twin cam to toilet

[birdseye]

OK this applies to a proposed change from a TC GS to a WC RT but test riding the WC yesterday I was impressed by many things but surprised by the gearbox and engine. The gearbox was fine at speed but putting it into gear from neutral at traffic lights, it made a Harley seem sophisticated. There was a big crunch, enough to mmake me woinder about how long it would last. The clutch wasnt dragging by the way. And the engine was at 4000 miles if anything more loose and rattley than my TC at a similar mileage.

The bike concerned had been returned to BMW and rejected because of the suspension recall. But is the clunky gearbox and loose engine typical of WC bikes?

Thought I would ask on here because there are far more WC GS about

 

[Beemerman59]

http://www.ukgser.com/forums/showth...s-or-cant-get-Neutral&highlight=gearbox+clunk

http://www.ukgser.com/forums/showth...OBLEMS-ON-2014-MODELS&highlight=gearbox+clunk

 

[birdseye]

thanks. the box was quite good at speed. the issue was the clunk into first from standstill and from the threads you quoted it seems to be normal. wonder if anyone has reported actual failure ie is the clunk a characteristic or a real problem.

what about the loose engine? I expect an air cooled engine with the wider tolerances they have to have to be a bit noisy, but a water cooled engine I expoected to be as quiet as a jap bike. but it wasnt. It was a bit like my old commando.

 

[Engineer]

OK this applies to a proposed change from a TC GS to a WC RT but test riding the WC yesterday I was impressed by many things but surprised by the gearbox and engine. The gearbox was fine at speed but putting it into gear from neutral at traffic lights, it made a Harley seem sophisticated. There was a big crunch, enough to mmake me woinder about how long it would last. The clutch wasnt dragging by the way. And the engine was at 4000 miles if anything more loose and rattley than my TC at a similar mileage.

The bike concerned had been returned to BMW and rejected because of the suspension recall. But is the clunky gearbox and loose engine typical of WC bikes?

Thought I would ask on here because there are far more WC GS about

My WC has done almost 20,000 miles and the clunk hasn't hurt the gearbox one little bit, by the way the clunk is caused by clutch drag.

The WC does have more apparent mechanical noise (or at least a different noise) to the TC not necessarily down to wider or narrower tolerances though, can be many reasons - it is after all a brand new engine design.

 

[birdseye]

There was no sign of clutch drag when, for example, the bike was in gear but stationary with no brake applied. But clearly the crunch has to be stationay bits meeting rotating bits on gear engagement. Does it happen if you hold the clutch in for a while before engaging first? I didnt try that.

I was expecting the engine to be like a jap liquid cooled one, but thinking about it, isnt it a case that only the heads are water cooled? So the crankcase wont have the sound deadening effect of a water jacket? Nevertheless, surprising that its noiser than my TC. I guess I was only raising the question to now whether this examp[le was noiser because it had been thrashed to death or whether the issue was inherent to the new design.

Any other issues in your 20k?

P.S. Your comment about the noise being apparent is a good one. The TC GS that I have has this ridiculous BMW exhaust valve which makes it sound like some spotty youths Sportster and probably hides all sorts of rattles

 

[rodsharp]

I was of the same opinion when I tried one. Ok its faster and the brakes are better but my TC is fast enough for me and the brakes are ok. I had a good trade in agreed and was visiting the dealer to buy but he asked if I wanted to try one first, good job he did as I changed my mind and stuck with my old one which is just coming up to 24k trouble free miles and running better than ever. Better put the money towards another old classic instead.

 

[Jimeroo]

Same here, the dealer kindly lent me one for four hours and on the plus side the engine and handling performance was amazing. But not so keen on the clutch drag and general engine clatter. I suppose you would grow accustomed to it given time.
My TC has done 12K and is sweeter now than its ever been, so maybe the 6 or so k to change I will invest in a dream being a classic 70s TR6 Trophy. In fact off to see one Sunday. It looks grand in the pictures, but then most of them do...

 

[stevemersey]

I traded a 2011 twin cam for a 2014 WC about three weeks ago.

The engaging gear clunk varies and I am not sure why, but I have quickly got used to it. The looseness you describe is down to the lower flywheel weight, but the upside is the engine revs up quicker. I would try a 2015 as it has a heavier flywheel and will feel different.

I almost regret parting with the twin cam when bimbling, but the new bike becomes noticeably better when you are pressing on. More responsive engine, better suspension, great brakes and I am getting better fuel consumption according to the computer. The twin cam remains better in some ways for me, but I can't give up the WC now I have tried it at full chat. Neither is better at everything, but the WC is definitely sportier if that is what you are looking for.

 

[Engineer]

There was no sign of clutch drag when, for example, the bike was in gear but stationary with no brake applied. But clearly the crunch has to be stationay bits meeting rotating bits on gear engagement. Does it happen if you hold the clutch in for a while before engaging first? I didnt try that.

I was expecting the engine to be like a jap liquid cooled one, but thinking about it, isnt it a case that only the heads are water cooled? So the crankcase wont have the sound deadening effect of a water jacket? Nevertheless, surprising that its noiser than my TC. I guess I was only raising the question to now whether this examp[le was noiser because it had been thrashed to death or whether the issue was inherent to the new design.

Any other issues in your 20k?

P.S. Your comment about the noise being apparent is a good one. The TC GS that I have has this ridiculous BMW exhaust valve which makes it sound like some spotty youths Sportster and probably hides all sorts of rattles

If the clutch lever is pulled in and there is no clutch drag then there are no rotating bits in the gearbox because it is disconnected from the engine so there can be no clunk into 1st.

No serious issues at all, just the little niggly thinks like switch gear, brake reservoir cover and screen replaced under warranty.

 

[MattW]

A small amount of drag / overspin is engineered into most constant mesh bike gearboxes. Otherwise it could stop 'between dogs' and refuse to engage. However, getting this drag right is something of a black art and not every box design is successful in this respect.

 

[birdseye]

A small amount of drag / overspin is engineered into most constant mesh bike gearboxes. Otherwise it could stop 'between dogs' and refuse to engage. However, getting this drag right is something of a black art and not every box design is successful in this respect.

Now that I can understand. But if you are correct, why did the WC not try to move forward when in gear, stationary with the clutch pulled in. And why does my TC running on the centre stand not have the back wheel trying to rotate. OK its not in gear but oil drag should mean some connection.

 

[MattW]

Now that I can understand. But if you are correct, why did the WC not try to move forward when in gear, stationary with the clutch pulled in. And why does my TC running on the centre stand not have the back wheel trying to rotate. OK its not in gear but oil drag should mean some connection.

Different clutches.
The drag in a wet clutch box is very small but always present due to oil drag and clutch geometry. It's usually far too small a force (or at least it should be) to actually move the bike but it will be trying to spin the input shaft slowly when in gear with the clutch pulled.

A dry clutch like your TC is totally different. Dry clutch BM boxes are designed to carry some inertia and rotation for a while after the clutch is pulled so that gear changes and then initial stab into first work reliably. However this rotation doesn't last forever which is why if you pull the clutch and then wait before selecting first, it doesn't always go in reliably. Some oilheads do actually rotate the back wheel in neutral on the stand - my 1100 does.

 

[birdseye]

are they differnt types of gearboxes or are they still dog engagements? If so, presumably the WC box would still need some slow roptation to allow engagement of first and the problem is simply that it has too much and therefore crunches. The cure is simply to slow down on putting it into first - slight hesittaion.

 

[MattW]

are they differnt types of gearboxes or are they still dog engagements? If so, presumably the WC box would still need some slow roptation to allow engagement of first and the problem is simply that it has too much and therefore crunches. The cure is simply to slow down on putting it into first - slight hesittaion.

They're both constant mesh dog boxes and yes, one theory is that there is too much rotation in the box causing the almighty crunch into first. However the WC has a multiplate wet clutch which it would appear, doesn't disengage properly however long you pull the clutch for. Hence mods like extended pushrods etc...

 

[Jacal]

Think I'll have to take my bike back as it doesn't 'clunk' any worse than the last two RT's I've owned, maybe I should not pull the clutch in all the way and see if that will make it normal and I'll be able to have an almighty crunch....I feel cheated

 

[strod]

I don't think mine is particularly clunky either. I feel robbed...

 

[Troppo]

My GS is much clunkier than my RT.

"They all do that"...

 

[Packer]

The WC GS that I test rode clunked into first badly, it was also near impossible to select neutral with the engine running. A big step backwards in terms of transmission over my 2004 1150GS. Nine years of product development to go backwards.

I bought a Yamaha instead.

 

[birdseye]

They're both constant mesh dog boxes and yes, one theory is that there is too much rotation in the box causing the almighty crunch into first. However the WC has a multiplate wet clutch which it would appear, doesn't disengage properly however long you pull the clutch for. Hence mods like extended pushrods etc...

A common gearbox / engine oil supply is the norm on cars but they have synchro. I dont know whether a common oil supply is the norm on bikes - I suspect not. And thin synthetic oil is obviously going to give less viscous drag compared to normal gearbox oil.

 

[MattW]

A common gearbox / engine oil supply is the norm on cars but they have synchro. I dont know whether a common oil supply is the norm on bikes - I suspect not. And thin synthetic oil is obviously going to give less viscous drag compared to normal gearbox oil.

Wrong on both counts I'm afraid.

Just about every car has a separate engine / gearbox with separate oil supplies (an exception being the A series in the original mini which had its gearbox in the sump and shared the engine oil).

A common oil supply is the norm on most bikes as they have integral gearboxes and clutches (exceptions being pre WC boxer BMWs and Guzzi's). Bikes with integral gearboxes / clutches use special oils with friction modifiers to help the clutches.