2005 BCR rough and splutter.

[masha]

A friend of mine (also with a twinspark BCR) has reported the following I thought I would quiz you all for any help with.....

"fired up the BCR again last night & and by the time garage door was closed it had stalled/stopped. So, sat astride it and hit starter button. It only just about turned the engine over; just like a flat battery (which it wasn't as there is no alarm on this bike and battery was new in November '14)! Ignition off. Left it for a minute and it spun over and it fired up OK.
Rode to see friend. Fine.
It started OK after I saw him but when I came to pull away it seemed to stop, shake then caught again. That's no good. So, pulled over. Blipped throttle and it wasn't happy. Seemed to have an ignition cut for a milli second then again OK. Tickover is still 1500 - 1600 when warm which seems far too high.
I wonder if the carbs are out of balance? and there is excessive vibration at the bars. Any ideas? I've done nowt with it yet since its first 'big' £800 24,000 major service in November '14"

[Merecat]

Check the little black caps under the throttle bodies.. If these are perished and cracked, or missing it will run rough

[metropolis2k]

It could be as simple as the TB's need balancing, but that would be a gradual descent into rough running, not happen over night (unless someone has been fiddling with it).

It could also be the stick coils. The best thing to do would be to do the following test:

http://www.boxertrix.com/phpBB2/viewtop ... 9b0d73f771

You could also try swapping them around with the stick coils from your BCR until you either work out they're all OK or one is at fault.

Obviously it could be lots of things like spark plugs, fuel pump, air intake, etc. but the high idle points towards stick coils or TB balancing to me.

[masha]

Thanks Metropolis and Mick - a couple of handy things to consider there. regards

[DPG]

Another thing, check the throttle cables where they seat on the throttle body adjusters. Occasionally they dont seat back down into the adjusters properly after you mess with them and that can cause rough running problems.....

[BlackDuc]

HAL sensor might be going bad. They seem to act up more when wet though. Battery not having enough juice to do a strong crank is an issue.
When running do you get an RPM bounce or low lights? Charging system might be iffy and killing the battery?

[masha]

I will check with my friend Chris and report back - as its his bike in question here. Thanks

[Jimmy Quadrophenia]

Chris here!
Well, when the bike is cold the idle is about 1100rpm ish (with throttle raiser/'choke' shut off).
Go for a ride and it isn't uncommon to see 1600-1700 idle. Switch off and turn back on and it's about 1200-1400 rpm then will gradually rise again.
The battery is a new one. Bike sits on an Optimate when not in use.
The starting can be straight off OK. But, if engine turned off then it's pushed out of the garage the starter 'sometimes' will not turn the bike over. Just like a flat battery situation (which it isn't). Leave it a while. Fires up fine (OK, has a horrible starter sort of noise but heard that in others too).
I suspect the balance of carbs isn't spot-on but did try the ball bearing -in-tube type balancer that worked really well with the Honda VTR twins. Off with the two rubber bungs under the TB's, connect etc. A tiny tweek of RHS brass screw had the balancer level.
When running all lights work strongly and nowt wrong. Vibration is more over the 4 grand mark (much more so than my RZV500R at 9,500RPM!) and is annoying but foam over grips have helped here.
So, not used to these issues. First BMW too. Hmmm

[DPG]

Not sure about the dodgy starting, could be a few things - electrical from the sound of it. I'll think about that one.

The vibration is easier to to diagnose.
Have you checked the coil packs /HT leads? If faulty or worn they can break down at higher revs and cause a misfire although the Throttle-body balancing is much more commonly to blame for boxer -engine vibes at higher revs. Did you balance it at idle? I mention it as the Boxers need a little extra work to make them smooth out - do that again at high RPM (2-4K) and use the throttle cable adjusters to make to the adjustment.

Instructions here:
http://www.ibmwr.org/r-tech/oilheads/tb-synch.shtml

Although old, those Internet BMW Rider pages are a good source of basic technical info. Search for Rob Lentini too - he did a load of write-ups back in the day, most of them published on IBMWR.

OO, Just a thought, do you have the OEM Bar-End weights? They make a big difference to handlebar vibes. Aftermarket ones are generally much lighter and not so tightly attached either.