fuel in the crankcase of a 50 elite

[towbar]

Hey guys, new here and looking for some info on my 93 elite SR 50, this is my first scooter and I've only owned it about 6 months and never had any real issues with it other than cleaning some debris out of the carb and a stuck closed vacuume petcock in the gas tank, all of this from it sitting for about 5 years. Anyway heres the deal, I parked it Sunday evening and came out Monday to get on it and noticed a big puddle of fuel under it coming from the carb overfolw hose....I thought no big deal, the float didnt seal off and overran the carb, I tried to crank it over and the engine bound up, so i pulled the spark plug and the crank case if full of fuel as well. So I crawled around under it and looked for a crankcase drain plug......but I couldnt find one . Now I know I'm pretty nieave about these rides but most everything I have ever owned, save for the push mower, has a crankcase drain plug.
Where is the drain plug?
Also does these units require oil changes like regular 2 stroke dirt bikes?
Does the crank bearings get oil from the oil injection unit if there is suppose to be no oil in the crankcase?
I dont see a fill plug or a place to check the oil level?

Any knowledge you guys can lend will be greatly appricated!!!

[Wheelman-111]

Greetings:

Both top and bottom end of the reciprocating assembly get all their oil from the pump and/or premix. There's no separate sump for the crank and big-end bearings. 2-strokes that run a proper gear transmission have a separate oil-containing compartment just for the tranny, but these belt-drive beauties do not. Only the rear final drive case contains Honda-prescribed 10W-30.

There's no crankcase drain plug. The carb overflow evidently trickled down the intake tract and filled the crankcase. Being non-compressible, the fluid contents of the crankcase hydrolocked when it ran up into the combustion chamber via the transfer ports. As long as you didn't use excessive force turning it over, probably no harm done. The good news is that your top end should be shiny-clean now.

After you correct your petcock and float valve issues, you'll still need to get the gasoline out of the crankcase.

1. Remove the spark plug.
2. Remove the reedvalve block.
3. Rotate the crankshaft so that the piston is at Top Dead Center.
4. Put on your yellow rain slicker and ducky rain hat.
5. Lift scooter overhead and invert.
6. Shake vigorously.

Seriously, just do 1 and 2, then spin it to slosh most of the liquid out. Evaporation should take care of the rest, leaving a generous coating of oil on all the critical parts.

[Clivester]

These 2 strokes have no crankcase oil reservoir. All of the cylinder and crankcase lubrication comes from the fuel/oil mixture. That's why its important to get the oil ratios and mixture right, and ensure that the oil pump is delivering properly if you use it. The final drive gears do have their own standing oil enclosed in the case at the rear of the motor.

For all that fuel to collect in your cylinder, you must have a free-flowing vacuum petcock (probably punctured diaphragm) that is not shutting off when there is no vacuum AND your needle valve above the float is not sealing properly. You definitely should pull your carb again and check operation of the float and valve. If you do a forum search you can find several prior posts describing how to do this, and how to clean up the valve seat by polishing it (if needed). Once that's working properly it will give you a little more time to solve the petcock issue with a repair or replacement.

Edit: Looks like Wheelman posted while I was penning my reply. Here it is anyway to back up his sage advice.

[towbar]

Hey, thanks for the reply, good info....I'm pretty mechanically inclined but with me not being familular with this scooter I thought I needed to go to the guys in the know, and I appriciate your help.

Nope, didnt force the issue with rolling the engine over, as soon as it bound up I knew there was an issue with interfearance in the cylinder and pulled the plug to inspect. saw the fuel in there and thought ahhh crap, then started looking for a drain then thought ahhh crap again.

The reedblock.....I'm assuming that is where the intake runner conects to the jug in the location of the oil injection unit?

So as long as I get the major portion of the fuel out of the crankcase and put a little coating of 2 strok oil in there I should be OK with firing it off?

I think there may be an issue with the petcock and it may that is trash in the tank causing the petcock to seep fuel from the debris! Is the fuel tank easy to remove on these? I think I''m going to clean it out so this doesnt happen again!

[Wheelman-111]

Greetings:

Fuel tank comes off with 4 10mm hex bolts on most. I used a Yamaha-branded 2-quart kit. Acid to clean and etch, followed by lots of rinsing, then a second quart of some sort of coating you slosh around. Be sure to let it dry completely between and after each step. It may be cheaper to find a new/used tank.

[Kenny_McCormic]

Go get some fogging oil, and spray it in the intake while cranking with ignition off and spark plug out after you have gotten the gas out of it. That will take care of lube. The reedblock is located under the intake mani which connects the carb to the reedblock.

[towbar]

Good deal, I have used tank sealers before and they can be combersome and messy to say the least, I just looked my tank over and it looks to just have just a few tiny (pensile eraser sized) light rusty spots, looks like there is actually more trash floating around in there than anything, maybe from a dirty gas jug.....believe I take the tank off and wash it out thoroughly then maybe try some muric acid to de-rustify the small spots then top off the tank with fresh fuel to prevent the flash rust effect.

[towbar]

thanks too all you guys.......you've all been a big help for sure!!
Maybe now I can get this thing buzzing again without fearing that I'll totally screw it up!!

thanks again!
Towbar

[Lunytune]

Looks like Wheelman posted while I was penning my reply. Here it is anyway to back up his sage advice.

SAGE:
1. a profoundly wise person; a person famed for wisdom.
2. someone venerated for the possession of wisdom, judgment, and experience.

Okay, ole sage, gird up your loins and give us the wisdom of your experience.
Towbar's scoot is a 93 Elite. That should = AF05E. I've got an identical system on my 88 and 89. However, principle should apply to 94-01 AF16 as well, as all are gravity feed and carbs similar, in that they have overflows and are level. When I had a similar problem with my 88 Elite, the flooding went to the ground, mostly through the overflows and possibly out the airbox side of the carb. How did the fuel on Towbar's go the other way, to the engine?

Second question: Shouldn't the reed valve have stopped the fuel from flowing on into the lower end? And then the fuel kept flowing until it traveled back UP, filling the combustion chamber? Seems the gas would have taken the path of least resistance and puddled under the carburetor, not flow on into the lower end and back up to the combustion chamber.

Clivester, jump in here too. Surely you've got some thoughts, wisdom and experience.

[Wheelman-111]

Greetings:

Tunes makes good points. Mine saturated the filter and puddled underneath the airbox too, but the facts are that his case was full of gasoline and had to come from the tank somehow.

1. The carb on mine pointed down/forward a little. On the centerstand even more so. Maybe parked downhill?

2. The reeds are hardly watertight, especially if the plastic block is a bit worn. Wouldn't take much pressure to dribble on by.

[Lunytune]

facts are that his case was full of gasoline and had to come from the tank somehow

Good point ole sage. I don't understand how, but it did happen.
I would still like to hear thoughts from the other sage, Clivester, or anybody else who dares to chime in.

Another question arises from Clivester's post:

you must have a free-flowing vacuum petcock (probably punctured diaphragm)

On two of my scooters, the 88 E and the 89 SA50, the petcock is open constant. I had assumed "frozen". I had also assumed a vacuum operated metalic valve, spring loaded in closed position until vacuum is applied. So how would a punctured diaphragm leave the valve open? Also in question, if the diaphragm is punctured, would this not cause a vacuum leak and effect performance?

Thus far, I haven't worried about the petcocks, now that I've got the carb valve issue solved on the E. The SA50 has never given me a problem on fuel delivery. Should I be concerned about replacing the petcocks? I have a Taiwan aftermarket here on my desk now, purchased from Tazland, but too lazy to install. I hate pulling plastic.

Meanwhile back at the ranch, How's towbar doing on recovery?

[towbar]

I had thought the same thing, however as mentioned earlier my center stand raises the rear of the bike up off the ground by about 3 inches and being that the intake angles downward to the jug this puts the path of least resistance toward the reedblock. Another thing is that the carb overflow hose is about 1/8" ID, and the hose from the tank to the carb is 1/4" ID so if the petcock was stuck fully open the fuel flow to the carb would be 2 times the volume as the carb overflow hose could flow therefore fuel could be pushed up through the carb and into the intake (however the needle seat should have stopped the flow but didnt). I did have a full tank of fuel so the head pressure in the line could have been high enough to force the needle off the seat if it wasnt sealing well in the first place maybe?

[Clivester]

I had also assumed a vacuum operated metalic valve, spring loaded in closed position until vacuum is applied. So how would a punctured diaphragm leave the valve open? Also in question, if the diaphragm is punctured, would this not cause a vacuum leak and effect performance?

Good point Lunytune. They are not necessarily directly related. "Possibly" rather than "probably" would have been better. However, from my several attempts to clean these petcocks, it is apparent that the diaphragm is in contact with the fuel. It's sometimes possible to release a stuck valve by carefully inserting a blunt stick (borrowed from Wheelman's toolbox) and gently pressing on the rubber. Sometimes results in a ruined valve though. So - if the valve is stuck open and the rubber is punctured it may be possible for gas to run down the vacuum line into the manifold. I should think it would affect performance, but we don't know how long the situation existed prior to noticing the flooded cylinder.

By the way, there should be a nylon filter in the tank, held in place by the petcock. Unless removed by the PO of course.

[Lunytune]

Oh Lord, don't borrow Wheelman's toolbox!
Back on point to towbar's problem. Possibly, a bad petcock/ruptured diaphragm helped leaked gas through the vacuum line, directly to the intake. Hmmm?

I've already removed the tank filter on my NQ50, but have an inline filter to protect the carb.

When I rebuilt my AF16E, there was a sizable accumulation of fuel in the lower end, but not knowing the history of the engine, I can't say what happened. I suctioned out as much as I could. I can only assume, and rightly so, that running it cleaned it out. So if all else is well, I would say to towbar, don't worry about getting it all out, and put Wheelman's slicker suit back in his toolbox. He may need it.

[towbar]

good deal,

ya know I checked the operation of the petcock by applying pucker power on the vacuum line and it seem to work correctly but it continued to dribble fuel for a couple minutes and then slowed, did this 3 or 4 times with the same results, was trying to see if I could get it to stick open again but it didnt. If theres a plastic strainer over the petcock then that throws a wrench in my therory about some debris sticking it open....
Could it just be gunk built up in or on the petcock from not being ridden in 5 years, cause there is a lot of floating junk in there...that might be allowing a slow closing operation and the occasional stuck open?

may need to borrow wheelman rainsuit after all, dive in there and take a looksee