patzx12
Registered user
Sounds banjaxed to me,there should be no side to side movment
fd refurb
- Thread starter Skid06
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TeaPig
Registered user
I agree. I've twice had FD input shaft bearings fail in this way with no sign of any play in the wheel bearings. With new bearings fitted the shaft is, as Pat says, rock solid.
I suspect many people with failing bearings in the FD never realise they are shot as the only way of telling, at least before the whole box sounds rough, is to wiggle the input shaft. This being the case, I suspect some FDs must run for a good while with failing bearings.
bottom line is they will need sorting at some point and running them for longer will only add to the rubbish floating about in the oil. Im sureyou will have noticed the metal particles stuck to the speed sensor when you changed the oil?
patzx12
Registered user
Does anyone know of any other bike manufacturer with bevel box issues?
FJ900, old GS850\1000, GTR kawasakis, CX500\650, FJR ?
The FD has got to be the easiest part of a bike to design, build and pre-production test.
FJ900, old GS850\1000, GTR kawasakis, CX500\650, FJR ?
The FD has got to be the easiest part of a bike to design, build and pre-production test.
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i think pat will agree, the whole final drive is under engineered,but this is one of the problems us 1200 owners are going to have to live with.pat has managed to manufacture a really high quality socket to assist in stripping the fd ,but without a fully equipped workshop and a good idea of engineering your not going to do the job at home!!on the plus side quite a few people countrywide have "tooled up" to work on the unit(myself included).so its not the end of the world...
..mike
..mikecrawling finn
Registered user
Thanks for your advice. Off it comes then. I wouldn't be affraid of attacking the problem myself, but don't fancy start making tools for it. Luckily it looks like we have some skills in the the forum for that.
I have play in my input shaft as well as crown wheel bearing but the nice man at BMW says it's 'within limits'. He even reassured me that it is not about to fail. And as I'm not a motorcycle engineer he reassured me that they know best. Apparently having spent 22 years designing and manufacturing aircraft parts is not relevant experience. I have my bmw warranty ready!
If my final drive was on an aircraft I certainly wouldn't allow it to fly
If my final drive was on an aircraft I certainly wouldn't allow it to fly
patzx12
Registered user
I have play in my input shaft as well as crown wheel bearing but the nice man at BMW says it's 'within limits'. He even reassured me that it is not about to fail. And as I'm not a motorcycle engineer he reassured me that they know best. Apparently having spent 22 years designing and manufacturing aircraft parts is not relevant experience. I have my bmw warranty ready!
If my final drive was on an aircraft I certainly wouldn't allow it to fly
If the oil is clear all should be well i would watch the condition of the oil as an indicator of failure.
Good advice, Ill do that.
TeaPig
Registered user
I reckon some of the problem is the very short pinion shaft which has to take extra lateral loads as as the suspension rises and falls. All the non BMW shaft drive bikes I can think of have conventional swing arms where the shaft alignment into the FD remains straight. Failure of the two pinion bearings is typical in knackered FD's. Just a thought anyway
I too have a theory and it is only a theory. I think that the large tolerance on wheel runout is a significant contributing factor. As the wheel rotates the runout causes the rear end to want to move from side to side-only a small amount but lots of rotations soon add up. A side line of this side to side movement is an increase in tyre wear and squaring off. The bike 'reacts' to this force as it weighs quite a lot so the force is transmitted to the final drive. I think this puts additional cyclical stress on the crown wheel bearing which in turn alters the clearances on the pinion shaft creating tight and loose gear meshing. Now there are two bearings on the pinion a large ish bearing on the input shaft and a small needle roller bearing as we all know. It would seem that the larger bearing gets lunched by water ingress as well as wear. The smaller needle roller bearing seems to collapse. I think this is due to the cyclical loads from the crown wheel as well as being too small. Bits fly off and then start to accelerate the wear on the crown wheel which in turn starts to increase its movement and so on until it starts to leak oil or makes a lot of noise.
Also the manufacturing tolerance on the wheels is just that, a tolerance. So some may be running true but other will be at the edge of the tolerance. Could this account for some final drives lasting forever and others destroying themselves after a few miles?
It is only a theory but as myth busters say its plausable.
Standing by for a good fragging
Also the manufacturing tolerance on the wheels is just that, a tolerance. So some may be running true but other will be at the edge of the tolerance. Could this account for some final drives lasting forever and others destroying themselves after a few miles?
It is only a theory but as myth busters say its plausable.
Standing by for a good fragging
TeaPig
Registered user
one problem with that argument in terms of it being the only cause of failure is that for both bikes I had which developed pinion shaft bearing failure, the wheel/crown bearings were perfect with absolutely no play at the rim hot or cold. On these FD's there was also no sign of water damage to the big pinion bearing, it had simply worn out along with the small needle roller which was well fecked
I do agree that if the crown wheel is wobbling it won't help matters
I do agree that if the crown wheel is wobbling it won't help matters
Actually, BMW dealer said to me that the play observed was "within limits"
....they removed one screw from the rear brake caliper and inserted a "clock" type gauge to take the reading. Reading was 0.73mm...so they smiled at me....saying that everything is OK.....but when I told them that 2000Km before there was no play at all, they started the "within 1mm limits" story...
For sure, the complete story is a joke.....the only think that actually calms me down is the condition, colour and no chip detection in the FD oil so far at least.
I am too in the aerospace industry (initial / continuous airworthiness) since 1999 and one think I can say for sure.....R1200 FD is at least under-designed....and most of the parts used are more than 100% from third countries...
i had the exact same wow wow noise at forty mph too,i really could not put up with it.nothing the dealer did could cure it.they eventually changed the bike for me.
btw the wow wow noise is nothing to do with the fd.
What was the cause of the 'wow wow'?
My '10' 1200GSA made a fearful 'whine' or 'howl' at 50 and 100mph from new - so spot on for the twisties. It was so lound that it was painful to ride without earplugs. I complained to Vines who couldn't hear it. I replaced the tyres in May with Tourances and the noise reduced and moved to 60mph.
Richard
as i said no one could pin the noise down.got another bike and they sold the one i rejected
as i said no one could pin the noise down.got another bike and they sold the one i rejected
Hmm
Good that they took you seriously.
How long did you leave it before rejecting the bike?
Richard
id had the bike about a week(my first dohc) and wasnt sure to start with if there was an issue,symptoms were the wow wow plus a vibration through the pegs and drive train.after a week i took it back and after a lot of head scratching it was deceided to drain gearbox oil to have a look.the gearbox oil was completly contaminated with metal particles(they showed me into the workshop),obviously a bearing had gone.they thought bm would only authorise a rebuild but i insisted that with that level of contamination the box was ruined so i would only accept a new box.so a new box was fitted,when i picked the bike up no vibration was evident but the wow wow (which everybody thought would be cured by the new box was still there.after a week of investigation they could not find a cure.i then negotiated a replacement bike.my new bike after just over 7000 miles has not missed a beat and has been perfect in every way no niggles at all.i do know that the wow wow bike was subsequntly sold someone else who presumeably is not tuned in to the noise.i have to say the dealer was really good through all this and i am totally happy at the end of the day.
vines.
vines.
I thought it might be them. Visited them on Friday to test a GSA with Enduro 'box.
All my dealings have been with their Caterham branch.
well despite whats been posted on here just recently,and about a specific person there i have found them very good over the past three or four years.in fact when i had my issues duncan bell sorted it all out to my satisfaction no prob.
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