New cable adjustment

[mylovelyhorse]

Afternoon all,

So I've installed new cables on my 1999 R1150GS - all four cables, in fact. I have balanced things to that both throttle bodies open at the same time and there is a small amount of slack movement at the twist grip.

I have two problems:

1. the bike feels a bit buzzy still, like it is very slightly unbalanced

2. the fast idle still doesn't raise the idle when cold at all - or when warm, in fact

I've gone over the adjustment several times now and whilst there must be a problem, I'm blowed if I can see what it is.

I've replaced the 'o' rings on the throttle bodies and I'm sure there's no air leaks now, so that's one possibility ruled out.

Any ideas?

 

[Trullion]

Have you checked that the cables move slightly at the throttle body end when you put the 'choke' lever on, and again a bit more when you put on the second setting (i.e. is the 'choke' lever actually holding the throttle open a little bit? -'cos if it isn't it won't do anything. Forgive me if I'm stating the obvious, but I don't know what you know, if you see what I mean.........

 

[MartinL]

How did you check synchronisation / balance? Did you use vacuum gauges? Just checking the throttles move at the same time by feel or sight isn't really good enough. Also what prompted the cable & O ring change? Were you having any running issues before?

 

[MattW]

Just a thought, but how about pulling back the inlet ducts between the TB and airbox (not sure whether you've an 1100 or 1150, but very quick on an 1100). Then operate the cold start lever while watching the butterfly you can now see. This'll tell you if the cable is actually doing anything?

 

[mylovelyhorse]

How did you check synchronisation / balance?

Yes well I thought so but seeing what you have written below makes me wonder.

Did you use vacuum gauges?

Yes. Just a tiny difference between left and right that stays the same through the rev range

Just checking the throttles move at the same time by feel or sight isn't really good enough.

So if I have got them balanced by the vacuum gauge, and the slack is enough to allow the throttle to work without being jerky, what else should do?

Also what prompted the cable & O ring change?

86,000 miles, a thick coat of Russian dust & grime and a throttle that needed the arms of a bodybuilder to open. As for changing the o-rings, I couldn't find the old ones from when I took things apart to replace the gearbox, so I put new ones in.

Were you having any running issues before?

None that wouldn't have been solved by a service. ObAnd a knackered gearbox that I swapped out but that's a different matter.

 

[mylovelyhorse]

Have you checked that the cables move slightly at the throttle body end when you put the 'choke' lever on, and again a bit more when you put on the second setting (i.e. is the 'choke' lever actually holding the throttle open a little bit?

Yes and this is exactly the problem - putting the 'choke' on first setting doesn't move the throttle body ends at all & 2nd setting only barely. Adjusting the slack on the cable a lot or a little makes no difference to this at all.

 

[littleredrooster]

Yes and this is exactly the problem - putting the 'choke' on first setting doesn't move the throttle body ends at all & 2nd setting only barely. Adjusting the slack on the cable a lot or a little makes no difference to this at all.

You've got not enough slack in the top part of the cable and too much in the two lower parts. The large 'wheel' in the splitter assembly is therefore in the 'wrong' place to be moved by the cam inside there.

 

[mylovelyhorse]

You've got not enough slack in the top part of the cable and too much in the two lower parts.

Ahhh. Right, I'll have another go. Currently have not much adjustment taken up on the lower cables & only a bit of slack in the top cable.

Cheers

 

[mylovelyhorse]

You've got not enough slack in the top part of the cable and too much in the two lower parts. The large 'wheel' in the splitter assembly is therefore in the 'wrong' place to be moved by the cam inside there.

And that was exactly what it was. Now sorted. Many thanks indeed