I recieved one as a gift BUT been wanting to build one. I have no idea in this field but been playing around with cars and engine for awhile. My question is " how do I find out what displacement is my engine" and " how can I make this a little faster because im a heavy guy". What are the aftermarket parts that add a little speed or should I change to a bigger engine? Help would be greatly appreaciated. Thanks.
very new to this motorbike thing with a few questions
- Thread starter bro-die
- Start date
rustycase
Gutter Rider
Welcome aboard!
Tell us a little more abt your bike/kit and we can help more.
IMO
just put it together AS IS for now and see what u got.
Read all the threads u can abt taking a motor apart for pre-run inspection.
It is a very important step in the build process.
Actually, it means life or death of the engine.
Big?
Well, I'm 6'2" and 236lbs, which ain't real big, but 48cc worn out skyhawk gets me around town pretty well.
Of course I'm looking for cheap, reliable, fun, personal transport...
Best
rc
Tell us a little more abt your bike/kit and we can help more.
IMO
just put it together AS IS for now and see what u got.
Read all the threads u can abt taking a motor apart for pre-run inspection.
It is a very important step in the build process.
Actually, it means life or death of the engine.
Big?
Well, I'm 6'2" and 236lbs, which ain't real big, but 48cc worn out skyhawk gets me around town pretty well.
Of course I'm looking for cheap, reliable, fun, personal transport...
Best
rc
foundmydog
New Member
Just put together what you have first... get it running and work out the bugs
THEN you can add parts and play with gearing to get what you want
THEN you can add parts and play with gearing to get what you want
nightcruiser
New Member
If I read you correct you are saying you don't know exactly what motor you have? If that is the case I guess a picture or at least a description of your motor would be needed to even start...
It also seems you were given a complete motorized bike, AND are going to build a second one??? If this is the case, do you have the motor for the second bike already?
Finally, you say you are a "heavy guy", how heavy?
Your post was a bit too vague to help you, fill in the details a bit and we will try to help you out....
Other posters have given you good advice already, but more specifics would help us give you more specific advice....
nightcruiser
New Member
Some guys are 145lbs and would call me heavy at just over 200lbs. At over 300lbs you need to also consider the sturdiness of the bike, brakes, wheels and everything. After all, if you get the motor setup well enough to get you flying you need to be able to stop too, and also be sure that the bike frame and wheels can safely support the weight and speed you are going to ride...
On a side note, when I started out last summer I was about 225lbs, I lost 25lbs over the summer mainly from building and riding this bike. People like to call me lazy, having a motor on my bike, but you DO get good exercise even riding a bike with a motor. So dig in, build up and RIDE my friend, you may be surprised how much exercise you get in the process...
Last edited:
And, in spite of what you might have been told, DO NOT START TAKING YOUR ENGINE APART.
This is bad advice for a new builder with little to no experience with these engines. The odds are in your favor that the crankcase doesn't have trash in it.
As for checking the displacement, it's almost certain that you have either a 49 or a 66/70CC engine. They only come in two sizes. You might see ads for an 80cc engine but that is measured by including the combustion chamber volume. There really are no 80cc Chinese bicycle engines out there. My guess is it's a 66/70cc. They seem to be the most common but even if it's the smaller version there's not that much difference in power output. To confirm you'd have to measure your bore and stroke.
Tom
This is bad advice for a new builder with little to no experience with these engines. The odds are in your favor that the crankcase doesn't have trash in it.
As for checking the displacement, it's almost certain that you have either a 49 or a 66/70CC engine. They only come in two sizes. You might see ads for an 80cc engine but that is measured by including the combustion chamber volume. There really are no 80cc Chinese bicycle engines out there. My guess is it's a 66/70cc. They seem to be the most common but even if it's the smaller version there's not that much difference in power output. To confirm you'd have to measure your bore and stroke.
Tom
killercanuck
New Member
Welcome!
The first thing that comes to mind is a larger sprocket to help get you going and up to speed, like a 52, 60, 67, or even 72(if you need to pull a stump
). A larger sprocket will help acceleration, but will lower your top speed.
Later on you can worry about expansion chamber, hi-po carb, and whatnot.
gl.
The first thing that comes to mind is a larger sprocket to help get you going and up to speed, like a 52, 60, 67, or even 72(if you need to pull a stump
). A larger sprocket will help acceleration, but will lower your top speed. Later on you can worry about expansion chamber, hi-po carb, and whatnot.
gl.
Allen_Wrench
Resident Mad Scientist
Listen to Tom up there: don't tear the engine down unless 1) you are more than capable of putting it back together the way it was, requiring ring compressor, torque wrench, and other more-common tools, and 2) you have a VERY good reason to suspect there is something horribly wrong.
Otherwise, I'd say: if you can get it bolted on right and get her running - try her out for a while. Get used to her. Then judge from your first few rides how badly you would need any performance upgrades. There's also quite a few of us who can tell you which performance upgrades work the best.
PS: I'm a tad over 200 lb. and if my motorbike performs like she hasn't noticed my weight, well, I'm not going to tell her. She seems pretty content to haul my butt wherever I point the front wheel. But if hills starting giving you problems, just let us know the particulars. We can usually help with recommendations.
Otherwise, I'd say: if you can get it bolted on right and get her running - try her out for a while. Get used to her. Then judge from your first few rides how badly you would need any performance upgrades. There's also quite a few of us who can tell you which performance upgrades work the best.
PS: I'm a tad over 200 lb. and if my motorbike performs like she hasn't noticed my weight, well, I'm not going to tell her. She seems pretty content to haul my butt wherever I point the front wheel. But if hills starting giving you problems, just let us know the particulars. We can usually help with recommendations.
Last edited:
UriDead
New Member
I'm 280ish and 6'1". The 66cc China Girls hauls my arse about just fine and it can go faster than i want or need to.
Used the bike to work today and lleft 45mins early so i wouldnt be late. Cam ot my surprise I was too early when I got to work. Almost a full 30 mins eearly. Had a blast using the bike but the problem is I had to walk the hill going up because it died out on me. This is a single speed bike. It looks nice but I thinkn ill be tranfering to something I can shift gear with.
nightcruiser
New Member
Looks like you have the NT or Speed carb, definately not the CNS carb. As for bore, I'm not sure you can tell from looking from the outside, so not sure if its 48cc or 66cc. Were there any stickers that were removed or other documentation with the motor?
nightcruiser
New Member
Wow, 10mm nuts on the head??? My Grubee 66cc has 13mm acorn nuts, and the newer Grubee's have 14mm standard nuts on the head studs. Are you sure you're not mistaken, 10mm seems kinda small for the head? (like intake/exhaust size)
DIdnt see any stickers at all. Perhaps I should ask the shop that donated the bike to the company I work for so I can finaly settle this once and for all. I need more speed in this thing hehe imme speed junky. Im not so familiar with 2 cycle engine but used to race Hondas as a hobby till I got into offroading. I need to lose some weight too. HEHEH. Where and how exactly do i chose the right performance carb for thise thing? I think itll be my first little upgrade.
Last edited:
leadfarmer
New Member
Yeah, man, you are getting good advice. I threw mine together as fast as possible. It ran, but the motor moved around. So then I got the SBP adapter and other items to do it right.
As far as performance, get it running right for a couple of hundred miles and go from there.
I am 215 lbs or so, and I have to pedal up steep hills, but the engine is still assisting, so it is not tiring. Just ride it!
As far as performance, get it running right for a couple of hundred miles and go from there.
I am 215 lbs or so, and I have to pedal up steep hills, but the engine is still assisting, so it is not tiring. Just ride it!
It running right and I ride it almost everyday. I also ride at night. I just want a little bit more speed and conquer that hill because if I do ill make it my dialy ride to work. hehe save some money on gas.