xr50 parts, crf50 parts, xr 50 swingarm, forks, pipes, crf 50 bar kits, 88cc big bore kits and tall seats, plastics, and more for you Honda crf50.
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We are now stocking big bore kits for chinese engines! (bottom of page)
Honda z50, xr50, ct70 xr70, and crf-50's

We sell complete kits and individual parts. If you need a single parts such as

cylinder, piston, gaskets ect.. Please call us at 702-889-1741 to order. Thanks

We stock 50 Caliber and Trail Bikes big bore kits!

88cc stage 1 big bore kit for honda z50, ct70, xr70, xr50, and crf 50's
88cc stage 1 big bore kit

88cc stage 1 Big Bore Kit (52mm):

- Lightweight aluminum cylinder with steel sleeve
- Cast in mounts on cylinder for aftermarket skid plates
- Oversized cooling fins on cylinder for efficient heat dissipation
- High compression 52mm piston with rings, pin, & clips
- Head gasket kit

We recommend purchasing a high volume oil pump kit (available at the bottom of the page).

Installation Note: It will save a lot of time and effort if the oil pump is installed while installing the bore kit (requires cylinder removal).

$129 shipped inside the USA

Select model:
$149 shipped international
Select model:

 

50 Caliber 88cc stage 2 big bore kit for honda xr crf 50's and 70's
88cc stage 2 big bore kit

Models this kit fits 88-99 z50, 2000-present XR and CRF 50

DESCRIPTION: 88cc Big Bore kit, 20mm Carburetor kit, and Race Cam Performance Kit:
- Lightweight aluminum cylinder with steel sleeve
- Cast in mounts on cylinder for aftermarket skid plates
- Oversized cooling fins on cylinder for efficient heat dissipation
- High compression 52mm piston with rings, pin, & clips
- Head gasket kit
- High performance race camshaft for stock head (or our race head)
- 20mm Performance carb assembly. Includes: 20mm carb, ported intake for STOCK head, heatstop, gaskets, mounting hardware/wrench, air filter and extended throttle cable.

$229 shipped to USA

$259 shipped international

 

88cc stage 2 Vintage big bore kit for honda z50 and ct70
z50 big bore kit

Trail Bikes 88cc Big Bore kit and 20mm Carburetor Kit:

- Lightweight aluminum cylinder with steel sleeve
- Cast in mounts on cylinder for aftermarket skid plates
- Oversized cooling fins on cylinder for efficient heat dissipation
- High compression 52mm piston with rings, pin, & clips
- Head gasket kit
- 20mm Performance carb assembly. Includes: 20mm carb, intake, heatstop, gaskets, mounting hardware/wrench, air filter and long throttle cable
- NEW! 12/08 - a main jet kit is now included too!

Easily double your power and fun with this quality, yet economical bore kit!!

We recommend purchasing a high volume oil pump kit (available in this section).

Installation Note: It will save a lot of time and effort if the oil pump is installed while installing the bore kit (requires cylinder removal).

$199 shipped inside the USA

Select model:
$225 shipped international
Select model:

 

88cc Race Head kit for honda xr crf 70, xr50, and crf 50's

Comes with assembled head!!!

88cc race head kit

Models this kit fits 88-99 z50, 2000-present XR and CRF 50 and 70

Race head kit now comes with FREE CDI box and HP Oil pump!

50 Caliber 88cc Race Head / Carb Big Bore Kit
DESCRIPTION: Race Head, 88cc Big Bore kit, and 20mm Carburetor Performance Kit:
- Lightweight aluminum cylinder with steel sleeve
- Cast in mounts on cylinder for aftermarket skid plates
- Oversized cooling fins on cylinder for efficient heat dissipation
- 52mm piston with rings, pin, & clips
- Head gasket kit
- High performance race camshaft
- Race Head – Larger valves and porting for increased performance. Also has bigger cooling fins. Includes all necessary parts. Comes assembled.
- 20mm Performance carb assembly. Includes: 20mm carb, intake, heatstop, gaskets, mounting hardware/wrench, air filter and lextended throttle cable

$349 shipped to USA

 

$389 shipped international

 

88cc Race Head Vintage big bore kit for honda z50 and ct70
ct70 big bore kit

Trail Bikes Race Head, 88cc Big Bore kit, and 20mm Carburetor

Our Race Head has been updated for even more performance! It now has 25/22mm valves with better porting/flow. We also kept the combustion chamber the same size and changed the angle of the valves slightly. This will really wake up your stock engine and is comparable in power to the much larger Chinese 124cc engines!!! Includes the following:

- Lightweight aluminum cylinder with steel sleeve
- Cast in mounts on cylinder for aftermarket skid plates
- Oversized cooling fins on cylinder for efficient heat dissipation
- 52mm high compression piston with rings, pin, & clips
- Head gasket kit
- High performance race camshaft and Honda cam sprocket
- Race Head – Larger valves (now 25/22mm) and better flow for increased performance. Also has bigger cooling fins. Includes all necessary parts and comes assembled! NEW! 06/08 - The exhaust valve has been upgraded to stainless steel (21-4N material).
- 20mm Performance carb assembly. Includes: 20mm carb, intake, heatstop, gaskets, mounting hardware/wrench, long adjustable throttle cable, and a air filter. NEW! main jet kit is now included too!

We recommend purchasing a high volume oil pump kit (available in this section).

Installation Note: It will save a lot of time and effort if the oil pump is installed while installing the bore kit (requires cylinder removal).

$359 shipped inside the USA

Select model:
$389 shipped international
Select model:

 

108cc stage 1 stroker kit

108cc stroker kit #1

for honda 50's and 70's

 $250 shipped inside the USA
$275 shipped international

Models this kit fits 88-99 z50, 2000-present XR and CRF 50

Stroker Kit 1

This is an affordable kit that will convert your 88cc Race Head kit into a powerful open class 108cc engine (much more powerful than the common Chinese 107 engines). Also, this crank was made specifically for the newer engines and thus, you will not have any fitment issues like trimming the piston skirts in order to clear the crank or the piston not lining up with the cylinder deck. The kit includes the following parts:

- 51mm Crankshaft with NTN bearings
- High compression piston with rings, pin, & clips
- 24mm Carburetor (This will match your intake that came with the Race Head kit, however, you will need two longer mounting bolts and two nuts as the mounting holes are not threaded like on the 20mm carb).
- Crankcase and clutch cover gaskets
- Head gasket kit

This kit requires engine disassembly and therefore, we highly recommend a professional technician install this kit. If you plan on doing it yourself, you will need to have a Clymer or Honda shop manual. Instructions do not come with the kits but the installation of the crankshaft is just like installing a Honda crankshaft. You should also have the following parts:

- High volume oil pump

 

108cc stroker kit #2 for honda 50's and 70's
108cc stage 2 stroker kit

Models this kit fits 88-99 z50, 2000-preset XR and CRF 50

New Filter with extra protection added to the kit 5-30-06.

Stroker Kit 2

This kit is the complete kit to convert your stock motor into a powerful open class 108cc engine (much more powerful than the common Chinese 107 engines). Also, this crank was made specifically for the newer engines and thus, you will not have any fitment issues like trimming the piston skirts in order to clear the crank or the piston not lining up with the cylinder deck. The kit includes the following parts:

- 51mm Crankshaft with NTN bearings
- High compression piston with rings, pin, & clips
- Race Head – Larger valves and porting for increased performance. Also has bigger cooling fins. Includes all necessary parts. Comes disassembled.
- Lightweight aluminum cylinder with steel sleeve, cast in mounts for skid plates, and larger cooling fins.
- High performance race camshaft
- 24mm Carburetor kit with intake, airfilter, and throttle cable. (Note: Presently, you will need two longer mounting bolts and two nuts as the mounting holes are not threaded like on 20mm carbs).
- Crankcase and clutch cover gaskets
- Head gasket kit

This kit requires engine disassembly and therefore, we highly recommend a professional technician install this kit. If you plan on doing it yourself, you will need to have a Clymer or Honda shop manual. Instructions do not come with the kits but the installation of the crankshaft is just like installing a Honda crankshaft. You should also have the following parts:

- High volume oil pump
- Rev box

$499 shipped inside the USA
$535 shipped international

 

117cc stroker kit#5 for honda 50's and 70's
117cc stage 5 stroker kit

Models this kit fits 88-99 z50, 2000-preset XR and CRF 50

117cc Stroker Kit 5

This kit is the same as the Stroker Kit 4 but also includes a 26mm carburetor for much better performance. Its an affordable kit that will convert your 88cc Race Head kit into a powerful open class 117cc engine (much more powerful than the common Chinese 107 and 125cc engines) with tons of torque! Also, this crank was made specifically for the newer engines and thus, you will not have any fitment issues like trimming the piston skirts in order to clear the crank or the piston not lining up with the cylinder deck. The kit includes the following parts:

- 51mm Crankshaft with NTN bearings
- Lightweight 54mm aluminum cylinder with steel sleeve, cast in mounts for skid plates, and larger cooling fins.
- High compression piston with rings, pin, & clips
- Crankcase and clutch cover gaskets
- Head gasket kit
- 26mm Performance Carb
- Intake Kit
- Jet kit with 10 different sizes (kit not pictured - recommend starting with a #100 or #105 with the 117 kit)
- Throttle Cable
- Air Filter

As with all 117cc kits on the market, installation requires engine disassembly and case boring. Therefore, we highly recommend a professional technician install this kit and the cases bored by a reputable machine shop. If you plan on installing the kit yourself, you will need to have a Clymer or Honda shop manual. Instructions do not come with the kits but the installation of the crankshaft is just like installing a stock Honda crankshaft and both manuals cover this. You should also have the following parts:

- High volume oil pump
- Oil Cooler (we do not carry these at the moment)
- CR8HSA spark plug (not required, but recommended)

Note: If you have one of our Manual Clutch kits, there has been no long term testing to see how it will hold up to the additional power with this new 117 kit. If you purchased one of our Manual Clutch Kits prior to 6/30/05, will recommend purchasing the Upgrade Disk Kit that is available in this section of the Catalog. Additionally, we do not recommend the use of an inner rotor kit with this clutch (on a 108cc or larger engine) as it can lead to premature clutch failure due to extra fatigue placed on the clutch housing. Also, do not tighten the clutch nut with a hammer and screw driver - it must be torqued on!

$420 shipped inside the USA
$445 shipped international

 
117cc stroker kit#6 for honda 50's and 70's
117cc stage 6 stroker kit

Models this kit fits 88-99 z50, 2000-preset XR and CRF 50

117cc Stroker Kit 6

This kit is the complete kit to convert your stock motor into a powerful open class 117cc engine (much more powerful than the common Chinese 107 and 125cc engines) with tons of torque! Also, this crank was made specifically for the newer engines and thus, you will not have any fitment issues like trimming the piston skirts in order to clear the crank or the piston not lining up with the cylinder deck. The kit includes the following parts:

- 51mm Crankshaft with NTN bearings
- Race Head – Larger valves and porting for increased performance. Also has bigger cooling fins. Includes all necessary parts. Comes disassembled.
- High performance race camshaft
- Lightweight 54mm aluminum cylinder with steel sleeve, cast in mounts for skid plates, and larger cooling fins.
- High compression piston with rings, pin, & clips
- Crankcase and clutch cover gaskets
- Head gasket kit
- 26mm Performance Carb
- Intake Kit
- Jet kit with 10 different sizes (kit not pictured - recommend starting with a #100 or #105 with the 117 kit)
- Throttle Cable
- Air Filter

As with all 117cc kits on the market, installation requires engine disassembly and case boring. Therefore, we highly recommend a professional technician install this kit and the cases bored by a reputable machine shop. If you plan on installing the kit yourself, you will need to have a Clymer or Honda shop manual. Instructions do not come with the kits but the installation of the crankshaft is just like installing a stock Honda crankshaft and both manuals cover this. You should also have the following parts:

- High volume oil pump
- Oil Cooler (we do not carry these at the moment)
- CR8HSA spark plug (not required, but recommended)

Note: If you have one of our Manual Clutch kits, there has been no long term testing to see how it will hold up to the additional power with this new 117 kit. If you purchased one of our Manual Clutch Kits prior to 6/30/05, will recommend purchasing the Upgrade Disk Kit that is available in this section of the Catalog. Additionally, we do not recommend the use of an inner rotor kit with this clutch (on a 108cc or larger engine) as it can lead to premature clutch failure due to extra fatigue placed on the clutch housing. Also, do not tighten the clutch nut with a hammer and screw driver - it must be torqued on!

$599 shipped inside the USA
$629 shipped international

 

Manual clutch kit for honda 50's and 70's
manual clutch kit for your pitbike

Models this kit fits 88-99 z50, 2000-preset XR and CRF 50

Manual Clutch Kit - Converts 3-speed semi-auto clutch to a 3-speed manual clutch.
- Unlike other similar kits on the market, this kit includes a 3 plate clutch.
- 67/18 Primary gears that makes first gear more useable than stock gears (some other kits do not include this nice option).
- Can properly handle 88cc - 108cc Bore/Race Head kit combinations without clutch slippage and loss of power.
- Correct length shift shaft for the newer Honda engines so no additional modifications are necessary.
- Comes with everything pictured including an allen head bolt kit for the engine cases. All you will need is a perch and lever and a few of your stock parts (we did not include a perch/ lever due to the wide variety of styles out there.

$165 shipped inside the USA

$190 shipped international

 

Heady Duty Auto Clutch

Trail Bikes HD Auto Clutch. Recommended for anthing 88cc and up.

$85 Shipped

52mm top end gasket kit

52mm (88cc -108cc) and 54mm 54mm (117cc) Head gasket kit

$12 shipped

Select size:
Honda 50 case gaskets

Left and right case gaskets for Honda 50, also fits all 50-125cc honda knock off chinese engines.

$12 shipped

pitbike gasket kit

Head gasket and clutch gasket kit for Chinese Lifan engines.

$18 shipped

Select size:
lifan gasket kit

Head gaskets 47mm and 52mm for Lifan Engines.

$11 shipped

Select size:
20mm carburetor

Blowout on 20mm carb's $45 shipped

20mm jet kit

Trail Bikes Jet Kit for 20mm carb jets included 82/85/87/90/92/95 $10 Shipped!

Perforamnce cam

Performance Camshaft. This will hop up your stock motor or your moded motor. Blow out sale price of $40 shipped!

intake kit

Performance Intake for stock head or race head $25 shipped

Select size:
Performance CDI ignition box

 Performance CDI rev box

(removes stock rev limiter)

Only sale only $25 shipped!

Performance CDI ignition box for chinese engines

 Performance CDI rev box

Works on chinese engines 50cc-125cc

Only sale only $25 shipped!

oil cooler kit

TB Oil cooler kit

Keep your big bore motor cool!

$135 shipped

z50 oil pump

k1-1978 Vintage High volume oil pump

(Deliveres 3 times the amount of oil over stock pump)

$32 shipped
vintage high volume oil pump

1979-81 z50 Vintage High volume oil pump

(Deliveres 3 times the amount of oil over stock pump)

$32 shipped
High volume oil pump

82-1987 High volume oil pump

( Deliveres 3 times the amount of oil over stock pump)

$26 shipped
High volume oil pump

XR CRF High volume oil pump

(Fits all years of xr and crf, Deliveres 3 times the amount of oil over stock pump)

$26 shipped

- - - Chinese Engine Bore Kits Below - - -

Fits 150/160cc YX/GPX Engine's
YP 150 big bore kit

150/160cc YX/GPX Race Head V2 Upgrade Kit:

- Race Head V2 - Roller rockers, 30mm intake valve, 24.5mm exhaust valve, 27mm intake port, 23mm exhaust port (valves installed).
- Race Camshaft for Race Head V2
- Lightweight high compression domed 60mm piston with rings, pin, & clips
- Head gasket kit - includes the cylinder head o-ring set and an exhaust gasket.

This kit is to upgrade the cylinder head on stock YX/GPX 150 or 160 engines to our new Race Head V2. The addition of this new head will dramatically increase the performance of your stock engine!! This kit includes our new Race Head V2 and while the new head may appear to be the same on the outside as our other KLX110 type race head, internally it has gone through numerous changes. The addition of roller rocker arms and a new camshaft are the biggest changes followed by bigger valves and ports. The exhaust valve is now stainless as well (21-4N material). This all adds up to a cylinder head that puts out a professional level of performance yet is still affordable for the privateer rider. Also, included is a piston with bigger reliefs to match the larger valves of the new race head. Additionally, our head gasket kit includes a head o-ring set and exhaust gasket so you don't have to re-use your old ones or make a trip to your local dealer to get new ones and spend more money. These are high quality parts and require no machining to the cases or other modifications - bolt on and go!

There are no installation instructions, but if you can replace your piston, you can install this kit. If you don't have any experience working on your engine, we highly recommend having a professional technician install this kit. The parts are installed in the same manner as OEM parts.

$359 shipped inside the USA

$389 shipped international

 

Click HERE to email us if you have any questions

Or call 702-889-1741


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 50 Caliber racing is your affordable crf50 specialist. We have a great selection of xr50 parts xr 50 crf and xr70