[avandr]

Hi guys, I have an issue where at approx quarter throttle and with no load on the engine there is surging present, I believe the correct term may be hunting? There are no missfires, just revs drop slightly and pick up again. I gave the bike a fist full and it seemed to disappear, however it returned after stopping at a set of lights. Idle is good and pulls well under acceleration.
Mods: Side stand switch disconnected, Hitchcocks Header pipe & Silencer, K & N Airfilter, NGK BP6EXI plug. 1080kms on clock.
Any suggestions to point me in the right direction would be greatly appreciated.
Thanks in advance

[Ducati Scotty]

Is your air filter in the original air box or mounted right on the throttle body?  What's your idle speed when it's fully warmed up?

Scott

[avandr]

Air filter is in original air box with plastic cover, no obstructions.
Not sure of actual idle speed but its not slow or high, I would guess it is ideal going by You Tube videos of other C5's.

[Ducati Scotty]

Chain tension?

[avandr]

2 inches on centrestand

[Ducati Scotty]

All the stuff you mentioned sounds good.  Is it possible you got a bad batch of gas?  Is the plug getting old?

Scott

[avandr]

Thanks Scott, plug is new also. Tomorrow is Melbourne cup day and we have a public holiday. I will take the bike for a good run on the highway at 100kph for a good stretch and see if the O2 sensor dials in, I fear all my riding has been at low speeds around suburbia not giving the sensor any time to calibrate.

[wildbill]

id remove the k&n filter and put the original back on and see if it returns back to a normal running motor.
mine did exactly the same and thats why the k&n is back in it's box

[avandr]

Thanks Wildbill, I was actualy thinking of doing this also, I will change the air filter back and see how it goes.

[barenekd]

I'd give the bike another 500 km. It'll probably smooth out by then.
Bare

[Ducati Scotty]

+1 to both of the above.  Change it back, see if it behaves.  Then you can go back to the K&N again and run it for a while.  If it smooths out fine, if not you know you can go back to stock.

Scott

[avandr]

Went through a process of elimination.
K&N airfilter back to std = no change.
New plug = no change.
Std header pipe & torpedo silencer back on = no change.
Now with the bike back to as delivered I spoke with the dealer who agreed to hook the analyser up and see if there was anything obvious.
It had to hapen didnt it, its around 20km trip to the shop, with the problem getting worse as I rode when at about 15kms problem all but dissapeared.
As expected dealer could not find any issues.
Put my Hitchcock header pipe and silencer back on and it is running fine.
I am at a loss as to what may have caused this issue.
Perhaps some condensation on connectors somewhere

[Ducati Scotty]

Your bike is just scared to go to the doctor.  Next time it acts up tell it, "If you keep doing this I'm taking you to the dealer!"

Scott

[gremlin]

Computer is "learning"

there are factory default "maps" that are a close approximation for the amount of fuel and spark advance needed for any particular combination of engine speed and vacuum.

as you drive the computer creates an offset table based upon hunting around the O2 sensor (deliberately driving the engine lean to see how much LESS fuel is needed for any specific combo of speed & density)

Your Modifications require *more* fuel than the factory maps.

hence the dropouts during hunt.

[avandr]

Thanks Gremlin, I figured that was the case.
Having said that with the Hitcock header, EFI Silencer & stock airfilter in place I went for a decent run yesterday with no issues, just appeares to be running rich going by the the color inside the pipe which was quite sooty, spark plug looks the right color though.
One thing I should have mentioned, with all of the mods there is no difference in seat of pance performance to the stock setup, I just like the sound of the Hitcock EFI silencer.

[ROVERMAN]

IMHO, (yes i abbreviated!) no cat more soot and vice versa.
My 20p worth.

[gremlin]

......................with the Hitcock header, EFI Silencer & stock airfilter in place I went for a decent run yesterday with no issues............

Interesting .....  was the K&N one of those POD types that attach to the throttlebody,  or,  an oiled gauze replacement that fits in the stock airbox. ?

There is a whole other thread about the apparent evils of short intakes, the main point being to have a stored volume of filtered air that can readily fill the cylinder during the intake period.

[tooseevee]

Hi guys, I have an issue where at approx quarter throttle and with no load on the engine there is surging present, I believe the correct term may be hunting?
Thanks in advance

             Surging is pretty much the correct term for bike engines. Hunting is more what older governor-controlled diesel engines would do when they couldn't get along with their old worn out governors. They would hunt for an RPM where both the throttle & the governor were happy. They'd oscillate up & down x number of rpm never quite being happy with each other.

[avandr]

An oiled gauze replacement that fits in the stock airbox