Gap in Head Cylinder

GoldenMotor.com

Cycleized

New Member
Oct 12, 2012
3
0
0
Washington
A few days ago I just put together my first kit, It's a GT5 skyhawk motor. Today I was tinkering around with it and saw a small gap where the cylinder head connects to the jug; large enough to see daylight through it. In addition it looks like some oil is coming through.

I tried tightening the bolts down, but the gap is still there. Is this something I should contact the company about, or just go ahead and lap it myself? This is my first real project with motors, so I'm not sure if running it with this gap and slight oil leak could cause problems or not. The bike does seem to run fine, just possibly with some power loss, but I don't really have anything to compare it to.

Any help would be great, Thanks!

:-||
 

Dave31

Active Member
Mar 1, 2008
11,199
47
38
Aztlán, Arizona
Hello Cycleized welcome to the forum.

Seeing daylight between the head and jug? Nah, if you see moonlight then I'd worry.

Just joking, are you sure a head gasket was installed on your motor?
 

Cycleized

New Member
Oct 12, 2012
3
0
0
Washington
Yep, I pulled the head off just to see if reseating it would help. There is an aluminum gasket in there and the kit came with a spare.
 

PAracer

New Member
Sep 14, 2012
284
0
0
Steelton, PA
Go ahead and lap it. it's a good idea on these motors. plus, you will increase the compression ratio a tad. After lapping, assemble the top end with a light coat of copper ultra RTV. You will have a nice seal.

Another good option is a Puch moped cylinder head. $30 from treatland.tv and you can order one with a nice bump in compression, as well as improved cooling. It's a very good upgrade on these motors.
 

Cycleized

New Member
Oct 12, 2012
3
0
0
Washington
Thanks for all the replies! I went ahead and added the other gasket, when I put it on I noticed there was a small lip around the head that may have made it look like there was space in there. Checked the seal with carb cleaner and no leaks except for one around the carb manifold. Just recently the bike has started bogging out and I guess that could be why. Anyone else have experience with power loss after the first tank of gas, or so?
 

PAracer

New Member
Sep 14, 2012
284
0
0
Steelton, PA
Thanks for all the replies! I went ahead and added the other gasket, when I put it on I noticed there was a small lip around the head that may have made it look like there was space in there. Checked the seal with carb cleaner and no leaks except for one around the carb manifold. Just recently the bike has started bogging out and I guess that could be why. Anyone else have experience with power loss after the first tank of gas, or so?

Power shouldn't drop after the first tank. If anything, it should get faster as the cylinder walls and piston rings break in. I would get that leak fixed though. You can usually seal it up with a little rtv.
 

PAracer

New Member
Sep 14, 2012
284
0
0
Steelton, PA

A. Thomas

New Member
Mar 24, 2024
1
0
1
57
Thanks for all the replies! I went ahead and added the other gasket, when I put it on I noticed there was a small lip around the head that may have made it look like there was space in there. Checked the seal with carb cleaner and no leaks except for one around the carb manifold. Just recently the bike has started bogging out and I guess that could be why. Anyone else have experience with power loss after the first tank of gas, or so?
was there a gap after all or just looked like it. I have the same problem!
 

wrench

Well-Known Member
Aug 20, 2019
753
1,019
93
So Cal
was there a gap after all or just looked like it. I have the same problem!
Don't hold your breath for a reply, It's from Oct, 2012
@Cycleized hasn't been seen since Nov 2012

BTW For your future enjoyment, the date is in the upper left hand corner and if you click on the persons avatar their Profile will pop up letting you know when they were last seen on line
 

wrench

Well-Known Member
Aug 20, 2019
753
1,019
93
So Cal
was there a gap after all or just looked like it. I have the same problem!
What up A Thomas, Welcome to Motorbicycling.com
You should introduce yourself so the members can get to know you

How about a pic of your bike and a story of why you like Motorbikes