transmission snatch or fuel mapping

[tomtom]

As much as i love my sf it's an absolute pig below about 45mph. I know there have been other posts for lowering the gearing to cure the problem but i was wondering if there was also a problem with the fuel mapping as it aint half difficult to keep it on song around town. Sometimes I've got to go to first gear which is ridiculous , feel like i'm driving a tractor rather than a bike. From a closed throttle especially when riding below 45 to 50mph i'd say that even if i changed the front sprocket the gearing would move up the rev range but the underlying problem might still be there . I'm going to try the different front sprocket and see what difference it makes.
Hope I'm wrong as it's spoiling a brilliant bit of machinery.
I really noticed the diference after driving my friends multistrada all day

[LWS66]

IMO, there's nothing wrong with the fueling. It's purely the gearing combination. It was setup that way for emisions/sound testing (lower engine rpm at designated speed for testing =less noise/emissions,etc) A majority of bikes come this way, but twins seem to be more of a problem. You really need to change the gearing, front and rear. I rode mine with the stock gearing for a few hundred miles after buying, and could'nt take it any longer. I could'nt ride down my gravel driveway without fear of loosing traction and dumping it...had to pull in the clutch and coast at a safe speed. I highly recommend changing both sprockets so you have a lower final gearing (numerically higher) Transforms the bike. You loose maybe 4-5mph tops. But it eliminates what your describing. From what I've read, just changing the front is not enough.

[tuxracer]

I'd be interested to hear how you get on with the gearing change as mine is much the same as yours. You've got to make sure the revs are high enough to keep it running smooth. Having said that a lot of big twins are just as bad, I had an RSV for a while and loved it but it was a right pain in town. If you cracked the throttle open hard below about 3k, you thought the pistons were going to fly out the top of the engine! The more miles I've done on the SF the less it bothers me but to be honest Ducati's are probably the best fuelled twins on the market, so I dont think you'll ever get it that good.

I'm going to have a go at syncing the throttle bodies on my one in the next couple of days, as the boys on the German site seem to think it makes a big difference. I'll let you know how it goes.

[boilermaker]

Tom Tom
One of the main reasons for the problem that you describe is the fact that a 180 deg vertical twin needs very little flywheel weight to "keep it going" as it were, (this also allows the engine to achieve a relatively high maximum RPM). The price that you pay for this low flywheel momentum is the symptoms that you describe. For low down torque then a 90deg (Ducati, Guzzi, TRX Yam) or 360deg (parallel) (Triumph, Rotax, all old brits etc) twin is a better bet, However there is no perfect answer, but as suggested by other contributors a change of gearing and good throttle body balance will certainly help. Personally, having put up with a lot worse over the years I have adjusted to its peculiarities.
George Waite I.Eng

[tomtom]

at least i know now i'm not alone. I thought i'd lost the touch when riding the bike. Appreciate the replies and i will let you know how i get on.

[tuxracer]

Hi tomtom,

Not sure whether you've had a chance to change the gearing yet but I balanced the throttle bodies on my one today and it did help a bit. The left hand cylinder was spot on but the right hand one was well of. After adjusting them the bike starts better and idles smoother. On the move it seems to pick up a little sharper, vibrate less and pull cleaner from low down. It’s not suddenly turned into a big Jap four when it comes to flexibility but certainly worth doing if you know anybody with the right kit. I used my Morgans carbtune balancer which might not be as high tech as the factory stuff but it does the job.

I'm going to change the gearing tomorrow and see what effect that has, so I'll keep you posted.

[tuxracer]

Well I changed the engine sprocket this morning, now running 16/45 rather than the standard 17/45. The bike does pick up better and is a litle smoother to use at low speeds, I would not go much lower as I dont do much town riding. However if you do a lot of commuting it might be worth lowering it a bit more by going bigger on the rear sprocket.

Hope this is of some help to you.

[LWS66]

You might also want to open up the airbox cover. The air intake opening is very small, restricting airflow. Some have removed the cover, I left it in place but drilled holes in it so there's no major increase in intake roar as there is with it removed. Back when the 1000S was first up for sale here in the states I talked to a man from the distributor who said removing the cover would gain around 8hp and help smooth things out. After drilling holes, changing sprockets, different pipes, etc I've got to say I don't see any of this particular problem with the bike. Vibrates some, yes, but snatch of any significance? Not that I can tell (it's a whole lot better than stock) Other than that, I guess it's "Character"

[tuxracer]

LWS66

To be honest I could have lived with my bike as it was but I can never resist trying to make things just that little bit better Balancing the throttle bodies and changing sprocket has improved the bike at very little cost, so was worth the effort. It will never be turbine smooth but that's the attraction for me. If I wanted smooth I would have stuck with my Fazer 1000. It will pull from 20mph in top all the way through to 165mph without any hesitation or snatch, is blindingly fast but soulless. Since I bought the MZ I've only been out on it twice and will probably sell it in the next couple of weeks, so I think that says a lot for the MZ.

That’s a good shot of your air box mod, which will be my next step along with the Remus cans. The only other thing I'm tempted to try is the TuneBoy software (http://www.tuneboy.co.uk) and having it re-mapped to see what happens. It looks interesting as you can use it for engine diagnostics as well as tuning.

[tomtom]

not had a chance to order the parts, but since you've listed the sprocket size you've used i'll order one up.

[zedhead]

Just out of curiosity really, has anybody tried the TuneBoy software? I've just bought a brand new 1000ST and my mate has a 1000S so I thought of buying it just so that I could keep on top of any errors/faults that might occur (I've had the yellow ECU light come on temporarily on both bikes) and I hate not being able to fix things myself. I'd also like to be able to alter the temperature point at which the cooling fans kick in, and 'cure' any lean burning through the rev range. It would also be interesting (perhaps I should get out more?) to compare the maps for the S and the ST as they are different. I'm wondering if generally reducing the lean-ness of the fuel/air mix would reduce the engine running temperature as I'm finding that these bikes run quite hot in town.

My german is non-existent but I'm guessing that there are revised fuelling maps on the http://www.ktm-faber.de site - is that right or is it just wishful thinking?

In any event, I'll probably buy the TuneBoy kit (and a PC laptop to run it on as I use a Mac) and keep you posted.

All the best

Karl

[boilermaker]

karl
Please notice that the tuneboy website does not list any OE softwear for the 1000 series. I do not know how this affects your ability to re-map the EMU but it may restrict the use of the programme to a purely diagnostic functions.

[boilermaker]

To all
I have just raised the gearing on my machine to 14/43 from the standard 14/45. The rpm at my usual cruising speed of around 80mph is down by about 500, and the engine is much more comforatable all round. There seems to be no significant effect on the low speed running.

[tomtom]

if you drill holes in the airbox as per the picture above, will the ecu automatically compensate for the fueling or do you require a powercommander

[LWS66]

I believe the ecu is a closed loop system and won't compensate for the increased free breathing.
Yet, I'm not running a Power Commander, have'nt had re-mapping done, and it runs fine, not popping on deceleration, no flat spots/hesitation, surging or anything that I can tell would mean it's lean. My plugs and exhaust look fine, definately towards the leaner side, but not lean. I'm sure doing the above would help, but it seems to be right at the fine line of needing to do that. If there was a proven map for my setup (open airbox, K&N filter, Sebring Twister w/baffles in/out, gearing change etc, I would probably do it, but being there's not, I'm not into buying a Power Commander and flogging it on a dyno.....for now. Maybe someday