Trullion
Registered user
That's why I've been running it with Redline Heavyweight Shockproof. It bought me maybe three years, but eventually you have to address the cause of the racket...
Gearbox noise - how much is too much?
- Thread starter Nick591
- Start date
That's why I've been running it with Redline Heavyweight Shockproof. It bought me maybe three years, but eventually you have to address the cause of the racket...
I have noticed a kind of knocking noise/feeling from my gearbox, mostly in 6th gear and only when I've shut the throttle and the engine is on the overrun. I notice it more as a feeling through the footrest rather than an audible noise. I know that the gearboxes are sometimes described as being agricultural and being new to BMW ownership I'm unsure if this is normal or something I should be looking into. Have no other issues with the gearbox, my previous bike was a Yamaha TDMa50 so I'm used to a less than slick gearchange.
I have a '94 1100 (although it had a warranty replacement M97 box at some point in its early life). When the input shaft seal failed last year (happily just <i>after</i> a 3000 mile trip to the alps), I sent it to Steve Scriminger for a rebuild (new bearings and seals throughout and anything else it needed). When I got it back I noticed that it was much quieter in operation (still a Massey Furgerson gearchange but that's normal for an M97) however the whine that I'd thought normal has gone.
I can't know how much of this noise reduction is due to the new bearings or Steve's care with preload (he also centres the preload rather than shimming from one end), but I ran the box with its whine for 25k with no ill effects - it did get very gradually worse but it's hard to quantify as you 'get used' to noises. My first couple of gearbox oil changes were quite dirty and had slight gold speckling in the oil (indicative of selector fork wear - and sure enough it needed a replacement fork during the rebuild), although paradoxically, the last few changes were always clear - I change all fluids every 3k, so the initial dirty oil might just have been residues from its earlier life.
I can't know how much of this noise reduction is due to the new bearings or Steve's care with preload (he also centres the preload rather than shimming from one end), but I ran the box with its whine for 25k with no ill effects - it did get very gradually worse but it's hard to quantify as you 'get used' to noises. My first couple of gearbox oil changes were quite dirty and had slight gold speckling in the oil (indicative of selector fork wear - and sure enough it needed a replacement fork during the rebuild), although paradoxically, the last few changes were always clear - I change all fluids every 3k, so the initial dirty oil might just have been residues from its earlier life.
Trullion
Registered user
Yes, a lot of early bikes had replacement M97 boxes under warranty. Sadly I bought mine as a low mileage "minter". I should have done my homework first; if I had, I would have verified that it had had the later box fitted. Mine has lasted about as long as they used to (around 30k miles) and I'm pretty sure it's bearing trouble, though it hasn't had anything on the drain plug or in the oil for ages. To get the M94 up to spec would be quite costly, because to do it properly it needs the dogs undercutting to sort the tendency for "skipping" in second or third gear (though mine doesn't do this yet). I'll probably get Steve Scriminger to check my spare M97 and rebuild as necessary. I bought this from Motorworks years ago when I found out about the issues with the earlier boxes, but AFAIK it hasn't been rebuilt. The 1100RS is not my main bike so I'm in no hurry.
In my experience the old 5 speed boxes certainly don't all whine, it gradually develops and gets louder, though if they do it's not a problem for a long time. Eventually though a bearing or two will expire, if the box doesn't start leaking first. Don't know about 6 speeders, but they seem to be a lot more reliable based on the various oilhead forums.
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