Whats this wire? Throttle body rebuild

[jacksdad63]

Hi, after rebuilding the throttle bodies I've 2 issues....

First, easy one: where does this black wire really go? 

Second: When restarting the bike, the Right cylinder wasn't firing, but when I just touched the Left throttle cable, at the body, the RH cylinder fired. I 'wiggled' the LH cable back and forth and the RH again cut out/revved away. I've finally managed to get the bike running well, but the throttle bodies just won't balance level on idle. 

I'm using Carbtune Pro gauges, turned upside down as instructed, the bikes running well, should I just leave it as is? Bikes done 67k miles. I'm waiting on the injector upgrade kit to be delivered so will be doing the balance/set up again and hope I'm doing the job correctly! 

[dirtrider]

54 minutes ago, jacksdad63 said:

Hi, after rebuilding the throttle bodies I've 2 issues....

First, easy one: where does this black wire really go? 

Second: When restarting the bike, the Right cylinder wasn't firing, but when I just touched the Left throttle cable, at the body, the RH cylinder fired. I 'wiggled' the LH cable back and forth and the RH again cut out/revved away. I've finally managed to get the bike running well, but the throttle bodies just won't balance level on idle. 

I'm using Carbtune Pro gauges, turned upside down as instructed, the bikes running well, should I just leave it as is? Bikes done 67k miles. I'm waiting on the injector upgrade kit to be delivered so will be doing the balance/set up again and hope I'm doing the job correctly! 

Morning  jacksdad63

 

It connects to the bottom of the L/H throttle body. 

 

On the throttle cables?-- Make darn sure that both throttle cables are FULLY seated in their adjuster cups at the throttle body. 

 

You didn't say if an 1100 or 1150 but if an early 1100 (single cable) do not use the choke to start engine before doing a TB balance as that skews the cable on the L/H side throttle body.  Fully open & close the throttle using the twist grip before doing your TB balance. 

 

On the Carbtune?-- Personally I don't like those things but some do use them with success. To check Carbtune accuracy, find a vacuum Tee then hook both Carbtune hoses to the same throttle body nipple. Then start the engine & look for the Carbtune to have EXACTLY the same readings. If they don't match exactly then you have Carbtune issues. If you have an exact match with both hoses on the same vacuum tee  then your Carbtune is ready to use. 

 

Did you get the throttle plates back EXACTLY where they were before working on the TB's. Throttle plate clocking, throttle plate centering, & same amount of air gap to the TB housing with closed throttle plate? If you didn't then it is difficult to get a good curb idle balance as the TB's will flow different air amounts at curb idle.  (you can't just stick the throttle plates back in then expect them to be centered correctly) 

 

Did you adjust your TPS sensor correctly using an accurate voltmeter after reassembly? 

 

  

 

[jacksdad63]

Hi  DR, I don't know why the cables were changing the revs but I've got them all seated correctly, its now running and idling well. I marked the throttle plates and kept both bodies seperate and went back in exactly the same way and checked that both were open the same amount when closed if you get my drift, and I didn't touch the throttle stops so the mech rests in the same position. 

The carbtune is a 4 cylinder one so I tried both pairs of gauges, just to rule out any faults with it. 

I fitted a marine cigarette lighter socket direct to the battery, its a heavy duty one with 1 metre cables so will be handy should I need to charge the battery (I also fitted a remote positive kit to the starter when I did that!) so the battery has been off whilst the throtle bodies etc. were off, I did open/close the throttle to reset things, and have removed #5 fuse inbetween doing the balancing and resetting. 

I'll fit the later injector kit and report back, will soon spot any difference now.

I'll refit that wire in the correct place now, and get out for a test ride...its a cracking day today, must be 70C and not a cloud in the sky 

[jacksdad63]

I haven't done anything to the TPS! I did test it was working using an analog tester and I marked its exact position before removing, so its gone back just where it was. Should I do any further ests or resets as its been off, along with me cleaning and polishing everything? 

[dirtrider]

37 minutes ago, jacksdad63 said:

I haven't done anything to the TPS! I did test it was working using an analog tester and I marked its exact position before removing, so its gone back just where it was. Should I do any further ests or resets as its been off, along with me cleaning and polishing everything? 

Afternoon jacksdad63

 

Personally I would at least  check the TPS voltage to verify it is somewhat correct. You can't easily use an analog meter to do this as most analog meters place too much load on the TPS output to read correctly. 

 

You need a very accurate digital meter reading to thousandths of a volt so before connecting the meter you might put it on the Ohm setting then touch the meter leads together to verify that your meter doesn’t have any resistance in the meter leads or lead connections.

 

Once your meter is connected to the TPS terminals 1 & 4 (with the TPS pigtail connector still attached), & your meter is back on the DC voltage setting, & you are SURE that the L/H side throttle body cam is solidly contacting the base idle screw, you are now ready to check or re-set the TPS.

 

With key turned on (engine not running) & throttle cam solidly on the base idle screw (but don’t hold it their by hand), you need to see the TPS voltage under .399 volts. Anything between .365v & .385v is good. Personally I set the 1100 (Ma 2.2 Motronic) to .380v-.385v. & usually set the 1150 Ma 2.4 to .365-.375 volts. 

 

Then once it is properly set, cycle the throttle a couple of times to verify that it returns to the same setting.

 

Also, when done with the adjustment, slowly open the throttle while watching your meter to make sure that it smoothly scrolls from the under .399v to 5.00v as the throttle is opened. 

[jacksdad63]

Thanks again DR!

I did the basic version of what you say, I checked the voltage and range using my digital tester, then used my analog tester to watch the needle and it didn't flicker or surge/drop at all, other than what it should show. I'll test it again following your method. My digital meter will measure 1/1000th V so I can get it done tomorrow 

[King Herald]

On 5/21/2023 at 11:03 AM, jacksdad63 said:

Hi, after rebuilding the throttle bodies I've 2 issues....

First, easy one: where does this black wire really go? 

Second: When restarting the bike, the Right cylinder wasn't firing, but when I just touched the Left throttle cable, at the body, the RH cylinder fired. I 'wiggled' the LH cable back and forth and the RH again cut out/revved away. I've finally managed to get the bike running well, but the throttle bodies just won't balance level on idle. 

I'm using Carbtune Pro gauges, turned upside down as instructed, the bikes running well, should I just leave it as is? Bikes done 67k miles. I'm waiting on the injector upgrade kit to be delivered so will be doing the balance/set up again and hope I'm doing the job correctly! 

 

What's the idea of turning the Carbtune upside down? Surely the weights will simply fall to the top and give no reading?

 

I have a Carbtune  that I use on my own Oilhead, and I plan doing that test DR mentions, connecting both to one vacuum port to test the action, as I'm sure one side moves more easily than the other. 

 

I also have a home made oil filled balancer that works well. 

[jacksdad63]

hi there, the Carbtune manual states that for R series engines and most 2 strokes, the gauges work better upside down. Obviously the numbers on the tubes wll be wrong, but it did go on to say how to read them: I've returned the set to the owner so cannot say exactly!

The steel rods don't move, until the engine is running, its all to do with the low vacuum these engines produce.

[King Herald]

14 hours ago, jacksdad63 said:

hi there, the Carbtune manual states that for R series engines and most 2 strokes, the gauges work better upside down. Obviously the numbers on the tubes wll be wrong, but it did go on to say how to read them: I've returned the set to the owner so cannot say exactly!

The steel rods don't move, until the engine is running, its all to do with the low vacuum these engines produce.

 

All becomes clear, I've just had a look at mine. I assumed gravity was all that held the rods down, but there's actually some sort of spring affair. I shall definitely use mine upside down next time I balance my TB's.

[BigtowH8]

Shortly after purchasing my new to me '03 RT, I decided that a new tool was in a necessity- carb/TB sync tool.  

After a brief comparison of what was readily available,  I chose the Digi Sync.  I chose the four channel model because others in the family have 4-cyl, and I haven't ruled out getting another K bike.  

I like my digi sync very much.  Pros: Easy to use! Con: magnet doesn't work on BMW tanks. 🤪

Just thought I'd throw in my three cents (although with inflation,  it should be a nickel). 

[jacksdad63]

Hi again! 

I've had another fettle with the settings, now got a steady and balanced idle, closed voltage is 0.370V, up to full open at 3/4 throttle,  4.59V

I'm still waiting on the conversion plates for the updated injector kits to arrive, then get shipped to me...I'm going on holiday on the bike in 5 days....