Changed Throttle Body-Need Help With Idle/Power

[99RTVET]

Bike was running good after last service (rebuilt HES, valve clearance, spark plugs, fuel filter, new battery, belt ect). I had no service history, so I figured I must do everything with the bike at 50,000 miles. The only thing left to do besides spline lubing was to sync the throttle bodies, but the left throttle body brass screw was frozen from being bottomed out by previous owner (likely bimetallic corrosion). The screw stripped trying to break it free/extract, so I had to replace the throttle body with another used one from an r1100rt off eBay. I cleaned it up/inspected and transferred all the parts over then tried to synchronize.  I couldn't get it balanced, so I tried "Throttle Screw and TPS Adjustment" by Stephen Karlan then a throttle sync which worked since I figured the TPS was incorrect and the replacement throttle body throttle idle set screw was likely adjusted differently. Now the engine is smoother running like before, but it is still hard to start / dies at idle. The engine is lethargic with poor throttle response when I ride it. I pulled fuse 5 from left to reset Motronic, and I have tried adjusting idle TPS wire 1 voltage from .370 to .390 with no improvement. When the bike is warm, it will idle at 1100-1200 rpm. I also noticed the choke lever seems to do nothing unless I hold it fully on past the stop, but even then it does little to increase idle. Does anyone have suggestions at what to do? 

[dirtrider]

41 minutes ago, 99RTVET said:

Bike was running good after last service (rebuilt HES, valve clearance, spark plugs, fuel filter, new battery, belt ect). I had no service history, so I figured I must do everything with the bike at 50,000 miles. The only thing left to do besides spline lubing was to sync the throttle bodies, but the left throttle body brass screw was frozen from being bottomed out by previous owner (likely bimetallic corrosion). The screw stripped trying to break it free/extract, so I had to replace the throttle body with another used one from an r1100rt off eBay. I cleaned it up/inspected and transferred all the parts over then tried to synchronize.  I couldn't get it balanced, so I tried "Throttle Screw and TPS Adjustment" by Stephen Karlan then a throttle sync which worked since I figured the TPS was incorrect and the replacement throttle body throttle idle set screw was likely adjusted differently. Now the engine is smoother running like before, but it is still hard to start / dies at idle. The engine is lethargic with poor throttle response when I ride it. I pulled fuse 5 from left to reset Motronic, and I have tried adjusting idle TPS wire 1 voltage from .370 to .390 with no improvement. When the bike is warm, it will idle at 1100-1200 rpm. I also noticed the choke lever seems to do nothing unless I hold it fully on past the stop, but even then it does little to increase idle. Does anyone have suggestions at what to do? 

 

Morning 99RTVET

 

You have a LOT going there with a number of things done at one time.

 

So that makes it difficult to figure out what (or what's) went wrong in the entire process (especially over the internet).

 

First question is, did you install the CORRECT throttle body? Does the bore size & casting numbers match the old one?  

 

Next, is your voltmeter that you  used for setting the TPS accurate enough, &  high quality enough, that it doesn't load the circuit & skew the voltage output?

 

Does the throttle cam on the throttle body look exactly like the one on your removed throttle body?

 

Do you have some cable slack in the short cables to each TB at choke-off base idle??????

 

If all above is accounted for then see if both side throttle plates/cams reach the wide open throttle stop at the  EXACT same time when using the twist grip.

 

Next, see if both side throttle plates/cams lift off of base idle screw throttle stop at the  EXACT same time when using the twist grip.

 

On the choke (fast idle) lever not working at normal 'ON' setting, there an adjuster in the choke cable up near the lever area so you can slide the boot down then adjust to  lengthen the cable outer sheath & that will increase choke function for starting & fast idle.   

 

If still no smoking gun found then maybe remove the new throttle body & make sure that the throttle plate is properly centered & is installed facing the correct direction & orientation.

 

If all else fails then you might be able to get the BBS screw out of your old TB  as it is probably just stuck on a dry corroded "O" ring.

If there is any flat surface left then drill a couple of holes in the screw head, then modify a screwdriver to have matching prongs that match those drilled holes. (once you get a fit) -- Then use a small pinpoint torch to heat (just) the BBS screw head (hot) then as it cools add some penetrating oil (might have to do this a few times).

 

Then heat it one more time & try removing it.

 

If the BBS screw is really torn up then use the BBS out of your  replacement TB as an example then drill the broken BBS as deep as possible to take an easy out, then do the above pinpoint torch/ penetrating oil thing & try to remove it.

 

We can probably guide you more on solving your runability problem but will need more exact info as you check & re-check what you have done. It shouldn't be difficult to solve but we need a definite direction as to what to address  what is already verified .    

 

  

[99RTVET]

Definitely more going on than I would like. Thanks for the reply. I only swapped the throttle body, and the bike was running great before doing that. Unfortunately I was an idiot, and I did not hold onto the old throttle body after taking it off. I did try most of what you suggested but the brass bypass would not budge and shredded.  I did compare them side by side and they appeared exactly the same, but I did not micrometer the bore. It was off an 2001 R1100RT and mine is a 99. I took a picture of the casting in case someone has a 99 to compare to. My voltmeter should be a good quality, it is made by Gardner Bender and measures to millivolts. There is cable slack on both throttle cables. Both cables move at the same time and the cams both click onto the base idle screw at the same time. I didn't adjust anything for the choke cable, so I am wondering why that is not working now. 

[dirtrider]

1 hour ago, 99RTVET said:

Definitely more going on than I would like. Thanks for the reply. I only swapped the throttle body, and the bike was running great before doing that. Unfortunately I was an idiot, and I did not hold onto the old throttle body after taking it off. I did try most of what you suggested but the brass bypass would not budge and shredded.  I did compare them side by side and they appeared exactly the same, but I did not micrometer the bore. It was off an 2001 R1100RT and mine is a 99. I took a picture of the casting in case someone has a 99 to compare to. My voltmeter should be a good quality, it is made by Gardner Bender and measures to millivolts. There is cable slack on both throttle cables. Both cables move at the same time and the cams both click onto the base idle screw at the same time. I didn't adjust anything for the choke cable, so I am wondering why that is not working now. 

 

 

Afternoon 99RTVET

 

That choke cable works through the Bowden (splitter) box so if you adjusted on the short cables at TB's then that can effect the choke cable adjustment vs operation.