Jump to content
Sign in to follow this  

New DRZ400S gas in oil problem

Recommended Posts

I have a brand new drz400s that has about 380 miles on it now. I did my first oil change at 250 miles. I noticed the smell of gas when i removed the crankcase drain plug. The consistency of the oil from this drain was less thick than the frame drain. Also, not very much oil came out of this drain compared to the frame oil drain plug which rushed out when i removed it. The next day i went on a 100 mile ride and it ran fine. Today i checked the dipstick and the oil was very clear and also smelled of gas. It was also above the full line. I took the hose off going from the petcock to the carburetor and no fuel leaked. I turned it to prime and fuel came out. I haven't switched the petcock from "on" since i've had the bike. The bike is in service by the dealership under warranty right now but i have concerns.

What most likely caused this and what is the likelihood that this damaged my engine?

How much oil (approx) is supposed to come out of the crankcase when removing the plug (assuming the motor was running 30 mins prior)?

I haven't dropped the bike or anything like that.

Edited by foggyrider
  • Like 1

Share this post


Link to post
Share on other sites

I suspect you have a petcock problem even thought it seemed to be all right.  Disconnect the fuel hose an run a hose into a catch container and let it sit overnight with the petcock set to ON.  Any accumulation of gas is a failure.

 

Yes it could be a float valve problem (or both) but a float valve has to leak awfully bad to put gas in the oil when the motor is running (when the petcock is open).  So probably it is just the petcock.

 

Dry sump motor - under normal conditions probably 3/4 to 7/8 of the oil will drain from the frame.  Ideally the motor would be completely free of oil in the sump but there is always some remaining the scavenge pump does not get.

 

Oil diluted with gas reduces its lubricating effectiveness.  But 250 miles, I would not sweat it.  Just get it resolved.

  • Like 1

Share this post


Link to post
Share on other sites

When I first had this very same problem I panicked. Got rid of the OEM petcock and went with the Raptor type. I changed my oil and filter twice back to back by filling and running with a less expensive oil for a hour then changed it again to a high quality oil. I had no problem after that. I should mention I also went through my carb and replaced all rubber parts and gaskets. I was not connected with my fellow DR-Z riders and any forums at that time and learned the hard way. Yes I have "Turn Off Fuel" stickers on my mirrors so I don't forget! :D

  • Like 1

Share this post


Link to post
Share on other sites

Seem the crap gas these days combined with an even worse petcock system and it's a guarantee leak. I still can't believe in the couple decades of "toys" and never turned a petcock off in my life and these can't hold gas even new . The DR650 have the same issue just not as often.

  • Like 2

Share this post


Link to post
Share on other sites

So i got the bike back earlier today and they said they couldn't find any problem with it. They changed the oil and checked it for any smells of gas and said it was fine. I took the bike home, checked the dip stick and sure enough still smells like gas. Back to the dealership it goes :(

Share this post


Link to post
Share on other sites

So i got the bike back earlier today and they said they couldn't find any problem with it. They changed the oil and checked it for any smells of gas and said it was fine. I took the bike home, checked the dip stick and sure enough still smells like gas. Back to the dealership it goes :(

the dealer doesn't read thumper talk or care about the real causes. fix your bikes petcock and do the loctite fixes in the FAQ section. yes, even new bikes succumb to the FAQ. yes, even brand new ones, because it's the same bike from 1999, just a new sticker.

  • Like 2

Share this post


Link to post
Share on other sites

Unfortunately, modern gas is causing a havoc with the the petcock and the float-valve o-ring.

This will eventually happen to every DRZ. I have  2001 and had to replace the rubber parts twice.

I have since replaced it with the Raptor Pcocka nd problem has never re-appeared.

 

If I were you, I'd do the following (I'm assuming this is a new bike from the dealer):

1 - keep all documentation that you have had this problem, tried to get it fixed etc etc

2 - let the bike stand for a couple of weeks with the Pcock in "run" and see if the engine 

hydro-locks (but don't run it obviously) and take it to the dealer like this, so they can see the

problem.

3 - let the bike stand for a couple of weeks and keep checking the oil - IF the level increases, then

fuel is getting into the crankcase. Again, don't run it but take it to the dealer so they can see it.

4 - remove the fuel line from the bottom of the Pcock and place a can to catch any fuel - this will

be a strong indication that the Pcock is leaking - again leave it for a week or so just to be sure;

Show the dealer how much fuel has leaked.

 

If you don't get the Pcock/float valve fixed, you will find that the bike will be VERY hard to start as

the plug may be wet with gas or you have gas in the combustion chamber. Also running the engine 

with gas in the oil is not ideal.

 

I had the same issue with my DRZ and it took me over 1 year to figure out what was going on.

  • Like 4

Share this post


Link to post
Share on other sites

Unfortunately, modern gas is causing a havoc with the the petcock and the float-valve o-ring.

This will eventually happen to every DRZ. I have 2001 and had to replace the rubber parts twice.

I have since replaced it with the Raptor Pcocka nd problem has never re-appeared.

If I were you, I'd do the following (I'm assuming this is a new bike from the dealer):

1 - keep all documentation that you have had this problem, tried to get it fixed etc etc

2 - let the bike stand for a couple of weeks with the Pcock in "run" and see if the engine

hydro-locks (but don't run it obviously) and take it to the dealer like this, so they can see the

problem.

3 - let the bike stand for a couple of weeks and keep checking the oil - IF the level increases, then

fuel is getting into the crankcase. Again, don't run it but take it to the dealer so they can see it.

4 - remove the fuel line from the bottom of the Pcock and place a can to catch any fuel - this will

be a strong indication that the Pcock is leaking - again leave it for a week or so just to be sure;

Show the dealer how much fuel has leaked.

If you don't get the Pcock/float valve fixed, you will find that the bike will be VERY hard to start as

the plug may be wet with gas or you have gas in the combustion chamber. Also running the engine

with gas in the oil is not ideal.

I had the same issue with my DRZ and it took me over 1 year to figure out what was going on.

I left the hose coming from the petcock to drain into an empty beer bottle overnight. This morning i checked it and no gas had accumulated. The end of the hose was completely dry. Perhaps my carb is leaking?

Share this post


Link to post
Share on other sites

I left the hose coming from the petcock to drain into an empty beer bottle overnight. This morning i checked it and no gas had accumulated.

The end of the hose was completely dry. Perhaps my carb is leaking? 

 

 

UUmmmm. odd..... Well you proved the pcock is not leaking and the only fuel in the carb is on the float bowl which is a relatively small

amount.  You could check this my unscrewing the the little tap at the bottom of the float bowl. if fuel comes out after sitting all night, then

you're okay.

 

Going back to your original post... you smell gas when you remove the dipstick, so fuel is getting into the crankcase. Go back to my third point

and check the oil before and after each ride. If the oil level increases after a ride, then fuel is being introduced while the engine is running - not 

sure how this would happen. What is your fuel mileage like? it should be 50-60 mpg

Share this post


Link to post
Share on other sites

I left the hose coming from the petcock to drain into an empty beer bottle overnight. This morning i checked it and no gas had accumulated.

The end of the hose was completely dry. Perhaps my carb is leaking?

UUmmmm. odd..... Well you proved the pcock is not leaking and the only fuel in the carb is on the float bowl which is a relatively small

amount. You could check this my unscrewing the the little tap at the bottom of the float bowl. if fuel comes out after sitting all night, then

you're okay.

Going back to your original post... you smell gas when you remove the dipstick, so fuel is getting into the crankcase. Go back to my third point

and check the oil before and after each ride. If the oil level increases after a ride, then fuel is being introduced while the engine is running - not

sure how this would happen. What is your fuel mileage like? it should be 50-60 mpg

My mileage has been about 45 mpg.

Share this post


Link to post
Share on other sites

So we can probably rule out the petcock.  Diagnosing the float valve is more difficult.  Here is a procedure you can try.  If the leak is significant it might show up fairly quickly. The usual problem is the O ring on the OD of the float valve seat. But since the motorcycle is new it might just be trash in the valve or just a bad valve.

 

Assuming the petcock is working, the float valve is only in play when the motor is running.  Its primary job is to maintain a constant fuel level in the carb.  A little leakage here is OK but it is difficult to determine if it leaks beyond acceptable or not.  Something you can try is to connect a clear hose to the nipple on the bottom of the float bowl.  Make a "U" bend in the hose and run it up the side of the gas tank, tape it in place.  Leave the end open.  Turn the petcock to PRI.  This allows gas to flow to the carb with the motor not running.  Open the drain screw on the carb float bowl.  After the level in the tube stabilizes, mark the level on the hose.  It will probably be just a bit lower than the float bowl parting line.  Now let this sit for a while and see of the fuel in the hose gradually rises.  I would initially check it fairly often to see if there is any significant change.  Assuming it is stable, let it sit over night.  I can't really say what is good or bad but if it rises very much say 1/4 inch, that would be bad.

 

There is another way but requires some disassembly.  Remove the air filter and remove the boot between the air box and the carb. It can be done. Remove the top of the carb and the slide (keep track of the small O ring under the top)  Hold the throttle open with tape on the twist grip.  Turn the petcock to PRI.  Watch for fuel percolating out of the jets in the floor of the carb.  I would say you should not see any fuel for at least an hr.  If it takes an hr for the fuel level to rise that much it is probably not a problem when running and if the petcock works it is not a problem when the motorcycle is not running.

  • Like 1

Share this post


Link to post
Share on other sites

Do these have a vacuum petcock, such as pri, on and res? If so the petcock could be broken allowing gas to flow at all times, prime, which as others have mentioned the float my be leaking or too high when the engine isn't running

Share this post


Link to post
Share on other sites

Have other people smell your oil , make sure it is truly gas your smelling . Could be nothing is wrong and your just smelling normal "used" oil , It does always have a hint of gas'ish smell from running , just not very strong nor noticable.

Edited by jjktmrider
  • Like 1

Share this post


Link to post
Share on other sites

My wife's cousin smelled it and detected gas. I have no doubt that at some point it had gas in the crank case because even suzuki acknowledged it. Oil looked thin and you could probably light it on fire with a match. They still have no idea what caused it. It may just be residual smell at this point as you suggest but at some point gas got in there and no one knows why. I will change the petcock out to a standard off on one though.

  • Like 1

Share this post


Link to post
Share on other sites

Good decision Foggy! Oh and I tried to light the oil from my crank case but, it would not catch fire. Even though it reeked of fuel.

Share this post


Link to post
Share on other sites

pull carb, blow in inlet, move float. if it seals, its good. if it doesn't, find out why.

now check the petcock, on and reserve should not flow, prime should. if this isn't the case, time for a new petcock.

the float level should be checked too, to ensure it isn't blasting fuel for no reason.

run a tank of two stroke mix through it now and again. two stroke has stabilizers and lubricators, user all the petcock positions, so it gets plenty of lube everywhere.

I doubt the dealership will ever figure it out, or try.

Share this post


Link to post
Share on other sites

The petcock has 2 failure modes.

1: fails to shut off flow to the carb while no vacuum exists

2: fuel leaks through the diaphragm assembly through the vacuum line and enters the intake downstream of the carb.

You've ruled out #1, which by default rules out the needle valve. If the petcock can't flow fuel to the carb, the carb can't overflow.

My bet is on #2. Pull the vacuum line off the petcock and see if it's wet inside. Stock a q-tip in the vacuum port on the petcock and check it in the morning, if it's wet you have a bad diaphragm in the petcock

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...