Turbo Seca: Diluted Oil w/Gas in Crankcase Oops

I am a new owner of a 83 Seca Turbo. I knew better but I forgot and left the gas on for a few days. Without thinking about the fuel running into the crank I started the bike and roade it for a about 5 minutes. It kept wanting to stall, got it home and thought about it, so I drained the oil and out came 3.5 quarts of oil & Gas. I flushed the crank with some 20w50. Refilled with some 10w40 Yamalube and it started right up and seemed to run ok.

My big question is: Is the motor ruined or was the five minute ride not enough to scorch the bearings?.

Thanks
Tom

 

Should be fine but I would switch to 20W-basis weight oil immediately.

Also, leaving the "gas on" did not cause the problem. The cause is one or more floats aren't doing their jobs.

 

Ok, Thanks, will do on the 20W50
TR

 

Also, don't forget that a Turbo Seca has a fuel pump. The pressure is regulated by a pressure regulator, which passes fuel back to the tank when the fuel pressure is 2 psi greater than the pressure in the airbox (so it can maintain this 2psi differential when on boost).

Likely your float height/float needles need adjusting or replacing, however, even with those perfect, if you pressure regulator isn't working properly, you'll overflow the carbs in a hurry even while the motor is running. Any more than 2psi differential and you'll have trouble.

You can also pinch the return line, that'll overflow the carbs, but it's only likely if you've turned the tank (I've done this while tuning).

Finally, there is also a check valve before the fuel inlet to the carbs that should prevent the overflow you described while the bike is off. It also will require servicing given your conditions.

For affordable carb rebuild kits, especially the float/fuel valve assemblies, you can't beat BDesigns. Even better prices than chacal for Turbo Seca Carb parts and some of the Exhaust gaskets.

Since you are a new owner of this bike, I highly recommend you fully go through your entire fuel system, and even check the play on the Turbo and consider a rebuild. You'll want the fuel system/intake/turbo perfect, then the bike will be reliable and really scream. I just rode my Turbo today into work, it sat for 20 years and only has 7k mi on the clock, but I went through all that I'm suggesting (and more, especially electrical) and it's been reliable and a blast).

 

Manbot13
Thanks for the info, I drained out the10w40 and left the drain plug out for 24 hours to see if the petcock was leaking (it was not). So tonight I filled it with 20w50 warmed it up carefully and took it for a test ride, luckily, no damage to the motor, ran great. I will go thru the steps you mentioned.
Thanks to all
Tom

 

Again; the petcock is only an "enabler" if you have the problem.

YOU HAD A STUCK FLOAT and may very well have a sticky float; which, if the petcock is functioning properly, would only have the ability to dump more oil into the gas when the bike is running.

Keep an eye on things, check your oil level before every ride and be wary of any increase in oil level. I suspect your petcock is fine and you have a float issue which could very well be dumping fuel; you really don't want to take a chance with a turbo motor.

Keep taking "whiff tests" of your oil filler (take the cap off, insert nose and smell.) If you smell gas and not just golden-brown oil, then you have a problem.

I doubt it was a one-time thing. More likely an omen. Are you running an inline fuel filter?

 

Manbot13
Thanks for the info, I drained out the10w40 and left the drain plug out for 24 hours to see if the petcock was leaking (it was not). So tonight I filled it with 20w50 warmed it up carefully and took it for a test ride, luckily, no damage to the motor, ran great. I will go thru the steps you mentioned.
Thanks to all
Tom

 

Bigfitz, sorry I did not see your reply, no, no inline filter. Other than filtering dirt, what other purpose does it serve? I think you scared me enough to call it quits until I fix the fuel leaking issue.

I read in another post that the float seats can be fixed instead of replacement, I will try that route first.
Thanks again
Tom

 

OK, So now I get it. Dirty Fule equals junk in the Float Seat. Sorry for my momentary ignorance.
TR

 

Float needles lose their tips; valve seats can become worn, pitted or just in need of a good cleaning.

It filters stuff that the built in plastic-gauze screen on the top of the petcock misses. The most common is rust-dust floating in the gas. The built-in Yamaha fuel-filtering measures are woefully inadequate.

You probably just need to clean and service the carbs. The turbo uses special-edition "pressurized" Mikunis; I broke down a Mik BS28 from a 550 here: http://xjbikes.com/Forums/viewtopic/t=31061.html

The overall construction is very similar and closer than that of the Hitachis; but the float bowls are o-ring sealed.

Float operation in the turbo is uber-important, because the fuel is pressurized and they have a whole 'nother challenge to deal with (that pressure.)

 

Good info, thanks