Hi, has anyone had any problems with low speed ( I.e town speeds) running? My ST3 seems to surge and chug at @30 mph and 2-2500 revs. It makes riding in town a pain. Is it a set up problem, fuel, plugs or does anyone have any different ideas? Cheers , Chris .
Hi I have an ST4S,and another duke before that,both would protest at being ridden below 3000rpm.absolute minimum<change of rear sprocket also helps urban riding alot.I would look at these areas before thinking anything expensive and mechanical.
By change I assume you mean number of teeth? If so which way? It had new chain and sprockets when I picked it up about 500 miles ago.
Archer check your front sprocket. If it is 15T go down by 1 or 3 up on back. Any Duc I had is bitch under 3k. Sorting the gearing out helps but still I just stick over 3k.
Althugh much easier to go down one tooth on the front not the best solution,far better to to go up to 41 42 or 43 on rear.suppose you could try changing the front sprocket to see if you like it and it helps,if so then put the 15 front back on and change the rear,changing the rear gives a far smoother ride and and is easier on the gearbox.i run a 43 rear,can get to rev limiter in top with urgency,does 30mph with ease and gives good fuel consumption,oh and new multidoodles cannot seem to get near on rolling acceleration till about 135mph
I had a similar problem and did all of the above, as in sprocket, throttle bodies sync'ed etc. Then I went to an independent guy and he checked it over for me and found the that RPM sensor on the front left of the crank case was not shimmed correctly and was way out of tolerance. This gave an inconsitent signal to the ECU at low RPM and loads so holding 50KPH was a right pain. He sorted it out in minutes with a new shim to give the right clearance. Just make sure and get it checked before buying a power commander to sort out the low range fueling. Don't ask me why I'm giving that last piece of advice. A
Interesting as at tickover my rev counter goes up and down like a night ladies underwear,i have been waiting for the cable to give out for a year now!and it can be quite snatchy at lower rpms,i wonder?
Eh, no. These all have an electronic speedo that reeds from a pick up that counts the teeth going past on a gear wheel. If your rev counter is eratic, it is more than likely the wiring to the dial that is at fault. A
My ST4 is also a pain in town traffic below 3000 rpm - I think the 916 motor is just not liking running below 3000rpm. The jerkyness just plays throught transmission slack to make the ride feel even worse. Once over 3000rpm everything settles down nicely. I am also thinking about going up a few teeth on the rear to lower the gearing a bit.
Even on my much lower powered 600SS I find 30 mph a real pain, it just isn't happy in third and second is too revvy, they seem to thrive above 5000 rpm, anything below that seems a bit rough, part of the charm I suppose!
My 750 is about the same........but I refuse to change sprockets............I mean why would I want to sacrifice top speed for low speed ease around town?...............I just look for the open roads...... .....unfortunately I sometimes have to use 30mph and 40mph roads, but it keeps my left ankle active.
Looks like open roads it is then - Arquebus - dont you think even with a slight lowering of the gear ratios you wont have enough top end speed. i find that my ST4 has more than enough grunt for me to be able to hang on to & well in excess of the legal limits too?
Its a 750 with 31K on the clock...........I reckon keep the revs as low as possible, but still maintain a degree of long legs..... If it was a 900 I would consider sprocket fiddling..........and lets face it, if the 750s (and 600s it seems) are b*ggers at low speed with constant changing between 2nd and 3rd; depending on which sprocket is changed and what speed limit you have to keep to, it might mean constant changing betwen 1st and 2nd or 3rd and 4th instead.... ....because the erratic running in one gear will only get moved to another gear..........the erratic running at the rev range mentioned isn't actually cured.
I find that the rear drive chain tension setting up makes a lot of difference to smoothness. Well worth some experimentation and doesn't cost anything. Just a tiny bit can make a difference.
Archer 17 - I have read that the CAN bus (Controller Area Network) simplified electrical system on the 06 ST3's caused poor / rough running at low speeds. I have no idea if this is correct but the Frenchies over here seem not to like it and suggest that it was never fully addressed by ducati right up until discontinuation of the range. They do , however , like everything else about the bike!
I think that's bollocks. The ECU uses the various sensors to adjust the fuel according to the firmware map. The CAN bus is simply a serial line that communicates information between different modules on the bike. It is not heavily use on the ST3 and sends some sensor measurements from the ECU to the dash for things like RPM and engine temperature.
I just spotted this. The revcounter is very sensitive to supply voltage. It could be a sign that the voltage regulator is on the way out but as it stops altogether with main beam on it could be an earth problem. Have a good look at the multi-way connector that joins the main and front looms on the LH side below the fuse box. Check beneath the rubber boot, especially the lower one. Water can get in here and create havoc with corrosion.
Further to the electrical /injection systems. The 06-07 St3 ran with a closed loop system (according to the US sites) which was not agreeable FWIW. I quote from the bi-monthly DESMO mag. here in France -talking of an ST3 ' 05 vs ST3 '06 "elle conserve une injection electronique sans sonde Lamba (arrive en 2006) qui evite les a-coups d'injection tres desagreables ". (please excuse my lack of appropriate punctuation ie "accents" I have a UK keyboard and forget how to make them! ). In other words unpleasant lumpy running.
