burning oil

[400exrida06]

My 400ex is starting to burn oil, i can fill her up and ride around for about 3 days then i'l have to fill it up again, does this mean im going to have to replace the gaskets or seals? Thanks

[fitethesystom]

<font color="green">That is a considerable amount of oil loss. I would look into it before riding any further.
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When does it burn oil? If it's only until it warm's up you will need new Valve seals, and a head gasket.
However, depending how much it is smoking, it could be a number of things. If it smokes all the time it could be either: Bad rings, worn bore, out of round, bad taper. Check for an oil leak. You will need new base gasket forsure if you decide to pull the cylinder and head. Get yourself a Clymer's manual and take your time. I'm rebuilding right now and I'm waiting no my part's and fresh bore & oversized piston and then it's time for Assembly (I'm really excited). Good luck, and keep us posted with your situation!

Mike,

[fitethesystom]

oh, and make sure it's blue not white or black!

[400exrida06]

Ya it basically just smokes when you first start it, and the smoke colour is blue, but i think i wanna pull out the engine and put in a piston or something, while i have it all apart.

[fitethesystom]

Ok, well basically if it smokes on startup chances are it's your valve seals. However, to fix this all you do is pull the head off, fix, and clean valves, dome, replace seals, clean the old gasket off, put new gasket on and re-install it. But if you want to you can just throw a new piston and rings in there. It's up to you!

Good luck.

[kyex40047]

It does sound like your valves. When you have it pegged, and then let off the gas completley, does it do it then too?

[400exrida06]

Umm i havent really noticed any smoke when i let off the throttle when i got it pinned. For the piston should i get a wiseco 11:1 and which bore? Thanks.

[xc_racer1]

i race a one hour race and im out of a quart.. and thats been for about a year now.. and mine still runs fine... just check ur plug.. if its black then ur rings are shot
u could also be running to rich..

[400exrida06]

Ya i think im going to end up changing my rings in it while i have it apart because the plug is pretty black.

[fitethesystom]

real bummer bro...

i couldnt handle the smoke so i took her apart, next week i'll have my newly bored motor back n oversized piston . i'm excited to ride again.....

If you dont take care of it one day youll be riding your engine will use all the oil and bang it seizes up. Not a pretty picture.

[400exrida06]

Ya it is pretty chitty lol, what kind of piston are you putting in yours?

[fitethesystom]

oversized Wiseco piston & kit

[400exrida06]

Oh cool where did you pick that up? Have your ever ordered anything out of the Royal Distributing, they got pretty good deals on stuff in there two. I think thats where im gunna order my piston from but i have no clue on which to get lol.

[fitethesystom]

I ordered it at Sturgess Cycle and yes I've bought many thing's from Royal Distributing, I recommend going to your dealer for a look over to measure for out-of-round, bad taper, and what not. Most dealer's send the engine away to a professional machine shop where they can bore it. It's quite an involved process once your in there, none the less it's not too bad. Originally I wasn't planning on boring, but my cylinder was scored and I wanted to start fresh, so here I am. I'm just working on my head now preparing everything and waiting for my part's to come on (base gasket, head gasket, cylinder, piston & kit, and then i'm going to start assembling :D Royal only offers the wiseco for 162 but check your dealer.

Good luck!


Mike,

[fitethesystom]

Depending how much of a bore you get, you will need to look in the summer catalog under 'pistons' and you look for your bike in Wiseco Pro-Lite. current price is 162. youll need gasket kit, too.

[400exrida06]

Ya im gunna do that, all the dealers around here are pretty expensive lol, but if i did get a piston from the royal would i get the bore size 85 or 86? And how much does it cost to get the engine sent to get bored out a little?

[fitethesystom]

depending how bad your cylinder is worn you can get a number of sizes, i would go to your local dealer for a free look over wont cost you a penny and they will tell you what you need, get a price quote while there but if the price is too high walk out. Boring is roughly 60 dollars or so. then honing is 25-40... then gasket kit is 40-60, and then the piston is whatever, and that should about wrap it up for the cylinder.youll probably wonna do some head work too, but its up to you... :D

[rooster300ex]

Originally posted by kyex40047
It does sound like your valves. When you have it pegged, and then let off the gas completley, does it do it then too?


I sure do wish somebody would of answered this question. But thats what it does you have to have it pinned and let of the throttle completly. if i have it pinned and let off the throttle to 1/4 throttle it does't do it.

[fitethesystom]

If you want to find out accurately, do a leak down test. You will know what it is then, when you follow the proper instructions.

[bigballz400]

thats not much oil to be burned........mine burned a quart every 3 hours
smoked rings in waynoka last time i was down there.....spend 36 bux on oil for 3 days

[fitethesystom]

Well it doesn't matter, that is a consiersable loss for a fourstroke, and it's not worth running it if it's burning oil, your not doing anything any good. Don't leave it as you will experience overheating and engine seizing, and you DON'T want it to seize.