TB major clean procedure?

[twins4life]

I want to reset the TB's, clean the insides and clean the brass idle air screw. I dont want to reset the TPS because my Fluke 87 is 12 years old and I dont trust it to the mV range.

Proposed steps:
1. Remove and clean the TBs.
2. Remove and clean the brass screws, reinstall to 1.5 turns out.
3. Warm engine and set idle speed to 1100 and balance using BOTH of the throttle stop screws (not the brass screws at this point)

Any thoughts?

TIA

 

[kbasa]

I want to reset the TB's, clean the insides and clean the brass idle air screw. I dont want to reset the TPS because my Fluke 87 is 12 years old and I dont trust it to the mV range.

Proposed steps:
1. Remove and clean the TBs.
2. Remove and clean the brass screws, reinstall to 1.5 turns out.
3. Warm engine and set idle speed to 1100 and balance using BOTH of the throttle stop screws (not the brass screws at this point)

Any thoughts?

TIA

Don't mess with the throttle stop screws. Use the brass screws. That's what they're for.

Leave the TPS alone.

Balance at idle by adjusting the brass screws, then balance at 3 or 4K using the cables.

 

[ANDYVH]

I just did my TBs on my 94 R1100RS. I got the TB loose (careful not to mess up the cable routings) and used an alcohol based cleaner with rags and swabs to physically clean the TB throats and throttle plates.

Make sure you actually clean the throttle plates. After time they can build up a grime edge around the perimeter that can cause the bike to stumble and die at idle, like mine used to do.

Before you take out the air bleed screws (big brass ones), turn them in, clockwise, until they lightly seat and note the numbers of turns. Then, remove each one and clean it and the passages with carb cleaner.

Then balance the TBs per normal guidelines. I just use mercury sticks (manometer) to do mine and its nice and smooth again, idles at 1050.

 

[twins4life]

Thats what I want to do. I used to clean the TB on my truck every yeay and the idle would be much smoother.

I'm still confused on the throttle stop screws. I understand about leaving the TPS alone, but what is wrong with setting both brass screws to 1.5 turns and using the throttle stop screws for a baseline 1100RPM and equal vacuum on both sides (Twinmax)?

No arguement here, just trying to understand.

TIA

 

[kbasa]

Thats what I want to do. I used to clean the TB on my truck every yeay and the idle would be much smoother.

I'm still confused on the throttle stop screws. I understand about leaving the TPS alone, but what is wrong with setting both brass screws to 1.5 turns and using the throttle stop screws for a baseline 1100RPM and equal vacuum on both sides (Twinmax)?

TIA

Because that's why the brass screws are there. You start with them at 1.5 turns and then adjust them for an even idle with your stix or twinmax. Why complicate things by getting two settings out of whack?

 

[BOKRIJDER]

TIA

I see your thought line, but I think the factory procedure is otherwise. If you need, I'll get my CD, review the procedure, and PM you. Heads up, my factory CD is for a GS.

Motard

 

[twins4life]

Because that's why the brass screws are there. You start with them at 1.5 turns and then adjust them for an even idle with your stix or twinmax. Why complicate things by getting two settings out of whack?

Because over the last 10 years wear may have occured.

I would welcome OEM guidelines.

But if leaving the throttle stops alone is best, so be it. I'm trying to correct a slight surging issue.

 

[mtboulder]

Thats what I want to do. I used to clean the TB on my truck every yeay and the idle would be much smoother.

I'm still confused on the throttle stop screws. I understand about leaving the TPS alone, but what is wrong with setting both brass screws to 1.5 turns and using the throttle stop screws for a baseline 1100RPM and equal vacuum on both sides (Twinmax)?

No arguement here, just trying to understand.

TIA

If you adjust your left throttle stop screw you will change the TPS setting (which you said you are trying to avoid). If you mess with the throttle stop screw you will more than likely have to do the zero = zero procedure on the IBM Internet Riders website to get everything set up correctly. You'll need a good volt meter to do that.

 

[ANDYVH]

this is what I got from our local forum BMW guru, Paul Glaves:
1) Turn the Air Bleed screws (the big brass ones) in and note the number of turns to seat each one. Then take them out and clean the screw and the port. Then turn them in to the original position you noted.
2) Make sure the throttle cables have enough slack such that both throttle cams are resting against the throttle stop/idle adjust screws.
3) Attach the Twinmax or mercury sticks to the TB vacuum ports and note which is showing the lowest vacuum with the bike idling at about 1000 rpm. Adjust the lower one to match the other, by turning the throttle stop/idle speed screw as required. The idle speed will drop as vacuum comes up
4) Now adjust the Air Bleed screws to fine tune/match the vacuum of each TB, and the idle speed should be about 1050 to 1100 rpm.
5) Finally, lock the throttle for a speed about 1500 to 2000 rpm and use the throttle cable adjuster barrels at the TB to match each side for vacuum.

I did this and my bike idles great and has smooth throttle response, and is nice and smooth on the road at speed. It took me aobut 1/2 hour to get this done. Make sure you have a big window box fan blowing at the front of the engine as you do this to avoid overheating it. Good luck!

 

[twins4life]

The main reason I wanted to reset / check the throttle stop setting is mechanical wear. All things mechanical wear and on a 10 yr old machine, resetting the primary idle speed and balance via the TB seemed like a good idea. The brass screws only make minute adjustments and can only compensate for a small amount of imbalance (if any exists).

Seemingly not...

So, I'll stick with the brass screws

 

[ANDYVH]

I should correct step one of my earlier reply.

Turn the air bleed screws in and note the number of turns to lightly seat the screws. Take them out and clean the screws and the ports with carb cleaner. Then, turn the screws back in to the port until they lightly "seat", then turn each one out 1/4 turn (not back to the original position).

Now you are ready to begin balancing the TBs with the other steps I mentioned.

 

[DrPaul]

I would suggest applying a light coat of anti-sieze paste to the threads of the Big Brass Screws before reinstalling.

Paul