Revenge of the Oil Leak

backfiring during deceleration is usually from loose exhaust manifold gasket or exhaust manifold nuts - cold air gettin in there on decelleration..

Hey Florida

The only time I have ever had that much oil "leak" was when I blew out my rings, and had crazy blow-by. The oil sprayed out that hose and got everywhere, so it was hard to see where the leak was

You might want to check when it running to see if your have oil coming out your vent hose.



Backfire - also had backfire. I fixed it with a new crushable exhaust gasket and a butload of copper gasket sealer.

Nope Just shiny mettle gasket. Not the silly little ring gasket

Well, I got rid of the backfiring exhaust leak with a good dose of gasket sealant... Thought I had eliminated the oil leak this weekend. No loss yesterday, but when I checked this afternoon, I was down to a half-stick. Topped it off and keeping an eye on it... No oil flying anywhere, tho. Valve cover is dry, haven't pulled the shroud again yet, I suppose I'll check that this weekend, and hope my head gaskets get here soon!!

I think I have a very slow leak now... I haven't really done anything but refill the oil in the last month, too busy for disassembly right now, but it /seems/ to be holding up pretty well, considering...

You may have unrealistic performance expectations for an air-cooled GY6 150cc engine

How about unrealistic expectations from a 150cc anything? He's doing roughly 300 miles a week, 1200 miles a month, 14,400 miles a year (15,600?). That's just on his commute. Didn't I hear him say he took the scoot out for a 120 mile ride one day?

Oil leaks, Blown exhaust gaskets, broken valves. Two words-Motor Cycle. All sorts of bikes available for little money that will stand up to this abuse. Old Honda Rebels by the truckloads. Heck, old Kawasakis, Hondas, Suzukis and Yamahas of every shape and size. If your speedometer was working you'd be astounded at how many miles you really have on that scooter already. You should be doing an oil change every other week.

Good string. I can't imagine sitting my my 150 for 30 miles. Now I used to ride a 90CC Honda about 25 miles to work most days. But my 150 no way. Most 250's would be something else.

I do suspect you may be building up a lot of crankcase pressure. Your vent hose may be moving and at times restricting the venting of ordinary ring blow-by. Good starting indicates good compression.
Backfiring is almost always a combination of LEAN mixture and an air leak in the exhaust near the head although running hard for 30 miles will get the entire exhaust hot enough to auto ignite.
I think your running perhaps on the rich side is what saves your engine. Rich runs much cooler. Lean burns slower so you still get flame going past the exhaust valve. We used to lean out engines on a B29 (3350's) till we had a bit of flame coming out the collector ring. (exhaust). At night you could see the exhaust pipe glow red. LEAN. It runs much hotter.

I would tackle the backfiring by:

1. remove the muffler hangers
2. get a now copper sealing ring
3. Carefully tighten the exhaust flange to the head. Use a torque wrench so you get all the tightening you can without breaking anything. Clean the threads first and use aluminum anti- seize to lubricate.
4. Now get an acetylene torch on the exhaust pipe and heat it up enough to soften the pipe and carefully bend it so that all the brackets are perfectly aligned so that no bend/twist pressures are on the flange. You probably are getting the copper sealing ring hot enough to be soft so it is opening up after a few days of riding

I would also stop at least once near midway each way and check oil level. Carry a quart or so and a rag and a funnel with you. Your engine will love a 3 minute rest.

Go for it. Amazing what you are doing and how well your scoot is doing it. New set of tires every 6 months or so?

Cheers
lefty2