STOCK SPECIFICATIONS:   

47mm Bore x 41.4mm Stroke

9:1 COMPRESSION

FYI

Although externally similar to the early 70 engines, the Honda XR and CRF 70 internals are significantly different.  No performance parts are readily interchangeable.  Click these links CT70 1991 & LATER   CT70 1982-1990   CT70 1981 & EARLIER   ATC, CT, CL 70  for our extensive lineup of parts for your particular model. 

Chinese and Taiwanese engines which are 'like Honda' design are not copies of the CRF or XR.  These engines typically share similarities to a variety of Honda engine designs, but aren't the same as any ONE Honda engine.

Who ya gonna trust?

Incredibly cheap prices, big horsepower claims, what's with these minibike parts available from other shops? Why are Powroll's prices more expensive?

We've been making minis go fast for 40 years.  We've really been there and done that - in fact, we probably invented it.

Our parts are designed and manufactured here in the USA, made by U.S. riders, for U.S. riders!

You can also count on Powroll to have the answers to your technical questions - whether it's your kid's CRF 70, or your own screamin' Z50. Buy Powroll and get quality products and service that'll last a lifetime!

BORE KIT 80CC

49.5mm piston, 11:1 compression

A great increase in torque and hp. Use with our Camshaft and Thrust Chamber for even better power!

INCLUDES: Piston, pin, rings, circlips, headgasket, basegasket.

REQUIRES: Boring, rejetting.

RECOMMENDATIONS: Bikes ridden at or near sea level may run better with a mix of 1/2 race gas and 1/2 premium pump fuel.

#00320

$165.00

BORE KIT -

+ .020" O/S FOR 80cc KIT

50mm piston, 11:1 compression

INCLUDES: Piston, pin, rings, circlips, headgasket, basegasket.

REQUIRES: Boring, rejetting.

RECOMMENDATIONS: Bikes ridden at or near sea level may run better with a mix of 1/2 race gas and 1/2 premium pump fuel.

#00320B

$165.00

STROKER - 9.5mm

WITH 'TOUGH ROD' ASSEMBLY

+ 9.5mm, 100cc’s with our 49.5mm Bore Kit

Incredible torque and awesome overall power increase. Gain another 40% more hp over the bore kit alone!

INCLUDES: Powroll Tough Rod Assembly: Rod, pin, needles. Work done on your crank.

REQUIRES: Send in your crank for modification.  Download our Stroker Booklet for details.

RECOMMENDATIONS: Works best with Powroll pistons. *Modifications may be required if using other piston or cam brands.

#16050RA

$375.00

CAMSHAFT - RACE GRIND

BILLET, NO CORE REQUIRED

Lift .266” IN/.266” EX. Duration 210° IN/206° EX @.050”

This new grind is specifically designed to give you the BEST power possible for your Powrolled 70! An awesome increase in mid to top end power when used with our bore kit. Also works as a race grind (top end power) with our high comp. piston. Uses stock bearings - not included.

#12746B

$150.00

CAM CHAIN - POWROLL HEAVY DUTY

Stronger and less expensive than the OEM Honda chain.

#18540

$30.00

19mm KEIHIN CARB KIT

Powroll-tuned to give you perfect throttle response, along with huge increases in midrange and top end. Better overall performance than any other carb kit on the market!

KIT INCLUDES: Pre-Jetted Carb. Throttle Assembly (fits 7/8” bars). Special Hi-Velocity polished aluminum manifold. 3 Extra Main Jets. Intake Gasket. Mounting Hardware. K&N Filter.

RECOMMENDATIONS: Works best on engines with at least a Powroll high compression piston and cam. Can be used on a stock engine for better top end power, but throttle response may not be as crisp.

#20538

$270.00

TITANIUM CLUTCH WEIGHTS -

SUPER PRO PACK - 16 Weights

Works like a slipper clutch on a Top-Fuel Dragster! (nitro not included).

Replace some or all of your stock (heavy) weights with lighter weight Titanium. Allows the engine to rev higher before the clutch engages. Lowers clutch rotating mass.

Can be installed in groups from 4-16. The more ti weights you run, the higher the engagement rpm.

INCLUDES: Super Pro Pack = 16 Weights. Detailed installation instructions.

#16853

$50.00

TITANIUM CLUTCH WEIGHTS -

STARTER PACK - 4 Weights

Best for stock engines.  Modified engines will work better with the Super Pro Pack.

Replace some of your stock (heavy) weights with lighter weight Titanium. Allows the engine to rev higher before the clutch engages. Lowers clutch rotating mass. The more ti weights you run, the higher the engagement rpm.

INCLUDES: Starter Pack = 4 weights. Detailed installation instructions.

#16852

$20.00

CLUTCH SPANNER SOCKET

Used to remove the clutch hub nut on Honda OHC 50's and 70's.  You'll need this tool to install any clutch modifications or replacement parts.

#18541

$9.95

EXHAUST -

THRUST NOZZLE -

Not Spark Arrested

No need for the spark arrestor?

The Thrust Nozzle will give you better power than running without the stock end cap. Power gains as good as or better than some complete aftermarket systems!

Louder and throatier sounding than the Thrust Chamber, but still more stealthy than aftermarket mufflers. Replaces the stock spark Arrestor unit.  Brushed Stainless Steel

Install with our Thrust Chamber for a more sano look.

#17102NS

$45.00