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Discussion Starter · #1 · (Edited)
Admin to delete if necessary. ( I do have 3 Ducati's...) This Forum has the tech knowledge. 1997 Laverda 750S, very similar to ST4.

My understanding is that the tps butterflies closed voltage, and rpm, are the critical reference data that the fueling and ignition tables rely on. (there are other lower level tables and inputs, but not relevant at present). If the tps is not set correctly, the ecu will be referencing the wrong column in the tables. I am using Tuner Pro RT. Is this correct?

The figure given in the Laverda manual, well known as a misprint, is 0.15 volts for closed butterflies. There is no Laverda Organisation as such these days to refer to, and the tps cannot be adjusted down to 0.15 volts. Minimum of 0.192v

It seems that a closed butterfly tps voltage that is often used is about 0.275 volts, with an idle voltage of about 0.425 volts. This equates to about 2.3 degrees, and leaves the lower 2 columns of both tables unused. On my current ride I have a tps setting of 0.412v/0.608v, about 4.3 degrees, which leaves the lower 4 columns unused. Not Good!

Am I correct in thinking that mapping in an OEM eprom will require the correct OEM tps base voltage for the bike to function correctly, otherwise the program will be reference the wrong data columns?

Is there any way of "reverse engineering" the OEM tps base voltage from the lookup tables in an OEM eprom via TunerPro RT?

The correct tuning process?
Set Co2 pot to midway
Set tps closed butterfly to oem base voltage
Adjust butterflies to about an idle voltage
Balance throttle bodies with air bypass screws
Adjust idle speed
Adjust idle afr
Re-balance throttle bodies
Datalog and adjust fueling to afr requirements over the rev range

Help and comments would be appreciated, we are struggling....

Thanks, Greg
 

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Admin to delete if necessary. ( I do have 3 Ducati's...) This Forum has the tech knowledge. 1997 Laverda 750S, very similar to ST4.

My understanding is that the tps butterflies closed voltage, and rpm, are the critical reference data that the fueling and ignition tables rely on. (there are other lower level tables and inputs, but not relevant at present). If the tps is not set correctly, the ecu will be referencing the wrong column in the tables. I am using Tuner Pro RT. Is this correct?

The figure given in the Laverda manual, well known as a misprint, is 0.15 volts for closed butterflies. There is no Laverda Organisation as such these days to refer to, and the tps cannot be adjusted down to 0.15 volts. Minimum of 0.192v

It seems that a closed butterfly tps voltage that is often used is about 0.275 volts, with an idle voltage of about 0.425 volts. This equates to about 2.3 degrees, and leaves the lower 2 columns of both tables unused. On my current ride I have a tps setting of 0.412v/0.608v, about 4.3 degrees, which leaves the lower 4 columns unused. Not Good!

Am I correct in thinking that mapping in an OEM eprom will require the correct OEM tps base voltage for the bike to function correctly, otherwise the program will be reference the wrong data columns?

Is there any way of "reverse engineering" the OEM tps base voltage from the lookup tables in an OEM eprom via TunerPro RT?

The correct tuning process?
Set Co2 pot to midway
Set tps closed butterfly to oem base voltage
Adjust butterflies to about an idle voltage
Balance throttle bodies with air bypass screws
Adjust idle speed
Adjust idle afr
Re-balance throttle bodies
Datalog and adjust fueling to afr requirements over the rev range

Help and comments would be appreciated, we are struggling....

Thanks, Greg
Brad the Bike Boy has great tips, that many of us use from this site. If you do a search, you will find a video on how to set up the TPS etc for your St4...
 

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The correct procedure is, what Brad describes BikeBoy.org - Ducati 2V Non Linear TPS Baseline Adjustment
Follow it to the letter.

You can waist down the m4 fixing screws on the unused portion of the threads (0.4mm off the 70mm diam. fixing screw circle), and remove a bit of the brass lining of the TPS holes (1 mm off).
That should give you approximately 2°, about two columns.
It is not uncommon for the bottom two columns of a map, to be unusable.

If you follow Brad's process faithfully and reiterate as needed, you may find that the TPS ° you need for idling, coming down some more.
Having used this process quite a few times, I was a bit overconfident, when I changed the ECU and TPS on my 996, resulting in abnormally high idle TPS °.
Tracing back each step and doing it again properly, sorted this out.

Same ratio of Ducati's / Laverda's here;)

Cheers, Angelo.
 

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Discussion Starter · #4 ·
Angelo.
I was not explicit enough in my detail. When i remove the PF09 tps and turn it with a screwdriver it jumps from 0.000 to 0.165v, which is now the lowest voltage i can get (better than 0.192). Certainly not the lower voltages that Brad shows in his Linear/Non Linear TPS comparison chart. I was using Guzzi Diag and back probing with a volt meter at the same time to comparison check accuracy of Guzzi diag. No more than about 20mV difference.

Interesting about filing away the bolt and sleeve, but not my fix. I can turn it down further, its just that it is all 0.000v.

After viewing/reading Brad's documents I am going to try setting the tps at 0.165v , adjust idle the speed screw to 1200rpm, then readjust the tps to show 0.405mV.

At this point in time I haven't been able to get tunerpro rt to connect to the ecu, even via the emulator. I was hoping to get tunerpro to highlight the point in the grids that are being used at the time, live. I am studying and learning about this process at present.

Yes, Zane Laverda are quite rare here in Australia. We only have about 22 of them in the database, and 4 of them are mine. We know there are more, but not where they are.

Thanks for your help, Greg
 

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Greg.
I measured the PF09 tps I had on my 996, the same way as you did.
Starting from 7mV, the lowest I could get it to show was 60mV.
So, obviously your tps is the culprit.
A good used one, or a new genuine will solve your problem.
I can measure some resistance values, if you need.

Mine is a '70 270° 750S.:cool:

Cheers,
Angelo
 

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Discussion Starter · #6 ·
Angelo,

Had not thought about it being faulty. No need to take resistance tests, but thanks anyhow. I have a few more.

I was thinking there were 2 versions of the pf09, and earlier round one and a later one. I was also thinking the earlier one went down to about 0.06v, and the later like mine, only went down to 0.165v, but yes, it may be faulty.

Are you talking about a Laverda 750 with a twisted crank? if so, was it done by Red?
 

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Angelo,

Had not thought about it being faulty. No need to take resistance tests, but thanks anyhow. I have a few more.

I was thinking there were 2 versions of the pf09, and earlier round one and a later one. I was also thinking the earlier one went down to about 0.06v, and the later like mine, only went down to 0.165v, but yes, it may be faulty.

PF09's are all the same size/shape. Can be found as PF09/03, /04, /05 ...
Don't know what (if any) the differences between them are.


Are you talking about a Laverda 750 with a twisted crank? if so, was it done by Red?

It is twisted alright.
Red is a bit far from Greece, were I live. ;)
I always like a good challenge, so I wrote some code to find the optimum balance factor, built a press and a jig, and did it all the balanching, pressing and straightening myself.
Was aiming at 0.01mm run-out, but settled to 0.02 mm.
Ignition courtesy of a IAW15M.


Product Automotive tire Rim Automotive wheel system Machine
 

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Discussion Starter · #8 ·
Yeh, I like a challenge as well, so thought I would work out what the issue with the Zane cranks were. Only took me 6 years....Im Ghwallice on the old Laverda forum...
 

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Discussion Starter · #9 ·
What you have done is impressive, very impressive. Interesting about the IAW15M. It would be interesting to have a chat. We may catch up elsewhere. Ive often wondered what it would take to twist a Zane 750....:)
 

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I believe, we've "met" in laverdaforum.com? - Might be wrong though.
Am I interested in chatting? Sure!
Although, I must warn you, I'm not well versed in Laverda matters.
I just love this old twin engine, and wanted to build one.

Searching to find out, how a Zane crankshaft is put together, I happened upon your post of 11 weeks ago in "Zanelist Laverda".
It appears that it is a much more complicated/exacting process than mime, with the old splined (camchain sprocket) vs the later round heavy interference fit, center piece.
Not that it would be a deal breaker.

I believe, Red uses a finely made assembly jig for the old twins.
Mine was just for checking run-out.
Are Zane camshafts split in the middle?

Cheers.
 
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