Trail Bikes Performance Parts Information

Our goal at Trail Bikes is to provide affordable performance parts to pit bike enthusiasts who cannot afford to spend $5000 on their little Honda. There are many retailers who sell $1000 bore/stroker kits, $1300+ frame/suspension kits and a host of other expensive parts. There is no doubt these are good parts, but they are out of reach for many people who would also like to get more enjoyment out of their stock bike.

Trail Bikes big bore kits and other performance parts are composed of high quality parts that are manufactured to our specifications. They have proven to be extremely reliable over the 5 plus years they have been on the market. The bore kits are not made in China (as many of our competitors like to say) and we use the same manufactures as the big Japanese companies to produce many of our parts such as the cylinders, camshafts and heads. Trail Bikes is the only distributor of Trail Bikes products and the parts are shipped directly from the manufacturing facility to Trail Bikes. When a product is purchased from Trail Bikes, it has not gone through several middlemen and thus, the savings goes to the consumer.


This is the typical flow of bore kits purchased from a local dealer:


Manufacturer > Japanese Company > US Distributor > Dealer > Consumer


This is Trail Bike’s flow:


Manufacturer > Trail Bikes > Consumer


The packaging is simple and installation instructions are not included (some other retailers provide instructions in Japanese but they aren’t of much use), but Trail Bikes does provide excellent prices, high quality parts, and the kits include all the necessary parts to add some power and excitement to your bike.

Installation Information:

Trail Bikes highly recommends a professional technician or your local Honda dealer install the bore kits for you. If planning on installing the kits yourself, there are helpful manuals, such as Clymer’s (visit or see our Catalog), that will instruct the novice mechanic on how to rebuild an engine and maintain it properly. Honda also has shop manuals for the more advanced mechanics. The part number for the XR50 shop manual is 61GEL03 and in most cases, can be ordered through any local Honda dealer (we also stock them). Both manuals also provide many useful specifications. Additionally, we have provided some information below that will be helpful. However, please don’t consider it a substitute for having a professional install your kit. Finally, please check out the technical links in our link section to visit helpful technical sites and bulletin boards. These sites provide a wealth of information and the bulletin boards are full of fellow enthusiasts willing to share their knowledge and experiences.

Reference documents, Tips, etc

Bore Kits/Oil pump

During a review of our products, Dano’s Bike Shop created instructions for the following:

  • Engine Tear Down
  • Race Head Assembly
  • Bore Kit Installation
  • High Volume Oil Pump Installation

    These are excellent step-by-step instructions with pictures and are definitely worth downloading. Click here to visit Dano’s Tech section where you can down load these documents and also check out many other useful instructions. By the way, you can also check out their review of our products here.

    The following are common installation errors:

  • Installing the cam incorrectly which results in loud knocking. Make sure when you line up the 0 on the cam sprocket with the mark on the head, the cam lobes are facing down towards the piston.
  • Clutch nut not torqued on (after installing oil pump) which will result in knocking, spline damage etc. Please do not try to tighten the clutch nut with a hammer and screwdriver – use a clutch nut socket.
  • Putting the piston rings on incorrectly – They should be installed this way and in this order:

    1 - expander ring - (wavy one) - lower groove
    2 - lower oil ring - below above ring in lower groove
    3 - upper oil ring - above expander ring in lower groove
    4 - install the black one in the center groove
    5 - Install the silver one in the top groove (markings on ring should face up)

    Make sure the end gaps of the piston ring are not aligned with one another -evenly space apart

    Z50/XR50/CRF50/CT70 Manual Clutch Kits

    Danos Bike shop put together top notch instructions for assembling this kit and they can be found here

    Clutch Diagram 1

    Clutch Diagram 2

    If the clutch nut is not torqued on, it will result in knocking, spline damage etc. Please do not try to tighten the clutch nut with a hammer and screwdriver – use a clutch nut socket.

    If your clutch needs adjusting, there is an adjusting screw within the locknut under the chrome faceplate. Real quick steps to adjust:

    1 - Loosen locknut
    2 - turn adjuster screw clockwise until resistance is felt, then stop
    3 - from this point, turn the adjuster screw counterclockwise 1/8 to 1/4
    4 - hold adjuster screw and tighten locknut - make sure screw does not move
    5 - adjust on top clutch lever - should be 10 to 20mm free play at tip of lever.

    KLX110/DRZ110 Manual Clutch Kit

    Here are the installation instructions for the KLX110/DRZ110 Manual Clutch Kit:

    MS Word File
    PDF File

    Carburetor Kits

    The kits go on like this:
    Cylinder head > gasket > plastic heat stop > gasket > intake > carb
    Make sure it is mounted tight to prevent air leaks.
    If your bike is not running properly with the new carb, here are some suggestions:

  • Do a plug chop - run it at high rpms and then kill it and check the color of the plug. Based on your plug reading, you may need to move the needle clip or go with a different main jet depending on if it is running rich or lean. When running properly, it should have a nice light brown plug color. If not familiar with how to read a spark plug or make basic carburetor adjustments such as moving the clip or changing the main jet, we highly suggest picking up a Clymers Manual as it covers these routine procedures.
  • Make sure you did not overlube the air filter.
  • Use fresh clean high-octane gas (race gas not needed).
  • As mentioned above, check for air leaks.
  • Check your petcock and fuel line to make sure you have good fuel flow.
  • If you experience backfiring, make sure you reinstalled exhaust gasket and that the exhaust is tightened down and there are no air leaks.

    Click here to go back to the Catalog

  • Oil Cooler Kit Installation Guide

    Here are the installation instructions for the Oil Cooler Kit:

    MS Word File



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