48cc vs 66cc power comparison

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Ok this may seem like stupid.
but i'm looking for some good opinions here.
Especially if you have ridded 48cc and 66 cc bikes.

Now legally the 48cc is good to go.

I have one now and it rocks.
Lots of mods.
But im thinking about dumping some Rock Solid High Performance parts into it which are alot of $$.

My question is how much more power will i really feel from the 66.
Should i buy a new 66 and get the High Performance Parts for it?
Or should i keep going with my 48cc.

Obviously the 66 could get me in trouble but fortunatly where i live they leave the MB'ers alone.
Unless you break traffic laws.

They haven't ever stopped me and i have seen many police in my travels.
My mb looks like a dirtbike and i don't hold it back at all.
The police arrested someone here once and lost the case.
The MB'er won, so now the police will not bother us.

I could get away with the 66er.

But how much faster will it really be?
I run high revs with a 36T and my 48cc will hit 40 / 45 mph now.

I might appreciate the bottom end a little more but it seems that the 66er's don't like the high RPM as well.

So i was thinking Rock Solid billet head / Ceramic coated piston / 50cc jug / and maybe the performance CDI.
Does there CDI change the timing?
If not it ain't worth the money in my opinion.

Now obviously thoose parts for the 48 cost more than what i can get a new 66er for complete.

What do you guys think ????

Remember legality isn't the issue speed is.
 
The 66cc will give you greater torque spread with more bottom and midrange torque.

Top end rpm is irrelevant as the 66cc motor vibrates something shocking above 4000 rpm.
The best way to take advantage and also build bottom end torque on these engines is to use the standard exhaust pipe - no modifications.

Speed isn't what you should be talking about as it's best to fly under the radar and not stand out by zooming along at a pace that's unrealistic for someone on a bicycle to be travelling at, also not having an engine that's screaming it's head off, attracting unwated attention.

What you should be talking about is maintaining a consistant 20 mile an hour "average speed".
To do that, you'll need an engine with lots of bottom and midrange torque, pushing you steadily uphills at reasonable speed without having to rev it's guts out.

There's a public perception that someone riding a screamer engine, must be going faster than someone with a quiet slow revving engine, even if both are travelling at the same speed.

For this reason i want a 100cc engine with port timing suited to low rpm and high torque and a very quiet exhaust system.

The best way to fly under the radar.


Fabian
 
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I run high revs with a 36T and my 48cc will hit 40 / 45 mph now.

At 45 mph with a 26" wheel your engine would be doing about 8000 RPM. That's screaming for one of these things.

More (low-end) torque is the way to go, I reckon. Then you can gear a little higher and achieve the speed without revving the guts out of the engine. The 66cc is better in that regard. (That's what I have.)

I, too, am ordering a billet head from Rock Solid Engines. The high compression ratio will improve bottom-end as well as increase HP at higher RPM.

... Steve
 
the way i look at it is, if you do get stopped...how can they prove that you have a 66 c.c. over a 48 c.c.? there is no real way to tell unless they took the jug off and measured the piston and stroke.

My 50 c.c. is as fast (maybe even a little faster) than my friends 80 c.c. (66 c.c). His has more bottom end torque and it has better take off, but i can catch him once we're moving and i can pass him. we both weigh about the same and our bikes are set up very similar, except he's using a 24" frame with 20" wheels, and i'm using a 20" frame with 20" wheels. I have added an expansion chamber and a high flow air filter since we last ran together. Last time we ran them together, both of our bikes were box stock (stock exhaust, stock air filters). By adding the pipe and air filter, i have increased my top speed from 24 mph, to 32 mph.
 
You guys in the states are luckier than most of us in Australia. Here, even a 50cc is technically illegal, so we have to be ultra-careful. According to the law, our engine output must not exceed 200W!
We only get away with it because they tend to turn a blind eye, but we can't afford to attract too much attention.
 
As far as legality where i live in pa particullarly i'm lucky.
My motor isn't that loud even with the expansion chamber and the men in blue leave us alone.
The slower i go the better chance of being run over.
 
Yes i'm sure i push 8000 rpm prolly higher.
My 48 runs sommther at higher rpm.

Now iv'e got to make a descision.

66cc or 48cc

I wish i knew if i could get the 66 to really rev up.
Obviously i could run a 30T or something and be ok.

But i like the revs and the smoothness.

I just don't know what to do.
I want to get a new motor today.
 
Guys,
If your in Australia the cops now have a mandate to bust any bikes with a power plant over 200 Watts , they can hit you with some big fines , plus confiscate your bike .
You could then challenge them in court to prove your bike is only 200 watts .
How ? :devilish:

Guess some riders could have a hidden throttle slide switch that will limit revs to just under the 200 Watt mark they can hit if busted !



Have Fun
Bobby.
 
Well i guess i'm gonna try a PK.
I heard Grubee shipped out the new Q4 GT-5 dated 8-30-2009

No speed carb / No wide 40mm Mounts ??????


Gonna go with

Model : PK80J-SILVER
Engine type :
Single cylinder, air-cooled, 2-stroke
Power * Rotary Speed
Rated Power :
2.0Kw / 5000r / min
(3HP/5000r/min)
Max Power :
3.5Kw / 6000r / min
(5-6HP/6000r/min)
Ignition Mode : CDI
Fuel type : Octane 89 and above
Lubrication Oil : 2 Stroke Synthetic Motorcycle Oil
Mixing Ration for Fuel and Oil : 16:1 for new sets (20:1 after running approx 500Km)
Spark Plug : Z4C 14MM
Fuel Consumption : 2.5L / 100Km
Clutch Type : Friction Plate / Dry
Speed Limitation : 38-53km/hour

Looks like getting the RPM up to 6000 which should be a piece of cake will output som serious power.

Guess i'll find out.

I will be dissassembling / Porting Crankcase Tranfers / and hopefully changing out the 6202's for some sealed 6202's if there not in there before i mount it.

Not looking forward to the Break in though, it's getting colder latly and long rides take a little more stamina.

I will be sure to post pics and findings.
 
well i'm pretty lucky then i guess. I live in the county and we never see cops around. If someone does call the cops, it can take them over an hour to show up.
But where i live, people ride 4 wheelers, dirt bikes, golf carts, go karts & mini bikes on the roads. No one ever bothers them unless they do something stupid.
My friend lives in town, and we have both ridden our mb's past police and they just smile and wave.
 
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