buning oil..

Started by hollisatp, Jul 14 2009 09:44 PM
19 replies to this topic

  • hollisatp

Posted 14 July 2009 - 09:44 PM

#1


Hey all... I went to change my oil today.. I unscrewed the plug but only .25 quart came out!! I had a full quart .25 when I filled it the other day.. I put 180 miles on it since then... what could be the problem? the cylinder is good... I had it honed about 200 miles ago.. it does smoke a little bit when started like maybe the valve seals were getting old but other than that runs great! any help appreciated..
thanks!

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed

  • CopaMundial

Posted 14 July 2009 - 11:23 PM

#2

What type of bike?

Are you losing oil through the air box?

  • YZEtc

Posted 15 July 2009 - 03:45 AM

#3

So, you're thinking that you burned a full quart in 180 miles?
Oil-injected 2-stroke engines (ones that use oil by design) won't use that much oil. :)

I'd drain as much out as I could, refill up to the maximum level, and monitor the oil level a couple of times a day to see how fast it goes down.
I'd think that you'd be leaving a trail of blue smoke using that much oil.
Are you sure it's not just leaking out somewhere?

  • jsnmid

Posted 15 July 2009 - 04:19 AM

#4

Smoking at startup usually pionts to valve seals. The oil pools up on the valve while the bike is sitting.

  • hollisatp

Posted 15 July 2009 - 08:08 AM

#5

CopaMundial said:

What type of bike?

Are you losing oil through the air box?

xt350... through the air box?

It is not smoking that much at start up though.. I am using full synthetic also 10-40... should I switch to something thicker?

  • warose

Posted 15 July 2009 - 10:00 AM

#6

Breather goes to airbox so it could be full if the case is overfilled or overpressurized. Check it if you have two minutes. Anyway as stated make sure you are full and monitor plug, ground, and exhaust. Plug oily? Ground oily under bike? Exhaust visable? Color of exhaust and when does it do it? Those are the main oil escape routes but that amount sounds like a leak or filling error not oil burning. Not to say you did this but I know a guy (friend of a friend) that suppossedly forgot to put his plug back in and because he still had the pan under it it flowed right down and he didn't notice. Kapow! Bye bye engine. Thicker oil won't help at that loss rate either. Rings seated properly? Valves good (start up smoke points there as far as burning oil)?

  • hollisatp

Posted 17 July 2009 - 08:46 AM

#7

warose said:

Breather goes to airbox so it could be full if the case is overfilled or overpressurized. Check it if you have two minutes. Anyway as stated make sure you are full and monitor plug, ground, and exhaust. Plug oily? Ground oily under bike? Exhaust visable? Color of exhaust and when does it do it? Those are the main oil escape routes but that amount sounds like a leak or filling error not oil burning. Not to say you did this but I know a guy (friend of a friend) that suppossedly forgot to put his plug back in and because he still had the pan under it it flowed right down and he didn't notice. Kapow! Bye bye engine. Thicker oil won't help at that loss rate either. Rings seated properly? Valves good (start up smoke points there as far as burning oil)?

ok so I checked after filled and drove 100 miles.. i blew threw another quart! There is a bit of smoke at startup.. Valve seals.. then also a little while driving but not forever.. only until it burns off what I think is the leftover oil in the valve stems... any help appreciated..
any idea of $ for valve seals?

  • warose

Posted 17 July 2009 - 08:58 AM

#8

Do it yourself cheap, pay to do it robbery. I still have never heard of that burn rate from valve seals so it must be pretty bad if that's it. You can't find oil escaping any other way but tailpipe? Is the plug an oily mess? I suspect more than worn valves but sounds like either way you have to check and repair them.

  • hollisatp

Posted 17 July 2009 - 10:56 AM

#9

warose said:

Do it yourself cheap, pay to do it robbery. I still have never heard of that burn rate from valve seals so it must be pretty bad if that's it. You can't find oil escaping any other way but tailpipe? Is the plug an oily mess? I suspect more than worn valves but sounds like either way you have to check and repair them.

well I am getting smoke when I get the rpms up and floor it... also I am getting some smoke when I am at a light and it idles for a couple of seconds... I did have it on the highway at close to full throttle when it burned through the last quart..
I just had the cylinder honed but did not replace the rings.. probably a mistake on my part! No other oil is escaping out anywhere else on the bike... will check the plug tonight..

  • warose

Posted 17 July 2009 - 12:36 PM

#10

I hate to say it but when you hone rings need to be replaced to fill in the larger cylinder. What's the compression test saying?

  • mr_beat

Posted 17 July 2009 - 01:22 PM

#11

Ahhhh rings are so cheap you won't make that mistake again!!!

  • CopaMundial

Posted 17 July 2009 - 01:32 PM

#12

hollisatp said:

I just had the cylinder honed but did not replace the rings..

Let me guess... you had that work done at the shop where you buy your oil. :lol:

  • hollisatp

Posted 18 July 2009 - 12:11 AM

#13

LOL NOT FUNNY!! well I guess I am going to open her up and check to see if I can get it rehoned or if it needs to get bored out..

  • hollisatp

Posted 18 July 2009 - 12:38 AM

#14

hey all also.. is it a necesity to but the valve clamp to change the valve seals? or is there another way to do it?? thanks

  • jsnmid

Posted 18 July 2009 - 09:17 AM

#15

hollisatp said:

hey all also.. is it a necesity to but the valve clamp to change the valve seals? or is there another way to do it?? thanks
If you're handy, you can fab something up to compress the valve springs and make your knuckles bleed a lot. I did it... once. A normal valve spring compresser won't work.
The next time I took the head to the dealer and had them do it. I was only charged 1/2 hour ($35) since it was a bare head. I think I had them lap the valves while they were at it. Don't remember if they charged extra for that. Likely not. I know the mechanic pretty well.
I thought about buying the tool, but I'd be suprised if I ever have to do it again.

  • highpeakz

Posted 20 July 2009 - 01:05 PM

#16

Hey there. I'm watching this thread closely because I am experiencing almost the same exact problem with my 86 XT350. MY only evidence of oil loss seems to be exhaust. My license plate has black soot on it and it never used to happen. My recent work was replacing the compression release lever assembly. I'm unsure if the two are related. I also replaced the right side case gasket and adjusted the clutch. All oil lines are torqued and checked on my 170 mile ride, but I still blew through a qt. of 20-50 yamalube. (this engine was bored one size over about 8000 mi. ago and valve clearence, TDC, cam and chain were all adjusted.)
No leaks anywhere but oil smell in exhaust.... thanks for all of your input!

  • maim

Posted 20 July 2009 - 02:52 PM

#17

on a fresh rebuild i would be using dino oil for at least 1000miles before going to synthetic.

the threory i have hears is that it is too slippery and does not let the rings seat to the cylinder. this causes increased oil consumtion and in 2 stroke sleds it runs like crap.

  • warose

Posted 21 July 2009 - 08:56 AM

#18

The compression release lever assembly can cause some problems if not in spec.

  • highpeakz

Posted 05 August 2009 - 02:18 PM

#19

Well, I pulled my top end, checked the piston with a feeler gauge and there was a gap on the backside of it.. some gold scuffs on the skirt of the pistons too. The dealer used the term "cold seize" when he looked at it.
Ordered new piston, rings, wrist pin and circlips and one gasket: 113 bucks.

My valves DO NOT look good. I cleaned the combustion chamber and discovered some serious pitting on them all around. Now I am contemplating getting valves, seats, guides, seals, and whatever else. Cant give up on this ride!!

  • jsnmid

Posted 06 August 2009 - 05:29 AM

#20

Odds are you just need valves, seals and a grind. Maybe guides, but I'd be suprised unless you actually siezed up a valve.
On the bright side, the engine should be good for a long time and it doesn't cost much to have a valve job done when you hand them the head.



  1. ThumperTalk
  2. → Dirt Bike
  3. → Make / Model Specific
  4. → Yamaha
  5. → Yamaha Dual-Sport
If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!