Oil overflow tube at intake By moss8448 (Read 1,968 times)

[moss8448]

I recently got this bike and have had a few posts and it is breaking in as well as can be expected but today after running an errand I checked the oil for the heck of it and to my surprize it barely registered, now this after putting about 30 miles on it and a week old oil change and after looking around and finding no leaks I pulled the underseat storage out and started looking around and sure enough there was that oil in the clear tube that hangs from the air filter box which on this model is under the seat...when I first got this scoot and went over it I noticed that it had about a half inch of oil and didn't think anything of it and drained it out...now it seems to be blowing it into the air filter area for some reason...everything else looks good and it has even gained a few rpms(like you said JR it is breaking in and stretching things out) so why all the oil blowby?

My other scoot even after several thousand miles only accumulated about an inch of oil in that same type tube so I am stumped as to why this newbie is doing this...anybody got any ideas on what causes this?

[JR]

Need to check for a pinched valve cover vent line, clogged air filter or even a crack air filter housing that could be pulling excess oil from the valve cover due to air vacuum. Even though it's new it could need the valves adjusted it's happened before. For sure keep a check on the oil and not let it get too low.

JR

[alleyoop]

I would pull that Valve Cover Vent Hose OFF the Air FIlter and put a Fuel FIlter on the end of it and tie it up high on the frame. It needs to Vent so maybe it is not venting enough when plugged into the Air Box. Besides you do NOT WANT OIL in your Air Box and Covering your Air Filter with Oil that will cause your motor to RUN RICH blocking the air. Take it off the Air Box BUT COVER the Inlet on Air Box that it was connected to.
Alleyoop

[sprocket]

How much oil do you have in sump?

[moss8448]

The sump was changed upon arrival (dumped the old and put in new 10w40) along with a shot of Lucas oil treatment and it was checked, run up, warmed up, rechecked and all was good. I also did the valve clearences(the exhaust was tight) ran it around the block a few times rechecked the oil (good) and ran a few errands and when I came back re-checked the oil and that's when I noticed it was about half full and got to looking around and noticed that the oil had backed up into the overflow looking tube (clear tube) when I did do the valve adjustment I noticed that it really pushed a lot of air out of the valve cover vent tube...I even started it with the valve cover off and it literally threw oil out which let me know the oil pump is in tip top shape....it seems like this 'blow-by' is a bit much and there are no cracks in the air box or pinched lines anywhere went over each line one by one and all good and properly connected...like I said in the original post my older scoot never did this sort of thing and it had a lot longer clear tube as the air box is situated rearward over the drive belt with that wedge looking air filter set up whereas this one is under the seat and I think I'll do what alleyoop did and re-route that vent tube deal towards the rear and let gravity do its thing and put a UNI sock on the intake...these things are fun to tinker with anyway...and I am an old tinkerer from way back anyway...back in the '60s til the '80s had MGs and god knows ya gotta be able to tinker to have one of those rascals...but this blow-by thing is a poser

[sprocket]

Gotta love those SU carbs!

[alleyoop]

Yea, back when I got married we got a Brand New MGB 98hp, my wife always wanted to drive it but she just could not get the hang of the clutch and gas cordination.lol

Yes thos SU carbs where neat I had a syncro gadget in order to adjust them the same.
I remember my neighbor had an MGB as well and my wife and I were on vacation, We lived in a townhouse and had only one garage so the MGB stayed on the drive. When we came back here is my MGB jacked up on the front and one of my wheels was gone!!!

Then the neighbor came over and said that he borrowed it cause he got a flat on his MGB and took my wheel to go and get his fixed we could not beleive it(HAHA).
Needless to say after that we kept the MGB in the garage and the other car outside.
Alleyoop

[silverfox96]

Don't quote me on this, but; I believe that it's possible that you are experiencing excessive blow-by due to the fact that your rings just aren't seated properly and the engine isn't quite broken in yet. The Lucas treatment you put in the oil has probably slowed the break-in of the rings. It's just too slick and isn't allowing the rings to seat properly. Like I said, don't quote me on this. I read somewhere within the past 2 or 3 months that these little engines like to be broken in hard. Not WOT consstantly, but varying speed speed up and down the throttle range.

[moss8448]

yeah Alley those MGs do have a way of drawing other owners to each other...a lot of it was necessity...back in the day tooling around with that rascal we were always helping each other out...out of necessity...I always kept good tires on it cuz my trunk was full of tools and spare parts no room for the extra tire..out of necessity...yeah I had one of those balancers too and boy did they come in handy...there was this glass spark plug thing that I bought that you could tune those carbs and look at the engine firing and tune her to blue...got it from England...I could go on and on about those things have a lot of fond memories....and those SUs remind me of the set up we have now sorta...the more things change the more they stay the same as the saying goes...hope you were friends with that neighbor...

and Siverfox you just may have a point ole buddy... makes sense to me and you are correctee mundo on breaking it in and it does seem to be getting better and better with the breaking in at various speeds and only wide open for short bursts and immediate deceleration then various speeds and cool downs yap better and better...but ya gotta like that Lucas stuff about a 20% mix and a shot in the rear gear too...
Sam~

[blitztek]

we break ours in with 10w-40 castrol 4t motorcycle oil. I would not use lucas during breakin. change that oil, put in oil only and go ride the dog snot out of it for 30 miles, then check the oil. after about 200 miles, change the oil.