Tb question

Jiffy176

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I've just taken both tbs off to have them refurbed. Whilst taking the cables off the right I noted that in resting position the butterfly wasn't touching the stop.

It appears that previous owners have just tried to balance by adjusting the rh side only as the left was very hard to unlock the adjuster screw was stiff. The rh side had been adjusted up considerably. This seems to explain a lot of things.

My question is when they come back what's the best base setting for the brass screws and the stops. Should there be any play in the throttle cables when properly set up. Logic says there should be slight as long as the cables pull together
.
I was thinking of turning both stops about 2 turns in to start with both cable adjusters with a little bit of slack, then set the tick over using brass screws. I have a harmonizer. Then balance up tbs from there adjusting cables as need be. Once balanced then adjust stop screws so the spindle rests properly.

Does this sound about right. Anyone give some good advise on installing tbs from scratch?

Thanks all.
 
Jiffy176 said:
I've just taken both tbs off to have them refurbed. Whilst taking the cables off the right I noted that in resting position the butterfly wasn't touching the stop.

It appears that previous owners have just tried to balance by adjusting the rh side only as the left was very hard to unlock the adjuster screw was stiff. The rh side had been adjusted up considerably. This seems to explain a lot of things.

My question is when they come back what's the best base setting for the brass screws and the stops. Should there be any play in the throttle cables when properly set up. Logic says there should be slight as long as the cables pull together
.
I was thinking of turning both stops about 2 turns in to start with both cable adjusters with a little bit of slack, then set the tick over using brass screws. I have a harmonizer. Then balance up tbs from there adjusting cables as need be. Once balanced then adjust stop screws so the spindle rests properly.

Does this sound about right. Anyone give some good advise on installing tbs from scratch?

Thanks all.
Click to expand...

I'd be interested to read what people have to say about this. As I understand, the TB throttle stops are factory set on a flow bench and should never be touched when doing a routine TB balance. However, not all owners (or indeed mechanics) know this and they are sometimes buggered around with. The only solution I've read about is the dreaded 0=0 procedure but those who know (including Steptoe on here) say it's a nightmare waiting to happen.

My interest stems from a previous owner having buggered around with the stops on my 1100 making it impossible to achieve a perfectly even tickover.
 
I recon as long as you don't move the throttle position sensor, and have a little slack cable when refitted, then balance the other side to it. both need some slack cable at idle, but should have the same vacuum readings at around 2000rpm. Woks for me :blagblah
 
Matt.
Problem is that the right pot was never resting on a stop. The throttle cable was always holding it open to some degree and there was no slack at all in the throttle cables on the right.
This to me doesn't sound right.
I thought the tickover was controlled by a small amount of mixture being Let through by the brass screws?

Duck. Your option makes sense to me but I'm sure someone with practical knowledge will blow me out of the water. I think I will set rests at a point get tick over sorted then go for a balance and take it from there.
Any other suggestions welcome.
 
This is what Haynes says!

a3esa7em.jpg


It mentions the two limiter screws on the inner face of the throttle pulley as being ones not to touch! Not throttle body cable adjusters.

It must be possible to setup correctly. If it wasn't possible outside the factory how would the cables get changed successfully?

And no, I'm not saying this is the way to do it!

Also, Didn't Steptoe offer Mr Magic Fingers an opinion on this a while back?

http://www.ukgser.com/forums/showthread.php?t=267329&highlight=magicfingers

Hardest thing for me is getting the locknuts tightened on the throttle body cable adjusters without mucking up the balance:) Good luck with it anyway!
 
Oh booh looks like I may have broke it then.
When back I will pop stops back in and set at an equal amount in. Then set all cables with slack and try and sort out the tick over.

I'm wondering if I set the left. See how it goes adjust the right to the left or see if i can balance with the brass screws Then check the TPS voltage as the butterfly position will have changed will it or not? If I have got a good tick over and all seems ok then check tps level resetting if needed.

Then do a tb sync at revs.

Won't get to play for a couple of weeks Things that worry me.
Getting tickover again as i have moved the rest screwd and has the rh cable stretched too far.
I guess only time will tell.
 
Jiffy176 said:
. Once balanced then adjust stop screws so the spindle rests properly.
Click to expand...



Do not touch the stop screws.
Everything that needs to be done to set up the throttle bodies perfectly can be done using the big brass screws and the cable adjusters. The more things you introduce that need adjusting and balancing just makes a simple job more difficult.

You must have slack in the cables to adjust the idle. Then adjust the cables to get the off idle balance spot on.
Adjust whatever cable you need to that will still give you play, if you know what i mean - - i.e. don't adjust a cable so you have no slack, adjust the other cable so that it has more.
 
The problem is I've been a numpty and Moved the stop screws so that's why I think I may have cocked it up. I fear finding tickover may be a mare.

I understand what you say about adjusting tb Neil. Clearly previous owners have just tightened the rh cable removing all slack and actually opening the slide slightly. When I reassemble will follow your procedure.

Ho hum.
 
nemura5e.jpg
This a photo of the underside of one my throttle bodies. It shows the stop screw.

Just thought I'd stick a picture up in case it helps positively identify the throttle stops... Their not cable adjuster locknuts!
 
Hi yep that was what I was talking about. I
Have moved both doh!
However my rh tb was adjusted so much that it wasn't resting on the stop.
I'm going to use volts on the tps to set the lh stop as I know the tps is set right then use the depth of the stop pin as a starter for the right and go from there when I put it back together.
 
Street. Brilliant link thanks. Popped the left tb back on and followed the procedure as described. The tps and stop is now set within range. That's all I can do until Vern has done the tbs for me and I can then reset the brass screws and follow the rest of the procedure.

All thanks so far for your help and comments.
Jiff.
 
My tb's are still with Vern as there has been some issues with getting the parts , so no I'm affraid. Though after my initial concerns I've read a lot on the 0-0 process and am fairly confident I can do it.
I adjusted the lh side with the tps on my multimeter before they went away to the correct reading. When they come back I just need to check the voltage, though Vern tells me he has a habit of putting them back exactly. Then I will set the tick over up using the harmoniser and go from there.

I suppose what I could do with is a base setting for the brass screws. I will report back when there is news.
 
Ok tbs are back all reworked. I reinstalled with new orings every where and reset the tps as I had done before I sent the bodies off using the zero zero procedure.
I hooked up my harmonizer and fired the bike up. The right pot was running far too high, so I wound the stop screw out until the harmonizer was showing balanced. This was about 950 rpm. I made sure the throttle was on the stop and not on the cable and locked off the stop screw. I then adjusted the rpm back up with the brass screws to around 1150.
So far the bike ticks over fine. I blipped it a few times and everytime it returned to balanced and would tick over ok.
Next job it to complete the TB sync at revs and then test ride.
So far touching wood but she ticks over.
 
Final result.

I was about during the day today so decided to to finish the job. I started with a tb balance. The first thing I noticed is how much easier it was to balance up. The harmonizer as those of you who have one will know measures the smallest difference once I got close a little fine tuning and careful lock nut tightening and we were there. Access to my lhs adjuster is made difficult by the crash bar rod so once I got close I did the minor adjustments with the rhs. Before when balancing I could never get the gauge to sit in the middle no matter how hard I tried. Now this was possible. I set first at 2k and then at 4 as between 2 and 4 k there was some vibration that was annoying.
Then took the bike for a test ride down to the next mway junct which is about 5 miles.
The bike is as smooth as it has ever been cruising and obviously quieter with the tbs not rattling.

Big thanks to Vern for the refurb. What a smashing guy.

For anyone who has adjusted or is thinking of adjusting the stop screws. Don't if you don't need to. But if you have the right tools namely voltmeter and vacuum gauges then it is possible to reset without too much bother. Fwiw my brass screws are now at about one and a quarter turn out each and within a quarter turn of one another. The main thing here is time. Don't rush I did mine over an evening a couple of hours here and there.

The bike runs like a dream again. Thanks to all that pointed me in the right direction to follow the procedure.
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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