Powervalve opens too soon engine has what appears to be adjustment on head thumb screw

It's all jet size and powervalve, also make sure your float level is sorted, then just swap jets eg bigger/smaller, and powervalve to suit timing

need to know what engine you have because they all adjust different but the rule of thumb... open throttle at carb all the way and pay attention to everything moving. then loosen the screw and adjust the governor... yeah see, it's easy

One adjustment screw (probably Phillips-head) is the Idle speed adjustment screw. Turn it in, to increase idle speed (it moves the throttle plate)...turn it out to slow idle speed down. The other 2 screws are the Low mixture screw and the High mixture screw. The L screw is closest to the engine and is used to adjust the engine at IDLE. The H mixture screw is to be adjusted when the engine is at wide-open throttle to get the proper RPM's....not too little and not too much. Here is a tutorial by Zama carburetor reiterating what I have just told you and HOW to go about your adjustment.
http://www.zamacarb.com/tipspage.html

Hi jamesbj44...
Before you remove or try to adjust your low and high speed jets you should always count the number of turns to lightly bottom the adjusting screws.
Be sure to write the number of turns down on a piece of paper so you will know when you go to replace them.
Normally you adjust your idle jet to 1/2-3/4 turn open from the bottom seated position to start with...you re-adjust when the engine is warm turning the screw in or out till the engine runs smoothly.
The high speed jet is normally adjusted to 1 1/2- 1 3/4 open from the bottom seated positon, then re-adjusted to run smoothly when running at high speed by turning the screw in or out.
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You probably need a slight carburetor adjustment. Try to turn the L mixture screw (the one near the bottom of the carburetor on the air filter side, closest to the engine) 1/8 to 1/4 of a turn counterclockwise. These mixture adjustment screws ( L and H) have odd heads on them and conventional tools won't turn them. I use an automotive type plastic wire connector (around 22 gauge) with a ring terminal end which I can hold. Tap the plastic end of the wire terminal connector onto the head of the screw with a small hammer and this will enable you to adjust the L screw. This adjustment will increase you high speed side and possibly allow it to run off choke in a regular manner.

Hello,
My name is Dane and I am going to assist you in solving your problem.
You will need to adjust the high speed setting on your Carburetor jet. Turning the screw out just 1/2 turn or so should do the trick. It is not so hard to adjust the Carburetor, however, yes you do need a special tool that is very hard to get your hands on, in order to adjust the jet screws. They don't make many engines with plain screw heads anymore. The newer Carburetors are factory set lean so they can pass emission standards. Since you just bought yours, a local husky dealer should adjust the mixture for free. I hope I've helped. If you found this reply useful, please leave me some THUMBS UP, if you feel I

Assuming that the adjustment screws 'H' and 'L' have slotted heads, turn both CW to stops (lightly), then back out CCW 1-1/2 turns each. This is a basic setting and the engine should start and run. Allow to warm up, then pull the throttle full on. Turn H CW until the engine starts to speed-up, but still 4-stroking. Proper adjustment is when the engine 4-strokes, but immediately 2-strokes when cutting. Release the throttle and adjust L CW for fairly smooth running, yet allows the engine to 'follow the throttle'. Adjust idle speed so that the chain stops turning, but the engine keeps running.

i have the same problem. i have recently bought a 1998 dtr, but when we had a closer look at the engin, it wasnt worth keeping. so managed to get a 2006 engin. i fitted this. but the bike seems reallys slow. I then opend the powervalve. but the bike boggs out just as i get in to the power band. i was told to re jett the bike to a 260. so will be getting that done soon. will tell you what it goes like mate.

rtcasper Clarification Request; It is the electrical adjustment (Thumb wheel Adj on facia panel) that is not functioning not the mechanical adjustment on the head lights (Plastic cross head screw adjust L/R and U/D). The thumb wheel is usually a potentiometre adjusting a control voltage applied to the head light motor. On the Merc I can't see the motor and wonder if vertical head light adjustment is vacumme operated, where the vacumme pump is located or where i can get access to the wire loom to trace it though as I don't see how to get behind the facia. ANy suggestions as to how to get to and proove which bits are working? At the moment the headlights are adjusted to point correctly by the mechanical adjustment but this does not enable me to lower the lamps easily when I put a load in the boot.

Try tripodquickrelease.com. They sell some repair parts for velbon tripods.