Riding in dusty situations, I have noticed that the throttle is "sticking" between 3000 and 4000 rpms. Pulling in the clutch and rolling off the throttle results in the rpms hanging for a few seconds if I am between 3000 and 4000 rpms. It then slowly returns to idle. If I am running at 5000 rpms, it returns to idle normally. After I return to pavement, the problem goes away in time. It might take 2 miles; it might take 50 miles. This seems to depend on the amount of dust. More dust, more time. I am managing the situation by rolling off the throttle and delaying pulling in the clutch for a few seconds. Any ideas what is going on here?
1 )when were the valve clearances last checked
2) Look for an air leak around the air box if you just did service on the filter .
3) when was the last time the carb sync was checked
4) have you verified that the linkage on all three carbs isn't hanging on 1 or more carbs
5) the fuel pipe is a pretty close fit to the carb linkage and I have had that cause the exact same problem you describe cuz it was rubbing on the linkage
6) could it be time for a new throttle cable , look for a break in the plastic housing where it comes out of the twist grip , been there done that on Mrs. M's 95 , was the same symptoms you describe