Power drop out

MetalHurlant · Post by **MetalHurlant** » Tue Nov 07, 2006 11:18 pm

G'day from the land down under and the wild west part of it.
I have had my Paso 906 for about 6 weeks now, and have ridden it for around 1200 wonderful Klms (The weather here is too good to waste!) and all has been great........until recently!
When I'm sitting on a given speed for any longer than 5 minutes, all of a sudden the power drops by half! - Seems like it's running on one cylinder or something! I pull the clutch in and give the throttle a couple of savage twists, then, after a couple of seconds, just as suddenly it cuts back in with full power - which is tricky if this happens in traffic, let me tell you!

Can someone help? Is this common? If it's a carby problem, is it difficult to overhaul the weber at home? - I have the workshop manuals.
Thanks people.
Ian

ducapaso · Post by **ducapaso** » Wed Nov 08, 2006 5:48 pm

There’re very little chances that you’re experiencing a problem with carb,just some powder in the main jet can cause a symptom like this, but not at idle rpm... :umm:
I think you should make an accurate check to the electrical plant: have a look to the f.a.q. post in the 750 section…
By the way, how old are timing belts? If they’re older than 2 years this might be a big trouble! :ugh: So, remove the belt cover and watch the timing dots.
Have a nice work, Nicola

Finnpaso · Post by **Finnpaso** » Wed Nov 08, 2006 6:37 pm

Ian, are You sure, that another cylinder drop, or something else???

If so, does that happen very fastly? (i mean, does it feel, that another drop), or does that go down "little by little" some way???

Can it be, that You have some shit in Weber, cause that "giving throttle" with clutch help?

It can be also ECU heating problem... There can be some "cold weldings", what start to cut another cylinder.

If You managed to keep that problem, when its at home, then better start to look closer sparks of coils.

I had quite similar problem in my ST4S: it started with one cylinder, when it was hot and i stopped engine for fueling. At end it was ECU problem. Some heat went from hot engine to cooling fin of ECU and cause, that some digital byte went wrong. It was ONLY, when get engine hot, never cold! I changed to FIM ECU and no problem since... Just thats why i asked, are U sure, that another drop and did that happen IN MOMENT....

Its NOTHING with timing dots(belts), cause sometimes function normally ! If belt / timing problem, then it function totally wrongly ALL time !!!!!!!

MetalHurlant · Post by **MetalHurlant** » Thu Nov 09, 2006 12:30 am

Thanks for your replies,
The power drops out SUDDENLY - engine is still running, bike is still moving (slowly) then it kicks back in suddenly.
It certainly feels like a cylinder dropout or crap in the carby(or water from bad fuel).
This problem started small and is getting worse every time I take it out for ride.
It does not happen on startup (thats fine). For example, on a 100 Klm trip this will happen maybe three times.
Electrics all seem fine - connections clean and tight.
I'm stumped.
Ian

Finnpaso · Post by **Finnpaso** » Thu Nov 09, 2006 8:03 pm

I think, coils, ECU, or carb/fuel pump.... But try to get that failure "at home", so then much easier to figure out problem, but surely need to know then, how ECU and coils/spark plugs are working.... Do You have any tools for that? I mean multimeter, or oscilloscope, or so...

Btw, Do U maintain Your bike, or how do U do that??? Now i mean, how much You know, how Your bike function tecnically?

MetalHurlant · Post by **MetalHurlant** » Fri Nov 10, 2006 4:51 am

I'm not all that technical Antti, but have basic mechanical skills -
not too good with electronics tho.
The ECU is the Marelli unit under the seat yes?
I have a multimeter but have no idea how to use it to test ECU, coil etc. I will start with the spark plugs and work back.
I went for a ride yesterday and one cylinder dropped out for about three minutes, cutting in and out intermittently, no amount of throttle twisting did anything, then it cut back in suddenly. The weather was about 30 degrees C.

Ian

Finnpaso · Post by **Finnpaso** » Fri Nov 10, 2006 7:53 pm

Sorry, but with those your notes i cant help You. NEED much more information, what is going on there... I give advice: Try to search some good Ducati meachanic as close You, as possible and let him check with good equipments ECU, coils, Fuel system at least.... Yes, Your 906 have ECU under seat and its just that Marelli unit....

JWilliam · Post by **JWilliam** » Sat Nov 11, 2006 11:45 am

Not overheating is it? The front cylinder runs cooler than the vertical one so if it was overheating (due to a faulty thermo thingy) that might cause a misfire on one cylinder first (the vertical).

ducapaso · Post by **ducapaso** » Sat Nov 11, 2006 7:01 pm

Actually largest part of cylinder fault while running come from overheating of ECU. Hard to debug without a prompt test of sparks (while the trouble is on). This mean run with a "naked " paso

Quite hard to do without a proper fitting of the oil cooler :ugh: and the appropriate electronical instruments

Finnpaso · Post by **Finnpaso** » Sat Nov 11, 2006 7:13 pm

There is plenty of work to do with those good "tools & electrical equipments", but If dont know more details, its very difficult to give any advices... Anyway those Marelli ECUs havent been so good stuff, many have been failed... Seems, that Marelli made very good ECUs to 907(P7&P8) and later M16, but 906 unit is not so good... same with my ST4S unit....

And hard to find Marelli ECU to 906 from markets... Anyway, we DONT know, what is real problem, but seems, that need "good tools" to figure out it..... Those heating problems can be very hard to solve... Like i had in my ST4S.

jomo · Post by **jomo** » Mon Nov 20, 2006 11:52 am

Ian,

Sounds like the ECU. I took mine to a Television technician friend, who reluctantly fixed the problem. I have since found an electrical engineer who will rework the ECU over here near Gosford on the east coast. Let me know if you need his number and I will find it for you.

I bought a "Silent Hektik" ECU from Germany. It ended up $1300AUD. Excellent service...very helpful....better idle...but I could not detect any better performance.

I used to carry a soldering iron with me on trips, for when the terminals would let go on the ECU. Disgraceful design!!! Silent Hektic has cured that problem!

Finnpaso · Post by **Finnpaso** » Mon Nov 20, 2006 3:56 pm

906 Marelli units are "piece of shit"... too many "cold weldings" (i have heard many stories about that....) :laugh: :laugh: :laugh:

MetalHurlant · Post by **MetalHurlant** » Wed Nov 22, 2006 11:31 pm

Aahhh well, I bit the bullet and put it in the shop - we will see?

I'll let you all know how much they charge.

On another note, someone right across the bloody road from me has bought a 906 Paso!!! What are the odds??!!!

Ride hard,

Ian

MetalHurlant · Post by **MetalHurlant** » Sat Nov 25, 2006 12:32 am

Well, after 5 days in the shop, they went right through the electrics - and replaced the HT leads and caps! That was it!

They also adjusted the valves and tuned the carby, which has improved performance out of sight!

All this was done by an ex- Ducati racing team tech. at Fraser Motorcycles Perth for AUD $288 - which I thought was very reasonable. Next time I'll check everything though.......

Ian

Finnpaso · Post by **Finnpaso** » Sat Nov 25, 2006 12:00 pm

... so, ELECTRICS again.... :laugh: :laugh: :laugh: