Burning oil

[Bigdaddy52302]

I have a 2002 400ex stock motor i belive, I was told it possibly has a hot cam stage 1 but I have never had it appart to tell. Anyway it seems to be running great no excesive ticking that I can tell and yet I blow some blue smoke and burn at least 1/2 a quart everytime I ride... What should I do. I checked the valves and they are within the tolarnce is it rings or what... Oh yeah I have a CHM PR-4 silencer and a K&N air filter with outer wear and no airbox lid, can anyone tell me what jets I should be running and is it alright for me to run racing gas like I do? I seem to destroy plugs fast...

[maxfior]

Before you go crazy with the race gas and ripping... you're going to want to track down the burning oil... chances are the rings might be shot, but in order to check that out, you'll have to pull the head and measure ring gap. If the rings are okay, and you notice oil usage but no smoke, your valve guides could be going. I had an older XR250 that would use oil since the guides were older... but your EX isn't that oil. Either way, it sounds like it might be time for a rebuild... I'm sure some others will chime in here... But that would be my first guess... Does your rig leak oil anywhere? Could it be a seal somewhere? Let us know.

Max

[Pipeless416]

half a quart each ride is a pretty huge amount. you're probably definitely due for a rebuild. i find it extremely unlikely that it could be the valve guides because usually that just lets a few drips of oil through during startup.

[Bigdaddy52302]

It is between a 1/4 to a 1/2 quart each ride witch for me is usally 4-6hours of ripping around a mx track. No it doesnt leak any fluids that would be great an easier fix. I guess I am wondering if it is the rings or valves why there isnt any excessive ticking?

[Pipeless416]

rings wont tick, they'll just let oil pass

[maxfior]

Originally posted by Pipeless416
rings wont tick, they'll just let oil pass

If you do run low on oil, you'll hear ticking, rapping, and metal to metal or metallic noise. When an air-cooled engine starts running low on oil it can start to idle very low and then just quit. I've seen engines run low on oil, still moving freely (aka, no broken rod(s)) but have wiped cams and rockers. So, you'll do some major damage if you don't get things looked at soon, rather then later. Looks like you might have a good winter project on your hands ;)

Max

[Bigdaddy52302]

Ok guys I give, you win its time to work on her.
Where do I start? Tear the motor off the quad and yank the head re-ring it put it back together and call it good, or do i pay a shop to do ring job and do some looking around for other damage since i wouldnt know what to look for. And if so how much should I pay for this? I can adjust valves and do piston swaps but thats about my ability.

p.s. if i keep her full of oil can i get one last ride this weekend...just one more please

[Pipeless416]

and thats most likely all you'll have to do, new piston, rings, and gaskets. buy a 400ex service manual, take your time, and you'll do fine. oh, you dont need to pull the entire engine out, just pull the head off while the bottom end is still in the frame.

[Bigdaddy52302]

Is that possible, the last motor i did a rebuild on was a blaster and i had to yank the motor to do it. just figured i have to do that agian. Will i have room to work comfortably with it still in there.

[Pipeless416]

yep.. heres when i rebuilt my brothers. as you can see, theres plenty of room to work on the top end.

[maxfior]

Originally posted by Pipeless416
yep.. heres when i rebuilt my brothers. as you can see, theres plenty of room to work on the top end.

LOL! few more bolts and then the motor WOULD be out of the frame! :) cool color btw!

Max

[Pipeless416]

lol that was a "rebuild rebuild," not just a top end rebuild.. and the color came out well for a rattle can.. as long as your garage floor doesnt look like this.. you're fine. :)

[maxfior]

Originally posted by Pipeless416
lol that was a "rebuild rebuild," not just a top end rebuild.. and the color came out well for a rattle can.. as long as your garage floor doesnt look like this.. you're fine. :)

Oh man, your floor looks great, what are you talking about :) LOL! And paint by rattle can, hell, that looked pretty okay to me! Nice work.... I just need to figure out how to get some heat in my shop, it's going to be getting cold SOON!

Max

[maxfior]

Originally posted by Pipeless416
lol that was a "rebuild rebuild," not just a top end rebuild.. and the color came out well for a rattle can.. as long as your garage floor doesnt look like this.. you're fine. :)

LOL! oh and I just noticed your "cheater-bar" funny stuff dude!

Max