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-   -   1998 400L sport top end rebuild questions/help (https://atvconnection.com/forums/polaris/315585-1998-400l-sport-top-end-rebuild-questions-help.html)

1996dragshee 07-17-2009 03:11 PM

1998 400L sport top end rebuild questions/help
 
Hey guys i'm new here.I personally own a drag banshee but have a few other play toys too.

I'm doing a top end rebuild on this 400L and it's running like crap.I tore the top end down,honed the cylinder and replaced the piston,rings,gaskets etc. Anyways it starts up fine but is real shaky like.kinda like a car off time.First i was thinking maybe i installed the piston in backwards lol...(which i have never ever done before!) but then called the local dealer and they said the windows on the piston should face the intake side correct? Also when this thing starts and idles for a few minutes (2-3) the cylinder gets super hot.And as it runs it backfires a little here and there after it starts to get warm and the carb sprays fuel out instead of sucking it in...wtf? I thought maybe it was really lean but i fattened it up a bit and not much changed/The plug is still dry and pretty clean,not oil fouled or even sign of oil,and the oil pump is working i double checked.But it does smoke,just doesn't smell like a 2 stroke.Also where the two exhaust flanges meet up it right in front of the cylinder smokes from there too...smells like something burning and it isn't oil mix.

I guess my question is how do i check to know if and where i may be leaking coolant in at? And would leaking coolant like this seem suitable to a problem such as mine?

I've done my fair share of top end rebuilds but this is my first polaris and so far a PITA. Any info guys? Thanks!

I even took the oil pump line off and plugged the intake and mixed up some 2 cycle oil in the tank to see if it would run off of mix and i got the same problem.It runs a little better but definitely not like it should that;as for sure

uncertifiedmechanic 07-17-2009 06:41 PM

Stator key in place and marks lined up?

old polaris tech 07-17-2009 06:47 PM

IF you didnt bleed 10mm screw on head to purge air from coolant,WILL overheat every time!! I've had several customers do this,usually blows head gasket,plus can warp head/cylinder if gets too hot!

1996dragshee 07-18-2009 08:55 AM

Alright I oped the rad cap and purged the 10 mill bolt on top of the head.not much air at all came out.I started it for a sew seconds and shut it off just to check the plug to see if its wet and it is but doesn't seem like an oil wet.also noticed when I took the plug out.smoke lingered out of the plug hole (only ran a few seconds) and the cylinder was still cold.I'm thinking its leaking antifreeze inside or something.what's the best way to check for it? Just pinch the hose and drain the fluid to pull the head off? Or is there an easier way? Thanks guys

1996dragshee 07-18-2009 09:37 AM

Ok another question,there is a tranny oil and a motor oil correct? Trans in the yellow dipstick and crank case oil fill on top of the case,grey fill plug correct? How much and what weight oil for the crank case?.sorry for the elementry questions fellas.this polaris is a little different than my 588cc banshee lol

1996dragshee 07-18-2009 10:52 AM

Was doin some reading and found that the crank case takes 70cc of oil.Also i pulled the counter balance plug i think it is (10 mill bolt very bottom right side case) and nothing came out...so that's good right?

Also seen another guy posted a similar question and was wondering if maybe my water pump or crank seal could be bad.If them seals are bad how can i tell?

Thanks guys

old polaris tech 07-18-2009 11:42 AM


Originally Posted by 1996dragshee (Post 2821883)
Was doin some reading and found that the crank case takes 70cc of oil.Also i pulled the counter balance plug i think it is (10 mill bolt very bottom right side case) and nothing came out...so that's good right?

Also seen another guy posted a similar question and was wondering if maybe my water pump or crank seal could be bad.If them seals are bad how can i tell?

Thanks guys

If the w/p seals were bad the counter balancer area would have antifreeze in it! Should have about 75 cc's of 30 wt oil in counter balancer area,should show on tip of grey or orange(depending upon year model) filler plug. If you cracked radiator cap and opened screw,POSSIBLE still didnt bleed long enough! Must have stream of antifreeze out of head with no air bubbles. There are TWO drain plugs at bottom of engine,one for the engine,one for the counter balancer,the only one dry should be the engine(crankshaft drain) its the one to the far right! Also should show coolant circulating in radiator,IF not then may have waterpump problem! Trans dipstick is behind engine,yellow dipstick.

1996dragshee 07-18-2009 12:24 PM

PM sent old

old polaris tech 07-18-2009 08:39 PM


Originally Posted by 1996dragshee (Post 2821906)
PM sent old

PM sent in return OPT


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