1990 dr250 flat spot
 

hi need help finding the problem with my dr 250 its got a flat spot between 2000 3000 rpms only. runs fine but soon as you hit 2000 it splatters then soon as you hit 3000 it run smooth anyone got any ideas thanks.:confused1:

Have you got the original type of air filter on it?

Cheers bloke,

Nigel in NZ

Flat spot
 

Hi.
Firstly, which you have probably done, give the carb a full strip and a good clean with an air line if poss.
Whilst it's apart, have a look at the main needle jet and emulsion tube (the brass part that the main needle slides into that you can see when you look down the venturi).
You will have to remove the main jet and push the jet/tube up from the bottom.
There are loads of small drillings in this tube (emulsion holes) that you need to make sure are clean.
Have a good look at the needle jet where the main needle slides in and out.
This can sometimes become worn due to the needle being "sucked" against it and develop a keyhole shape.
If this is the case it will need to be replaced.
I've had this a few times on singles and it causes the flat spot you mention.
Check the other other "usuals" such as float height, needle valve ect.

Hope this helps. Dave.