If you have the 2 stroke carb,you can loosen the 10mm lock nut on the choke adjuster at the carb and screw it in until you have a little play on the choke lever,then tighten the lock nut.

 

It's a magnum 425 four stroke....

 

Same thing but the choke adjuster is on the side of the carb.Loosen the nut and screw it in until you have about an 1/8" play at the lever. Also on cold days you can do as many call it "double choke" to get one started easier. Flip the lever all the way over to crank,back to middle position then off when it's able to idle on its own. Here's a good pdf section on carbs from the manual that includes your BST34 Mikuni.https://www.google.com/url?sa=t&rct=...U2gGlaHJWSIlbA

 

Thanks for the great info. You are the man!

 

I took my mikuni bst 34(?) carb apart to clean it. It's on a 1995 Polaris Magnum 425. A bitch to get to by the way. The choke was the toughest to get to as there isn't much room to work. Anyway , as I was removing all the jets , it seemed like they were screwed all the way in. Aren't they supposed to be adjusted out a certain amount of turns? If so, could someone please give me some guidance? I'd like to know before I put it back on and find out the hard way. I also have a Yamaha Raptor 660 but man , they are two totally different animals ! Also the needle looks like it's in the #3 position. Is this correct? And is the drain screw supposed to be pointed or flat on the opposite end of the slot? Any help is appreciated. Thanks guys

 

Jets screw in snug. 3rd position is usually ok on the needle. Only the pilot jet(if the block off plug is removed) is adjustable along with the idle control screw. Normally 2 turns out from a lightly seated position on the pilot jet(fuel screw). Turn the idle adjuster until you have around 1050-1100 rpms.

 

Thanks for all your replies. Is it better to run rich or lean? I'm thinking about going up a notch on the needle. And why the hell did they put the spark plug where they did?? Holy moly.....ha

 

Running lean can heat things up bad enough to wreck your engine so I'd say that's worse than running rich which will keep fouling plugs but not cause a meltdown AFAIK.

 

Just do a simple plug check after a high speed run. Get it warmed up,get to speed and slide the kill switch and stop as soon as you can. Let it cool down enough to pull the plug. Electrode should be a tan to medium brown.

 

Thanks for the replies guys. I'm waiting for a coil wire to come in along with a throttle body cable guide. I lost it while cleaning my carb! I can't find it anywhere. I'm hoping it didn't go down my intake.I've had the quad idling since then so I don't think so.