Is it normal for these bikes in stock form to have a slight flat spot/bog/hesitation at the very bottom of the RPM range? After that initial hesitation the bike winds right up, w/o any issues. I only ask because I just want to know what is normal and what might require some more fixin'

Thanks for the insight.

My 2001 XR400 does - but so far, I don't think it's too bothersome (just got the bike).

There are many posts here about upgrading to a 'pumper' carb to get rid of the issue. As I understand it, it means replacing the carb with an aftermarked one, ~$300. Search for this topic and you'll find a lot of info.

Rob

How much of a bog are u talking about?
If you are grabbing a handful of throttle and just snapping it open then you will get a slight lag, if your revs are low enough you could even kill it.
Aside from that, [grabbing too much throttle] if you are getting lag then you need to sort out your idle mixture screw/jetting.
Also, an airfilter with too much oil/dirty~blocked will definitely cause some lag.

Yes it is normal for stock XR's to do this.

If the idle system is clean and you are rich enough at the pilot jet, then you might try raising the idle a few hundred rpm passed the bog. When running tight deer trails with lots of stumps and boulders that will cause you to stall out lots, that is what all of my crew do !! Works wonders.

Cheers,

Look in the FAQ for "Bog"

I have a 98 400, and was plagued by this and was contemplating the pumper. But after several months of tuning and jetting changes , its gone. Proper jetting will eliminate it. the higher idle will help also. I can spend the 300-400$ on suspension now!:ride: