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2004 749S, 2006 MTS620
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Discussion Starter · #1 ·
Guys,

Am waiting for the Lonelec cables to arrive from the UK in order to do the following on my 2004 749s:
  • Reset TPS
  • Balance the throttle bodies (both at idle and 3,000 RPM)
  • Set CO trim to the 4-6% range
I am the original owner of the bike and right now it has 7,000 miles on the clock. The valves were just serviced with the openers set at .005” and closers at .002”…the belts were changed and tensioned, along fresh spark plugs and fluids all the way around. Before I do the electronic work I will also run a tank of fresh ethanol-free fuel through it and Redline fuel injector cleaner, too.

Having read about everything I can on the TPS reset, balance and CO trim process, the one question I have is with regard to setting the TB balance at a fast idle of around 3,000 RPM. For setting the TB’s at idle you should use the two air bleed screws found on the TB’s and get equal readings on the manometer which will be hooked up. This I understand and have already popped out the two plastic “anti-tamper” plugs from the left side of the airbox and can now see each of the exposed bleed screws (Euro rubber plugs are already ordered).

And this brings up my question about balancing the TB’s at a fast idle of around 3,000 RPM…

How do you access the “TB balance adjusting screw” which is located on the forward TB? This screw points up and I do not see how the fuel tank can be mounted on the bike when running the engine and still being able to access the screw. Further, there is no access hole through the airbox cover at this point, either.

And that is my question…how is the TB balance adjusting screw actually adjusted when the bike is running if I cannot see any way to access it?

Thanks!

Head Tomcat
 

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pull the lh air duct is the easiest, how i always do it. there is a big rubber cap cover piece of crap thing down under the horizontal air bleed access cap, but it's a pita to refit.

wind the air bleeds full in and do the running balance. 749/999 can be very inconsistant, so go for best compromise. then use the air bleeds to set the idle speed, then set the idle mixture ball park-ish then use the air bleeds to get the mixture the same on both cylinders.
 

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2004 749S, 2006 MTS620
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30 Posts
Discussion Starter · #3 ·
Got it! I have seen that large rubber plug which is mostly hidden by a frame rail and will be looking at taking it out and seeing how the access is.

And...

I pushed it from inside of the airbox toward the outside and found it does come out if you slide it down and through the small area between the battery box and cam head cover. Then, rotate it under the left-side fan motor and out it comes.

Even with it removed, it appears Ducati could have designed better access to the TB balance screw itself as it faces up - and there is still no way to get a flathead screwdriver in there as the tank will be installed. So, the only way I see to actually adjust the TB balance screw while the tank is installed and the 749S is running....is with a long-reach set of needle nose pliers that grab the side of the screw head and carefully twist it to do the balance adjustment. From what I understand, there should not be much adjustment involved to balance the two TB's at 3000 RPM so this seems sort of a reasonable method of doing it.

Thanks for the information about the large rubber plug....it appears to be the only answer to access the TB balance screw while the tank is installed and the bike actually running!

Head Tomcat
 

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2004 749S, 2006 MTS620
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30 Posts
Discussion Starter · #5 ·
I see just what you are talking about!

With the left side air runner/filter removed, and the large rubber plug out of the way to allow viewing the screw, it will permit a 7mm hex driver to come down from the top (via the air filter hole) and engage the hex head of the TB balance adjusting screw. This seems a lot better to me than grabbing the screw from the side with a pair of long needle nose pliers.

Once the Lonelec cables arrive I will give all this a try and let you know how it comes out.

Again...thanks so much!

Head Tomcat
 

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2004 749S, 2006 MTS620
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Discussion Starter · #7 ·
When I take out the large rubber plug on the left side of the airbox it makes it easier to get the 7mm hex driver onto the TB balance screw as you can see the tip of the driver as it searches for/engages the screw. With a bit of practice, taking this plug out will not be necessary...and when the cables arrive from the UK I am sure to get some practice!

Head Tomcat
 
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