Transmission back lash

[jetjock]

I know the subject has been done before , but is it normal on the 1250s ?

Doing a throttle adaptation does help but there seems to be quite a bit of transmission lash that’s worse at low speeds .
The cardan shaft has been inspected and seems fine . Is it just R1250 character ?

 

[TommyS]

I was wondering the same thing. I'm new to BMW having just got a 1250 GSA. My last bike a Yamaha TDM I had for 27 years and it started to lurch a bit at low speeds. I just assumed it was cush drives. I spoke with a guy at BMW and he said they just do that. I think the drive shift has been looked at on recall. Any views would be helpful

 

[jetjock]

The more I ride it I think it’s just a case of they all do that . I’m just gonna ignore it as thinking about it seems to exaggerate the issue

 

[G&T]

When you say back-lash, what do you mean? I’m confused when you say at low speed. My 1250 can back-lash when winding her up but that’s on the beans.

 

[TommyS]

Maybe backlash isn't the right word, snatchy might be better. I have to slip the clutch at low speeds to keep it smooth, say in traffic. Once I give it the gutty smooth as silk

 

[DJ123]

Try it in different driving modes and see if that helps. Wet & road have a 'delay' built/a soft delivery of power which means your input is not happening immediately so could be exacerbating the snatchy feeling.

 

[jetjock]

Try it in different driving modes and see if that helps. Wet & road have a 'delay' built/a soft delivery of power which means your input is not happening immediately so could be exacerbating the snatchy feeling.

Ahh that might explain it . Thanks

 

[TommyS]

I'll have a go at that, thanks

 

[GSMarky]

To my mind 'Backlash' is the mechanical play in the drive system that can be evident if the drive pressure is removed, so on/off the throttle and would feel like a worn chain drive.

The throttle map is a different thing altogether and is simply the response due to that particular engine map.

I'm surprised you need to clutch it in traffic - what speed is this at?

My 1250 GSA is super smooth unless I really abuse the throttle not allowing the bike time to respond in normal riding conditions.

 

[TommyS]

It would probably be about walking speed,just what you would do in queues or slow moving traffic in town. It's a mattering feathering the clutch balancing it with the throttle. When you shut the throttle down, then reapply without feathering the clutch it's jerky. Just wasn't whatI was expecting from BMW. Otherwise handles great.

 

[GSMarky]

It would probably be about walking speed,just what you would do in queues or slow moving traffic in town. It's a mattering feathering the clutch balancing it with the throttle. When you shut the throttle down, then reapply without feathering the clutch it's jerky. Just wasn't whatI was expecting from BMW. Otherwise handles great.

I guess if you completely off load the transmission and then open the throttle again as you're still decelerating that'll happen. I've never felt anything untoward at walking pace in 1st/2nd +/- the clutch.

Definitely the road/rain modes slow the throttle action down and maybe also try some grip puppies as they give a larger grip diameter so you get more feel as a consequence - oh & no vibes at your fingers either after a long day!

 

[TommyS]

Thanks for your replies

 

[G&T]

The first thing I noticed moving from chain to shaft is ‘the kick’. But only when winding her up and quickly moving up the gears fast. I never noticed this with a chain and thought maybe the chain takes some of that energy and smooths things out. I’ve never experienced it at slow speeds as I’m smooth on the clutch and not dumping the clutch.

 

[Victor c]

Throttle response at low speed has been smooth on all my LC bikes. A throttle recalibration may cure your issues @TommyS

 

[Hann]

I think any bike would feel like there is too much slack in the drivetrain if you were in first gear at walking pace and constantly going from an open throttle to closed, shaft drive or not...... Every bike i`ve ever had has done that and it`s impossible to avoid with all the accumulated lash in primary drive, clutch, gearbox, shaft/chain etc.....

I tend to select second gear whenever moving and feather the clutch for complete smoothness (especially with passenger onboard to avoid the dreaded pillion heatbutt syndrome).

 

[TommyS]

Think I've got the snatchy thing sorted. I went into BMW a few times and explained what was happening but they said it just does that and didnt seem interested.The engine light came on and they found a problem with the exhaust flap. While there I asked them again about the snatchy drive. They checked and this time found that there was wear in the drive shaft. They replaced the header pipe, driveshaft and recalibrate the throttle. All done under the 2 year warranty that came with it. It's now a different bike sill a tiny snatch at low speed but acceptable. Thank goodness as I was looking at Triumphs

 

[jetjock]

Think I've got the snatchy thing sorted. I went into BMW a few times and explained what was happening but they said it just does that and didnt seem interested.The engine light came on and they found a problem with the exhaust flap. While there I asked them again about the snatchy drive. They checked and this time found that there was wear in the drive shaft. They replaced the header pipe, driveshaft and recalibrate the throttle. All done under the 2 year warranty that came with it. It's now a different bike sill a tiny snatch at low speed but acceptable. Thank goodness as I was looking at Triumphs

How many miles has the bike done ?

 

[Bem]

Think I've got the snatchy thing sorted. I went into BMW a few times and explained what was happening but they said it just does that and didnt seem interested.The engine light came on and they found a problem with the exhaust flap. While there I asked them again about the snatchy drive. They checked and this time found that there was wear in the drive shaft. They replaced the header pipe, driveshaft and recalibrate the throttle. All done under the 2 year warranty that came with it. It's now a different bike sill a tiny snatch at low speed but acceptable. Thank goodness as I was looking at Triumphs

The replacement driveshaft was evident to me in a small improvement in vibes and slow speed jerkiness ( the bike not the rider, but now you mention it....)

 

[TommyS]

How many miles has the bike done ?

It has just turned 10000