You can do a leak down test shown above to see what is leaking,but for most people it's not that practical,but it's the best method to eliminate the base gasket,head gasket,intake manifold, engine case,etc as the source of the air leak.If they are ok (tested with soapy water) then you know the seals are leaking. Most times it is the seals with the one behind the front drive clutch being the worst culprit.You can see fuel/oil traces a lot of the time around the seal and shaft. Once you pull the clutch plus the flywheel and stator plate,you're already there anyway! Just go ahead and pop em out and replace em..

 

Okay makes sense. We checked the intake manifold and the base gasket was replaced when we replaced the rings so I know that's good. I read that with the clutch puller, the clutch side seal was fairly easy but that the other side was more of a task. Any pointers? Should we replace the clutch side first and see if that does the trick?

 

Do the clutch side first. If it still runs crappy,you can get a "loaner" harmonic balancer puller from most Autozone or O'Reilly dealers,etc to pull the flywheel. Once off, mark the stator plate position "IF" it doesn't have index marks on it and the engine case,and remove out of the way to get to the seal. A simple seal puller or even a drywall screw can help pop em out.

 

Awesome, thank you. I'm sure ill post back after the first one.

 

Not sure where the clutch side crank seal is... I was gonna post a picture but I can't figure out how. We pulled off the primary clutch and all we see behind it is a bunch of rubber and a metal plate with a hole in it and 4 screws holding it in. Where is the crank seal?

 

The crank seal is right behind the metal plate and engine rubber seal. You should be able to see the crank seal behind this,but if it makes it easier,pull the 4 screws from the plate and remove it.#28 and 29.Dirt Cheap Yamaha, Honda, Arctic Cat & Polaris OEM Parts & Accessories – Cycle Parts Warehouse

 

Hi I have a Polaris 1996 250 trail boss.
i need to replace the front sprocket-1 broken tooth!
question: how to remove the sprocket. when

 

Have to remove the caliper,rotor out of the way to get to the sprocket.Then remove it from the frame hole. Dirt Cheap Yamaha, Honda, Arctic Cat & Polaris OEM Parts & Accessories – Cycle Parts Warehouse

 

Okay, Replaced The Clutch Side Crank Seal And Put Everything Together And Now It Runs With The Choke On And When You Shut The Choke Off, It Revs And Shuts off. We Have Adjusted The Carb Every Which Way And Cleaned It And Can't Figure It Out. This Thing Is Getting Annoying! Any Ideas?

 

Again it can be BOTH crank seals leaking,the crank case itself could be leaking around the seams, lean carb jetting,leaking around head/base gaskets even though they may be new,plus if you just replaced the rings only (mentioned from your first post) I'd do a compression check to see where you stand on the top end. Must have at least 120 psi if not more. Also if you know someone that has a leak down tester it can save a lot of frustration on tracking down any problems.