F650 slow to pick up - any ideas?

[Mouse]

I've been servicing Clare's 650 and gave it a bit of a test ride today. The thing I noticed immediately was that the engine was slow to "pick up" from under 2000rpm, in any gear (well, 1-3 anyway).

In other words, if you're trickling along with the engine almost idling, in 1st gear, and you open the throttle gently, there is a short period where the engine seems to be struggling before it picks up and accelerates normally.

I'm not sure what could be causing this. The things I have recently done to the bike are:

New chain / sprockets.
Oil change.
Air filter change.
And general cleaning, fettling.

I haven't been anywhere near the throttle body or ignition system

Any ideas? Thanks in advance

 

[Timolgra]

Perhaps a bit obvious, but is the gearing the same with your new sprockets?

 

[Fanum]

Sounds more like a fuelling issue to me....

 

[LivNorway]

-Is it a GS or a Dakar?
-Carburated?

My 2002 CS Scarver is OK.

Liv.

 

[Mouse]

It's a fuel injected GS, not Dakar.

Definitely not a difference in gearing, you can feel the engine struggle and then pick up. Sounds like fuelling or ignition to me, but I haven't touched any of those systems, not deliberately anyway. I wonder if I might have dislodged a cable or something? Like the infamous throttle cable problem on the boxers.

Gonna try a new spark plug, it's probably still on the original

 

[andy]

You changed the air filter,
There is some sort of sensor in the snorkely bit have you pluged it back in .

 

[LivNorway]

You changed the air filter,
There is some sort of sensor in the snorkely bit have you pluged it back in .

That gave me an idèa:
-Did it work just fine until you started to fix it? If it did then I guess you have put someting together not like it was.
--------------------
Hi Clare!
Never let a man fiddle with your bike! Send him back to the kitchen!

Liv.

 

[VAL. H.]

You changed the air filter,
There is some sort of sensor in the snorkely bit have you pluged it back in .

Hmm I'd be inclined to have another look at the air filter.

First of all is it the same type as the one you have removed (shape/manufacturer/spesification/OE/pattern)? If you have used a different one from the privious one, check the packaging for any info that may suggest re-jetting or other adjustments.

If all this is ok then check you have not trapped anything, and that the filter is correctly fitted and that there are no 'unofficial' gaps for air the get in the air box.

Check the sensor that Andy mentioned.

If all this is as you think it should be then ask Clare to ride it and tell you if it feels different to how it was before you serviced it.

If she tells you it feels the same then you know it's nothing you have done and get a BM dealer to stick it on their diagnostic computer to find out the fault.

 

[Mouse]

Andy got it! I had forgotten to plug in that sensor in the snorkel!

Thanks for all the ideas, I got there in the end

 

[LOLGEOFF]

Andy got it! I had forgotten to plug in that sensor in the snorkel!

Thanks for all the ideas, I got there in the end

Better get back and check the oil drain plug again then.

 

[andy]

And the reason why i got it Because i did it when i put the k&n on thought it was the filter at first.
but after a week took it to bits again and found that plug dangle'ing