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I'm not impressed w/ 4 strokes yet...
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Posted by: stuntman_12

Just bought an 02' 400EX that was still apart from the jug up. It has a new piston, rings, and it got rehoned... I went by the books and put her back together w/ out a problem. I pulled it down the road try and start it more aggresively and it firers around everyother combustion stroke then blows smoke like crazy. Then i realized that oil is some how getting in the chamber AND oil is coming (a lot of oil ) out the front of the motor (around the exhaust) some how?

I wanted to go 4 stroke to get AWAY from this! I've torn this thing down twice... the oil rings are perfect and so are the compression rings. Gaskets are good too?????????

Posted by: DieselBoy

did you check the bore for out of round, taper, scores, etc?

i got one too, i should of listened to myself and bought a raptor.

Posted by: stuntman_12

Nope... i checked out the piston whn it was in the jug and it apeared to be fairly round. However i ran my finger over the TDC point and could feel a VERY small wear difference. It should not be enough to THROW oil out of the top of my motor...

thanks for the help guys!

i like your sig saying bout the revolving door... i needed a laugh!

Posted by: johnsls

You could'nt have installed it properly.. I'm no pro BUT

1) I'm thinking you didn't put the rings in properly
2) "i ran my finger over the TDC point and could feel a VERY small wear difference"

There are a few people on here that should be able to help but noway you can spill that much oil if something wasn't put together correctly.

Hey,, I just did mine a few months ago,, and NO PROBLEMS, I didn't do the install but still no problems

4-strokes are way better than 2's Just my 2¢

Posted by: stuntman_12

The rings were installed by someone else... i bought it w/ the jug on it. Just the top end needed assymbled. I tore it down and reassymbled yesterday to check the oil rings. I guess i'm gonna tear it BACK down and double check, may even take pictures or somethin... Still, why is oil coming out of the front of my motor? Where else could oil come from except under the piston? It's not through the vavles...

Posted by: DieselBoy

where exactly is the oil leaking out of the motor? the head is actually full of oil while it's running. it sounds like the bore could be your problem. You need to check the taper/uneven wear, or scores. These will allow it to burn oil. Pictures would help alot.
Also, if the Compression ring isn't at the top with the T facing up you will run into problems. If oil is puking out of the the head there could be a crack or a bad valve cover gasket, etc.

I'm actually having a somewhat similar problem, but my compression dropped after it ran for 5 minutes, so I'm still tackling it. I'm putting new rings in again, and adjusting the valves. It smoked when you gave it, but I just had a new bore, rings, piston, etc. so I'm lost also. Currently waiting on parts.

So get some pictures and I'll try and help you.

as far as the missing goes, it could be a fuel delivery problem.

Posted by: newrider4002001

quote:
Originally posted by DieselBoy
did you check the bore for out of round, taper, scores, etc?

i got one too, i should of listened to myself and bought a raptor.

why so you can get your @ss kicked by everything out there

Posted by: DieselBoy

quote:
Originally posted by newrider4002001
why so you can get your @ss kicked by everything out there

Yes, that's exactly it.

Posted by: stuntman_12

I tore her down to the rod, for the third time. I have given up and am taking the jug w/ the piston in it, and the head to get everything checked out at the local shop. For 30 bucks they can make a diagnosis.... I'll keep yall updated from there.

I went four stroke mainly to get away from all this and to really persue flat ground freestyle.... maybe it'll work out

Posted by: wilkin250r

The oil could easily be coming from the head if you have a bad valve seal, crack, or other problem.

Posted by: garandman

I don't think that's a problem with 4 strokes....sounds like a problem with YOUR four stroke.

I'm not impressed with 4 strokes cuz I like the sound and power of the 2 smoke.

4 strokes are easier to ride, tho...

Posted by: QuadJunkies

quote:
Originally posted by wilkin250r
The oil could easily be coming from the head if you have a bad valve seal, crack, or other problem.

agreed!

SOMETHING is NOT installed properly,thats not a "4-stroke" problem, thats an mechanical error

Its most def oneof the problems everyone has already listed

Posted by: johnsls

[SIZE=3]FOUR STROKES RULE[/SIZE]

If you don't know how to boil water,, STAY OUT OF THE KITCHEN

Sorry but posting that 4strokes suck or "Thats why I never bought one" Thats crap,, its either bad parts or the builder.

Good luck on finding out what it is..

Posted by: stuntman_12

I never said that they suck.... i'm just having A TON of problems with my first one... I've rebuilt them for friends and stuff but when it comes to mine i'm just at a loss for what is going on...

Posted by: H400exRacr

ive been rubuilding atv and dirt bike race engine for years and the 400ex is one of the most reliable quad engines out there.....you just gotta know what your doing there are dozens of things that need to be correct on a 4-stroke to make it run properly

Posted by: patches85

quote:
Originally posted by wilkin250r
The oil could easily be coming from the head if you have a bad valve seal, crack, or other problem.

I'm with him, did you put those little round seals on the top of the valve guides? If so maybe you should get the head magnafluxed to check for cracks. This is where they magnatize the head in a vise like thing and spray this solution on in and look at it with a black light to check for cracks.

Posted by: QuadJunkies

quote:
Originally posted by H400exRacr
the 400ex is one of the most reliable quad engines out

AMEN!

Posted by: DieselBoy

quote:
Originally posted by QuadJunkies
AMEN!

further more reliable than the 400ex is the 350 yamaha hands down.

Posted by: H400exRacr

If somebody gave me a brand new warrior for free i would sell it and put new tires on my ex....thats how much theyre worth to me.

Posted by: patches85

quote:
Originally posted by H400exRacr
If somebody gave me a brand new warrior for free i would sell it and put new tires on my ex....thats how much theyre worth to me.

How bout it! My buddy had one and it was slow and heavy and not worth a s**t!

Posted by: DieselBoy

quote:
Originally posted by patches85
How bout it! My buddy had one and it was slow and heavy and not worth a s**t!

The warrior design is extremely old, and that's why it's heavy, and slower. The warrior was designed in the late 80s, and it was built in 1987 or 1988 (can't remember now), since then the machine has been virtually unchanged until the new one was released, and i'm not even sure if they still make it.

The 400EX began production in 1998.5, and comparing the 2 in such a way is like comparing banana's to apples.

I would own a warrior in a heartbeat. I'm a trail rider myself, and the warrior is just fine for that application.

i see dozens of OLD warriors for sale today, and still see em around everywhere. They're tanks and they are extremely tough.

Posted by: patches85

quote:
Originally posted by DieselBoy
The warrior design is extremely old, and that's why it's heavy, and slower. The warrior was designed in the late 80s, and it was built in 1987 or 1988 (can't remember now), since then the machine has been virtually unchanged until the new one was released, and i'm not even sure if they still make it.

The 400EX began production in 1998.5, and comparing the 2 in such a way is like comparing banana's to apples.

I would own a warrior in a heartbeat. I'm a trail rider myself, and the warrior is just fine for that application.

i see dozens of OLD warriors for sale today, and still see em around everywhere. They're tanks and they are extremely tough.

Yeah and the 250r was released in 86 and it isn't a heavy peice of sheet!

Posted by: patches85

Now that I think about it I would sooner have a 250x than a warrior!

Posted by: DieselBoy

again, apples to bananas. the 250r is a racing machine, and it's two stroke.

Posted by: patches85

quote:
Originally posted by patches85
Now that I think about it I would sooner have a 250x than a warrior!