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Discussion Starter #1
Hey guys,

im here again as i am working on my bike again since ages.

so to start.. Best riding wishes to all of you!

the issue i am dealing with that got me to dive into my tools(shed) again i have is hat i have a feel that my bike doesn't idle nicely.. and i find myself riding with choke on to stay above the 1100 rpm, even after it is warmed up.
also i feel like the the main part of the choke lever travel is in effective (meaning that it does not increase the rpm)

so i am now going to clean the throttle bodies and my airfilter (found it to be dirty..) so either cleaning should make an impact already.
but i would like to try to fix this in effective choke lever travel part too.

i read the manual and it literally says the following.

"To adjust the travel of the choke cable, turn the cold start lever on the handlebars fully on and check that the arm (5) rests against travel stop (B).
Make sure that with the choke in this position the engine turns at 2000 rpm."

but when i engage my choke fully (the lever) it does not rest against the end stop at the end of the travel and the rpm of my engine is high (5000 rpm).. out of experience. haven't checked now in the garage exactly. when i not engage my choke it runs really low in rpm.. more like 900.. or even lower.
and the bike has the tendency to stall when i close the throttle completely (even when i need to change gears) untill the temp comes to a (normal) 70 degree C (160 F). anyway definitely more then when it comes out of "LOW"

so i have two questions. what should i do to make sure the arm comes to rest to the stop when fully engaged.. and will this solve the high rpm when fully engaged.
as you understand.. the in effectiveness at the beginning of the travel and high rpm at the end. leave my choke setting very delicate. which is a nuisance when riding with the choke on (which i need to other wise it stalls when i close my throttle)

Additionally. i find that my throttle has not much play (none really) and when i close my throttle. i feel like the throttle body really falls close (with a tap) and doesn't close gently. this is something i have not noticed with my st4 before. could be oke.. could not be.anyone any thoughts on this ?

kindest greatings.

Matthieu
 

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Hi Matt. The first point to address is the low idle. Don’t worry about the cold start lever for now. Sounds like you’re in need of a tune. Replace you filters, check for proper valve lash clearance, synchronize the throttle bodies, adjust the CO trim. That should take care of the low idle. Once that has been done, adjust the cable for the cold start lever.


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Discussion Starter #3
@mlukason:

Well it has had a major service a 1000-1500 km ago, so the valves should be oke.
also i tried this one on my ST4 and decided to leave that stuff to the real mechanics.. same as syncing the TB's and adjusting the CO trim.
At the moment i do not have the proper experience (and tools) to do this, and also not the time to dive into this theory again.

for now i am cleaning my air filter ([email protected]) and indeed clean the TB intakes (strange that that wasn't done at the service though??.) and then i will put it all back together and let it be.

taking this in consideration. should i still not address the cold start lever cable?.
as i feel that the not hitting the end stop, and high rpm at that point are neither valve, nor TB sync or CO levels related (could be wrong ther though!)

kindest greatings
 

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900 rpm at idle sounds fine to me. Actually a engine that will idle at a low rpm reflects a good tune in many cases I think. Not sure what year you have but on my 03 the fast idle cable is on the right side of throttle body and a set screw holds the cable by pinching it, just loosen and position the cable where you want it for the correct fast idle.


Paul 03 ST4s, 15 675RX, 96 ZX11, 76 KZ900LTD B-1, 72 SL125
 

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Matthieu,

I had same low idle problem.

Clean your throttle bodies before doing anything else.

I found a thin ring of dirt inside both of mine that were blocking air bypass at idle.

This fixed it for me.

Bob
 

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I assume we're talking about Spikey's ST3?? Please specify when UR posting a trouble note!

Also, doesn't the ST3 have an AIC valve? (Auto Idle Control) ??
 

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Discussion Starter #7
@BobM : indeed, i did just that as i found the same.

Afterwards i ran the engine inside to get it out of the low, and i felt it ran better.
This time i ran it while standing inside,in the past i ran it after a night out in the cold, which on it's own will make a big difference.
anyway I did turned down the max. choke rpm as it was actually way more then "just" 5000 rpm. when it was "warm"
i am not sure it will be just 2000 now, can be a little bit more then that, but did notice the screw was turned out nearly at it's max.. that didn't seem right to me anyway.
Anyway. i know what i did and can always reverse what i did without issue.
but i feel like a clean airfilter and no gunk at the throttle body will already make a big difference.

@Stick: sorry for not being specific, as it is my only bike it htought it was clear in my mind. but mine isn't yours so..

about the AIC valve. not that i know... but i coulc be wrong, anyway the TB's looked rather the same to me as my former ST4, maybe the st3s?

kindest greatings

Matt
 

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Coming from a very inexperienced with Dukes point of view, on my ST3 there's a fast idle lever that I originally thought was a choke.
There's no choke lever.
I find my fast idle really needs to be on a bit as the bike won't idle if it's totally shut off.
It seems to like about 1500 rpm to just burble on. If it goes below 1000 it shuts down.
Low idle has always been this way during my ownership.
I find on my long rough driveway that I must feather the clutch to get down there or it gets a bit jolty.
I assume this is typical highly strung Italian desmo behaviour though of course there are those who maintain that their steed is always smooth as silk. I am doubtful but with only 6K added to my odometer in my ownership I am in need of advice from those who know about this stuff. My bike only has 38K kilometers on it and I changed the belts when I bought it at 32K. Does anyone think I need to have the valves checked?
 

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Coming from a very inexperienced with Dukes point of view, on my ST3 there's a fast idle lever that I originally thought was a choke.

There's no choke lever.

I find my fast idle really needs to be on a bit as the bike won't idle if it's totally shut off.

It seems to like about 1500 rpm to just burble on. If it goes below 1000 it shuts down.

Low idle has always been this way during my ownership.

I find on my long rough driveway that I must feather the clutch to get down there or it gets a bit jolty.

I assume this is typical highly strung Italian desmo behaviour though of course there are those who maintain that their steed is always smooth as silk. I am doubtful but with only 6K added to my odometer in my ownership I am in need of advice from those who know about this stuff. My bike only has 38K kilometers on it and I changed the belts when I bought it at 32K. Does anyone think I need to have the valves checked?

Once the engine is up to operating temperature you should not need to use the idle advance lever to keep the engine from stalling. You need a tune-up.

I find that I have to feather the clutch (even after changing sprocket ratio) until the bike is above 15 mph.

Yes...you have to check the valve lash. Especially if you’ve never done it before.


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that's just the romantic bullshit people like to spread. it's just a motorcycle, it should be able to function as one.
Eh, sometimes NOT. My 500SL Pantah was OEM'd with 36mm Delortos. It was an animal that really enjoyed being out of its cage. Get it in town traffic, and sometimes it would just_plain_die.

And the only way to restart was to use the choke (note--it was a REAL choke lever..). And then UR off again.

The 36 Delortos did not draft well at an idle. Quite an "over-carb'd" engine. Shit, they were placing 32mm D's on the 900's of the era. 40's on my MHR Mille (2x engine capacity!) 36's on a 500?

Yeah, but she did like to sing all the way up to 10,000 rpm (and past?) -- hey, no valve float 'ya know...

My ST4s is pretty civil, but I would not say it's as civil as a Honda VFR (or whatever). Ducaties to me, have always been a niche-running bike. Better now than the "old days", but still slightly quirky (as compared to the Jap, and other Euro brands).
 
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