Slow throttle response

[Transient]

Hi Guys,
I'm a newbie to the world of Ducati and I have a couple of issues with my 2002 M400 (carbie).

Firstly, it takes forever to warm up with the choke on, and I mean a good 7 minutes. Only then do I feel confident enough to disengage the choke with the hope that it wont stall. Even then I have to blip the throttle to keep her alive enough to take off in first. Is this normal? Once warmed though she runs fine and idles fine (around 11,000rpm).

Secondly, I feel as though my throttle 'sticks' sometimes. For example, i will be at the lights and I go to take off and the first twist of the throttle does nothing, but the second twist revs and all is good. It feels like the first twist of the throttle is not opening up the carbies, but the second throttle twist unsticks the carbies and she is good to go. how can i remedy this?

I hope this all makes sense, and any advise is most appreciated.

[monstermick58]

Hi Guys,

 Once warmed though she runs fine and idles fine (around 11,000rpm).

There's the problem right there.   

A little more info is required here.

   What type of fuel are you using?

   And when you say 'the first twist of the throttle does nothing, but the second twist revs and all is good.' Do you mean after the first twist of the throttle you let the throttle back to the stop and then twist again or are you twisting the throttle twice so its close to full throttle?

But as a rough guess, it sounds like your carbies need to be removed and cleaned and serviced with a new needle and seat installed, diaphrams need to be checked to see if they have cracked or split as they will tend to do this if they have sat for some time.

   The throttle grip is on properly isnt it ??





                                      Mmick

[Twizted]

And lube the cable for your throttle. The 400 Monsters are grey imports from Japan. Most sit in open yards in the weather before they are exported here for extended periods of time. So a few things may need lubing and servicing. I would make sure your chain isn't rusted either.

[Transient]

thx for the responses guys,


I'm using just normal unleaded, no ethanol and nothing high octane, usually Shell 91.


I twist the throttle, there is no response, so I let it drop again and then twist. On the second twist there is a response. Feels almost like the throttle cable is not opening the carbie, like the carbie itself is stuck closed.


The throttle movement is perfect (withing the 2mm band)

How do I lube teh throttle cable? Any instructions or pics??
Thx again 

[Two dogs]

Transient , have a really really good look at your cable , I had one fray on me around the throttle tube and jam on at full throttle during acceleration , it was not fun 
But more than likely it is carbie /tuning related as others have sugested.

[monstermick58]

thx for the responses guys,

How do I lube teh throttle cable? Any instructions or pics??
Thx again 

Go to your fave m/c shop and ask for the clamp that goes on the cable to lubricate it (usually found in the dirt bike section) you will need some chain lube in a pressure pack can, you then have to disassemble your throttle (two little screws under the throttle housing) unclip the two throttle cables put clamp on insert the little extension tube that comes with your spray can, squirt lube in then repeat on the other cable.

   Just thinking, do the same to your choke cable as well, you dont want that to stick open.






                                      Mmick

[dragonworld.]

That lengthy warm up on choke might not be doing your plugs any favours either!!

My 750 will foul plugs if I use the choke to warm it up! I start it on choke and then choke off and use the throttle to warm it up, no probs after that! 

That initial throttle fluffiness could be some carbon buildup on the plugs and once blown off all is good!

Worth a try!?

[Transient]

That lengthy warm up on choke might not be doing your plugs any favours either!!

My 750 will foul plugs if I use the choke to warm it up! I start it on choke and then choke off and use the throttle to warm it up, no probs after that! 

That initial throttle fluffiness could be some carbon buildup on the plugs and once blown off all is good!

Worth a try!?

Yeah good point mate. I plan on checking the spark plugs this weekend, new plugs could do the trick...

[NFG]

I had a similar problem recently, and it turned out to be the emulsion tubes in the carbs.  I tried plugs, cables, everything else first.  Basically, it was not producing the right fuel/air mix at low RPMs, so it didn't want to run cold, and would hesitate when getting back on the throttle, like when coming out of a corner or after slowing for traffic and then accelerating again.

Luckily the tube swap was a relatively painless operation.  Figure less than an hour easy, now that I know how it's done.  2 hours the first time.  =)

[Transient]

I had a similar problem recently, and it turned out to be the emulsion tubes in the carbs.  I tried plugs, cables, everything else first.  Basically, it was not producing the right fuel/air mix at low RPMs, so it didn't want to run cold, and would hesitate when getting back on the throttle, like when coming out of a corner or after slowing for traffic and then accelerating again.

Luckily the tube swap was a relatively painless operation.  Figure less than an hour easy, now that I know how it's done.  2 hours the first time.  =)

Thx mate, I think i will look into it also. Do you know where I could find a tutorial on how to do this?

[NFG]

Sorry, no.  Someone found it and printed it for me, all I had was a handful of A4 sheets with a step-by-step.