Oil on front of motor

haoleboy · Nov 14, 2012

Hello everyone;
I have a DAX motor, 80 cc, and have oil on the front of my motor. It is very hard to tell where it is coming from, and have noticed that the head is not against the cylinder. There is a slight gap between the two. Is this where it is leaking? Is this supposed to be like this? I have not measured the distance, but it looks like it might be a sixteenth of an inch. Do I need a thicker head gasket? I have torqued the head at 8 ft lbs. I like this motor and I don't want to screw it up! Your help is appreciated!
Thank you, Dave

borntofli · Nov 14, 2012

Could be head gasket or exhaust gasket... Clean your motor w/ carb cleaner and run it to see where the leak is....

haoleboy · Nov 14, 2012

Yes, I have, but the trouble is, I can't see where it is coming from.....
Thank you

wan37 · Nov 14, 2012

Try and clean it again and try a new exhaust gasket and see if it's leaks again if it does then do the head gasket and tighten at 10 ft pounds becareful when tighten it down go in a x pattern.

JonnyR · Nov 14, 2012

if its splattered on the front it is usually the exhaust gasket if its up on the top fin where the head meets the cylinder then its the head gasket

2door · Nov 14, 2012

I doubt seriously that you have a 1/16" gap in the cylinder mating surface. You wouldn't have enough compression for the engine to run very well, if at all.

I suspect it is the exhaust manifold gasket. They are notorious for leaking. The problem is usually a warped exhaust pipe flange. They warp from the weld process. You need to make sure that surface is flat and fits flush with the cylinder and use gasket material made for exhaust applications. Preferably no less that 1/8" thick.

Remove the pipe/muffler and clean the gasket surface well. Paint it with a magic marker or machinist dye and run it over a flat surface, like glass, with a sheet of sandpaper on the glass. You'll quickly see where the high and low places are and that's what you don't want. The gasket mating surface must be uniform for a good seal. Keep sanding or grind until you have a flat gasket area.
Torque the fasteners to 50 to 60 inch pounds after installing a new gasket. Allow the engine to reach operating temperature a couple of times then recheck your torque.

Tom

Groove · Nov 14, 2012

I am a noob (first post to this board but have been "lurking" for weeks now getting great advice from you all!!!). I was wondering about the same thing Haoleboy originally asked and had another related question: In lieu of sanding the imperfections out of the metal gasket or seating surface.... could hi-temp RTV gasket be used as a lazy man's fix, etc?

JonnyR · Nov 14, 2012

not realy a good fix is getting exhaust gasket material from your local auto store and making a gasket the high temp RVT dosent like the oil and gas from the engine so it will get eaten eventualy it may work in the short term but its not a fix

Groove · Nov 14, 2012

Thanks. So the exhaust gasket material would compress when the bolts are tightened and make up for imperfections in the seating surfaces? Would this work for the metal gasket that is sandwiching the top head to the cylinder also? or just the exhaust gasket..

JonnyR · Nov 14, 2012

the head gasket is a aluminum gasket and you need a direct replacement you can flip the one you have over once and use it a second time but it squishes to much after that to use a third time

the gasket material will take up some of the imperfections but as 2 door said to do it right making it flat will make it seal for the long haul

2door · Nov 14, 2012

Groove said:
Thanks. So the exhaust gasket material would compress when the bolts are tightened and make up for imperfections in the seating surfaces? Would this work for the metal gasket that is sandwiching the top head to the cylinder also? or just the exhaust gasket..

The cylinder head can benefit from lapping (sanding it flush) as well as the intake and exhaust manifold flanges. The same method described earlier, painting the surface with ink or dye to show where the imperfections are.

You need a known flat surface, glass, sheet steel, anything that you know is flat, and a few sheets of 220 grit sandpaper or emory. The important thing with a cylinder head is to keep rotating the head in your hand as you sand to keep from sanding an angle into the gasket surface. I like to use a rotary motion, like waxing a car.

Head bolt torque is also important as well as discarding the chrome acorn nuts in favor of hex nuts, preferably the shouldered type and using a torque wrench. Tighten the nuts in a cross pattern until you reach 120 to 140 inch pounds. Recheck your torque after the engine has run a few times.

Most silicone based gasket sealers are not compatible with gasoline. Read the label of any product you plan to use. Do not rely on a silicone based sealer on the head gasket or exhaust manifold.

Tom

Groove · Nov 14, 2012

Thanks for describing the process Tom! I'll do that and let you know how it turns out.

haoleboy · Nov 16, 2012

To all; Thank you very much for your answers. I shall clean the entire motor once again, and every run I make I will keep an eye on it to find the source. thank you all.

BikeBerryKelci · Nov 16, 2012

haoleboy said:
Hello everyone;
I have a DAX motor, 80 cc, and have oil on the front of my motor. It is very hard to tell where it is coming from, and have noticed that the head is not against the cylinder. There is a slight gap between the two. Is this where it is leaking? Is this supposed to be like this? I have not measured the distance, but it looks like it might be a sixteenth of an inch. Do I need a thicker head gasket? I have torqued the head at 8 ft lbs. I like this motor and I don't want to screw it up! Your help is appreciated!
Thank you, Dave

I would definitely check all your gaskets to make sure none are busted or broken. Sometimes you have to double up on the top head gasket to fit it properly. Also what type of oil are you using? And whats your oil to fuel ratio your using? .cs.

BarelyAWake · Nov 17, 2012

BikeBerryKelci said:
Sometimes you have to double up on the top head gasket to fit it properly...

I'm sorry Kelci, but that's a "duct tape workaround" & should only be done if the piston is contacting the plug, unlikely w/a unmodified motor.

These engines are notorious for poor castings & warped heads, "doubling up" gaskets and/or the use of sealants will only postpone a recurring problem if the cause isn't resolved - the following procedure will not only illustrate the extent of warpage/casting flaw but actually fix it w/o a preformance loss (head gasket/compression) or recurrence of the leak (exhaust);

2door said:
The cylinder head can benefit from lapping (sanding it flush) as well as the intake and exhaust manifold flanges. The same method described earlier, painting the surface with ink or dye to show where the imperfections are.

You need a known flat surface, glass, sheet steel, anything that you know is flat, and a few sheets of 220 grit sandpaper or emory. The important thing with a cylinder head is to keep rotating the head in your hand as you sand to keep from sanding an angle into the gasket surface. I like to use a rotary motion, like waxing a car.

Head bolt torque is also important as well as discarding the chrome acorn nuts in favor of hex nuts, preferably the shouldered type and using a torque wrench. Tighten the nuts in a cross pattern until you reach 120 to 140 inch pounds. Recheck your torque after the engine has run a few times.

Most silicone based gasket sealers are not compatible with gasoline. Read the label of any product you plan to use. Do not rely on a silicone based sealer on the head gasket or exhaust manifold.

Tom

haoleboy · Nov 20, 2012

I am using 20-1, just what DAX instructed me to do, and the oil is Lucas. This week, when the weather gets better, I'll do a total clean-up, and look every time I use the bike to attempt to find the source.....
Thank you all for your inputs.

Groove · Nov 20, 2012

LOL , be sure to at least keep one eye on the road. One time I drove over a dog toy and then into my own mailbox while I was trying to check my chain alignment. Then I was diverted into an old tree stump which caused me to "take a sit down". Problem was, one of the branches snapped and hit me right in the nads. Not fun, especially with the neighbor girl watching and laughing. Insult to injury. Well, I got the last laugh because right before all that happened I figured out that the rear sprocket needed adjusting.

Groove · Nov 20, 2012

In your case though, it seems like a gasket issue. When you solve the problem be sure to let us know the root cause and solution.. Good luck

haoleboy · Nov 21, 2012

Hello everyone; Well, after cleaning, and tightening the exhaust once again, no oil is leaking. I just did not tighten the gasket enough. Sorry for the alarm, and thank you for your inputs. I didn't want to snap any nuts or bolts, so I have more homework to do. Thanks.....

DaveC · Nov 25, 2012

haoleboy said:
Hello everyone;
I have a DAX motor, 80 cc, and have oil on the front of my motor. It is very hard to tell where it is coming from, and have noticed that the head is not against the cylinder. There is a slight gap between the two. Is this where it is leaking? Is this supposed to be like this? I have not measured the distance, but it looks like it might be a sixteenth of an inch. Do I need a thicker head gasket? I have torqued the head at 8 ft lbs. I like this motor and I don't want to screw it up! Your help is appreciated!
Thank you, Dave

....uuuhhh, yeah, that's a big problem. I'm suprised it runs at all. Sounds like something is warped or just badly machined. Trust me, it's not the exhaust gasket...

New gaskets top and bottom will be needed because you need to check for flatness of the head and top of the jug. Clean well and use some kind of a flat surface like a mirror or sheet of glass to check the head. Place the head on it and see if it rocks, it shouldn't. Use a straight edge like a ruler on the top of the cylinder going from bolt to bolt side-by-side, going across won't help. If you see a gap under the edge or if it rocks then the jug needs to be ground down. Get a pack of assorted grit wet/dry sandpaper from 220 to whatever finer grit. There are tutorials on how to do this here somewhere. You have to take the jug off to do it. That's why you'd need both gaskets. Get a can of Permatex Copper Spray-a-gasket and apply as per instructions.

Before you do any of this if you have 8mm head studs your torque should be 12 pounds, 8 pounds is for 6mm studs. That might pull things together correctly. Start with the studs nearest to the exaust port.

Worse case you have torched the head. Hot exhaust gases can melt the aluminum and leave paths that can't be sealed and then new parts are in order. Let's hope it's not that

Oil on front of motor

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