First time TBS question

[moshe_levy]

All-

 

Today I whipped out my new Twinmax, adjusted the valves, and attempted a TBS on my GF's '04 R1150R. The valve adjustment was straightforward, but the TBS less so. I used the "TBS for Dumnmies" article from advrider for reference.

 

Upon initial inspection, the right hand Big Brass Screw was "normal" at 1.5 turns to seat. The left, on the other hand, was barely 0.4 turn before seating. Instructions said a deviation of more than 0.5 turns is uncommon and cause for concern.

 

Synching at idle was easy enough. But at 3-4k revs, the best I could do was get the needle to waiver between "1" and "2" to the right on the Twinmax. Everything would zero back out at idle. I could not get it to zero out no matter what I tried at revs, though. Admittedly, I gave up after about 30 minutes, and there's plenty of time to get it right before the big trip in May, but I'm wondering:

 

1) Why the disparity on the Big Brass Screw position? Last TBS was at the 6k mark and done by the dealer.

 

2) What am I doing wrong?

 

As I left it, I had messed with the Brass Screws and right hand throttle cable to the point where both Brass Screws at 1.5 turns out. It's definitely better all around than when I first started, but not perfect yet. Any help appreciated.

 

-MKL

[Jim Moore]

Are your butterflies rseting against the stops when you are at idle? You should be able to hear a loud click on each side of the bike as you roll the throttle closed.

[moshe_levy]

Will check and see...

 

-MKL

[T__]

 

All-

 

Today I whipped out my new Twinmax, adjusted the valves, and attempted a TBS on my GF's '04 R1150R. The valve adjustment was straightforward, but the TBS less so. I used the "TBS for Dumnmies" article from advrider for reference.

 

Upon initial inspection, the right hand Big Brass Screw was "normal" at 1.5 turns to seat. The left, on the other hand, was barely 0.4 turn before seating. Instructions said a deviation of more than 0.5 turns is uncommon and cause for concern.

 

Synching at idle was easy enough. But at 3-4k revs, the best I could do was get the needle to waiver between "1" and "2" to the right on the Twinmax. Everything would zero back out at idle. I could not get it to zero out no matter what I tried at revs, though. Admittedly, I gave up after about 30 minutes, and there's plenty of time to get it right before the big trip in May, but I'm wondering:

 

1) Why the disparity on the Big Brass Screw position? Last TBS was at the 6k mark and done by the dealer.

 

2) What am I doing wrong?

 

As I left it, I had messed with the Brass Screws and right hand throttle cable to the point where both Brass Screws at 1.5 turns out. It's definitely better all around than when I first started, but not perfect yet. Any help appreciated.

 

-MKL

 

 

MKL, there are a few possible reasons that those brass screws cold have a different base settings to achieve a decent balance..

 

*Either or both brass screw tips or corresponding throttle body seats could be coked (carboned) up therefore altering the air flow through those passages__ Just pull both brass screws & clean their tips & the seats in the throttle bodies with carb cleaner,, then re-set to 1.5 turns out,, then re-check the balance on a hot operating engine..

 

*You could have a leaking intake boot between the throttle body & cyl head__ Check the clamps for being tight.. You might also use an Unlit propane torch & play the propane around the intake boot area,, if the idle speed improves look for an intake leak..

 

*There is always the possibility that you have a worn throttle body throttle plate,, or an improperly centered throttle plate,, or worn throttle shaft bushings,, (or some other reason the base throttle plate setting or base air flow is incorrect)..

 

*I know it’s mentioned above but BE SURE that BOTH throttle body throttle plate arms are returning SOLIDLY to their idle stop screws..

 

*It’s also possible you have one cylinder pulling harder than the other (you already checked the valve lash),, maybe also run a hot engine compression test or a quick leak down test..

 

*Make darn sure your twin max is set up correctly.. Try swapping the hoses side to side to see if the balance readings remain the same.. Personally I don’t use a twin max as I like to use a Delta U-tube type inches of H2o set up as the accuracy is better in my opinion..

_______________________________________________________________________

--- As for the difference in adjustment at idle vs. mid throttle?

 

_The brass screws are ONLY for base idle balance,, the throttle cable barrel adjusters are used for mid throttle range balance.. Make sure there is throttle cable slack at hot base idle, then set the IDLE balance with the brass screws.. Then run at 1000, 2000, 3000, 4000 RPM’s & set the mid range balance using the throttle cable barrel adjuster(s).. Try to get the best balance at all RPM ranges (could take some give & take to get it close through ALL the mid RPM ranges..

 

You Ask____________________________----

 

1) Why the disparity on the Big Brass Screw position? Last TBS was at the 6k mark and done by the dealer.___

 

*See the list above + possibility it could even be something I forgot to mention..

 

2) What am I doing wrong?___

 

*Look for intake leaks,, tight throttle cables,, worn throttle plate shaft bushings,, coked up brass screw tips,, improper twin max initial set-up,, basic engine power on each cylinder..

 

As I left it, I had messed with the Brass Screws and right hand throttle cable to the point where both Brass Screws at 1.5 turns out. It's definitely better all around than when I first started, but not perfect yet. Any help appreciated.__

 

*Make darn sure you didn’t use the throttle cable adjustment to make the idle balance (the BOTH need to be loose at base hot idle..

 

Twisty

[ShovelStrokeEd]

*Make darn sure you didn’t use the throttle cable adjustment to make the idle balance (the BOTH need to be loose at base hot idle..

 

In point of fact, they should not be loose, but rather at zero tension, zero clearance, kinda like a solid lifter HD pushrod. To be frank, even though I'm Ed most days, I leave just a little, tiny bit of play in them.

 

Excellent advise otherwise.

 

 

Missing the days when I could synch a pair of carbs with two swizzle sticks.

[philbytx]

And don't sweat getting the idle perfect either. You need to focus on it running sweetly between 3 and 4k which is where most of your steady state stuff will be. I synched mine at 1k intervals up to 6k using my Throttlemeister and focussed at 3k 3.5k and 4k. Mine idles around 1200 with an occasion hiccup.....