Jen,
My XRR consumes also quite a bit of oil when cruising at high speed on a steady throttle, although perhaps not as much as yours. My engine is still quite new, it’s got around 5K miles, and there’s no smoke either from the exhaust. When I rode the entire length of the Baja peninsula last year, the engine used a little oil on the leg down south, which comprised 90% trail riding (a combination of rocky and sandy tracks in the mountains and desert, and occasionally on the beach) but nothing really unusual for a big thumper. However, on the leg north back to the US border, it was 80% highway at constant high speeds, and at every fuel stop I had to add a fair bit of oil. On the north-bound leg, over a 1,000 miles, I had to add more than 1L (fully synthetic). Although I found the oil consumption quite high, I was not overly concerned since it only occurred at constant high revs/loads.

I have had similar experiences with my other thumpers, particularly the XT’s, which are notorious for their excessive oil consumption without anything being wrong with the top end, especially when ridden in hot temperatures. Also my KLR consumed significantly more oil on the high-speed return leg to Melbourne via highways than on the leg up to Ayers Rock via the sandy/muddy tracks. On long trips across Africa my wife’s XT350 was mostly riding at full load to keep up with my R80G/S, and its oil consumption also resembled that of a two-stroke. Nevertheless it never missed a beat and I only overhauled the top end when it had 85,000 kms.

If your XRR’s oil consumption is also excessive at lower engine loads, you should take off the head and cylinder and inspect the rings, piston, valves and valve guides. Before dismantling the top end, you could start with a compression test, as a leaky valve might well be a cause. However, a compression test will not reveal a leaking valve guide or a problem with the lower piston ring (the oil scraper).

You might ask my riding buddy gaspipe (username on both HU and Advrider.com) for his view on your problem. He has done a lot of off-road traveling with his XRR (TAT, Continental Divide, Baja, Copper Canyon) and is very knowledgeable when it comes to engine/bike technology.

Jen, is there any chance of you emailing/PM-ing me a copy/scan of your 3-part TAT travelogue that was published in TBM? My guess is that TBM has exclusive rights to your story and doesn’t want any infringement on their rights, but since I live in Thailand, I’ve got no access to EU bike magazines and I would love to read your story.
Cheers!