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Cadwell Park track day broke my M2 https://ukbeg.com/forum/viewtopic.php?f=7&t=8859	Page 1 of 2

Author:	smarty [ 26 Oct 2010 22:08 ]
Post subject:	Cadwell Park track day broke my M2
Well.... I fitted the standard silencer to the M2 on sunday to get it through the noise test at Cadwell Park on Monday, which it did easily (85dBA). It was so quiet on the way to the track that I could hear the tappets at 50mph Monday was a very cold, bright day with a thick frost on the way to the track. I hadn't pre-booked, but just turned up on the off chance and I got in easily. The maximum number of entries was limited to 35, split between Novice and expert groups, there were in fact only about 25 riders, so the track was virtually empty all day. We had a slightly delayed start due to ice on the track ...... initially those with tyre warmers found there tyres were cold again after a couple of laps, but as the beautifully sunny day went on the track dried and warmed up. I had an absolutely fantastic time on the Buell and was regularly grinding the pegs on the tight turns and hitting 120 (indicated) on the straights............. until it broke...... I'm not yet sure what damage I have done, but the engine is mechanically very very noisy with what sounds like a heavy mechanical knock deep in the engine, really noisey on tick over, increasing with revs, the noise reduces under load but is very loud on the over run and sounds like its in distress. There was no apparent loss of power just the noise. Clutch feels OK Gears select Ok Engine starts and ticks over evenly(ish) I would appreciate any suggestions as to what the problem may be.... Or even where to start looking. I would point out that this is not a Buell reliability issue....... I was wringing its neck at the time and had knocked up over 80 miles on the track before it gave up....

Author:	kevmean [ 26 Oct 2010 22:27 ]
Post subject:	Re: Cadwell Park track day broke my M2
Big end gone ..............M2's do seem prone to that for some reason .......hope not as i guess it is a very expensive problem if it is mate.

Author:	Adam [ 26 Oct 2010 22:33 ]
Post subject:	Re: Cadwell Park track day broke my M2
I'd put money on it.

Author:	smarty [ 26 Oct 2010 22:39 ]
Post subject:	Re: Cadwell Park track day broke my M2
Thanks Kev, Adam, Yep I thought about that too, the only thing that doesn't quite seem to add up is that the noise reduces under load. I don't have a lot of experience of big end failure but would have thought it would get louder under load and that I would feel it right through the bike

Author:	spen [ 26 Oct 2010 22:49 ]
Post subject:	Re: Cadwell Park track day broke my M2
Before you run off to harm yourself, check the nut on the end of the crank.... .... probably is the big end, but check other things first.

Author:	Maz [ 26 Oct 2010 23:04 ]
Post subject:	Re: Cadwell Park track day broke my M2
My money is on the crank nut....or possibly sprocket to rotor bolts sheared. Big end failure makes a very strange/distinct sound that's unlike anything you've ever heard before.

Author:	smarty [ 26 Oct 2010 23:12 ]
Post subject:	Re: Cadwell Park track day broke my M2
So..... best place to start is behind the Primary cover... Someone at the track suggested that the Clutch basket might have come loose, although I pretty much ruled that out as clutch operation and gear selection was not affected. Will check the crank nut and primary side in general cheers .

Author:	Maz [ 26 Oct 2010 23:53 ]
Post subject:	Re: Cadwell Park track day broke my M2
Bastid thing is this......if it is the crank/sprocket nut and you've run the engine after the noise first appeared, then the splines on the crank will be bolloxed ie. the splines in the sprocket are much harder than the crank

Author:	Maz [ 26 Oct 2010 23:57 ]
Post subject:	Re: Cadwell Park track day broke my M2
....and if it's the 4 rotor to sprocket bolts (pre 2001) that've sheared, then the stator is toast and the entire trans is contaminated with magnet particles from the rotor

Author:	smarty [ 27 Oct 2010 08:46 ]
Post subject:	Re: Cadwell Park track day broke my M2
Thanks ........ Keep the good news coming I Will be getting into it today...

Author:	Martinwill [ 27 Oct 2010 09:59 ]
Post subject:	Re: Cadwell Park track day broke my M2
that sound like the same symptoms when the the crank pin was worn on my x1, (not sure if the m2 has a pressed or bolt together crank). I started by taking the primary off , nowt wrong there, on futher stripping of the motor revealed verticle play in the center rod (along with a load of other shite). I removed the crank, pressed it apart to reveal the wear on the pin, (luckily the rods big end had not worn oval). SEP engineering in kegworth, derbyshire, http://www.sep-kegworth.co.uk had a new crank pin made, honed the rods, replaced the big end bearings, rebuilt and balanced the crank for £230. 2500 miles on from the rebuild with no probs. If i remember right, a complete new crank shipped from the states was about £800.

Author:	spen [ 27 Oct 2010 12:58 ]
Post subject:	Re: Cadwell Park track day broke my M2
You never know Smarty, you may have caught it in time........

Author:	smarty [ 27 Oct 2010 17:47 ]
Post subject:	Re: Cadwell Park track day broke my M2
spen wrote: You never know Smarty, you may have caught it in time........ Mmmmm.... could be.. ..... Took the primary case off and found the rotor/sprocket were moving around on the shaft. It is the earlier 4 bolt rotor and all these were still in place. I removed the crank nut and withdrew the primary, chain and clutch assembly. The transmission oil was clean and there was only a small amount of swarf on the mag plug. Now here is the rub.... there is no significant damage to the crank splines, magnets or rotor splines, but when I loosely reassemble the rotor there is alot of rotational play between the rotor and the crank.... So I'm thinking that this play is the cause of the problem as there will be some movement between acceleration and decelleration, which over time will cause looseness of the rotor even though the nut is still tight, as it is only frictional grip which will hold the rotor completely still. There was some graphite type material on the crank splines, not sure if this needs to be replaced . I assume that I should torque up and use thread lock on the crank nut and clutch hub nut

Author:	paulalig [ 27 Oct 2010 19:28 ]
Post subject:	Re: Cadwell Park track day broke my M2
Maz wrote: Bastid thing is this......if it is the crank/sprocket nut and you've run the engine after the noise first appeared, then the splines on the crank will be bolloxed ie. the splines in the sprocket are much harder than the crank From my experience of this sort thing happening to machines and looking at what Maz has already said I rather think that your splines on the shaft have had it - I've never found anything that would repair the splines permanently. I hope someone else can tell you of some breakthro' solution that's come on the market - but beware of "snake oil" cures (if you know what I mean), no locking compound will last in that environment. Equally,no amount of tightening the nut etc. will sort a problem like this. I'm sure that someone with better direct Buell experience than me will be along shortly to tell you your best course of action. Sorry to hear of your trouble and I hope that you find an economic repair.

Author:	Maz [ 27 Oct 2010 19:33 ]
Post subject:	Re: Cadwell Park track day broke my M2
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