49cc vs 80cc

[whelan wheels]

I,ve tried both types of engines and i found that the grubee gt5 h.p. range vrs. the ch80 h.p. range was compleatly different to each other. the grubee was 1.8 h.p. and the ch80 was 3.5 h.p. and when it came to perfomance the gt5 motor did ok on the flats but i found it to be a little weak on even the slightest hill i encountered while testing the motor compared with the ch80 motor i found a huge difference in the tourque values especially when it came to hill climbing on shallow gradients and i could feel the motor tourquing a whole lot more on the ch80 than the grubee motor. Istill need to do further research to finalize a better report on the performance.

 

[bairdco]

was that with the 49 or the 66? my grubee gt4 66 claims 2.85 hp. never heard of any of these motors rated at 3.5...

 

[george_n_texas]

I go with the <50cc kits for several reasons
1) Legal or at least best attempt at legal...laws are really gray in TX
2) I need SOME exercise so peddlin uphill I get a little
3) I am a cheapskate and unemployed
4) Lower speed is less likely to be noticed
5) Easier fit in frame

My first kit was a grubee skyhawk 48cc from King's better carb but I just found out the muffler is better on the zoombicycle.com 48cc kit...it is chrome with a heat shield. The grubee was $180 shipped to Tx the Zoom was $109 on Thanksgiving day shipped to Tx. I don't remember how long the Grubee took to ship but Fed Ex was a hassle waiting around on the day before it finally came but that's the driver in my area. The Zoom sent emails keeping me informed every step of the way getting here and arrived 8 days later as scheduled via UPS...not bad during this season coming across Canada border. I think the Zoom has much better compression.

 

[flybytaco]

i never tried a 49, but i've got a grubee starfire gt4 66cc that i like so much i go in the garage in the middle of the night and make sure it's comfy...

where did u score a gt4 66? i just scored a phantom 58cc

 

[bairdco]

about 10 miles from my house. i've got 3 of them. they all come with 2 headgaskets, but that's only because they have an extra, not because they machined the head too small like the pk...

 

[Bikeguy Joe]

Anything less than physically measuring your engine is a folly.
I have seen a lot of "80cc" engines lately that are really "47cc's".

Assume nothing.

 

[flybytaco]

ok heres my new verdict. swapped my pk 80 with a pk 50 and thats goin in the trash too like my grubee 49 biggest waste of my money once agn

 

[flybytaco]

about 10 miles from my house. i've got 3 of them. they all come with 2 headgaskets, but that's only because they have an extra, not because they machined the head too small like the pk...

i removed on headgasket from all my pks and they dont hit. but it makes it harder to start but when its runnin look out

 

[Riding Rich]

My PK 68.8cc exact totally blows my 48cc grubee away.
The grubee would go 40+ mph but it took a wile to get there.
This PK pulls right from the start.

 

[momentummotorgroup]

hey if you're just throwing them out you can always send 'em my way!! ;P

 

[Riding Rich]

Ya mee too if anyone wants to get rid of any engines broken or not let me know.

 

[vincent713]

I have a 49cc kit, would it be possible if I change the head and make it a 66cc?

 

[spit_fire]

hey guys im back to report 4000km later as well as 6 engine swaps later and i can say that with a good pipe (i have the spb expansion chamber) the 49cc starfire isint to bad this is the 4th time ive put this engine on my bike, the nice engine i built i ended up frying after about 2000km due to the intake gasket disentegrating on a long trip and the intake leak did wonders on the motor, then i put the starfire back on till i found a pk for 20 bucks of some kids that said it didint work, i got that engine running but it was just a dud so i whent back to the starfire and then i odered a nice new pk80 wich one of the bearings seized solid on the crankshaft after makin a bad noise for about a day (guess i shouldnt have ignored it), and now im back to the good old starfire again and i must say it doesnt have as much torque but this thing just wont die i keep using it as a back up engine and it fires up everytime and runs like a charm

 

[Diesel Dan]

If you are afraid of running into trouble with your local Barney Fife about engine size just get a cheap stamp set from Harbor Freight and stamp "49cc" on the side of your larger-than-that engine case, no one but you will ever know the differance!

 

[spit_fire]

srry vincent i highly doubt u can get 17 cc by putting on a diffrent head you would sinmply have something like 3:1 compression ratio (just guestimating) and that low of compression is pretty much useless, if you want more power try getting a head with a smaller combustion chamber for some extra compression