48cc head 66cc

[cigron]

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.

 

[Gator Wrestler]

I DONT THINK SO!

The bore is not the same. They are usually under $15 on Ebay A good time to go with the slant head.

 

[crobo]

From what i've heard the bottom end for most HT motors is the same between 48cc and 66cc. except for the piston and cylinder size of course. your best bet is just to buy a new head cap 80cc Cylinder Body Cap For Bicycle Engines - BikeBerryMotors BikeBerry Motors

 

[Whiplash]

Would this not bump the compression?? Might be worth looking into!

 

[noco]

buy the 66cc engine.....heli coil your spark plug back in on the 48

 

[mdlee1958]

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.

 

[tintor]

If you still have the head for sale let me know

 

[www.cowboy]

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]

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]

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.

 

[ipwnr]

Yeah lol sorry I ment 8mm studs

 

[Ibedayank]

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.

on some of the BGF rico 66cc motors one end of the stud is 8x1.0 the other ende is 8x1.25