gas in crankcase problem

[Mharal]

thanks for the reply,,

I am using a clear vacuum tube, so I can verify gas is not running through the vaccum line.

I will pull some oil out and ck it again using your process. I am pretty sure I have gone throught this process, but will not hurt to ck it again.

thx
Mark

[tom203]

Mharal said....
"started the bike,, for a minute,, turned off,, cked the oil and needed to add some-- filled it up to halfway between the F and L sightglass."

Only check oil when bike has been off awhile-checking after a one minute run will leave lots of oil in the attic giving a false level. After a run, my 650 takes a good half hour for oil to drain back.

New petcock, carbs floats bench checked OK- there's nothing else to fill crankcase so quick except you!

[Mharal]

yep, understand,, I had changed the oil and the oil filter,, filled up the oil between F and L,, then started the bike and let it run for a minute or two to circulate the oil. turned off and cked the oil after it sat for while,, I did not wait 30 minutes,, more like 15,, then cking at this point the oil level was low because it circulated throughout the engine. i then added to get the level between F and L,, and then started it and let it warm up,, turned it off,, let it sit and the oil level appeared to stabilize at the same level,, but then it starts creeping up,, to past the F level and all you see if oil and thats when i noticed the air bubble in the fuel filter getting larger. I think the gas in the fuel line below the petcock is somehow getting past the floats and into the crankcase.

I am going to remove some oil from the crankcase,, ck the level,, it should not be changing at this point. put on a clear fuel line,, start the bike and let it warm up,, turn it off and then let it sit,, I would expect the oil level to be low at first,, then gradually fill to the originally level,, then I will watch the fuel line and see if the fuel drains down through the carbs,, if it does,, then the oil level will rise also.

if the above does happen,, that would mean the float needles are not shutting completly right? Just not sure why it would work on the bench and not on the bike.

[tom203]

I'm not understanding why you start with oil level between F and L, run it briefly and then add some more oil before it has drained back down. I run my bike all the time with cold level at 3/4 full mark- I don't fret that running oil level is below L mark- I think/hope that that's what suzuki wanted.
Your bench test proves that carb float seats are sealing well enough- and your new petcock is working.

Get cold oil level correct ,start bike, run briefly then disconnect clear fuel line at tank and observe. Oil will eventually come back to your original level - be patient.

[Mharal]

Wanted to update what i have done. So I drained oil out of the bike until level was between full and low. Stone cold,, level was between f and L,, cranked it up,, went for a 20 minute ride, bike ran fine,, parked at same location, put bike on center stand,, i always do that,, disconnect the gas line below the petcock ,, could see gas in the line, , cked the oil level,,completely full,, let it sit over night,, oil completly full still and gas still in the clear gas line???

So i have completly drained all the oil out which smelled of gas,, gas line connected,, could see fuel in the clear fuel line to the carbs. I am going to ck the oil in the morning and see if there is any gas in the crankcase,, I suspect that there will not be.

it seems that gas is getting into the crankcase while riding the bike. Open for suggestions,, next step would be to pull the carbs again and go through them again. Could i have problem with the mid or high range jets? I really do not have a clue at this point only that it points to the carbs. could I have a cylinder not firing while riding? and would that cause the problem,, all pipes are hot and the bike does not hesitate or miss,, runs strong to me.

Need a plan of action,,

thanks
Mark

[tom203]

That part about oil level rising after 20 minute ride and yet you saying "the bike ran fine" does not compute. That much gas sneaking into crankcase during run, would cause the bike to run pitifully. My failed petcock fouled out #2 plug, causing idle drop, noticeable missing,and exhaust popping. I don't see how even oversized main jets would create this problem without the bike running poorly and passing gas into exhaust.

[Nessism]

I believe the problem is the way you are checking the oil level. Gas can not leak into the crankcase while the engine is running.

Sorry for the struggle.

[Mharal]

I hope you are right,, I drained the oil competely yesterday so there was no oil in the crankcase,, sight glass clear, no oil in the system at all. Then I hooked up the vacuum and gas lines and let it sit like that over night.


this morning I cked the sight glass,, still empty, there is no visible fluid in the sight glass, which is expected if the petcock and floats are working properly.

So that would confirm the petcock and the floats are working fine.

I will add oil,, 3.4 is listed as capacity with an oil filter change, also I am using Rotella T 15w-40 oil.

Going to add 3 qts and see where the level ends up in the sight glass.

thx for your patience.

[Nessism]

The shaft drive 650 uses engine oil to lubricate the secondary reduction gears (shaft drive), and there is a cubby hole inside the engine which has it's own drain plug. I'm not sure how oil flows though the system but it's possible oil is accumulating somehow in various pockets inside the engine and draining back into the crankcase slower than one would expect.

The factory specified oil checking method involves starting a cold engine, running it for a few mins., shutting down the engine followed by waiting ONE min., then check the oil. The idea is for the oil to be cold, so it's not expanded. Run the engine so all the nooks and pockets inside the engine are filled up. Then let the oil drain back somewhat (but not fully). When you check this way the oil level will be lower than if you just let the engine sit over night.

When you first fill the engine with oil it tends to pocket in the clutch cavity so the level may seem higher than actual.

I mention all this to make you aware that you must take into account all the variables when judging oil level. Target the middle of the sight glass so it's easy to see the level. There have been lots of people around here over the years that think their oil level is too high/low, when in truth their was either no oil showing in the sight glass, or it was overfilled.

Good luck and hope you get it sorted.

[Mharal]

okay,, I added 3 qts, ran the bike for a few minutes, turned it off and waited ~ 1 minute,, oil level was slightly below the L mark. I had to step away for a few hours and when i came back and cked it the level is halfway between the F and L mark. I think that is good. Going to try it there,, will ride it for while and ck it later and let you know

thx
Mark

[Nessism]

okay,, I added 3 qts, ran the bike for a few minutes, turned it off and waited ~ 1 minute,, oil level was slightly below the L mark. I had to step away for a few hours and when i came back and cked it the level is halfway between the F and L mark. I think that is good. Going to try it there,, will ride it for while and ck it later and let you know

thx
Mark

Suzuki specifies you check oil level at 1 minute, so officially your oil level is low. I suggest you add oil until its at the F mark when fully cold, such as over night. After you run the bike and do the 1 minute test, the level should be between the marks.

[Mharal]

Just wanted to let you know that I was indeed putting too much oil in it,, I should have just looked at the specs in the manual,, but was going by the level in the sight glass at the wrong times. Anyway,, its a good thing, cuz I do not have to take the carbs off

thanks everyone for the help and being patience with a newbie
Mark

[Mharal]

Well,, I still have a problem.. did some riding today and when I came back I was cking the bike over after I had turned it off and noticed bubbles in the gas line, moving from the fuel inlet tube up the clear gas line to the filter below the petcock. removed the gas line from the petcock and watched it,, still had bubbles moving up the line,, so that means gas moving into the carbs. I had a few things to do,, and when I came back later.. oil level past full,, sign,, real bummer.

going to pull the carbs and ck the floats, float level and float needles again,, also will ck the o-rings in the float valve assembly.

thinking about putting the old float valves back in, as they looked fine are are oem parts.

seems to be an intermittent problem,, I did not see any bubbles in the line the last couple of days of riding when i was cking the oil level and the oil level was consistently in the same spot.

any other suggestions? or things to look for in the carbs when i have them off.

thx
Mark

[Nessism]

Bubbles in the fuel line are normal. Leave your bike along and ride.

If you want to do something, make sure you valves are adjusted...or check Basscliff's list of maintenance tasks.

[Mharal]

I just do not get how my oil level can go from 3/4 full for several days and then to completely full today,,, and then when I saw the gas in the gas line drain out into the carbs,, it just seems like a problem to me.