How to balance throttle bodies and adjust idle speed: R1100RS & R1150RS

[Dee Duble Yuh]

Boxer Twin engines that don't have counter-rotating balance shafts vibrate a bit. It's one of those TADTS ("They all do that, sir") that we get used to. However, balancing the throttle bodies will help to keep vibrations to a minimum. You'll need some gauges, and good ones can be expensive.

Unlike most motorcycle engines, you can't just adjust the idle speed at will. You have to adjust each side, and that means keeping them in balance (again). So adjusting the idle speed is a similar task to balancing the throttle bodies.

[cat0020]

Easy task as long as you hacve the right tool, mainly a Twinmax.
Unplug the vaccum hose underside of the fuel injectors that goes to teh carbon canister and connect the Twinmax to both vaccum. Sync the throttle body with Twinmax at idle then rev the engine up to 4500 rpm and check balance again, then back to idle and check again. The Adjustment is made with the flat screwdriver by turning the brass screws that are located just at the very "outside" of each throttle bodies.
After the throttle bodies are balanced, turn both flathead screw clockwise to lower idle RPM, counter clockwise to raise idle RPM.. as long as you do both left and right flathead screw in equal amount your throttle body balance should stay in tact.. or you can always check again with the Twinmax.

I watched Dhager perform adjustments on mine two three time already.
I'm sure he can offer more technique than me.

[honard]

Here is the link for the informative and humorous Throttle Body Synch for Dummies. http://www.advrider.com/Wisdom/TBS4Dv1.0.pdf

Also, this is the link to the Internet BMW Riders website Oilhead Maintenance Manual. There are multiple instructions on performing throttle body synchs as well as other normal maintenance procedures. http://www.ibmwr.org/r-tech/oilheads/R11Manual/Oilhead_Maintenance_2-25-02.pdf

[MikeT]

Any suggestions on whats are good vacuum gauges / manometers to use for throttle body sync and where to get them ( prefarably this side of the pond)

[Oil cooled]

I made one of these

http://www.airheads.org/contrib/4dollarmano.html

and used it many times with great success on my airhead. :) I am seriously thinking it should still do the job on my 1100rs. After all, even if the absolute inlet pressures are higher (or lower) this is a differential guage (and very sensitive too).

This may be the answer you're looking for - has anyone ever tried this approach?

[honard]

Mike,

I use the Twinmax. It is very easy to use, however it is a bit pricey as they run about $85. One main benefit is that you can connect it to your throttle bodies and check your synchronization while you ride your bike. Read the Throttle Body Synch for Dummies pdf in my post above. It describes using the Twinmax and may be helpful in determining whether or not you want to buy one.

[MikeH]

Any suggestions on whats are good vacuum gauges / manometers to use for throttle body sync and where to get them ( prefarably this side of the pond)
Hi Mike,
I can recommend the vacuum guages made by Davida. They are high quality instruments and are well damped - there is little or no fluctuation in the readings and they respond immediately to any change. The company is based near Liverpool and their website link is below.
http://www.davida.co.uk/gauges/describe.html

[Oil cooled]

Further to my post above, I used the home made £5 carb balancer on the 1100rs over the weekend. Worked a treat :) .

Obviously it cannot be strapped to the bike and used on the move, but as a static balancer it works very well (for me anyway).

Link here

http://www.airheads.org/contrib/4dollarmano.html

for anyone who's interested.

I'm sure there are down sides over more expensive devices, but this is certainly good enough for me, and the bike seems to like it. You pays yer money etc etc. :Beer:

[rdfarr]

I use a homemade manometer like "Oil Cooler." Works great and is easily and cheaply assembled. It's highly sensitive and has no electronics or calibration error. However, contrary to the link provided, I found that motor oil and 2-cycle oil are too heavy for the plastic tubing: they respond much too slowly due to their high viscosity. I also found that water is much too lively: it bounces around too much, and can be sucked into the injectors if they're too unbalanced. I personally use hydraulic oil, but I'm sure ATF should be just as good. (Attached is a pic of my manometer in action.)

[jvfante]

After using the home-made sync device described in numerous articles, I finally broke down and bought the Twinmax. For about half the price of a bike shop tune-up, if one looks at it in that fashion, you can have the real tool for the job that doesn't leak any fluid if you happen to drop the thing. Most of the tools in my garage were purchased with this rationale, btw.

As mentioned too, you can take a test ride with the Twinmax attached and check TB sync on the bike under load conditions, which seems a great advantage.

my 2 cents.

[rdfarr]

..... that doesn't leak any fluid if you happen to drop the thing.
And if you drop the Twin Max? $$$?
Whatever works for you. I just chose to save the price of the Twin Max although I'm sure it works just fine.

[MikeT]

After using the home-made sync device described in numerous articles, I finally broke down and bought the Twinmax. For about half the price of a bike shop tune-up, if one looks at it in that fashion, you can have the real tool for the job that doesn't leak any fluid if you happen to drop the thing. Most of the tools in my garage were purchased with this rationale, btw.

As mentioned too, you can take a test ride with the Twinmax attached and check TB sync on the bike under load conditions, which seems a great advantage.

my 2 cents.
Guys, I am sure the home made device works just fine, and I admire those with the patience and ingenuinty to make one and use it.

My position is most accurately described in "oilhead valve adjustments for dummies" , see the section on page 6 "Wait - Can't I Buy SPECIAL Tools ?", so I also ordered a Twinmax today :D

PS: If you have not read "Oilhead Valve Adjustment for Dummies" (http://www.advrider.com/Wisdom/OVADv2.1.pdf), I recommend you do if only for the pure entertainment value

[Dee Duble Yuh]

Some owners of the R1100RS report that overfilling the engine oil can cause vibration. You might want to check this thread before undertaking extensive adjustments/repairs to your 1100 engine:
Oil Level in sight Glass. (http://www.bikersoracle.com/rs/forum/showthread.php?t=818)

[dickybeau]

I bought and used a Morgan carbtune at www.carbtune.com . These guys are Belfast based and I can recommend them. I bought the twin vacuum gauge but perhaps should've bought the 4 in case I upgrade the bike to a K. No taxes to pay and lower postage costs. I paid around £39 sterling. After sales are really good. :Bow:

These are easy to use if you follow the instructions CAREFULLY. :o I followed the www.ibmwr.org Oilhead Tuning instructions and it took about 5 minutes.

When I was having the brakes checked at the dealer the other week, I watched the guy measure the CO2 and my next tool will be a gas analyser if I can get 1 cheaply enough.

[stationo]

:help: Help...Just been reading " balancing etc. for dummies", as this is my first bike with injection thought I would see how easy /hard it was to do, however I'm a bit stuck on the Brass screw bit. According to article it is to adjust the air setting and balance bodies, I realise that it is INJECTION and not CARB but I have a 1964 BSA lightning Clubman and use the air screw on that , and all the other carbed bikes I've had , to adjust the mixture , for example ensure plug is light chocolate colour; then use the cables to ensure the valves, (slides), open at the same time, then use the throttle stop screw to get the correct idle speed ,adjust mixture again then adjust to ensure higher engine speed balance.
As I said I know it's injection and it's different from carb , but I believed the air screw adjusted the mixture & I know it will change the engine speed slightly but believed balance was gained by getting mixture right for certain throttle screw settings.
Apologies if I've missed something obvious and I would be grateful I someone could point me in the right direction as to the function of the big brass screw on injectors. :confused:
Cheers
robert

[MikeH]

The brass screws bypass the throttle butterflies at tickover and are soley to adjust tickover speed. They don't alter the mixture. To carry out a throttle balance first set the brass screws for correct idle speed. Then carry out the main balance at higher revs by adjusting the individual cables to each butterfly quadrant. Depending is whether your RS is an early or later model ('96 onwards) there is a different arrangment for the throttle cables.

There's a fully detailed procedure elsewhere on the forum.

[stationo]

The brass screws bypass the throttle butterflies at tickover and are soley to adjust tickover speed. They don't alter the mixture. To carry out a throttle balance first set the brass screws for correct idle speed. Then carry out the main balance at higher revs by adjusting the individual cables to each butterfly quadrant. Depending is whether your RS is an early or later model ('96 onwards) there is a different arrangment for the throttle cables.

There's a fully detailed procedure elsewhere on the forum.
Thanks Mike that does help , too many years of working on twin carbed bikes and I just couldn't get my head round the air mixture screw thing on an injection controlled bike.
The bike is 2004 got it a few weeks ago with 7 miles on clock , it had been reg. in Nov and sitting in showroom, initially phoned about the new ST but in conversation they mentioned the RS and got it for a song because it had been pre reg and they had to shift it , oh lucky me!
Still trying to figure out comfortable screen position though!
Thanks again
Cheers
Robert

[MikeH]

Hi Robert, Just FYI if you intend to do a full service followed by a throttle balance, you need to do the valve adjustment first followed by the TB sync.

If you need any help when you come to do it just send me a PM and I'll try to help.

BTW if you don't already have the equipment for this, I can recommend the Davida vaccuum gauges. They give accurate and well damped readings.
Davida Gauges (http://www.davida.co.uk/gauges/describe.html)

[lorazepam]

I find that the screen all the way down gives me the most comfortable option. When I first got my RRS, I figured that higher was better, but discovered that unless I am getting really cold or really wet, the lowest position works best for me.

[Jason]

I find that the screen all the way down gives me the most comfortable option. When I first got my RRS, I figured that higher was better, but discovered that unless I am getting really cold or really wet, the lowest position works best for me.Ditto for me.

As has been mentioned already, here and in the parallel thread in General Chat, our bikes run 'closed loop', i.e., the Motronic determines how much fuel to deliver, not only by factors such as throttle position, engine speed, and (possibly, I'm not sure..) mass air flow sensor, but also by feed back from the O2 sensor in the exhaust. So, basically, short of installing somthing like the techclusion - which essentially sits between the computer and the injectors and massages the signals to the injectors - or sensor/computer/injector failure, there's nothing you can do to screw up the mixture. Well, maybe messing with the TPS adjustment, but that comes under the 'very advanced' category, and I don't think you'll ever find a need to adjust that.

Since yours is brand new, I'm guessing you haven't even done the 600 mile service, yet. You may want to just not worry about any of this until after that has been done (both the valve adjust and the TB sync can, and I believe should, be done at that time). I suppose you could be planning on doing that yourself, but conventional wisdom (for what THAT's worth... ;) ) suggests it's best to just let BMW do that one service.

[stationo]

Ditto for me.

As has been mentioned already, here and in the parallel thread in General Chat, our bikes run 'closed loop', i.e., the Motronic determines how much fuel to deliver, not only by factors such as throttle position, engine speed, and (possibly, I'm not sure..) mass air flow sensor, but also by feed back from the O2 sensor in the exhaust. So, basically, short of installing somthing like the techclusion - which essentially sits between the computer and the injectors and massages the signals to the injectors - or sensor/computer/injector failure, there's nothing you can do to screw up the mixture. Well, maybe messing with the TPS adjustment, but that comes under the 'very advanced' category, and I don't think you'll ever find a need to adjust that.

Since yours is brand new, I'm guessing you haven't even done the 600 mile service, yet. You may want to just not worry about any of this until after that has been done (both the valve adjust and the TB sync can, and I believe should, be done at that time). I suppose you could be planning on doing that yourself, but conventional wisdom (for what THAT's worth... ;) ) suggests it's best to just let BMW do that one service.
yes BMW did that service , the bike is now nearly a month in my hands with just over 1100 miles on clock , I'm finding it good with a good engine , I'm not planning to fiddle about with any sensors , I'm a great believer in leaving electronic stuff alone, especially black boxes, everything else I'm ok with.
probably search this site and get a few ideas on what is good and not so good with the bike and what could do with altering.
It's good to know that there are so many people out there with a vast knowledge of the bike between them :Bow:
Cheers guys
Robert

[muser3]

Greetings!
As an owner of a 1980 R100RT airhead, I have used this many times with excellent results. And now I'm ready to adjust the valves and balance the TB'S on my 1994 R1100RS. In theory this should be the very best method because it compares and balances each TB with the other. I have used ATF in mine for years and it is about right for me. BTW, this little gem also works great with my older Honda GL1000. Thanks for affirming that is is good for the RS.
Muser 3