48cc head 66cc

GoldenMotor.com

cigron

New Member
Nov 18, 2009
59
0
0
wormleysburg pa
I would like to know if the head for 48cc will fit A 66cc motor.
I was riding wot and the spark plug along with the threads came out.:-||
 

mdlee1958

Member
Feb 22, 2009
204
1
18
Fort Collins, Colorado
NO....tried it. The bolt hole dimensions for the 50cc are approx. 4mm narrower than the 66cc head. PS. If anyone is interested in a new never mounted 50cc slant head I have one.
 

www.cowboy

New Member
Jun 1, 2011
15
0
0
Columbia Falls, Montana
After reading this post no one has said if they have tried to swap out the jug and piston. I checked on the grubbee sight and they make a 48cc, 55cc, 60cc and 66cc engine. The stroke on all these engines is 38mm.
The bore for the 48cc is 41mm, for the 55cc is 44mm for the 60cc is 46mm and for the 66cc is 47mm. The 66cc engine is the only one that uses the 8mm head bolts.
Is it possible to bolt a 55 or 60cc top end to a 48cc bottom end without any machining?
Is it possible to bolt a 66cc top end to a 48cc bottom end with minimal machining?
 

ipwnr

New Member
Feb 3, 2012
30
1
0
maple, ontario
i have tried this on my ht and it works like a charm! i tried it only because my old head got warped and wonders if it would work so i got a 48cc head with the bigger stud size( srry i forgot the stud sizes lol) and bolted it right on and i gains some speed outs of it, i never measured compression before and after but if you look at the combustion chamber size you can tell its a big difference, and by doing this with the current mods that i have(dellorto she 14.14 carb,trimmed piston skirt) i was getting 53kmh but after the head swap i got 56kmh :)
 

Al.Fisherman

New Member
Sep 9, 2009
1,966
5
0
Calera, Alabama
i have tried this on my ht and it works like a charm! i tried it only because my old head got warped and wonders if it would work so i got a 48cc head with the bigger stud size( srry i forgot the stud sizes lol) and bolted it right on and i gains some speed outs of it, i never measured compression before and after but if you look at the combustion chamber size you can tell its a big difference, and by doing this with the current mods that i have(dellorto she 14.14 carb,trimmed piston skirt) i was getting 53kmh but after the head swap i got 56kmh :)
As far as I know, the cylinder studs only come in two sizes, a 6mm and a 8mm. BUT with the 8mm you may have either a 8x1.25 (most common) OR a 8x1.0 thread.