Does anyone smell oil?


30 replies to this topic
  • Keanan

Posted April 18, 2009 - 08:14 AM

#1

Looking for some help. I am having the dreaded popping on decel like tons of others. I started by taking the bike to get the valves checked, still popping. After getting the bike back I started smelling some burning oil. Could the mechanic have done anything to cause this? I recently bought a "carb rebuild" kit and exhuast gaskets to try to stop the popping. My buddy was telling me that due to the smell and noises, he seems to think I am due for a rebuild. Is this true?

Any help would be greatly appreciated!

Thanks.

  • Beaz

Posted April 18, 2009 - 12:04 PM

#2

If you changed the oil and put to much it it will smell of burning oil

  • 642MX

Posted April 18, 2009 - 04:24 PM

#3

Sometimes mine smells like its burning oil, but (on my bike) the smell is coming out of the breather tube, not the exhaust.

Decel pop is normal to a point. They all will do it if jetted properly. Excessive popping is an exhaust leak or a lean condition. If its lean on the bottom end, you can turn the fuel screw out about 1/4 to 1/2 turn and it will probably help.

  • Keanan

Posted April 21, 2009 - 06:24 PM

#4

Ok, latest update...

I added new exhaust gaskets, and a new air screw. Is it called the air screw or fuel screw? I set it to 1 1/2 turns out from bottom. It is still backfiring on deceleration. The jetting is stock like it has been for the last 6 years. I am afraid my buddy may be right on the rebuild idea.

  • 642MX

Posted April 21, 2009 - 06:38 PM

#5

Ok, latest update...

I added new exhaust gaskets, and a new air screw. Is it called the air screw or fuel screw? I set it to 1 1/2 turns out from bottom. It is still backfiring on deceleration. The jetting is stock like it has been for the last 6 years. I am afraid my buddy may be right on the rebuild idea.


Yamaha calls them "pilot screws", I call them fuel screws. Have you tried to turn the screw out a little more? Do you know how to properly set the fuel screw?

  • WGP

Posted April 21, 2009 - 06:38 PM

#6

I would think its your jetting, you didn't say what year it is, but you can look at the jetting database to find a similiar bike , altitude, temp ect...

Usually just richen the needle and pilot jet and it should take care of it.

  • rdrata

Posted April 21, 2009 - 09:12 PM

#7

I concur w/ WGP; I used that database and it turned my '06 YZ450 int a whole new bike, and got rid of most of the decel popping

  • Keanan

Posted April 22, 2009 - 04:19 AM

#8

I was taught to turn the screw all the way in and then back it off 1 1/2 turns. This thing is shooting flames out of the exhaust now.

  • 642MX

Posted April 22, 2009 - 04:46 AM

#9

I was taught to turn the screw all the way in and then back it off 1 1/2 turns. This thing is shooting flames out of the exhaust now.


Here is the 642mx method of adjusting the fuel screw.....Start the bike and let it run for about 1 minute, then kick the idle up about a turn. Back the fuel screw in until the engine wants to stall, then slowly rotate it out until you hear the idle increase, once the idle increases to its peak, then leave the screw alone and re-adjust the idle. It should be set. Now, if your sweet spot on the screw is more than 3 turns out or less than 1 turn out, your going to need a pilot jet.

  • spark250

Posted April 22, 2009 - 07:42 AM

#10

I was taught to turn the screw all the way in and then back it off 1 1/2 turns. This thing is shooting flames out of the exhaust now.


Yeah it has to be specifically set for each bike and sometimes for the conditions. 1 1/2 turns is a starting point. just follow the procedure outlined above.

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  • grayracer513

Posted April 22, 2009 - 11:15 AM

#11

Decel backfire is not all bad, either. Properly jetted and with a leak free exhaust, the big YZF should pop a little on decel. If it's excessive, that's another matter. As has been said, the 1 1/2 turn "rule" is just a guideline, and in fact, if you look at the jetting database lists for the different bikes, you can see that the base setting is different for each model. It will also vary by weather and altitude enough to be noticed and need tweaking, especially with the older carbs.

Follow 642's method. It should do it for you.

  • Keanan

Posted April 23, 2009 - 03:57 AM

#12

The bike is a 2003 and I have had it since it was new. I have the original jets in it that have never had any issues before. Now the thing sounds like I have someone chasing me with a shot gun. Where is this jetting database? I am willing to try everything I can before rebuilding. Thanks to everyone!

  • yzf426f

Posted April 23, 2009 - 05:17 AM

#13

hey mate.had the same problem.i had contaminated fuel.and fuel over a week or to is considered no-good for your bike.it could also be your carby needs to be cleened it had gunk in it.take it to your local shop and have them clean the carby out and they will reset the floats and idle screw.it fixed my problem.anyway good luck.as for the burning oil smell.im not to sure about whats going on there but i have been told u over filled it or its burning the old oil out.aslo i hope you droped the oil and not just topped it up.anywayz buddy good luck.

  • grayracer513

Posted April 23, 2009 - 10:04 AM

#14

Where is this jetting database?

Top of the list, 4 down:

http://www.thumperta...isplay.php?f=21

Be sure to check your exhaust for loose clamps, or other leaks.

  • Keanan

Posted April 23, 2009 - 11:48 AM

#15

Another thing I failed to mention, is that I haven't been very good with the maintenance. I usually change the oil once a year. It does more sitting than anything. I know that isn't good, but it is what it is.

  • grayracer513

Posted April 23, 2009 - 12:22 PM

#16

It does more sitting than anything.

There you are. Check the pilot jet in particular, and the carb in general for a deposit of varnish.

  • TIG88

Posted April 23, 2009 - 01:26 PM

#17

If it sits like that, pop the carb off, and blow it all out. Jets, passages, etc..

  • Keanan

Posted May 14, 2009 - 07:37 AM

#18

UPDATE-- Bike shop says the throttle positions senser was bad. 200 dollar part! UGH

  • 642MX

Posted May 14, 2009 - 09:29 AM

#19

UPDATE-- Bike shop says the throttle positions senser was bad. 200 dollar part! UGH


Not saying it doesn't happen, but its the first one I've heard of....

  • mitchicle

Posted May 14, 2009 - 11:28 AM

#20

My TPS is out of spec but it doesn't cause these issues. If there bad supposedly they just go to the full throttle map.





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