Tech Tips for TPS and Throttle Body Adj. Pt1 - Sportbike Forum: Sportbike Motorcycle Forums
 
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post #1 of 8 (permalink) Old 09-17-2002, 01:12 PM Thread Starter
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Tech Tips for TPS and Throttle Body Adj. Pt1

So this weekend I tackled the throttle position sensor and throttle body adjustment on my 1999 900ss. Here is a quick summary followed by some more details.

Cost:
About $85 (all for tools)
74 dollars for mercury carb syncs 11 dollars for multitester.

Time involved:
6-8 hours if you are by yourself less than half that if you have a spare pair of hands around.

Worth it to do it yourself?
Maybe, it depends on how broke you are.

Well my shop wanted 135 bucks or thereabout to do this job. I figured I could do it myself for less than $90 in tools plus it seemed interesting. As this met my criteria for bike maintenance I dove right in.

First let's get one thing out in the open. To do this job by the book would require about $2000-3000 dollars in tools as you would need all of the following.

A mathesis tester & computer adjuster from ducati.
Factory shop manual (Important for dissassembly and reassembly info and for reference values)
A high quality dual channel CO meter with special plumbing to match up with your ducks headers.
A set of mercury carb synchs.
Screwdrivers.

However if you are a clever hack and not terribly picky about emissions you can get by with just a set of carb synchs and a garden variety multitester and still get very good results.

Basically the procedure involves
1.Setting the TPS to optimal output level at a fully closed position. 2. Balancing the throttle body airflow.
3. Adjusting/Balancing the mixture using the air bleeds.

I don't want to reiterate too much of what's been said before so I'll point you to a reference.

http://www.fuelinmoto.com.au/
Check the FAQ under ? #11

These guys have the sequence correct so I'll just specify what's specific to supersports.

Initial TPS setting should be 150mv with the butterflies fully closed. (This is much harder to do than it sounds.)
Measure TPS voltage between pins 11 & 22 of ECU.
Idle TPS between 500-560mv (This seems to happen automagically )

First remove the fairing, fuel tank,

A note on supersport fuel tanks: I have found that by placing 2 5 gallon buckets stacked up next to the right side of the bike you can undo the fuel tank at the hinge pivot it and support it between the frame and the buckets without draining it and undoing all the hose clamps. This is real handy considering you'll need fuel later to make your adjustments.

battery, airbox (bonus you get to pull half the wiring harness away from the frame Yeay!) and everything else blocking your access to the all important adjustment screws under you throttle bodies. Then reconnect all the electricals, and balance the batery on the frame. Back out the 2 stop screws so that the throttle body butterflies are all the way closed.Tap them with your finger to be sure. If you have lots of carbon you may need to clean your butterflies first.

Without a mathesis tester you will have to poke your little probes into the wires going to pins 11 and 22 on the ECU. On my bike they are red/white and yellow but yours might differ. yes this is borderline bike rape but at 1500 bucks for a mathesis tester I think it's justifiable. Plus you can fill in the holes with your sealant of choice later. Hold the probes on there and turn on the ignition switch. You should get a reading of 150mv give or take 10-20 or god forbid something else entirely. If you can't get a steady reading you probably don't have good contact with the wire. Mine was 162mv, now the fun begins.

This part would be much easier with a helper as they could hold the probes and read the meter while you adjust the potentiometer. I didn't have that luxury.


A note on the TPS. The screws holding it in place are covered in paint which you get to clean out. After cleaning the paint out it was difficult to tell if they were small allen heads or star bit screws. Suffice it to say a small craftsman torx or star bit driver fit well enough to get the job done.

So go on and back the screws out and find out just how sensitive this tiny device is. What you thought was a little nudge will change your reading by 300-400mv. Ideally you want it to be exactly 150mv. So now you can benefit from my experience and maybe save some time.

Loosen it up just enough to where you can turn it and try to get it within say 10mv. Then tighten the screws up some. Then while watching your readings tap it gently (really gently) with the back of the driver until you get to 148-150. When you get that reading slowly tighten the screws until they are good and tight. Recheck your reading and repeat as necessary.

Once this is done your TPS is set and you shouldn't touch it again.

A quick note if your bike hasn't been ridden in a while you might want to do the tear down the night before and let your battery sit on a charger over night (check those fluid levels (This Means you Bill ) as this process involves long periods of time with the bike switched on but not running.

Pt. 2 throttle bodies synchronization to follow....

There are some things nobody needs in this world, and a bright red, hunchback, warp-speed 900cc café racer is one of them -- but I want one anyway, and on some days I actually believe I need one. That is why they are dangerous.
H.S.T.
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post #2 of 8 (permalink) Old 09-18-2002, 06:38 AM
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Re: Tech Tips for TPS and Throttle Body Adj. Pt1

Quote:
Originally posted by lucifer
....let your battery sit on a charger over night (check those fluid levels (This Means you Bill ) as this process involves long periods of time with the bike switched on but not running.

Pt. 2 throttle bodies synchronization to follow....
LOL...

You just knew I would be tuning in for this didn't you?

Great stuff Lucifer, thanks - looking forward to part deux - (you like to keep us in suspense don't ya?) - From what I've seen so far I might give this a go... totally new territory for me though.

Cheers, Bill (BamBam)


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post #3 of 8 (permalink) Old 09-18-2002, 07:43 AM Thread Starter
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I'll try to do part 2 tomorrow. i just got tired of typing. I may compile all my stuff and put them on a website sometime.

There are some things nobody needs in this world, and a bright red, hunchback, warp-speed 900cc café racer is one of them -- but I want one anyway, and on some days I actually believe I need one. That is why they are dangerous.
H.S.T.
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post #4 of 8 (permalink) Old 10-09-2002, 05:22 AM
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bump...

Lucifer - did you ever post Part II - Synchronizing anywhere on the web??
Just axing...

Cheers, Bill (BamBam)


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post #5 of 8 (permalink) Old 04-21-2003, 07:21 AM
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Well Lucifer, I used your write up to great effect over the weekend - did the TPS and throttle body balancing. THANK YOU!!

My TPS was 161mV when I checked it - you're right about it being a bear to adjust that potentiometer - they could have done well to put in a differently calibrated unit. Still, after about 15 attempts I managed to get it bang on 150mV.

Used the Evoluzione sync tool to get the throttle bodies in sync. They worked just fine but could they have made that balance screw any harder to get at? Even with the airbox off and everything exposed it was still a contortionist act to get the thing to move!! Wow... and I've heard of people who can get at it without removing the box!?!?

I used the balance screw to sync the throttles at idle (1100rpm) and by happy coincidence that worked for 5000rpm also!! I haven't taken her out to test the results yet though.

PS: When setting the TPS did you have to clean out your intakes at all? - mine had some carbon buildup which I cleaned off with kerosene but afterward the butterflies were still a bit 'sticky' with the stop screw wound out. Hence I had to do a few attempts to get the closed position consistant, by letting the throttle slam shut a few times til I got the same reading every time. Only the stop screw on the LHS (the throttle body with the TPS) seems to have any effect - did you notice that?

All in all, a fun and educational exercise - I feel like I'm on much more intimate terms with Isabella now.

Oh, I forgot to mention - I topped off the battery while I was at it!!

Cheers, Bill (BamBam)


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post #6 of 8 (permalink) Old 05-21-2003, 04:19 AM Thread Starter
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Well it looks like you did pt2 for me...

Yeah supposedly if you have a long enough screwdriver you can get to the balance screw with the bike still together.
All I know is that since I did this my baby runs like a screamin demon.

Although the thought of an 11:1 944 kit has crossed my mind lately...

There are some things nobody needs in this world, and a bright red, hunchback, warp-speed 900cc café racer is one of them -- but I want one anyway, and on some days I actually believe I need one. That is why they are dangerous.
H.S.T.
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post #7 of 8 (permalink) Old 05-21-2003, 04:56 AM
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Well .... hello stranger! Where have you been - it's pretty quiet around here.

After the tune up, Isabella has been running really nicely - noticeably smoother. I took her down to Deal's Gap for a few days and we had a bloody marvellous time This bike is such a beauty, 23.5K miles and the only issue I've had in all that time was that little 'senior moment' when I let the battery dry up!!

Thanks for the tecchie tips Lucifer, without your article I would never have even attempted it.


Cheers, Bill (BamBam)


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post #8 of 8 (permalink) Old 05-21-2003, 09:29 AM Thread Starter
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Umm I'm always around on the web. Just not here. I havent done much riding lately. its been the rainiest spring in recent memory...
Gonna change my oil this weekend and try to get back in it finally.

Hopefully june will be drier.
Ours is a great bike...
I see no need for ever trading it.

There are some things nobody needs in this world, and a bright red, hunchback, warp-speed 900cc café racer is one of them -- but I want one anyway, and on some days I actually believe I need one. That is why they are dangerous.
H.S.T.
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