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Bike Review - Posted 29th June 2016
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Harley-Davidson XL1200S Oil Leak

It rattles, it shakes, bits fall off and now it leaks oil. Martin Gelder's Harley-Davidson Sportster Sport does its best to claim (Real) Classic Motorcycle Status...

Sometimes, you can get so engrossed in fixing one problem that you fail to notice another one developing right under your nose. Or right under your crankcase.

I spent most of last summer chasing down a misfire caused by a split carb diaphragm, a worn needle and a failing coil. I'd tinker with the Sportster, ride it five miles, tinker with it some more, ride another five miles, and then put it back in the shed and go out on the BMW. Sometimes there'd be a single drop of fresh oil on the shed floor, but because of the constant shed-shuffling I was never sure which bike it had come from.

Then I noticed the Harley's final drive belt was spotted with oil, and decided to have a proper look under the bike. I'm not the most diligent when it comes to keeping my bikes clean but the bottom of the motor did appear unusually moist. There was no obvious leak, just a sheen of oiliness. I cleaned the bike and parked it over a piece of newspaper. Twenty four hours later, there were no drips on the paper. Cleaning it had obviously fixed it. Result! I went for a ride to celebrate, parked the bike over the same newspaper, popped back into the shed an hour later and... oh. A 5p sized black stain had appeared.

It seemed to be dripping off a piece of frame that connected the two main tubes running under the engine and gearbox. And it seemed to be getting onto the frame via the oil lines connected to the oil pump, which lives tucked away behind the timing chest on the right of the bike. This made sense as some weeks previously I'd removed a set of 'Highway Pegs' from the bike; immensely heavy but hopelessly impractical things that I never use. Getting them off had involved flexing a couple of the oil lines, and I'd obviously disturbed something down there; nip up a few joints and she'd be as good as gold.

Harley-Davidson Sportster XL1200S Oil Leak Oil pump hiding place arrowed

Sure enough, one of the connectors stood a quarter tun of nipping and the other took a little more before it felt tight. I went for a ride to celebrate, parked up outside a cafe, came out half an hour later, and... Was that drip in the ground already there? Oh dear.

I took the two easy to reach connectors off, cleaned their joint faces, gave them a wrap of PTFE tape... and the leak got worse. If it wasn't the connectors, it must be the oil lines themselves, sixteen year old flexible rubber hoses held to spigots by crimped on hose-clamps. I removed the crimped on hose clamps and replaced them with tighten-uppable hose clamps. And tightened them up. The drips continued. I replaced the old oil hoses with new hose, bought from a shop. The leak carried on leaking, and I discovered that the 'new' hose I'd bought was older than the old hose it had replaced. The shop gave me my money back, but that didn't stop the leak either.

Conventional wisdom tells us that oil leaks go down and back. Gravity pulls the oil down, airflow pushes the oil back. So I started looking for the uppermost, forward-most point of oil flow. Oil appeared to be coming from the oil pump. Well obviously. I mean oil appeared to be leaking from the oil pump. Or at least the area of the oil pump. I cleaned every trace of oil from the underside of the bike then lay underneath it with a torch while my glamorous assistant revved the bike, much to the joy of my neighbours. No oil leaked out. I went for a ride; oil had leaked out.

Harley-Davidson Sportster XL1200S Oil Leak And there is is, squeezed behind a frame tube and some mesh-sleeved wiring. That mesh can hold a lot of oil...

No oil came out when the bike was on its stand, but it did while the bike was being ridden.

We repeated the 'underneath the bike with a torch' exercise with the bike on a stand that held it vertical, kept the throttle at a steady (deafening) 2,500rom... And look! Clean, fresh oil oozing slowly and lazily down the oil pump body while my neighbours looked for pitchforks, lit torches began to assemble outside. Sorry everyone.

The oil pump bolts up vertically to the bottom of the timing chest, sealed by a gasket. A gasket which had obviously failed. I took to the interweb to see if the pump could be removed with the engine still in the frame and found out that it could. Or that it couldn't. Definitely. Or not.

Just on the off chance that anyone is still reading, having Googled for 'Sportster oil pump removal with engine in frame', the oil pump on a 2000 Harley-Davidson Sportster *can* be removed with the engine in the frame.

Harley-Davidson Sportster XL1200S Oil Leak The oil pump *can* be removed while the engine is in the frame. Just... Note 'new' oil line with '96' date code. Lower left fitting is for the feed from the tank, lower right fitting is the pressurised feed to the filter, upper fitting is scavenge feed back to the tank.

The two lower pipes (the supply from the tank and the pressurised feed to the filter) need to be disconnected, two bolts removed, and then it can be kind of squirmed out between the timing over and the frame, finally slipping in the manner of an oily calf being born into your hands. The 'return' pipe can then be removed, the sealing faces cleaned up, and a new gasket (available from stock over the counter from main dealers) fitted. The old gasket came away in several inconclusive pieces, with no obvious sign of where it had failed. Refitting the pump is easy, once you find the correct angle to slip it into place. Finding that angle took me several attempts, however...

I refitted the pump, reconnected the oil lines, topped up the oil, started the engine, and the oil pressure light went out. I grovelled beneath the ticking-over bike with a torch, and all seemed well. I went out for a ride to celebrate. Oil was still leaking out.

Harley-Davidson Sportster XL1200S Oil Leak Oil pump with original gasket. Scavenge 'funnel' on the right; notice that if the gasket is not perfectly lined up when the pump is refitted, sealing is likely to be poor.

The scavenge side of the oil pump is fed by a kind of funnel shaped scoop on top of the pump, and the weakest area of the gasket is the part that seals this scoop shaped area. If my torchlit explorations were correct, this was where the oil was now coming from' perhaps I had damaged the gasket when struggling to get the pump back into place

I bought a new gasket (available from stock over the counter from main dealers), then I bought another one, just in case. You can't have too many spare oil pump gaskets. I removed the pump, removed the pristine and unmarked 'old' gasket and fitted another one, with the merest hint of sealant to hold it in place, just in case. I went out for ride, celebrations temporarily on hold. Oil was still leaking from the same place. I sighed heavily and went for a ride on my BMW.

Just above the oil pump is the joint between the timing cover and the timing chest. Could the timing cover gasket have failed at a point just above the oil pump? Only one way to find out...

Harley-Davidson Sportster XL1200S Oil Leak
Leaky Harleys on Now...

The timing cover looks like it just unbolts and pops right off. It doesn't. The ignition timing pickup gubbins needs to be removed first, and that hides behind a circular cover that is riveted in place. With rivets. It's a legacy of the American EPA legislation that tried to stop owners tinkering with their bikes and increasing emissions, and only mildly inconvenient to a man with a drill. Beneath the riveted on cover is another cover, held on with rusty screws.

Once the ignition gubbins are dealt with, the pressure that the valve springs put on the cams needs to be released. This means removing the rocker covers and rockers, a process which in itself involves disturbing many other gaskets as the rocker covers consist of separate 'slices' which allows them to be taken out while the engine is in the frame (good) but potentially introduces more leaks than the one you're trying to fix (not so good). The top end gasket set for an Airhead BMW comes in an envelope. For a Sportster, by way of comparison, it comes in a substantial cardboard box.

Harley-Davidson Sportster XL1200S Oil Leak The first slice of rear rocked cover being slid out sideways. It just fits. Each slice needs its own gaskets, and each gasket has the potential to leak.

With the tank, coils, ht leads, wiring and a sensor or two out of the way, access is pretty good and the top two slices of rocker box slip out leaving room for the section that carries the rockers to be loosened enough to take the pressure off the cams. Then the timing cover can be prised off, hopefully leaving the four cams in place and in sync - behind it. That almost happened, but one of the cams made a bid for freedom, meaning they had to be retimed. After I'd worked out that there were two different sets of timing marks on them, this was fairly straight forward. Harrumph.

Harley-Davidson Sportster XL1200S Oil Leak The timing cover comes off to reveal four cams and the crankshaft gear (below the second cam from the left) that drives them. Ideally they all stay in place as the cover is removed, and one of them doesn't make a bid for freedom on the shed floor. Note the bits of old gasket stuck to both faces.

The timing cover gasket like the one for the oil pump broke apart as the cases were separated so it wasn't possible to tell if there had been a definite failure. The gasket was brittle and flakey, though, and the replacement appeared to be made of sterner stuff. One thing Harley-Davidson are good at is continuous improvement of service parts. Everything went back together easily enough, with the exception of getting the rear cylinder's rocker box pieces back into place, which was like trying to assemble a bacon, lettuce and tomato sandwich bread first, filling second.

I started the bike. It ran, which was only a mild surprise considering my cam-juggling, and the oil appeared to be staying inside the cases. I rode It three miles and stopped. Still no leak. I rode another three miles. No leak. I rode the six miles home, parked it over a pristine sheet of plain white A4 and went inside for a coffee. Thirty minutes later... still no leak. I went to bed a happy man.

Some three or four days later, I noticed spots of oil staining the final drive belt.

I sighed deeply, grabbed a torch and started probing round the oil pump and timing cover. No signs of any dribbling, oozing or seeping. Oil leaks flow downwards and backwards, remember, so I started at the drive belt and worked upwards and forwards. There was oil on the starter-motor, on the rear cylinder's fins, and a substantial smear on the joints of that awkward to fit rear rocker cover.

Harley-Davidson Sportster XL1200S Oil Leak Rear rocker cover, nicely stained with fresh engine oil. Sigh.

I'd been so focussed on finding non-existent leaks at the front of the motor, I hadn't noticed the steady flow from next to my left knee.

Harley-Davidson Sportster XL1200S Oil Leak Crimped oil seal gasket, damaged while struggling to slide piece of lettuce in sideways between two slices of bread.

One more gasket, one more (practised and careful) reassembly, and for now, at least I appear to have an oil tight engine. For now.

Harley-Davidson Sportster XL1200S Oil Leak Life is a roller coaster when you own a Sportster. Note lack of drips under bike.

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