will england :: motorcycle notes and tips
will england :: motorcycle notes and tipsOn Tue, 28 May 2002, Tom Baumen wrote: > Some of you folks own or have owned BMWs. > > I have never had to put a clutch in any bike I have ever owned. I Have > never worn one out. I came close on a BMW airhead but I don;t think I > will ever wear out the clutch on the Concours. > I seem to notice in used BMW bike ads a lot of folks have clutches > replaced a relatively low mileages (40,000 to 80,000) compared to > Japanese bikes. Any one have any insight as to why this is? Do K bikes > need clutches too? BMW bikes use a dry clutch like cars and trucks. Most other bikes, including the Concours, use a wet clutch. Regardless of how much you slip the clutch it is nearly impossible to burn up a wet clutch - the oil just takes the heat off of it. However, if you ride a BMW like a wet-clutch bike (lots of slippage on takeoff, etc), you'll waste the clutch in a short time. The key to BMW clutches is to ride it like you drive a car - clutch in, shift gear, clutch right back out. On startup, smooth quick release, no slipping the clutch at the friction point. Will === also === Conc clutch is a wet (runs in oil) multi-disc clutch. In general, wet multi-disc clutches can withstand lots of abuse. BMW clutches are like car clutches, a dry (runs in air) single disc clutch. Besides that, the Conc is geared relatively low - BMW's tend to be geared rather tall, and to require a bit more clutch slippage to get rolling. So in the context of the above, BMW clutches tend to fail for 2 reasons: 1. Folks slip them more than on similar Japanese bikes due to tall gearing. 2. The rear main seal on a BMW goes bad and oils the clutch and it's then destroyed by slippage. FYI - I've put clutches in 3 bikes. A 1984 GPz-550 (cable was dragging, and not allowing the clutch to engage as it should've), a 1978 BMW R100rs (wear, at about 60k miles - it had the tallest gearing of any Airhead), and my 1994 BMW R11rs (at 75k miles, rear main seal went bad and oiled the clutch - though that was an early Oilhead and the clutch was a bit weak anyway....). I've never had to put a clutch in a car, but then I've ridden 300k miles and I don't think I've drivven quite that far yet. One more thing to remember - even here on the Cog List, there's a lot of bikes that don't make it to that 40k-80k mileage you mentioned, for whatever reason. While many BMW's do, though I think that's partly a reflection of higher purchase price making it easier to rationalize the repair on the BMW's. Best, Doug Grosjean Pemberville, Ohio
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