2000 2 stroke 400 polaris xplorer

[Pennywise]

well the quad is lacking bottom end ??????????? ..... also now starts fine neutral it runs great with throttle when it is in gaged high gear or low or reverse she bogs out no power what could it be?

[DirtDemon]

A tired motor perhaps? I would start by doing a compression test. Perhaps a leakdown test as well to check the seal on the crankcase.

[Pennywise]

thanks alot man i will do sum testing

[DirtDemon]

You are welcome, let us know how it goes.

[Ajmboy]

How many miles/hours on it? I agree with DirtDemon, do a compression test.

[Pennywise]

i did compression test 90 105 with pull start tore down engine gunna replace piston rings n top n bottom gaskets clean carborator spark plug was black got new 1 clean air filter umm just waiting for piston rings to get in from ordering them??any suggestions anyone?>

[DirtDemon]

It is very importand that there is a good seal in the cylinder/crankcase area on a two stroke. It's operating principals are heavily dependent on alternating pressure and vacuum signals in the crankcase. Google "leakdown test" there are ready made kits on the market, but they are expensive. You can make your own using cheap parts that you can get from a hardware store. The hardest part to find is an air guage that reads in small increments, you need to be able to read a drop of just 1 psi. The idea is that you plug the exhuast port off, and pump the motor up with air from the intake side. Google "leakdown test" and do some reaserch. It is a real pain, but it can help you avoid catostrophic damage to your motor. Here is a pic of a home made leakdown tester, the rubber squeeze plugs on the right are what was used to seal off the exhuast port, the pump, hose, guage unit has an end on it that fits snuggly into the intake boot, and you just tighten it down with the clamp just as you would the carb. Note the ball valve between the pump and the guage, this is necessary to seal the air pressure in the motor. I have no idea what the object in the lower right hand corner is for, I just found this pic on the web and thought it was a good example. The downside is, if there is a leak it will need to be fixed, if it were in the the internal crank seal, or a leak between the case halves, you would need to take the top end back off and split the cases to fix it. It would have been best to do the leakdown test prior to tearing the top end off, that way you would have known it there was something else causing problems. My suggestion would be to just take care of potentiol problem ahead of time. While you have the top end off, just split the cases, get a full gasket and seal kit for the motor. This will aslo give you an opportunity to check other things like the crankshaft and bearings. Either way, when you get the motor together, do the leakdown test, it can save you from blowing up the motor you just put back together.