Hi Folks,

I just received my new-to-me KLX250SFF here in the sunny UK. It has 500 miles on the clock and was first registered in 2016. It is a EFI model (with an ECU and electronic fuel injection).

I took the bike for a run first chance I had and carefully recorded the following stats once it was nicely warmed up:

Gear RPM MPH
1 10,000 31 - I did not allow it to exceed 10,000 RPM.
2 10,000 45 - I did not allow it to exceed 10,000 RPM.
3 10,000 62 - I did not allow it to exceed 10,000 RPM.
4 9,000 67 - max'd out RPM.
5 7,800 68 - max'd out RPM.
6 5750 81 - max'd out RPM.

The engine is consistently hesitant and stuttery when accelerating (using 3/4 throttle) between 5,750 and 8,000 RPM in all gears. There is no misfiring or backfiring or overheating; just an obvious hesitancy or stutter (like a carburation flat-spot). This is not acceptable for a dirt bike. It will be uncontrollable under power.

So, can another 2016 DFI KLX250SFF owner chip-in and please tell me that this is not normal for the bike?

I am talking to the dealer to try and get someone in Kawasaki technical support to talk me through the issue.

NB I worked on engine controller software for 5 long years so I am not totally unfamiliar with control-systems-engineering on automotive applications. I didn't design engines; I designed ECU software under the guidance of the cleverer bods that designed the engines.

I know my employer would not sell a vehicle with such poor engine control for fear of recalls so I guess there must be a fault somewhere. But, before I wade into the dealer, and Kawasaki, I just want to be able to say this is not the norm. So, can someone confirm that their KLX250 EFI bike runs smoothly across the rev range please and has roughly similar performance.

Many thanks in advance.

Transit.

 

Before I did the big bore my klx250s ran fine in those ranges as far as I remember.

Is your bike bone stock? Any mods done that you know of?

 

Ii has only done 500 miles. I can't see any mods so far.

The story has moved on slightly inasmuch as I did the clutch-engaged switch mod I.e. short circuited the wires leading to the cluch-engaged switch.

New stats are more encouraging:

Gear RPM MPH
1 10,000 31 - I didn't exceed 10,000 RPM.
2 10,000 46 - I didn't exceed 10,000 RPM.
3 10,000 61 - I didn't exceed 10,000 RPM.
4 10,500 78 - it pulled 1000 more RPM!
5 9,500 83 - it pulled 1500 more RPM!!
6 8,200 80 - it pulled 2500 more RPM!!!

The hesitancy and stuttering have disappeared. Yippee.

So, I know have an engine that is usable. Not nice to run but useable. I now need to look into freeing up the power that the ECU is still determined to hide from me. Kawasaki technical support say that the next thing to change is the exhaust to get rid of the restricted flow due to the cat.

Not sure what to fit by way of aftermarket silencer. They are all sooo loud. NB 10db increase equals double the noise level. Most of the systems I have looked at so far double the noise.

Many thanks.

Transit

 

I'd say break in period......

 

you can also get a O2 eliminator and remove the snorkel from the airbox

 

Now there is a puzzling subject. I just got the bike with 500 miles on the clock. I have no idea how it has been treated. That is problem number 1. The next problem is the plethora of diverse advice for how to run it in.

For breaking in, the user manual says. . .

Distance traveled Maximum engine speed
0 ∼ 800 km (0 ∼ 500 mi) 4 000 r/min (rpm)
800 ∼ 1 600 km (500 ∼ 1 000 mi) 6 000 r/min (rpm)

So, for the first 500 miles you run below 34 mph? I don't think so. You will be killed within minutes where I live. I have been thrashing the bike to get stats. I hope it survived. It was warmed up and has fresh oil. I'll be more merciful for the next 500 miles. It won't take long to do them. It is a real pleasure to ride. However, I have a Street Triple and Sprint ST that also need some exercise.

 

Could you have had a little bad fuel, maybe some water in the tank that ran through?