Bike Develops Slight Jerky Movements Especially at Low Gears

[bmwfbd628u]

Hi,

I am riding a 05 Rockster with 29,000 km on it. Over the last month or so, the bike has developed a rather worrying behaviour - jerky movements similar to when in the wrong (higher) gears, only of course that the correct gear has been engaged. Eg when riding in the carpark in low (1st or 2nd) gears, the bike does not feel smooth as before in the same gears. When I open up on the highways, bike feels fine as before. almost. Not sure if physchological, added 'almost' cos it does feel a little heavier than before at times.

Any thoughts on possible causes - fuel delivery (lines, senscors, etc), clutch, what-else? Intend to get it checked during the 30,000 km servicing, and decided to tap on the wealth of experience here to focus the checks.

Thanks much.

Justin

[sweatmark]

Where are you located? Just curious.

First guess is that motor operation is being impacted by stick coil(s). Have you replaced the stick coils or investigated per instructions found elsewhere within the R1150R board?

Second guess would be drivetrain problem, at either the final drive or clutch assembly weakpoints. Really, I'd investigate the ignition issue first.

[riceburner]

what revs does this occur at??

[bmwfbd628u]

Hi,

I am from Singapore, South East Asia.

Yes read about coil sticks, clutch & final drive issues on this site in the past. Had a previous problem with ignition, so did search through the forum rather extensively. Hope the cause for the current problem is electrical (coil sticks) and not mechanical (drive train). Rode the cruiser R1200C close to 10 years ago, and had to replace clutch plates 2 years after taking delivery of the new bike.

The jerky movements occur at low rev, say around 1,000 or less, at 1st or 2nd gears.

[riceburner]

Hi,

I am from Singapore, South East Asia.

Yes read about coil sticks, clutch & final drive issues on this site in the past. Had a previous problem with ignition, so did search through the forum rather extensively. Hope the cause for the current problem is electrical (coil sticks) and not mechanical (drive train). Rode the cruiser R1200C close to 10 years ago, and had to replace clutch plates 2 years after taking delivery of the new bike.

The jerky movements occur at low rev, say around 1,000 or less, at 1st or 2nd gears.

In that case I'd say it's "normal" (but checking the coils won't hurt).

It's known as "lugging" the engine - you're basically trying to use the engine at revs where it's not really putting out enough torque to actually drive the bike along, and so it attempts to do so - but what happens (in effect) is a series of lurches as the engine tries to turn the drive shaft but can't.

Apart from pulling away from a standstill the R1150R won't really pull well below about 1,500 - 2,000 revs (no bike will). 1,000 revs is approximately tickover speed (in fact I think it's lower than standard tickover).

[sweatmark]

Agree with Riceburner - the boxer motor does have torque, but requires at least moderate (2500+ RPM) engine speed to develop the power required for manuevering. How long have you owned the bike? If you have previously ridden a v-twin and are accustomed to engine torque at very low RPM (<1000) then the BMW will require a different riding style. The good news is that the boxer has a wide and very usable "sweet spot" of 2500-5500 RPMS which matches well with most operating conditions.

If on the other hand, you have owned the bike since new and are now experiencing a change in performance, then some troubleshooting is likely needed.

[riceburner]

Agree with Riceburner - the boxer motor does have torque, but requires at least moderate (2500+ RPM) engine speed to develop the power required for manuevering. How long have you owned the bike? If you have previously ridden a v-twin and are accustomed to engine torque at very low RPM (<1000) then the BMW will require a different riding style. The good news is that the boxer has a wide and very usable "sweet spot" of 2500-6500 RPMS which matches well with most operating conditions.

If on the other hand, you have owned the bike since new and are now experiencing a change in performance, then some troubleshooting is likely needed.

just corrected that for ya....

has to be said though - I don't know of many bikes at all that'll have enough torque at 1,000 revs to pull themselves along..... diesel Enfields apart.

[bmwfbd628u]

Thanks for the all the advices. Would like to update on the matter. Sent the bike for regular servicing, tho no requirement for 30,000km. But considering age of bike, decided to bring forward the replacement of various filters - fuel, air, oil, and changed the engine oil (7,000 km since last) and gear & final drive oil (last changed before I bought the bike at 16,000 km). Now bike is running smooth, at least since I picked it up earlier today. Guess henceforth will be more diligent in replacing such wear & tear items on regular basis.