Jump to content

R 1100 SA Acceleration Lag/Hesitation/Power Loss


DFTB

Recommended Posts

After all the great help last time I thought to pick your brains again guys!

 

My 00' R 1100 SA has been experiencing what I consider to be a air/fuel mixture problem.

 

Bike had 2100 miles when purchased and ran very well. Now, 4 months later I have 5200 miles and it is acting odd. Under moderate to heavy acceleration I am seeing a power loss or lag as if the intake sucked in a large cottonball.

The bike cuts out (does not shut off as with the vapor lock post) or is very slow to react to a twist of the wrist.

 

Plugs are clean, not fouled. Plug wires are pliable, appear undamaged. Fuel is always fresh (usually just a few days old).

 

Bike idles normally with a subtle surging when rolling at slow speed.

 

Still learning about this bike and now I am really confused. dopeslap.gif I have checked the other postings on the board and I cannot find anything related to my issue so any assistance would be most grateful.

Link to comment

I would be tempted to check the air filter and then fuel pressure.

 

I have seen similar symptoms in various cars when the TPS had failed.

 

Good luck!

 

Peter

Link to comment
I would be tempted to check the air filter and then fuel pressure.

 

I have seen similar symptoms in various cars when the TPS had failed.

 

Good luck!

 

Peter

I second that, I'd probably start with the fuel pressure regulator.
Link to comment
ShovelStrokeEd

At your low milage, I would not think the air filter or fuel filter are at fault although a fuel filter can clog with only the slightest amount of water. I would really need more information before attempting a diagnosis. Given the age of the bike and the very low miles, was it stored for any significant period of time? Could be the inlet screen on the fuel pump

 

What RPM? What gear? Is a slow roll on of the throttle better than snapping it rapidly open? How is your battery? Alternator?

Link to comment
At your low milage, I would not think the air filter or fuel filter are at fault although a fuel filter can clog with only the slightest amount of water. I would really need more information before attempting a diagnosis. Given the age of the bike and the very low miles, was it stored for any significant period of time? Could be the inlet screen on the fuel pump

 

What RPM? What gear? Is a slow roll on of the throttle better than snapping it rapidly open? How is your battery? Alternator?

 

RPM range is between 2200 and 5800.

 

A slower roll does seem to make a difference as the sudden snap of the throttle will usually offer little in the way of acceleration.

 

Battery is factory new replaced a week before I purchased the bike. (roughly 4 months old.)

 

Alternator I do not know about. It is original to the bike and I have not had it checked out as there are no local dealers in town.

 

I have heard that the electrical systems on BMW's (or maybe the R1100's specifically) experience many issues and that the batteries frequently get burned up however I really do not know this to be fact. The way the bike is running I have to wonder if it is just leaning out at the higher RPM's as the right exhaust pipe is much more 'blued' than the left. Also, with the sporatic occasional backfire when rapidly returning to lower RPM's but then again, I was informed that it just be the StainTune exhaust as there are less baffles than the factory pipes.

Link to comment
ShovelStrokeEd

OK, some information.

 

RPM first, 2200 is way to low to be whacking the throttle open. IMHO it is too low to even operate the motor although, with judicious application of thr0ttle, the bike should be able to pull from that RPM in even top gear. I will seldom apply full throttle at anything below 4000 RPM and even there, I really prefer to down shift first. Take note of your tachometer and see where the red zone is. 1/2 that as a lower limit for application of full throttle.

 

I'm not so sure about the lean mixture idea unless the hard acceleration is accompanied by severe pinging or spark knock, which it certainly should at those lower RPM's. The fact that one pipe is much more blue than the other leads me to think the bike is in dire need of a throttle body synchronization. Stretched cables come to mind here.

Link to comment
OK, some information.

 

RPM first, 2200 is way to low to be whacking the throttle open. IMHO it is too low to even operate the motor although, with judicious application of thr0ttle, the bike should be able to pull from that RPM in even top gear. I will seldom apply full throttle at anything below 4000 RPM and even there, I really prefer to down shift first. Take note of your tachometer and see where the red zone is. 1/2 that as a lower limit for application of full throttle.

 

I'm not so sure about the lean mixture idea unless the hard acceleration is accompanied by severe pinging or spark knock, which it certainly should at those lower RPM's. The fact that one pipe is much more blue than the other leads me to think the bike is in dire need of a throttle body synchronization. Stretched cables come to mind here.

 

I believe I misstated myself. When the RPM's are near 2200 I begin to notice the roughness and/or lag but I do not swat the throttle this low (as you stated it is much too low to do so.)

 

As far as a throttle body sync let me guess, a dealership is the only one with the equipment to perform such a task?

 

Sounds like I need to move to a different city! thumbsup.gif

Link to comment

As far as a throttle body sync let me guess, a dealership is the only one with the equipment to perform such a task?

 

Sounds like I need to move to a different city! thumbsup.gif

 

Throttle synch is an easy DIY task. Do a search on +manometer or +twinmax, then look here for all the detail you need on how to service your oilhead.

 

Andy

Link to comment

As far as a throttle body sync let me guess, a dealership is the only one with the equipment to perform such a task?

 

Sounds like I need to move to a different city! thumbsup.gif

 

Throttle synch is an easy DIY task. Do a search on +manometer or +twinmax, then look here for all the detail you need on how to service your oilhead.

 

Andy

 

Thanks Andy for the technical information. I just ordered a Twinmax from out of state as the local dealer was unable to locate information about Twinmax.

 

I read through your hyperlinked directions and the procedure seems really straightforward so I hope an amateur like myself can handle the process.

 

Thanks to everyone! wave.gif

Link to comment

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...