Retro-fit fuel injection to a classic bike?

[BIG MOLE]

Hello all

I have a Ducati Paso 750. Not everyone's cup of tea, but I love it. However, due to the fact that it is fueled via a single weber twin choked carb the throttle response is wooly to say the least. I have looked around online, and found a few people who have converted them to twin carbs but my thinking is, if I was to have it converted, wouldn't fuel injection be the way to go?

With this in mind, does anyone know anyone who specialises in this type of work? I have spoken to a couple of local bike mechanics who seemed reluctant to take on such a job. I am pretty handy with the spanners myself, but i think the electrical side of this is over my head so a specialist would be better.

Has anyone done anything similar?


|https://thumbsnap.com/SG9HoFHS[/url]

[gareth_r]

Should be no problem. A programmable ecu, a fuel pump, throttle bodies, a few sensors, a rolling road and someone to do the mapping, and you're away.

https://youtu.be/OmAfNGKYG2A

[Drawweight]

Is it still the original carb?

Just skimming through Ducati forums there are several suggestions for the Weber carb and most of them include a bin.

I’d be trying a different carb setup before FI.

[xstian]

Interesting idea. I don't suppose getting the hardware and software up and running to get the bike started would be too difficult, after all many classic cars have been converted to EFi. I would imagine the trouble might come getting it to run nice. EFi bikes are still a fairly recent thing compared to cars. A lot of the early EFi bike where not very nice to ride at low speed because of the very snatchy throttle.

Could you look into robbing parts from a flat twin BMW?

[ThreadKiller]

I was going to do this with my Caterham. But cost was too high…. With one element being a new fuel tank for petrol return feed (or a dashpot - right word?). Is this not a problem for bikes?

[gareth_r]

xstian said:

Interesting idea. I don't suppose getting the hardware and software up and running to get the bike started would be too difficult, after all many classic cars have been converted to EFi. I would imagine the trouble might come getting it to run nice. EFi bikes are still a fairly recent thing compared to cars. A lot of the early EFi bike where not very nice to ride at low speed because of the very snatchy throttle.

Could you look into robbing parts from a flat twin BMW?

I reckon the rideability problems were more to do with emissions legislation (and crap mapping by the manufacturers) than inherent problems with EFi. My 1991 BMW K100 was fine, a 2004 Triumph Speed Four was rubbish.

[AceOfHearts]

It could definitely be done but would end up costing thousands once you buy throttle bodies, ecu, injectors, wiring, fuel pump. Then with all of the fabrication work to make it fit plus tuning, I can't really see it being worth doing, especially if you are paying someone else to do it for you.

I would suggest just changing for a better carb, or accepting the bike for what it is and saving your money

Very cool bike by the way

[KTMsm]

AceOfHearts said:

I would suggest just changing for a better carb, or accepting the bike for what it is and saving your money

^^^ This

These type of projects are ok if you're doing the job but not if you're paying someone else

[HustleRussell]

Correct and well-setup carbs will have pretty much instant throttle response.

[Scorched yellow]

I'd never heard of this bike before, but it looks absolutely class

I would also have thought you'd be better off with a good replacement carb, but if you are stuck on doing EFI, have you thought about looking at how they did EFI with the later versions?

Wikipedia said:

In 1989 the Paso 906 was introduced to replace the 750, with a six-speed gearbox, a 904 cc engine which provided 88 hp[8] and a 220 km/h top speed. The bike still had the same automotive carburetor and unreliable electrical system, but its greatest development was the incorporation of liquid cooling. 1,802 Paso 906's were built between 1988 and 1989.

After further development, the final version of the design came in 1991 with the 907 i.e. (iniezione elettronica); now without the name "Paso".[8] The engine remained liquid-cooled and the carburetor was replaced by the most modern Weber-Marelli IAW 043 system that integrated ignition and electronic fuel injection, which transformed the rideability of the bike

[BIG MOLE]

Thanks for the replies everyone. As I suspected, it looks like a carb conversion is the way to go.

[WhisperingWasp]

Am of no help whatsoever but just wanted to say what a great looking bike! Wasn't aware of these and had to look to see if the "screen" was standard or not! Fantastic thing.

[Chipchap]

Please speak to Iain at RPM Bikes in Northampton. He is a 20 year plus Ducati mechanic and actually likes the Weber on the PASO's.

He is amongst a very few that go back to early Pantah based belt drives and even less that can properly work on Bevels.


Allan

[kimducati]

I agree that a specialist in setting up the Weber carb could sort it out on a rolling road session. Imo it'll never be as good as a properly set up efi system though.
If you wanted to explore injection, Jenvey throttle bodies are a direct replacement for the Weber twin choke carb https://store.jenvey.co.uk/heritage-twin-t-body-40... .
Would need to add some kind of ecu, a Megasquirt or Emerald would do it and you could also map the ignition too, if you can fit the right sensors. Won't be cheap though.
Kim
eta I've also got vague memories that there is a mod that can be done to some Weber carb bodies to improve the part throttle response - something to do with re-drilling with 5 pilot holes, rather than 3 but I may be mis remembering

Edited by kimducati on Thursday 6th January 18:57

[BIG MOLE]

WhisperingWasp said:

Am of no help whatsoever but just wanted to say what a great looking bike! Wasn't aware of these and had to look to see if the "screen" was standard or not! Fantastic thing.

Many thanks. Some people say that I should just get a bike that doesn’t have the technical problems that the Paso does (including the strange rear tyre size) but the replacement bike wouldn’t look like a Paso. A Tamburini design classic.

[BIG MOLE]

Chipchap said:

Please speak to Iain at RPM Bikes in Northampton. He is a 20 year plus Ducati mechanic and actually likes the Weber on the PASO's.

He is amongst a very few that go back to early Pantah based belt drives and even less that can properly work on Bevels.


Allan

A bit of a trek for me, from Dorset, but still worth looking into. Thanks for the advice.

[rodericb]

If I was looking to fuel inject a Paso 750 I'd be inclined to start looking at shoving in a later engine - like a 800cc from the early 2000's. But you could probably look at the fuel injected and air cooled SS and Multistrada models to lift the whole injection setup from. The undoubtedly easiest option is to get a Weber-whisperer onto your bike. The second easiest to get some Japanese carbs and manifolds off an early nineties 750SS - they may even bolt right onto the engine but the airbox would be a custom job.

[NITO]

BIG MOLE said:

Many thanks. Some people say that I should just get a bike that doesn’t have the technical problems that the Paso does (including the strange rear tyre size) but the replacement bike wouldn’t look like a Paso. A Tamburini design classic.

Well I don’t know, the 907ie looks fairly similar



I love the Paso/907, it’s a beautiful bike to ride. The 907ie is fuel injected and I have to say it works very well indeed. The Paso 750 and 906 was dogged with fuelling problems which killed sales, they shook off the Paso name with the 907 but by then the damage was allegedly done which is a shame because they are massively underrated bikes.

If I were you, if there is someone who specialises with those carbs then I’m sure they could get it running sweet, would def be my first port of call. If needed bin the carbs for better ones. I wouldn’t go the route of FI on yours, you may as well go to a 907 or fit a 907 engine if you were going that route. I’m not sure how similar the lumps are if you could even retro fit the FI side of things but sticking with carbs makes more sense.

Interesting nugget about your smaller rear wheel. The 907 went to a 17” wheel but they never amended the sidestand. Hence so many 907’s have an extra inch or so added on to the sidestand so it no longer leans at a silly angle!!

We’ve crossed on her before, yours has the wonderful charm of the Tamburini hallmark eccentric chain adjuster which was lamentably dropped from the 907

Great to see it still looking good and that you’re looking to put some energy into it.

[graham22]

From memory, these were based on the Pantah motor but with the rear head reversed, which lent itself to a shared carb. It was a problem from the start but alternatives weren't available due to space between the V.

Ducati since launched the Monster and 900SS with similar head set ups, the early ones having carbs - I'd be looking at options for carbs & airbix off of either of these rather than trying to fuel inject it.

[BIG MOLE]

NITO said:

We’ve crossed on her before, yours has the wonderful charm of the Tamburini hallmark eccentric chain adjuster which was lamentably dropped from the 907

Great to see it still looking good and that you’re looking to put some energy into it.

Many thanks NITO. I did consider selling it recently but knew that I would regret it so I want to make it more rideable with a view to keeping it for a while.

Yes I do remember us conversing on the "Show us your classic Italian bike" thread.