2T oil tank overfilled?

Mr.FixIt · Posted: Fri Oct 05, 2018 1:36 pm Post subject: 2T oil tank overfilled?

I really do like the concept of the automatic oil system on the 2T. Have I just made a noob mistake? I wanted to ask if its possible that I've overfilled the oil tank?

Everything was running great until a few days ago when I noticed that the oil tank sight glass showed a low level. Gone through my first tank of oil since I got the bike. So I dumped a whole bottle of oil in there. It all fit, it didn't come up into the neck of the tank TOO much. I figured I was ok.... until I let her sit overnight and tried to start in the morning. I did turn off the fuel.

A HOLY COLOSSAL CLOUD OF SMOKE came out and blanketed the neighborhood. I noticed some oil dripping out of the exhaust resonator. It wasn't atomized oil with fuel, it was just oil.

So do I trust the AOM system now? Should I limit the amount of oil I put in the tank? I didn't have access to the same oil I started with on the first tank she burned. Did changing oil to a non-synthetic cause it not to atomize? I thought that about any appropriate rated oil would be ok. The owners book doesn't really say exactly what to use. I read through the forums and got the general opinion that synthetic was better, but people were running other stuff just fine.
I don't want to start an oil-religion discussion, this is more about why the oil is running out the bottom of the bike.

I want to drain the tank of the oil that's presently in there, put some synthetic 2T oil in and not over-fill the tank to test it.

Any thoughts oh scooting gurus?

dasscooter · Joined: 14 Feb 2016 Posts: 332

1. Did you leave the gas on? That'll do it on the smoke issue

2. There's a seal that can leak between the oil tank and the filler tube

Mr.FixIt · Posted: Fri Oct 05, 2018 4:41 pm Post subject:

The fuel was turned off.

Maybe the filler tube seal leaked. I did fill it up too far, but that doesn't explain the excessive smoking.

Stanza · Posted: Fri Oct 05, 2018 5:53 pm Post subject:

If it keeps happening, you may have uncovered a problem with your bike that you didn't know you had. There is a gasket between the carburetor and the cylinder which, upon failure, will allow excess oil to seep into the cylinder while the bike is sitting. It will also burn extra oil while running, with the main noticeable symptom being that the rear wheel starts getting coated with oil.

The extra weight of oil coming down the feed line, now that you'd brimmed the tank, may have been enough to start seeping through a failing gasket.

If you are lucky, all you need to do is tighten the mounting bolts for the carb body, and it will tighten up and re-seal. If you are unlucky, you will need to replace the gasket itself.

Of it could be something else entirely. I only mention this because I've seen it a few times with the 2t bikes.

Mr.FixIt · Posted: Fri Oct 05, 2018 6:08 pm Post subject:

I have a whole carb rebuild kit that I was waiting for the right circumstance to install. This sounds exactly like what is happening, the crankcase has an over-abundance of oil in it, which is going down the exhaust port and running onto the ground.

I really dislike the lack of clamping force on this particular gasket. If over-tightened even once it can cause warping and will never seal correctly. Realizing they were trying to create something that was backward compatible with original Vespa parts, I would have thought they would have made some accommodations for the required gasket clamping force needed to keep this tight around the oil passage.

I hesitate to apply a gasket sealer to it, but that may be prudent if it fails to seal. I've never had much luck with containing oil without a proper sealant.

I'll investigate this gasket and just rebuild the carb while its off.

Thanks everyone.

Mr.FixIt · Posted: Sat Oct 06, 2018 1:38 am Post subject:

There was a puddle of oil sitting on top of the reed, and the gasket is frelled.

New gasket, this time with a gasket cement. It will be a royal pain to clean up next time I have to take it apart, but maybe this time it won't leak.

Waiting until tomorrow or the next day to fire it up... its too late tonight.

Mr.FixIt · Posted: Sun Oct 07, 2018 5:08 pm Post subject:

Situation update: took a good hard ride to burn off the excess oil. The exhaust then burned clean.

So the test was to let it sit overnight to see if it smoked in the morning. It did smoke... so now what. The gasket is guaranteed intact.

So now what... back to premix?

youkiddin · Posted: Sun Oct 07, 2018 10:12 pm Post subject:

your problem maybe the check valve in the auto lube pump

Stanza · Posted: Mon Oct 08, 2018 2:49 pm Post subject:

FYI the exact torque spec for those carburetor bolts is 14 ft-lbs, pulled from the service manager. Tighten them incrementally, rather than going full torque on one, and then doing the other.

Mr.FixIt · Posted: Mon Oct 08, 2018 3:27 pm Post subject:

Mr.FixIt · Posted: Tue Oct 09, 2018 2:48 am Post subject:

ahhh... enlightenment.

http://modernvespa.com/forum/topic124633

youkiddin · Posted: Wed Oct 10, 2018 9:05 pm Post subject:

I also wait for the sight glass to show that I need to add some oil ( you still have about 8 oz of oil in there) and I add a 355ml bottle of oil to keep it out of the tube.

Mr.FixIt · Posted: Fri Oct 12, 2018 1:39 pm Post subject:

I finally made some time to work on this issue again.

I stripped the oil pump and found that the check ball was rather small for the seat. Using compressed air at low pressure, it was obvious that the check ball wasn't able to provide any seal whatsoever opposite the direction of oil flow. This means that when the engine is off overnight, the oil will not be stopped from flowing and fill up the space above the reed.

So, I found a slightly bigger ball bearing that was in my junk box. It fit in the hole covering the seat much better, so I put it back together. I did a quick 5 mile run last night in the rain and burned off the oil that had collected in the crankcase. In the morning I went out and fired her up. There was a little smoke, as I would normally expect. However it was not the huge cloud of objectionable smoke that would cause the tree-huggers to come and have a demonstration at the end of my driveway.

I ran her up the street and back, and the smoke was normal. I pulled the airbox cover and air cleaner off. Then every so carefully with a very tightly wound cotton swab, I covered the oil injection port in the throat of the carb. To my pleasant discovery the Q-tip swab came out oil-colored and soaked. This tells me that the pump is delivering oil.

Just how much oil it is delivering is now in question. If I put a bigger ball in there, and it restricts the passageway a little more, did I change my oil mixture by doing this? I'm still pondering that one. I could risk running it the way it is, and see how it does on a longer term test. I could also petition the wife for her approval to buy a new airbox / oil pump assembly.

Stanza · Posted: Fri Oct 12, 2018 2:21 pm Post subject:

If it's smoking normally while riding, and feels normal, I'd say you've solved the problem adequately. If you are concerned with it being a lighter oil mixture than before, you could upgrade to an oil that is rated up to 100:1 mixture.

jimmbomb · Posted: Mon Mar 04, 2019 3:33 pm Post subject:

Is your bike a 09?
If so, those had a problem with the check valve staying open when too much oil in the tank. A solution was to only put a half quart at a time when adding.

Mr.FixIt · Posted: Mon Mar 04, 2019 4:02 pm Post subject:

Thanks. Yes it is a 2009. I only fill as much oil in the tank as needed now and there hasn't been a problem.