Displacement	Bore x Stroke	HP	@ RPM	Torque	@ RPM	MEP	Base Brand	Head	Cam	Carburetor	Air Filter	Piston	Crank	Exhaust	Ignition	Dyno	Notes
72cc	47 x 41.4	3.6					Honda	Honda GB5	Stock CRF70	Keihn 17mm	Honda CRF70	Honda 47mm	Honda 41.4mm	Honda CRF70	Honda CRF70	Dyno	Stock performance
72cc	47 x 41.4	4.2					Honda	Honda GB5	Stock CRF70	Keihn 17mm	Uni Pod	Honda 47mm	Honda 41.4mm	Honda CRF70 - Gutted	Honda CRF70	Dyno	Cheap Mods only
72cc	47 x 41.4	6.5	10800	3.8	7500	6.62	Honda	E22 - AHP Port	Stock E22	Mikuni VM20	Uni Pod	Powroll 47mm 11:1	Honda 41.4mm	Big Gun 70	Kitaco IRK	Dyno	Cylinder shaved .020"
72cc	47 x 41.4	7.4	11500			7.078	Honda	DRP Heavy Port				Honda 6v 47mm	Honda 41.4mm Lightened	Custom Supertrapp	Kitaco IRK	Dyno	What I aim to beat with my 70...
88cc	52 x 41.4	8	9300	4.7	8000	7.742	Honda		TB Race Cam			TB 52mm	Honda 41.4mm			Dyno
95cc	54 x 41.4	7.3	9500	4.4	7200	6.406	Honda		Hot cam				Honda 41.4mm	FMF		Dyno
98cc		6.2	7000	5.22	5500	7.158	Vicious 50s		Stock Import	18mm				Big Gun		Dyno
106cc	51 x 52	9					Pedshed Stroker 106									Dyno
106cc	51 x 52	13.1	12000			8.156	Honda	Kitaco SE	Kitaco 'race'	Kitaco 24mm	Uni Pod	Kitaco 52mm	Kitaco 51mm	Ti-Force	Kitaco IRK	Dyno	Petcock needed to be switched to reserve mid run, causing the dip up top.
107cc	52.4 x 49.5	6.7					X-Sport 110					Stock 52.4mm	Stock 49.5mm			Dyno
107cc	52.4 x 49.5	8.2	9250	5	6375	6.561	AHP Stage 3	E22 - AHP Port	Stock E22	TB 24mm		Stock 52.4mm	Stock 49.5mm	Fast 50s 1"		Dyno	Stage 3 baseline
110cc	52 x 52	8.2					Pedshed Stroker 110									Dyno
113cc	54 x 49.5	9.4					Pedshed Stroker 114			20mm						Dyno
119cc	54 x 52	10.8					Pedshed Stroker 119			28mm Flatslide						Dyno
120cc	52.4 x 55.5	8	7400	6	6400	7.135	Lifan 'Monster'	Import 27/23	Stock Lifan	24mm Flatslide		Stock 52.4mm	Stock 55.5mm	Ultima	Stock Lifan CDI	Dyno	Out of the box
120cc	52.4 x 55.5	10.6	9600	6.5	8000	7.285	Zongshen	Import 27/23	Crower	Takegawa 26mm		Stock 52.4mm	Stock 55.5mm			Dyno	RC125 mill tweaked by Crower
123cc	52.4 x 57	7.3	8500	5.6	5800	5.53	Lifan					Stock 52.4mm	Stock 57mm			Dyno	Out of the box
123cc	52.4 x 57	9	8300	6.5	6400	6.982	GPX	Import 23/20	Crower G2			Stock 52.4mm	Stock 57mm			Dyno
124cc	54 x 54	16	11000	8.6	8300	9.29	Honda	Takegawa Twin Spark - Heavy Port	Crower	Mikuni VM26	UNI Pod	Takegawa 54mm Skirt Trim	Takegawa 54mm Lightened		Kitaco CDI	Dyno	Hand built race motor
124cc	54 x 54	17.2	13200			8.322	Honda	Kitaco SE		28		Kitaco 54mm	Kitaco 54mm		IRK	Dyno	Classic Honda 'Kitaco 124SE kit' for 50s
143cc		17	10300	8.9	9100	9.141	Kawasaki									Dyno	Classic Honda 'Kitaco 143SE Kit' for 110s

MEP - Mechanical Efficency. mep = hp x 792,000 / displacement x rpm

MEP is a handy way to compare different motors, by factoring out rpm and displacement. Higher MEPs mean the motor is more effective at turning fuel and air into usable power. Two motors of the same displacement but differing MEPs, the higher MEP will be the faster motor. The other use for MEP is to determine if a given HP goal is realistic when you can't find a comperable displacement motor to compare against. If your target peak HP and RPM requires a MEP that is higher than any motor you can refrence, you're probalbly dreaming. Not that silly things like that should stop you... :)

Handy Formulas when dealing with motors.

PLEASE READ BEFORE VIEWING THE BELOW GRAPHS

The comparisons below are very crude, and are only to show rough comparisons for those of us that prefer pictures to tables of numbers. The data is based on my eyeballing dyno charts, and only using datapoints at 1k RPM boundries. This means there will be errors, and some data is lost. Many bikes have their peaks at say, 9750 RPM, the peak won't show.

GPX vs RC Motors - Blue is the RC, Red is the GPX

Both mills are in VERY mild states of tune. The RC appears to like to rev out longer, which many would attribute to the larger valve sizes. Given the unkowns in setup between the two I'm not ready to make that call just yet. Given the long stroke on each, you need to be finding a new gear before you pass 11k RPM or you risk ring issues and other problmes as your piston speed exceeds 4000 fps. This makes 'winding out' kinda moot on boht. What will be MORE interesting is when the high comp heavy massage builds come out. THEN we'll see what each is capable of.

Stock Stroke Motors - 41.4mm stock stroke sillyness

Big Bore Big Displacement - Motors from 106cc and up