because the oil pump gear failed. the teeth just break up/off. cams seize, pushrods bend, valves hit pistons, ooooh it gets messy for whatever the new gear cost, just do it imo.

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BUELL-Turning riders into mechanics since 1983!!!

Yup. That's the whole reason I stripped mine to check it and am buying the replacement. You planning rebuilding the damaged engines or what the plan for them ?

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1998 Buell S1
1998 Buell S3T

Are the failures due to poor part- or fitting tolerances, or is it a matter of inevitable wear?
The setup on my M2 (late model) is still standard after nearly 70k, gear seemed OK at a 60k visual inspection - whatever that's worth.
In other words: Am I just lucky to have a properly built gear or is disaster about to happen?

Well, firstly you are a bit of a legend, not just for doing 70k on your M2, but also for checking your oil pump gear at service time. Not many people will have done that...

But back to your question, another forum member, who has seen a lot of HDs, and I were discussing this at a recent get-together. He has seen a number of Buell engines lunched like this but no Sportsters, which interestingly use the same gear. He thought that was cos Buells were used harder...

I always thought it was a bad batch of gears, cos the failures appeared to happen on 03/04 models (I have an engine that failed after around 10k), but more recently there has been at least one failure on a tuber. However looking back, I got some M2 bits off a guy who was breaking his, and his engine lunched cos of the oil pump gear after less than 7000 miles, back in 2001.

Buell introduced a revised gear in 2006, which as Maz points out, was designed for their race bike (pre-XBRR which had a revised oil pump).

My gear out of my Firebolt showed some wear, it was probably nothing major and would probably have lasted many years, but when you think your engine could be destroyed because of the the weakness of this one component, it makes sense to put something more robust in.

Not really answered your question, but preventative maintenance is better than a lunched engine.

will be along in a minute to put me right...

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08 Specialized Langster

I remember seeing a backlit photo on Badweb showing how the gears don't actually fit each other very well, resulting in all the contact being concentrated in a narrow area, plus I suppose they're made of lower quality cheese than the later version... There were obvious narrow bright spots where the gears had worn...

I also seem to remember someone on here saying that lack of an oil pressure bypass valve increases the load on the gears if you thrash the engine before the oil has warmed up....?

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2001 M2
2001 XLH 883
2016 MT-03 660cc single

I've seen far more trashed tuber motors than XB due to gear failure

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Mithered ta death.
92 MB
96 S2T
98 S1W
00 M2
01 X1
03 P3
10 CR

But I thought tubers were God's gift to the motorcyclist...

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08 Specialized Langster

They are, which is why they're ridden hard by real men and cover loadsa miles

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Mithered ta death.
92 MB
96 S2T
98 S1W
00 M2
01 X1
03 P3
10 CR

Like you

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08 Specialized Langster

Nope

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Mithered ta death.
92 MB
96 S2T
98 S1W
00 M2
01 X1
03 P3
10 CR

It's definitely not part of my regular servicing regime - I usually loose interest quickly after the obligatory oil & filter change
It was some worrying posts earlier on the topic that made me peek inside, but without undertaking any major deconstructive work (picture here).

Interesting that Sportster drives suffer less. Wasn't the problem pressure related, esp with "cold oil"? Perhaps the Sportster has a heavier fly-wheel (has it?), naturally avoiding high and sudden revving. My riding style is far from spectacular but it regularly sees 80+ mph on the speedo within minutes of firing up from stone cold (my office is right next to the motorway - and I am usually in a hurry). It will still rev relatively modestly at that speed though, even on "half US" gearing.

It sounds like I better start planning a holiday in the Manchester area next year to prepare my M2 for its next 70k of pleasurable riding

I remember an early post by whitebuell on badweb machining 1/8" off the base of the pump on his tuber, raising the pump drive gear giving fuller contact with the pinion gear reducing the wear.

I saw that too, but I seem to remember looking at the pump and dismissing the idea cos (from memory) the drive gear tended to lift the gear on the pump up getting full contact... Will check my photos again...

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08 Specialized Langster

Thats the lucky hand's oil pump gear fitted to my bike and it is running well. Thanks for the advise and parts lists from this post, made it easier to order necessary spares.

Cheers

Neil

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1998 Buell S1
1998 Buell S3T

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08 Specialized Langster