TB balance from scratch?

[MattW]

1100GS, one piece throttle cable.

I've had my throttle bodies re-bushed and rebuilt by Steve Scriminger and yesterday bolted it all back together with a new throttle cable.

As soon as I've made a new manometer (robbed a big chunk of the tube for another 'emergency' ...) I'm going to try to get them balanced and I'm hoping the end result will be better than when I last tried it (could never get it perfect, hence the rebuilt TB's and new cable).

However, I'll have to start from scratch with a stone cold bike and have no idea what the correct initial settings for the air screws etc should be. With new shafts bushings and ultrasonically cleaned TB's, I'd imagine the settings will be quite different?

My sort of plan of action was as follows:

• Set the TPS
• Get the slack out of the throttle and choke cables and get them as near as I can by feel.
• Set the air screws about 1.5 turns out (more or less their old settings).
• See if it'll start and run.
• If it does run and is rideable, go for a quick spin to warm it up and then do a TB balance (setting a 'balanced' idle speed using the air screws).
• If it won't run, swear a bit and try to work out why.

Is this the right sort of procedure for a start from scratch situation like this?

I hope that Steve will have reset the butterfly throttle stop screws when he rebuilt the TB's but I won't find out until I try the idle balance (and see if the air screws end up wildly different). If they need alteration is there any way to set them without a flow bench?

Any advice gratefully received

 

[DrFarkoff]

My sort of plan of action was as follows:

• Get the slack out of the throttle and choke cables and get them as near as I can by feel.
• Set the TPS
• Set the air screws about 1.5 turns out (more or less their old settings).
• See if it'll start and run.
• If it does run and is rideable, go for a quick spin to warm it up and then do a TB balance (setting a 'balanced' idle speed using the air screws).
• If it won't run, swear a bit and try to work out why.

Set cable slack before TPS in case it's hung up slightly

 

[MattW]

[/LIST] Set cable slack before TPS in case it's hung up slightly

Thanks Jaythro.

 

[uncle dick]

Fit the later cables and splitter box

 

[MattW]

Fit the later cables and splitter box

Thanks but that's not going to happen (at least not yet...) - I'll stick with the one piece cable for now. I'm fairly sure that my previous problems getting it to balance properly were at least partly due to slop in the throttle spindles (and possibly air leakage past them) which made it nearly impossible to get repeatable settings off idle.

 

[Gundog]

Get someone who knows what they are doing to do it for you......

 

[MattW]

Get someone who knows what they are doing to do it for you......

Inspirational as ever

 

[Trullion]

Thanks but that's not going to happen (at least not yet...) - I'll stick with the one piece cable for now. I'm fairly sure that my previous problems getting it to balance properly were at least partly due to slop in the throttle spindles (and possibly air leakage past them) which made it nearly impossible to get repeatable settings off idle.

I had the r/h side one re-bushed on my 1100RS a while ago. It also has the single throttle cable. Now back together it runs much more smoothly than it did and I balanced the throttles without difficulty, even with the old cable. The awful clacking noise on the r/h side (why I had the body re-bushed) has disappeared completely.

Not sure why you want SED (whom I also used) to have adjusted the throttle stop. I hope he didn't touch mine (or if he did, that he left it in the same position he found it). I have never adjusted the throttle stops on my RS or GS.

 

[MattW]

I had the r/h side one re-bushed on my 1100RS a while ago. It also has the single throttle cable. Now back together it runs much more smoothly than it did and I balanced the throttles without difficulty, even with the old cable. The awful clacking noise on the r/h side (why I had the body re-bushed) has disappeared completely.

Not sure why you want SED (whom I also used) to have adjusted the throttle stop. I hope he didn't touch mine (or if he did, that he left it in the same position he found it). I have never adjusted the throttle stops on my RS or GS.

After a quick email today, Steve has confirmed that he didn't touch the throttle stops (they still have the paint blob seals on them). My concern was that removal of the butterfly and the new shafts he makes would have changed the butterfly rest positions (due to manufacturing tolerances etc) even with the stops being untouched.

However, I just had a quick play and adjusted the cable by feel, set the TPS and it started fine - rough at idle, but I only guessed the air screw positions. So, when I get some proper time, I'll go for a spin and do a proper balance. I guess that'll tell me about throttle stops

 

[Wrigsby1]

My way is...

Roughly set cable slack but still with slack.

Set brass scews to 1 1/2 turns (although this may change).

Set TPS.

Warm bike up.

Get throttle pick up to desired slack (but keep some slack).

Set RH TB to balance to LH TB at higher revs.

Fine tune brass screws to desired tickover.

Recheck TPS.
Done

All this can be rechecked and rechecked but keeping slack in initial throttle pick up or you will "fool" the TPS.

I always make sure that both stop screws still audibly snap back into position.

 

[MattW]

My way is...

Roughly set cable slack but still with slack.

Set brass scews to 1 1/2 turns (although this may change).

Set TPS.

Warm bike up.

Get throttle pick up to desired slack (but keep some slack).

Set RH TB to balance to LH TB at higher revs.

Fine tune brass screws to desired tickover.

Recheck TPS.
Done

All this can be rechecked and rechecked but keeping slack in initial throttle pick up or you will "fool" the TPS.

I always make sure that both stop screws still audibly snap back into position.

Thanks

You gave me good advice regarding this a few months ago but I couldn't get balance as good as I wanted (hence the TB rebush and refurb). I'll see how things work out this time around...

 

[Kenny]

Here ya go Matt

http://www.ukgser.com/forums/showthread.php?t=258320

 

[MattW]

Here ya go Matt

http://www.ukgser.com/forums/showthread.php?t=258320

Ooh ya bugger

Too late now - I've just had Steve S redo my throttle bodies - can't afford to give him another pot of money just yet