Ducati.ms - The Ultimate Ducati Forum banner
  • Hey Everyone! Enter your bike HERE to be a part of this months Bike of the Month Challenge!

1 - 12 of 12 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter · #1 ·
Hello all,

I am having an issue where my bike breaks up, stutters, and loses power consistently at 6k rpm. I didn't ride too much last year but never noticed the issue until I got the bike out this spring.

Acceleration is completely normal until 6k rpm pretty consistently. It doesn't matter if I am WOT or barely getting on it, it will break up once I hit 6k. If I stay in it, it will sputter and if it makes it to around 7k, it accelerates again. Downshifting is fine and it doesn't break up at all as I let off the throttle and it passes through the 6-7k range.

I have already changed my plugs and just changed out both coils today thinking that it could be a bad coil. I have thought about the TPS but that doesn't make sense as well since it only happens at 6k regardless if I am at 25% or 100% throttle. Not only that, but I know that I will have to swap the entire throttle body out which I can do but not without a reasonable possibility of it fixing the issue.

I checked the valve clearances about 4500 miles ago and all were within tolerance. I have tried searching through old threads but haven't been able to find a similar scenario. I am typically pretty mechanically inclined and cam troubleshoot my issues but this one is throwing me for a loop.

I am supposed to be taking off for a bike trip in two weeks and I am not sure if that is going to be able to happen if I don't get this straightened out. If anyone has any potential tips or has experienced a similar issue, I would be be extremely grateful for any support.
 

·
Registered
Joined
·
3,503 Posts
i'd do the fuel filter, or even check the fuel pressure in case it has a soft pump. i did the cam timing on one a while ago and the inlet advance gave it a real 6k hole, so maybe the fuel map is light on there anyway.
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #3 ·
i'd do the fuel filter, or even check the fuel pressure in case it has a soft pump. i did the cam timing on one a while ago and the inlet advance gave it a real 6k hole, so maybe the fuel map is light on there anyway.
Thanks for the input. I ordered a new fuel filter that should be here tomorrow. If that doesn't help, I will have a new fuel pump early next week. I also decided to get some sea foam to to run through it but haven't had a chance to run it since.
 

·
Registered
Joined
·
7,360 Posts
What condition is the air filter element in ?
 
  • Like
Reactions: Strega

·
Registered
Joined
·
7,360 Posts
Dirty throttle bodies can do cause a stumble.
 

·
Registered
Joined
·
346 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter · #8 ·
I know you mentioned you don't think it's a TPS issue, but in case you do want to explore that possibility, you don't need to buy the whole TB assembly. You can buy the TPS unit alone extremely cheaply online, and it works a treat. Throttle Position Sensor TPS 40443002 Fit For Fiat Chevrolet Zhonghua Ducati | eBay
(running this in my bike currently to fix a bad previous unit)
Thanks for sharing that, I might order one to have anyways. How did you swap it out? I have read that it is glued into the TB.
 

·
Registered
Joined
·
346 Posts
Thanks for sharing that, I might order one to have anyways. How did you swap it out? I have read that it is glued into the TB.
I don't think it's glued... a pair of pliers had it out in short order. There's a O-Ring and a metal spring ring that's designed to give it sideways tension when in place that holds it in.
 

·
Registered
Joined
·
15 Posts
I'll be surprised if you find that the fuel pump or filter is bad, since the bike accelerates hard again when you get to 7K rpm. If you had fuel starvation it wouldn't take off again. On a carbureted bike the first thing I would look at would be carb needles, and so on an injected bike I'd be thinking mapping. But you said the bike ran fine last year and this problem occurred after a lay-up. Even the TPS seems unlikely to me, since you say the problem occurs no matter what the throttle position, whether you're running wide open throttle, or sneaking up on it at 1/3 throttle.

Does the bike have a Power Commander installed? Do you have a shop with a dyno nearby? It might well be worthwhile to pay for a run and see exactly what's happening. Good luck! And let us know what you find, it's a poser for sure!
 

·
Registered
Joined
·
346 Posts
Or you could invest in some DIY diagnostic stuff... adaptor and cables to run TuneECU (or DucatiDiag if it's still around), and you might be able to rule out anything electric/electronic.
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #12 ·
I'll be surprised if you find that the fuel pump or filter is bad, since the bike accelerates hard again when you get to 7K rpm. If you had fuel starvation it wouldn't take off again. On a carbureted bike the first thing I would look at would be carb needles, and so on an injected bike I'd be thinking mapping. But you said the bike ran fine last year and this problem occurred after a lay-up. Even the TPS seems unlikely to me, since you say the problem occurs no matter what the throttle position, whether you're running wide open throttle, or sneaking up on it at 1/3 throttle.

Does the bike have a Power Commander installed? Do you have a shop with a dyno nearby? It might well be worthwhile to pay for a run and see exactly what's happening. Good luck! And let us know what you find, it's a poser for sure!
The bike is still completely stock except for cored mufflers. I am with you that I don't think it is the TPS based on it not being specific to a certain percentage of throttle. As far as fuel goes, if an injector is partially gummed up and the fuel filter has enough pressure drop, the two together may be causing an issue as the bike demands more fuel at that point in the map. Around 6k is when the powerband really starts to kick in. I am going out for a ride now to get the sea foam running through the engine and then will go from there.
 
1 - 12 of 12 Posts
Top