blew head gasket already

GoldenMotor.com

GearNut

Active Member
Aug 19, 2009
5,104
11
38
San Diego, Kaliforgnia
Sick Bike Parts LLC - Performance parts for your motorized bicycle

Look in the middle of the page for a complete hardware kit, bottom of page for head gaskets and cylinder studs.
No one that I know of sells copper head gaskets. The aluminum ones work very well if.....if... you true up the gasket surfaces on both the cylinder and head.
The gasket surfaces as they come from the factory leave alot to be desired. Very poor quality control from the factory.
 

DaveC

Member
Jul 14, 2010
969
1
18
Boise, ID
Use something like Permatex Copper Hi-Temp Spray-a-Gasket and a torque wrench. You might also need to tap the head stud holes, too. The Chinese have a tendency to not fully tap the holes. That goes for the mounting and intake and exhaust studs too. That has been the problem with many heads that haven't sealed right. The stud bottoms out too soon and the the acorn nut gets to the bottom of it's thread and you get false torque readings. M6 1.00 torque to 10 lbs and an M8 1.00 or 1.25 to 15lbs. Use some kind of a torque pattern like an "X" or "Z" , don't just go in a circle around the head. That causes an uneven force on the head and can lead to failure.
 

2door

Moderator
Staff member
Sep 15, 2008
16,302
175
63
Littleton, Colorado
Dave C is correct about the acorn nuts bottoming. I've seen too many for it to be a random issue. Replace them with shouldered hex nuts. Proper torque and a flat sealing surface is essential for a good head gasket seal. Good luck.
Tom
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
Yep good advice Dave C & 2door

I put an extra washer under my acorn nuts to make sure they didn't bottom out and as DaveC said Permatex Copper Coat Spray is very goodto coat the head gasket with, I always spray mine and then let them hang to dry a bit for maybe 45 min. or so before I put the head back on.

As to the Copper Head gasket question, I haven't seen anyone offering them for sale, but I make my own head gaskets from Alum. sheets that I get at my local hardware store, they can be bought in several different thicknesses, I use somewhere between .016" & .020" thickness when I make them, the stock ones that I have measured have all been around
.027" so by making mine from thinner material I increase the compression a bit which helps to increase the power & torque of the engines, it doesnt make drag racers out of them of coarse but every little bit helps.

I f you have some basic tools this may be an option for you and you can just make your own gasket and improve how your engines runs a bit as well.

Best wishes, Peace
 

bill gurreri

New Member
Mar 30, 2011
42
0
0
york , pa, usa
thanks gyuy i jusst got back from the beach... I just bought a kit from sick bikes... and it was here in no time... I also upgraded my sparkplug...went for small test ride and wouldn't you know,,,,85 degdance1dance1dance1dance1ree day turns to rain so i'll keeop ya posted....also my loal hardware store has the copper sheets but i wonder how it would hold up,,,, any input...
 

Al.Fisherman

New Member
Sep 9, 2009
1,966
5
0
Calera, Alabama
Use something like Permatex Copper Hi-Temp Spray-a-Gasket and a torque wrench. You might also need to tap the head stud holes, too. The Chinese have a tendency to not fully tap the holes. That goes for the mounting and intake and exhaust studs too. That has been the problem with many heads that haven't sealed right. The stud bottoms out too soon and the the acorn nut gets to the bottom of it's thread and you get false torque readings. M6 1.00 torque to 10 lbs and an M8 1.00 or 1.25 to 15lbs. Use some kind of a torque pattern like an "X" or "Z" , don't just go in a circle around the head. That causes an uneven force on the head and can lead to failure.
I feel that M6x1.0 should be torqued to 6 to 8 foot pounds (72-96 inch pounds), and the M8x1.25 should be a MAXIMUM of 204 (17 foot pounds) INCH pounds. I use 50 and 150 respectfully. I upgrade all studs and only use lock nuts. With these specs I have NEVER blown out a head gasket. I mill (sand) the cylinder and head, also use copper cote sealer, permatex 80697 will do the same job. I also have a inch torque wrench, which will give a much more accurate results.

my $.02
 

rohmell

Active Member
Jun 2, 2010
1,531
6
38
New York
Dave C is correct about the acorn nuts bottoming. I've seen too many for it to be a random issue. Replace them with shouldered hex nuts. Proper torque and a flat sealing surface is essential for a good head gasket seal. Good luck.
Tom
i had that problem with the acorn nut bottoming out against the dome, so I simply Dremeled off the dome portion of the nut, and everything has been fine ever since.