1100 throttle stop / tick over problem

[Hambo]

After replacing my worn throttle body shafts on my '95 1100 GS with new shafts from Bing, I reset the TPS to 370mV, balanced the bodies and all was ok; tick over at 1100rpm, smooth running, etc. This was conducted in Santiago, Chile which I'm guessing is less than 1000m (3000ft) altitute.

Heading up into the mountains, i.e. 2000m+, tick over became an issue, i.e. it wouldn't tick over, but at higher revs ran well. I was lead to understand the motronic system compensates for altitute therefore tick over should not be a problem. After all, we're not looking at extreme altitutes of 5000m, etc. I then rechecked the TPS was set to 370mV, removed the 5th fuse and twisted the throttle twice to reset the motronic. Tick over was obtained once again. However this didn't last for long, later that day returning to no tick over.

Thinking I'd disturbed the factory set up by changing the shafts, I decided today to sort out this situation and carried out Rob Lentini's "zero-zero" procedure for setting up the throttle bodies, i.e. backed off LH throttle stop, set the TPS to more or less 0mV (6mV), wound in the stop screw until 370mV was obtained, attempted to balance the RH throttle stop, etc.

However, after obtaining 370mV on the LH throttle body, I can't get the bike to tick over, therefore can't set the RH throttle body. I've tried adjusting the brass air bypass screws from 0 to 3 turns out with no difference whatsoever.

Am I a twat and missing a fundemental point, or is my TPS (or something else) f**d? As I'm now in north Argentina, about to cross into Boliva next week, it's not as if I can pop into the nearest BM dealer!

Any worthwhile advice would be appreciated.

Cheers, Hambo

PS I'm aware BM stipulate not to touch the throttle stop screws, but needs must!

 

[pomm001]

After replacing my worn throttle body shafts on my '95 1100 GS with new shafts from Bing, I reset the TPS to 370mV, balanced the bodies and all was ok; tick over at 1100rpm, smooth running, etc. This was conducted in Santiago, Chile which I'm guessing is less than 1000m (3000ft) altitute.

Heading up into the mountains, i.e. 2000m+, tick over became an issue, i.e. it wouldn't tick over, but at higher revs ran well. I was lead to understand the motronic system compensates for altitute therefore tick over should not be a problem. After all, we're not looking at extreme altitutes of 5000m, etc. I then rechecked the TPS was set to 370mV, removed the 5th fuse and twisted the throttle twice to reset the motronic. Tick over was obtained once again. However this didn't last for long, later that day returning to no tick over.

Thinking I'd disturbed the factory set up by changing the shafts, I decided today to sort out this situation and carried out Rob Lentini's "zero-zero" procedure for setting up the throttle bodies, i.e. backed off LH throttle stop, set the TPS to more or less 0mV (6mV), wound in the stop screw until 370mV was obtained, attempted to balance the RH throttle stop, etc.

However, after obtaining 370mV on the LH throttle body, I can't get the bike to tick over, therefore can't set the RH throttle body. I've tried adjusting the brass air bypass screws from 0 to 3 turns out with no difference whatsoever.

Am I a twat and missing a fundemental point, or is my TPS (or something else) f**d? As I'm now in north Argentina, about to cross into Boliva next week, it's not as if I can pop into the nearest BM dealer!

Any worthwhile advice would be appreciated.

Cheers, Hambo

PS I'm aware BM stipulate not to touch the throttle stop screws, but needs must!

Try this method

remove brass idle bypass screws , clean carefully esp where they can seat into the TB, put the lightest smear of grease on them and screw gently all the way in until they bottom , this closes the by-pass .
adjust the throttle cable at the twist grip end to tale out any slack, start engine , it will be as rough as old boots, adjust cable to give you a speed that the bike will run (guess about 1200)
when it running at that speed syncronise the TB'S to both give the same reading via the 'dreaded' throttle stops, in theory you should only need to adjust one .
Stop the engine loosen of the throttle cable at the grip to give some play, undo the brass bypass screws about one turn.
Start bike and syncr the TB's and TPS as normal
I used this method on an 1150 and it worked OK not sure if the 1100 is different
you will need to have some fans to cool the engine down with while your doing this as it will get hot quickly

best of luck

 

[Tsiklonaut]

Check your ignition coil, plugs and plug wires too.

Google around the net to find the resistance spec for the primary and secondary spec for the ignition coil. You can measure it with regular multimeter.

Faulty coil can create such problems too.

 

[Tsiklonaut]

Starting prob pt II

This came into my mind too - the simplest hard-starting reason of all - have you checked that the throttle cables are properly seated in?

Look at the pic:

http://www.ukgser.com/forums/showthread.php?t=109856&highlight=throttle+cable

Let us know any updates you have!

 

[Ash]

my 1999 1100 GS also lost it's tickover during my recent trip to the dolomites whenever we went high up.
as did my 1995 r1100RS on three tours of swiss etc'.
so i thought 'they all do that sir'
so any info as to the cause would be handy. .
ps----
when we came down from the mountains all returned to normal.

 

[Vendome 41]

Dirty air filter??

 

[Hambo]

Thanks for the feedback. I should have mentioned valve clearances were checked, K & N air filter cleaned, air bypass screws cleaned and cables confirmed seated before I attempted the zero:zero set up.

Thanks to Pomm001's post, it got me thinking, so I tensioned the throttle cable to create a gap of 0.5m between stop and screw on the left hand side. I then matched the right hand side to the same gap and hey presto, the motor was ticking over.

The bike seems to be running ok now, however tickover is still on the low side, 950rpm or thereabouts. Adjusting the air bypass screws seems to make naff all difference.

Now I can adjust the throttle stop screws equally to obtain a tickover, but then the TPS voltage will increase, i.e. be greater than 370mV. Theoretically no problem, but I've read if the TPS voltage is greater than 400mV when against the stops, the motronic trips to auto-mode (rich), requiring to be re-set by removing the 5th fuse and twisting the throttle twice to reset the TPS. Quite how this works I'm in the dark, as when you open the throttle the TPS voltage increases anyway...

So how can I increase my tick over without tripping the motronic?

 

[pomm001]

Thanks for the feedback. I should have mentioned valve clearances were checked, K & N air filter cleaned, air bypass screws cleaned and cables confirmed seated before I attempted the zero:zero set up.

Thanks to Pomm001's post, it got me thinking, so I tensioned the throttle cable to create a gap of 0.5m between stop and screw on the left hand side. I then matched the right hand side to the same gap and hey presto, the motor was ticking over.

The bike seems to be running ok now, however tickover is still on the low side, 950rpm or thereabouts. Adjusting the air bypass screws seems to make naff all difference.

Now I can adjust the throttle stop screws equally to obtain a tickover, but then the TPS voltage will increase, i.e. be greater than 370mV. Theoretically no problem, but I've read if the TPS voltage is greater than 400mV when against the stops, the motronic trips to auto-mode (rich), requiring to be re-set by removing the 5th fuse and twisting the throttle twice to reset the TPS. Quite how this works I'm in the dark, as when you open the throttle the TPS voltage increases anyway...

So how can I increase my tick over without tripping the motronic?

I think what you have done is a static version of my rough arsed method
by setting the distance on the stops this has given you an idle but with the bypass screws partly open.
If you had have done it with them closed and balance the TBS your idle would have come right.
When i did mine and reset the idle balance on the bypass screws, in there set position they were almost in identical positions,which made me feel assured,like yours,before i did this the bypass adjustment made almost no difference,your almost there