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Discussion Starter · #1 ·
First post here. I have a big issue, I hope someone can help with. I put a 440 kit on a 99 400. I was very particular with assembly. I put in a new chain, clutch, complete cylinder, new piston, rings, filter, oil, etc etc. I had the local shop do valve seals and check the head. Jet kit in carb, valve lash done myself, new fuel, gaskets, seals, FMF(used old head pipe, new slip on),on and on. So anyway, I start it about a month ago and it fires right up, sounds good, but smokes out garage and neighborhood! Oil in pipe is so bad it showed my every little pin hole there could be! Keep in mind it has fresh oil in it, the oil draining out of my slip on is black, I assume from the carbon build up in old head pipe.

Back up two years ago...I got this thing for a steal. Had some aftermarket bolt ons and could tell been rode hard. I got it fired up, wiring issues, and it smoked bad so I go for the 440 kit, tear the whole quad down for complete rebuild. I mean everything, paint, brakes, engine, harness, etc.

Back to present...I am very mechanical, own a custom car shop, so I know a little. I figure has to be rings or seals, so I tear it back down. When I get down to the piston, there is oil puddled in the reliefs. I get one of the guys at shop to do the seals again and check the head, all good. I pull the cylinder and recheck the rings, all good. Back together today and same same. Oil literally blowing out exhaust.

I did use a head gasket from GT Thunder along with oversize studs. I machined and installed studs myself so I know they are the correct depth. The gasket was thicker then stock, almost a plastic feel, with multiple layers.

The only thing I know that is missing is the decompressor, but didn't need with the new cam, oil filter is correct, correct amount of oil, maybe a little low until I got it warm. Double checked everything.

At wits end. please help, Any ideas are appreciated greatly. Thank you.
 

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First of all - if there's oil in the exhaust pipe it's going to take quite awhile to burn it out and quit smoking - but, if you had oil on top the piston, it's more likely a ring problem.

There is only 3 ways to get oil into the combustion chamber of a TRX400EX - intake valve seals, head gasket and rings.

There is no top side or bottom side to an oil ring and the oil has to get past the oil ring to make it to the top of the piston. So that means: if there is no evidence of oil on the intake valves, you are down to head gasket or rings. If it's a ring problem there will be oil trapped between the compression rings.

Since the rings are new, what kind of oil are you breaking it in with? The wrong oil might get past the rings and/or prevent the rings from seating.

Although the oversize studs are the correct depth, are they the correct length above the cylinder?

So much for my guessing
 

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Discussion Starter · #3 ·
Thanks for the reply. I am not sure the correct length above the head. I did measure the acorn depth and stud and seemed to have plenty of thread. Torqued to 43 ft/lbs per GTThunder. The instructions gave the proper length out of cylinder, so I assumed that to be correct. It did dawn on me last night I might try a standard nut and not the acorn to be sure of that.

I did not notice oil between rings when I pulled the cylinder this past time, but I cant say I was truly looking either. I made sure the ring gaps were in the correct places, and fit the compressing rings to the bore. I did notice one compression ring was thicker and would only fit in the lower compression slot. But other then that no difference in top/ bottom etc.

The intake side of the head was completely clean. I did clean the head pipe out completely before this past install with brakekleen and ran the hose through it for about 20min.

Using 10-40 conventional 4 stroke oil. Will prob go to semi syn once the thing is running and broke in.

If I am remembering correct there was evidence of oil on head gasket when I pulled apart but not sure if that spilled out of head. I disregarded it becasue I have no leaks to the outside of engine when I fired it. Just in the pipe. I would assume if the head wasnt seating properly then it would leak to the outside also, maybe not.

Thx again
 

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OK - provided the nuts did not bottom out (and I will presume you had the flat washers under the nuts), then the head would have sufficient pressure on the gasket to seal - there is an oil passage on the RH side of the cylinder that feeds the camshaft. That's why the RH cam bearing is sealed on one side and the LH bearing is not sealed, but the passage is separated from the combustion chamber by the cam chain well. I'm going to stick my neck out and lay blame on the rings. There is a up side on the compression rings, but not the oil ring. The oil has to get past the oil ring first. The second ring serves two purposes, scrape down oil and hold compression. The top ring holds compression only.

Change your oil to a 10w40 or 5w30 JASO rated oil (API rated SJ or lower) or a diesel grade 10 weight and see if that helps. If not, get a new set of rings, have the cylinder BALL honed to get a good break-in surface and try again.

And I almost forgot - there is an o-ring that goes around the sleeve at the bottom of the cylinder. It's somewhat a remote chance that oil is getting sucked up past the sleeve and into the chamber, but if whoever installed the heavy sleeve into the cylinder did a sloppy job and the o-ring is missing, it might happen.

Install the rings with the marks to the top side.
 

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Discussion Starter · #5 ·
No marks on rings, Namura piston, not sure whos rings. I put rings serial number up since no dot as I thought there should be. I followed 400ex top end rebuild to a t .

That all makes sense. I did not put an oring at bottom of cylinder, was no groove for one as the oe cylinder had. Figured being 440 sleeve it didnt need it.

I'm leaning to rings or cylinder too. I don't think the head was checked to a true flat but I did check w a good straight and feeler gauge.

Thx again H2H , will keep posted what I find. I hate for someone else to go through this.
 

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Namura rings have an N on the up side.Sounded like upside down rings or the oil ring center is lapped over itself. Do yourself a favor and put a wiseco in it next time. Im with H2h on the oil having to burn off as well.I also utilize a solid copper head gasket. Had real good luck with the copper. Oh, I havent seen a big bore sleeve that provides an O ring groove but I might be mistaken. Do a compression test for the cylinder, if its out of round it will show there.
 

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Discussion Starter · #7 ·
Had a buddy tear down and see if I was missing something. He didn't find anything but he could not remember if the oil spacer was overlapped or not. So again I tore it down, it was not overlapped. Its back together now but I haven't started it. Kind of aggrevated with it. Thought about pushing in barn, and getting something else.
 

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You learn from your mistakes as well as your successes. Don't give up - find out the cause.

Try removing the exhaust and run the engine - if it smokes, then it's in the motor - tear it down and find out what is causing it to use oil - it's just a machine - if everything is in sped and all the parts are new, it has to work right
 

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First post here. I have a big issue, I hope someone can help with. I put a 440 kit on a 99 400. I was very particular with assembly. I put in a new chain, clutch, complete cylinder, new piston, rings, filter, oil, etc etc. I had the local shop do valve seals and check the head. Jet kit in carb, valve lash done myself, new fuel, gaskets, seals, FMF(used old head pipe, new slip on),on and on. So anyway, I start it about a month ago and it fires right up, sounds good, but smokes out garage and neighborhood! Oil in pipe is so bad it showed my every little pin hole there could be! Keep in mind it has fresh oil in it, the oil draining out of my slip on is black, I assume from the carbon build up in old head pipe.

Back up two years ago...I got this thing for a steal. Had some aftermarket bolt ons and could tell been rode hard. I got it fired up, wiring issues, and it smoked bad so I go for the 440 kit, tear the whole quad down for complete rebuild. I mean everything, paint, brakes, engine, harness, etc.

Back to present...I am very mechanical, own a custom car shop, so I know a little. I figure has to be rings or seals, so I tear it back down. When I get down to the piston, there is oil puddled in the reliefs. I get one of the guys at shop to do the seals again and check the head, all good. I pull the cylinder and recheck the rings, all good. Back together today and same same. Oil literally blowing out exhaust.

I did use a head gasket from GT Thunder along with oversize studs. I machined and installed studs myself so I know they are the correct depth. The gasket was thicker then stock, almost a plastic feel, with multiple layers.

The only thing I know that is missing is the decompressor, but didn't need with the new cam, oil filter is correct, correct amount of oil, maybe a little low until I got it warm. Double checked everything.

At wits end. please help, Any ideas are appreciated greatly. Thank you.
Did you solve the smoking problem
 

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Did you solve the smoking problem
You are pretty optimistic about getting a reply from someone who has not been on here in 5 years

You would get a better response by starting a new thread describing your problem and the circumstances leading up to it.
 
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