


View Larger Map

For the desert exploration part of our trip, we based ourselves in Ejea de los Caballeros. It's about 250 miles from Santander using minor roads, but we broke our journey overnight as the ferry didn't arrive in Spain until the evening. The national park that we rode through is the area marked in green on the map below; we skirted the edge of the purple zone.


View Larger Map

For the mountain excursion we moved north to Roncevalles, near the French border. Our explorations took us eastwards to the lake on the right of the map below, then north-westwards and across the (unmarked) border into France.


View Larger Map

Some Further Thoughts

When we'd been concocting The Plan, we'd worried about a variety of things.

I worried about breaking down but despite what you've just read, my 35 year old, 100,000 mile, worn out, saggy, baggy and generally tired BMW got me home. If it hadn't, I had enough tools with me to fix it, and I'm sure I could have bought a battery and a regulator of some sort in Spain. Failing that, Motorworks can deliver to Europe. The only problem for Ted's Harley was a side stand spring getting knocked loose, which in turn triggered the sidestand cut-out and stopped his engine. Easily fixed on the spot, and I won't make any more comments about his toolkit consisting of cotton buds and cleaning wipes. Sorry.

We both worried about falling off - we were riding off-road, remember - but in the event neither of us did. We prepared for minor spills by protecting brake and clutch levers with brush guards, and by wearing various combinations of protective clothing depending on where we were riding and what the weather was like, but the closest either of us came to an off was Ted locking his front wheel on a grass verge when we pulled over to check the map while riding on road.

Top of the world...

I worried a little about getting stuck, brought to a halt by un-passable boulders or mud, but the trails we rode were comfortably within the capabilities of our bikes. At least while the BMW was running properly, that is. We worried about our road tyres but they were fine for the terrain and the conditions. By the time off-road tyres would have become necessary, we'd have been in trouble for other reasons, not least the weight and ground clearance of our bikes.

Having done some trail riding in the UK, I also worried about being chased by angry land owners or finding our way blocked by locked gates. In fact, the few people we encountered while off-road were friendly and smilling, and the local 4x4 drivers left us room to pass safely and easily.

Some Things We Didn't Expect

We didn't expect our bikes, an old classic and a new Harley, to suit gentle off-roading so well. Their engines (when running properly, ahem) both had a soft but strong power delivery that made loose surfaces a breeze, and their upright riding positions gave us more than enough control. Who'd have thought?

We also didn't expect to have the trails to ourselves. The ferry was heaving with 'Adventure Tourers' to the point where they outnumbered all the other classes of bike on board put together, but we didn't encounter another two wheeler once we left the tarmac behind. On the queue to board the ferry home one spotlessTiger 800 rider was very dismissive of our "soft-trail" exploits, but I'd lay odds that our bikes were the only ones in the line that had ventured any further off road than a gravel car park.

He didn't know what he was missing. He had the adventure bike, but we'd had the adventure.

No shade, relentless heat...

Words and pictures: Martin Gelder

Thanks to Big Kev for the loan of the regulator while I was fault-finding; invaluable.


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