Just checkin' this out

[Wraithwrider]

Now if I connect my Carbtune II to each throttle body when the engine's warmed up and adjust with RHS cable adjuster to balence at 3,000 to 4,000 rpm that'll be the business then?

Just that the bike was smoother before it was serviced, bloody BWM tuning!!

 

[Marty Hill]

Yes, that will do it. We always seem to do better then the dealers. Guess we can take a bit more time.

Cheers.

 

[impi]

Correct, but sync at idle first before you sync at 3-4k

 

[Marty Hill]

No need to sync at idle. That is done by the stepper motors. At least that is what we have found.

 

[Wraithwrider]

impi wrote

but sync at idle first before you sync at 3-4k

But is there a need to unplug stepper motors or something to do the idle set up?

I understand that the running (throttle cable) setup is independant of the idle one.

It's not that I'm not prepared to do the idle check, I just believe that it may be shrouded in mystery/difference of opinion as to how to do it.

 

[bgregor]

No need to sync at idle. That is done by the stepper motors. At least that is what we have found.

I got my 1200 back from the 600 service and it was running like a bag of bolts. Took it to a friend who has worked on BMW's for years, he checked the vacuums and found the were off at idle and a all the way through the rev range. There is also a flat spot off idle which causes a lag.

The bike is being picked up tomorrow by the dealer. Hopefully they will fix it.

 

[Panzer Patrol]

No need to touch anything for idle set up, let the electronics and the other gizmos do that. You have done all you need to do.

 

[Howard Millichap]

See now! You lot have paid 91/2 grand for these bikes and they run like a peice of shit. Bmw dealers have NEVER been able to tune a boxer properly. They just plug it into their computer these days.
You ALWAYS have to take it to an "expert" or learn to do it yourself by trial & error.

Bring back bing carbs.

 

[Wraithwrider]

I think BWM dealers just tune the TBs until the computer or whatever they use says, effectively 'in spec'. Tis just a job for a lot of these guys who've been doing it for years for little pay or incentive. So I'm not over critical.

 

[Dinger]

I just got mine back from the 600 service. They said they'd remapped it etc but it doesn't feel any better to me. It's still lumpy at 2500rpm and makes slow manouvering tricky. On one occasion I was breaking fairly hard for a slow hairpin and I swear I was fighting a "surge" with the break, almost like I hadn't throttled back properly (but I had).
Does anyone have a definitive step-by-step-balance-your -throttle-bodies-for-numptys guide including what kit is needed?

 

[Wraithwrider]

Dinger

Very basically, you connect a sensing device to both throttle bodies when the engine is warm and the bike stationary.

You can use a carbtune manometer (I or II) or better still a Twinmax which as I understand it measures pressure differential and has fine and coarse ranges of measurement.

Start up and make sure the engine is warm. In neutral raise revs to say 3000 and check for a diffential across the throttle bodies as indicated on the gauge. Adjust the RHS throttle cable stop at the engine end to get the difference to a minimum and then tighten the locknut.

Do not overheat the engine.

This is not how to set the idle. I'm not sure where you would adjust the throttle bodies to change the idle differential but on the 1200 it appears to not be so simple as the last bike I did this on (a '81' R100RS called Hildegard!).

Any further thoughts/advice on idle set up on a 12 would be welcome

As for stepper motors I cannot see how they minimise pressure differential at idle as airflow through the bodies is not measured. I think that the stepper motors are more likely to adjust idle speed as the motor warms up from cold. But what the feck do I know

 

[ROB A]

My 1200 runs like a dog the bike never run very well.Its been back to the shop 6 times now .I have set the tbs and bike runs great but the next day its back to its old tricks

 

[Howard Millichap]

On one occasion I was breaking fairly hard for a slow hairpin and I swear I was fighting a "surge" with the break,

So did it break whilst you were BRAKING?

 

[Wraithwrider]

I know that earlier 12's had a problem on the overrun with a marked and disturbing period of reduced engine braking on the overrun.

The test 12 I rode did this a little but the re-map supposedly cured it.

Tobers has commented on this odd characteristic.

Mine hasn't had any symptom from new and the 600 mile service hasn't induced it. My bikes been supersmooth before the 1st service and is nearly as good now. Having experienced how good it can be I want it back!!

 

[Dinger]

So did it break whilst you were BRAKING?

No, it broke while I was breakdancing.

Now shurrup it's been a long day.

 

[Paul Wakefield]

It's still lumpy at 2500rpm

If its anything like mine was, it needs a few more miles before its really happy below 3k rpm.

Mine now pulls willingly from 2k and will take higher and higher gears at lower & lower revs - part of this is certainly down to the latest mapping but most is just the engine loosening up.

Like Wraithrider, I thought the latest mapping had sorted out the surge (I've never suffered from it). Wasn't the ABS kicking in was it?

Paul

 

[Mouse]

Mine's always surged, after the 600 mile service the surge was at lower rpm (about 1500-2000) and a bit less pronounced but still there.

When I get round to it I'm gonna play with balancing, and when the time comes for the 6k service I'll make sure the dealer does the new map thing. Until then I can live with it.

 

[Mouse]

Just to report back...

I had a go at balancing over the weekend. Used my not very accurate dial type vacuum gauges, so probably didn't get as good results as I would have with a manometer type gauge.

But it was very simple. I didn't bother about the stepper motors etc, just connected the gauges, and tweaked the right hand cable adjuster. The balance was slightly out at about 4k rpm so I adjusted it. In all this took about 5 minutes, not counting the time to let the engine warm up.

The result is that the bike definitely feels smoother, and there is less "surge" below 3k, although there's still a pronounced lack of engine braking in that range.