tracerben Posted November 15, 2018 Share Posted November 15, 2018 So I'm doing the throttle body sync. I have the tank and the airbox off, and the carbtune is connected. The cylinder all the way to the right has the paint on the screw so I can't adjust that one. The middle cylinder is fine; it matches with the one to the right. But the left cylinder is off. It is too low. I screwed the screw all the way in and it is still too low. What do I do now? I'm tempted to adjust the reference cylinder and the middle cylinder (I guess I should be saying throttle body). I'm tempted to adjust the reference screw and the one next to it (i.e. lower those two since I can't raise the other one any more). But my understanding is you are not supposed to mess with the reference screw. So what do I do, just leave it as is? That doesn't seem right either. Help! Link to comment Share on other sites More sharing options...
tracerben Posted November 15, 2018 Author Share Posted November 15, 2018 I'm using the carbtune pro 4. I checked everywhere and you apparently don't have to calibrate it. I guess I'll try checking for leaks.... Link to comment Share on other sites More sharing options...
skipperT Posted November 15, 2018 Share Posted November 15, 2018 To build on what Piotrek said: If all your equipment checks out and you’re sure that there aren’t any leaks, there’s a method that’s not published anymore that you can use. The white paint mark simply indicates which TB the factory feels should have the lowest vacuum reading. IF IT DOESN’T, wind all 3 air screws in until lightly seated. Take note of which TB has the lowest reading (if you have done all this correctly up to this point, it should NOT be the TB with the paint mark!). Whichever TB now has the lowest reading is the one you use as Reference. Sync the other 2 TB’s to the reference cylinder. Usually you will find the the TB with the paint mark has its airscrew all the way seated. If not, I’d recommend counting how many turns out it was from the factory, and setting your NEW Reference airscrew out the same number of turns (or not at all depending on your bike). Then perform the sync. All the white paint mark indicates is which TB the factory feels should be the one with the lowest vacuum reading. Sometimes depending on how the engine breaks-in, this can change. Remember the valve lash affects the vacuum reading at idle and valve clearances should always be set to spec before performing a sync. -Skip Link to comment Share on other sites More sharing options...
tracerben Posted November 15, 2018 Author Share Posted November 15, 2018 I don't like the fact that you can't calibrate the Carbtune. Next time I do this I'm going to use a different manometer.... Link to comment Share on other sites More sharing options...
Supporting Member betoney Posted November 15, 2018 Supporting Member Share Posted November 15, 2018 To build on what Piotrek said: If all your equipment checks out and you’re sure that there aren’t any leaks, there’s a method that’s not published anymore that you can use. The white paint mark simply indicates which TB the factory feels should have the lowest vacuum reading. IF IT DOESN’T, wind all 3 air screws in until lightly seated. Take note of which TB has the lowest reading (if you have done all this correctly up to this point, it should NOT be the TB with the paint mark!). Whichever TB now has the lowest reading is the one you use as Reference. Sync the other 2 TB’s to the reference cylinder. Usually you will find the the TB with the paint mark has its airscrew all the way seated. If not, I’d recommend counting how many turns out it was from the factory, and setting your NEW Reference airscrew out the same number of turns (or not at all depending on your bike). Then perform the sync. All the white paint mark indicates is which TB the factory feels should be the one with the lowest vacuum reading. Sometimes depending on how the engine breaks-in, this can change. Remember the valve lash affects the vacuum reading at idle and valve clearances should always be set to spec before performing a sync. -Skip Great, informative post as always. Thanks for the tip!! ***2015 Candy Red FJ-09*** Link to comment Share on other sites More sharing options...
tracerben Posted November 15, 2018 Author Share Posted November 15, 2018 I thought the ECU was programmed to work with the reference screw set where it was, and that's why you can't mess with it. If that's not true, that's really helpful to know. Thanks! Link to comment Share on other sites More sharing options...
tracerben Posted November 15, 2018 Author Share Posted November 15, 2018 On a related note, I lost one of the end caps trying to put them back on. And now I see how important it is not to let them happen. Every auto store where I live sells vacuum end caps but none of them are the right size (5mm inside diameter). I hope the dealer has them or I will have to order them in the mail and wait (or I guess I could make one with some tubing and a small bolt). Link to comment Share on other sites More sharing options...
jonno12345 Posted November 16, 2018 Share Posted November 16, 2018 I don't like the fact that you can't calibrate the Carbtune. Next time I do this I'm going to use a different manometer....You can't calibrate it because it doesn't need calibration. Any attempt to calibrate it would only make the outcome incorrect - why would you want this additional hassle :-S Small piece of tubing clamped off somehow would be just as good a replacement for the rubber caps. I was concerned I have slightly split one of mine, I think the fact it's under vacuum would seal it off anyway but I bought some large sturdy ones that would be easier to handle than the tiny ones provided. Will fit them next time I have the airbox off.. Link to comment Share on other sites More sharing options...
skipperT Posted November 16, 2018 Share Posted November 16, 2018 On a related note, I lost one of the end caps trying to put them back on. And now I see how important it is not to let them happen. Every auto store where I live sells vacuum end caps but none of them are the right size (5mm inside diameter). I hope the dealer has them or I will have to order them in the mail and wait (or I guess I could make one with some tubing and a small bolt). Oh no... They can be ordered, but try first rooting around with a magnet (to attract the clamp) on the rubber/reflective cover which sits on top of the back of the engine. Maybe you’ll get lucky. -S Link to comment Share on other sites More sharing options...
Premium Member 2and3cylinders Posted November 16, 2018 Premium Member Share Posted November 16, 2018 I have an very old mercury-filled manometer for engines with more than 2 cylinders though my trusty fairly old Twinmax can be used for more than 2 cylinders but it means juggling the second hose. Can't get much closer than this... I also plumbed extension hoses from the TB ports so O can check sync without touching the fuel tank... Link to comment Share on other sites More sharing options...
tracerben Posted November 16, 2018 Author Share Posted November 16, 2018 That is exactly what mine looked like! I thought the reading to the left was a little low. But I guess it's close enough. Wish I had thought of plumbing extension hoses before I put it all back together. Damn good idea! Link to comment Share on other sites More sharing options...
Premium Member 2and3cylinders Posted November 16, 2018 Premium Member Share Posted November 16, 2018 Anything within 2 cm for the 3 is close enough for the girls we go out with! Link to comment Share on other sites More sharing options...
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