Just for the record......

Last Novemeber, after 61000 miles (97600 km), my Tenere suffered what appeared to be just a failed main bearing. As I am a motorcycle courier I assumed that the engine had just suffered from high(ish) mileage wear and tear. On further inspection my dealer discovered that there had been significant corrosion between the r/h primary drive side main bearing and crankshaft which had in turn resulted in significant wear between both components. This meant a new crankshaft was required as well as the bearings and all the parts needed for a rebuild.
At the same time I was informed that the rest of the engine was in perfect condition and considering the bike's use made the occurance of the corrosion seem very strange.
Fortunately, all the work was carried out under warranty.

Unfortunately, nearly 12 months and 30000 miles later the same thing has happened again. As the bike is now out of its warranty period I am facing very large repair costs - even by doing the work myself. Having stripped the engine I can see the extent of the corrosion and that the crankshaft had been spinning inside the inner race of the main bearing. Not sure if this was caused by the nut not being tight enough or if the nut wasn't tight enough due to wear on the plate washer.

The bike has had sufficient oil & filter changes and was being used constantly all year round so has not been stood still for any great length of time. To further illustrate the lack of abuse my bike has had, at 91000 miles (145600km) the rest of the engine/gearbox is in amazing condition. The cylinder barrel still has honing marks on it, the transmission gears and selector forks show no sign of significant wear and the bike still has the original clutch.

The corrosion is entirely concentrated on the right hand crankshaft/gear cluster/main bearing. There was no sign of water in the oil.


Cue Bruce Willis (Die Hard 2):

"How could the same s*** happen to the same guy twice!"

I've given my fair share of abuse to Suzuki singles over the years (TS125, TS250X, DR600, DR650, DR800 x 3) but NEVER had one wear out/fail due to internal corrosion.

It was suggested that night time condensation (hot engine cooling in cold garage) was making a beeline for the crankshaft and subsequently not being burnt off in time on next use. On a freekin' courier bike!! Have a word! Could I actually not be riding the Tenere hard enough??

I'm flummoxed. And skint......and in need of a new job.

Is the dream finally over??
I'm waiting for details of cost and availability for the parts before I decide whether to fix it or buy a second hand engine or break it up for parts or just stuff it and hang it on the wall as a trophy.

Ouch.....


but then again, your story does have some hope... 91,000 miles and it's still in <otherwise> great shape.

Is it possible, to have the shaft ground and some oversized bearings fitted ? it would need a specialist engineering setup ?

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Never underestimate the power of stupid people in large groups.

I looked into the over(under?)size bearing option but the nearest I can find to a 6308 (ID 40mm) is a 6406 which has an ID of 35mm. I assumed that would be too much "meat" to take off the crank journal?? Certainly the cheapest option - if I can find someone who can split the crank to remove the rod.
Been given names of a couple of places that might be able to help with re-engineering (journal spray welding & grinding or journal grinding and sleeving).
But given the amazing condition of the rest of the engine/gearbox I'm in two minds as to whether to risk a possible bad fix that might cause more extreme damage.....???

Any good. http://www.ebay.co.uk/itm/xt660-xt-6...d#ht_500wt_922

Probably not much help to you now, but I wonder whether your water pump seal might have been weeping and allowing coolant into the engine. Otherwise it's very weird you've only got corrosion on the drive side.
Hope you get it sorted, mate.

I should have added in my OP that this all started about two weeks ago but I didn't want to jump straight on the forum for fear of letting my frustration make me post inappropriate, over-emotive disparaging comments.

So a big thanks to Kev for all the "behind-the-scene" advice and being a soundboard.


@Bond: Thanks for the link. I did think about another engine but I have always been put off second hand engines for fear of the unknown. As my engine is in bits I can see what great condition the gearbox and cylinder is. Mind you at �200 it's bloody tempting - pity it's a bit of a trek from me. Interesting that there has been no bids on it though???

@66T: Good call. I racked my brain when this first happened for all possibilities and one of my thoughts was to get the water pump assembly pressure tested for that very reason. I left it hung up over night with coolant in it to see if it leaked at all. However, there was no sign of water elsewhere or emulsification of the oil. In any case when running I would have thought the great pressure in the crankcase would force oil into the coolant but I didn't see any signs of that. Can't really rule it out though as a possibility so will change the seal anyway. Afterall, the bike has done 91,000 miles.

Clearly, moisture has got in from somewhere but there is absolutely no corrosion anywhere else in the engine which made me wonder immediately about dissimilar metals and galvanic reaction between the crankshaft, bearing, drive gears, washer and woodruff key?? Surely can't be the case though otherwise there would be horror stories all over the interwebbynet.

I can only put the whole thing down to a series of unfortunate circumstances: condensation in engine (hot engine/cold garage at night) and not getting the engine to warm up quick enough in the morning due to taking too long to allow the oil to distribute before opening up the throttle and/or constantly trying to max out on fuel efficiency by chuffing along in highish gear on barely open throttle - for most of it's 91,000 miles.

If you didn't see/realise the previous link you can see pictures of the corrosion here.

Anyway, got a new bearing in the fridge that should be chilled by now so will soon find out if it is enough to remove the excessive clearance - probably not!

I hope it works out for you, mate. It's definitely odd, that one. You'd think if it was a condensation issue the rust would be evenly distributed throughout the engine.

Just something else to throw in the mix, but sadly isn't really help you... Since fitting a water temperature gauge to my Z, I've noticed that bimbling around in high gears up to 4K revs the engine barely gets warm enough to open the thermostat even through the summer and on longish rides. Spirited riding (not thrashing) seems to maintain "normal" engine temperatures. Needless to say I am now much more careful about engine warm-up times now because I know what's going on.

Cold running is a possible cause of you woes, not so much from condensation but from acid oxide build ups in the oil over time, which have different corrosive effects on different bearing materials. Could explain why only one bearing is affected?

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hi rick, only now have i spotted the photo's,

i too noticed a rusty film on the crank surface when i had mine stripped recently to replace a broken gear, it appeared to be a slimy brown coating not unlike rust, thought fortunately no corrosion/ deterioration had taken place so i wiped it off and never really gave it much thought

i'm not convinced it could be water related, low lying parts like the gear drum selector etc would be at least stained, even the crank face looks nice and shiny. i would not be supprised if it was somekind of metalurgy thing going on

hopefully the new bearing will be a more snug fit, though i have seen locktite [bearing spec] working wonders on gearboxes and the like where the next resort was replacement. edit. http://www.loctite.com.au/cps/rde/xc...ID=10000009RLA

all the best and keep us posted! b

Hmm...that's interesting comments there Pleiades and Stoic Bloke. I was reading about high temp oxidation due to acidic oil last week sometime. Guess I'll have to get myself a supply of litmus paper for periodical checks. I wonder if there's higher than normal temp due to friction of the crank spinning inside the inner race of the main bearing?

Whilst my oil changes may not have always been on time my riding style and use means that the engine generally gets regular smoothish operating conditions. My dealer also suggested that it can be equally detrimental to change the oil too soon.

Anyway, new bearing seems to have done the trick! It might have been a tighter fit (less clearance) than the OEM bearing. Thanks for the Loctite link Stoic - I might give that a go.
And then when the bike's rebuilt I guess it's time to stop *****footing around and just ride it like I stole it!