hi im new to the forum but today i bought a 2001 polaris scrambler 400 i already had one but it blew up and i bought this one today because it was cheap but to day i rode it for about an hour and it ran fantastic but when i was riding it going preatty fast i let off the throttle but then i went to give it gas after it slowed down and it just boged down it stayed running but i could barely give it any gas because it just bogged the guy i bought it from put a twist throttle on it and he premixed the fuel and he said the ratio was 32/1 what could case this thanks for the help

 

Like I said in your pm 32-1 is way too rich! Drain the tank and try 40-1 first and see if it helps on the bogging issue. You can actually have too much oil and not enough octane.A lot of people think more oil the better,but it's really the opposite. This may or may not be the problem,but it's the first thing I'd do. If this doesn't help,it might be time for a carb clean/rebuild, plus even a small tear on a reed pedal can cause problems. A simple compression test can tell a lot also. If it's at least 125-130 psi you can eliminate piston/rings as a problem. OPT

 

will the compression be the same if it is bore .020 over

 

Compression depends on how old the bore is,if it was set up properly,etc. There's no two engines that are the same. As a general rule of thumb on the 400 a new engine should be around 145 psi or more. This is what they were with stock bores on average. .020 over wont increase the compression that much unless you've had the head or cylinder work done that would. We only ran 36-1 on stock KTM 2 strokes and 32-1 along with 108 octane race gas/pump gas mix on higher compression modified engines.

 

today i checked the compression and it was at 76 psi but after i checked the compression i went to try and start it and it wanted to but couldnt because it was flooded would this be the piston rings or what thanks for the help

 

Sounds like you found the problem. 76 psi is way too low. You'll have to tear the top end down to see whether it is a piston or ring seizure or if this is a new bore as I assumed from your pm,sounds like someone may have allowed too much clearance? The crank seal behind the front clutch can cause compression problems also. You might see if it has popped out or seeping before you do anything to the engine. I have had this happen several times.

 

What would it be sepping and would it still be piston or rings if it wants to start but just dies

 

But I took the compression with no throttle would that make a difference

 

Try the compression test again with throttle wide open and see what the results are. Even if you get to a 100 psi or so,it's still too low. It may try to start,but won't have enough compression.

 

Today I checked the compression with the throttle open and it was at 99psi but I removed the motor and I can check out the piston