Leaking head, and terrible MPG

geoldr · Jul 27, 2011

Hey guys, so Im gonna attach pictures of the head of my motor. Today was the first time I rode for a long period of time, 20 miles, and when I got home I noticed that it leaked all over the place. Its not the exhaust, and it all looks like its coming fro the head. Not sure what to do.
Also, I have a 2 litter tank. So thats half a gallon. My tank lasts me like 20 miles, or less.
40 MPG?? Aren't they supposed to get like 100?

Venice Motor Bikes · Jul 27, 2011

Simply remove the head & install a new head gasket. (it's easy!)

As far as MPG?, they don't always get great MPG, especially when you ride at WOT & up a lot of hills.

geoldr · Jul 27, 2011

Just a headgasket? Why would it be leaking from the top though? Because that's what it looks like.

But ill check the sites to see where I can get a new head gasket.

Al.Fisherman · Jul 27, 2011

The main reason why you have a leak around the head gasket is that the head is warped....from the factory. I doubt that replaceing just the headgasket will solve your problem
1. Remove the head
2. Mill the head..flat glass, 250 or finer sand paper. Rotate the gasket surface in a up, down and circular motion. Remove enough so you can see the shiny gasket surface. More if you want to up compression.
3. Spray both sides of gasket with a spray on gasket sealer. I use Copper Kote.
4. Replace the cylinder studs if you haven't already done so. Chinese are about a grade 3...go with grade 5 (metric 8.8).
5. Replace head nuts with locking nuts.
6. Torque head nuts in a "X" pattern, 120 inch pounds or more..I use 150 inch pounds. Max on the cast aluminum is 204 inch pounds, for a 8mm stud.
Doing all of above I haven't blown a head gasket in 5 builds. No oil leak either.

I'm 210# and maybe get 80 mpg. Actually I don't care about gas mileage...it's a toy.

geoldr · Jul 30, 2011

Ok, ill do that soon. But do you know why it's leaking from the top? At least that's what it looks like

Al.Fisherman · Jul 30, 2011

geoldr said:
Ok, ill do that soon. But do you know why it's leaking from the top? At least that's what it looks like

Re-read my post. The answer is there. Unless you asking about the spark plug. On the top the head...probably blow up from gasket leak.

geoldr · Jul 31, 2011

From the very very top area though? I don't think it could have gotten there from the headgasket. I think it's from one of the bolts. Because there are 4 nuts as you know, 3 of them are clean, and one is dirty and gunked up. I think it's because I can't tighten it properly, my sockets dont fit. Theyre too shallow

biknut · Jul 31, 2011

geoldr said:
From the very very top area though? I don't think it could have gotten there from the headgasket. I think it's from one of the bolts. Because there are 4 nuts as you know, 3 of them are clean, and one is dirty and gunked up. I think it's because I can't tighten it properly, my sockets dont fit. Theyre too shallow

Harbor Freight is your friend.

Al.Fisherman · Jul 31, 2011

geoldr said:
From the very very top area though? I don't think it could have gotten there from the headgasket. I think it's from one of the bolts. Because there are 4 nuts as you know, 3 of them are clean, and one is dirty and gunked up. I think it's because I can't tighten it properly, my sockets dont fit. Theyre too shallow

Stop and think ...it's either the head gasket or the around the plug. If you look at the head gasket there will be 5 holes. One for the cylinder and 4 for the studs. If the gasket is leaking oil mix it can escape between the head and cylinder. Or around the stud. SANE SAME..gasket leaking. Did you mill the head, did you spray gasket maker on the gasket (both sides)? If they are not torqued down, I use 150 inch pounds, the head can leak. Go buy a proper length socket.

ddesens · Jul 31, 2011

Dont forget to get rid of the acorn nuts!

adb140275 · Jul 31, 2011

'mill' both the top of the head, AND the top of the cylinder with the sandpaper on glass... and dont use a head gasket. more compression, less gaskets

happycheapskate · Oct 17, 2011

re: adb140275 How did that work out for you? Did yours run any differently? Have you seen any evidence of leaks? I like the idea but mine is working ok so far, so I will just use stock gaskets. These motors are made of soft aluminum though so it should work if sanded fine enough before mounting.

adb140275 · Oct 17, 2011

works great if you get mating surfaces flat, no evidence of leaks on my bike or any of my mopeds that i've done this on.

maniac57 · Oct 31, 2011

always retourque after engine gets hot a few times too...Good insurance against more failures.

Al.Fisherman · Oct 31, 2011

maniac57 said:
always retourque after engine gets hot a few times too...Good insurance against more failures.

I have built way too many engines in my life, and have never had to re-torque. I guess if you use the soft cheap studs that are installed from the factory...maybe so. As far as no head gasket...it will increase the compression ratio as stated above, but may make starting harder also.

maniac57 · Oct 31, 2011

Al.Fisherman said:
I have built way too many engines in my life, and have never had to re-torque. I guess if you use the soft cheap studs that are installed from the factory...maybe so. As far as no head gasket...it will increase the compression ratio as stated above, but may make starting harder also.

Simple insurance. You never retorque? Then you have been lucky so far. EVERY gasket manuf. reccomends retorque after a few heat cycles.

happycheapskate · Oct 31, 2011

Did you omit the gasket on the bottom of the cylinder, too? Or only the top/head gasket?

adb140275 said:
works great if you get mating surfaces flat, no evidence of leaks on my bike or any of my mopeds that i've done this on.

rustycase · Oct 31, 2011

Really Alf???

That's amazing!

I've built any number that a re-torque was not necessary, but also a bunch that required it when it grew and shrunk...

and my guess would be that these china girls really do need a gasket !
Top and bottom, for double protection!

morini ???
Well, a lite coat of silver spray paint may be sufficient for a motor machined to their quality with proper metallurgy when the mating surfaces are lapped.

rc

nightcruiser · Nov 1, 2011

I know this thread is old, and Geoldr probably got it all worked out buy now... but I think he was assuming the head was one piece from what he was saying, not realizing there is a gasket under the cylinder body, and another gasket under the cylinder head cover up on top...

Leaking head, and terrible MPG

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