Remove all items to get down to a bare frame. It’s optional to leave the front end on.

Measure and mark the top tube 14⅛” from the neck tube back.

Double check the cut position from the back of the top engine mount. The proper measurement is approximately 1.25”.

Measure and mark the two lower tubes using a straight edge, tape measure and fine tip Sharpie. Keep the tape measure in line with the bottom tube, hold the straight edge to the edge of the engine casting. The desired cut length from this intersection is 5 1/8”.

Note: this is a solid starting point. You will need to verify fitment with the engine installed and trim to the correct length if necessary.

Use a square and transfer this cut line to the other bottom tube.

Double check this dimension from the bottom brace and make sure that it is approximately 2”. Note: the kickstand mount isn’t always in the same position so do not use this for taking measurements.

Use painters tape and wrap it around the top tube and two bottom tubes to help mark the cut location and use it as a guide for keeping the cuts square.

OPTIONAL STEP - If you’d like to take your engine out because you don’t think you’ll be able to make these cuts without damaging something, this is the time. You will have to re-install it after making these three cuts.

If the engine is in, cover it with a blanket and place the piece of metal directly under the top tube where the cut is being made.

Cut the top tube first using either a cut off wheel, sawzall, hacksaw, or some other cutting tool of your choice.

Cut the two bottom tubes next using the same tool.

Remove the 4 bolts holding the rear of the motor/ transmission to the frame and remove the back section. Leave all of the other engine mounting bolts.

Use a square to check the squareness of all the cuts. If the cuts are not square, grind them square using a grinder.

Using a marker, mark a center point ½” from the edge of all cuts.

Using a center punch and a 5/16” drill bit, drill a hole at the ½” locations which will be used for the rosette weld. Visually make sure the drill bit is square while entering the second side of the tubing.

Remove all burrs from the interior and exterior of the tubes using your tool of choice. Make sure the burrs are also removed from the drilled hole for the rosette weld.

 

Remove at least ¾” of the paint off the exterior side of where the tube was cut to prevent weld contamination.

Grab the hardtail and check clearance of all stock tubes individually to verify fitment and that there are no restrictions. The slugs from the hardtail should be able to slide easily into the stock frame tubes with very little force.

If this isn’t the case you will need to double check the squareness of all the cuts. If the cuts are not square, grind them square using a grinder.

OPTIONAL STEP - If you took the engine out, now is the time to re-install it

Install the hardtail to the stock frame starting with the top tube first and the bottom tubes second. You will not want to put the top tube slug all the way in. We suggest sticking it in the frame just enough to hold it in position for you to get the bottom tubes in. At most, a slight wiggle and occasional force from a rubber mallet may be necessary for installation.

If you have a jack, place the jack underneath the two axle plates to hold the hardtail in place.

Hold a square to the left or right side seams of all tubes to verify straightness. Make adjustments accordingly. (See Figure 14) It is normal to hold a square to the top of the top tube and see a slight gap. This slight change of angle will not be noticeable when everything is together. (See Figure 15) Just make sure the top tube is straight from side-to-side.

Tack weld all tubes in place. Visually inspect straightness a second time.

OPTIONAL STEP - If you took the engine out, now is the time to re-install it

Once the 4 rear motor mount bolts are in and started, loosely install the rest of the motor mounts.

Now tighten all motor mounts, starting with the 4 rear motor mount bolts. This will snug the seams between the hardtail and the stock frame. All of the seam gaps should not be any larger than ⅛”. If the gap on the top tube is larger than ⅛” use a mallet and hammer directly down on the seam, which will help tighten the top seam.

Final weld as much as possible while the engine is in the frame.

The engine is essentially acting as a jig so make sure you let the frame cool before removing the engine. This gives you time to run to the fridge for a beer or three.

Remove the engine.

Final weld all the seams making sure you don’t forget about the 6x rosebud holes.

Remove installation cross-brace between lower tubes (See Figure 17)

Begin the installation process for the engine and remaining parts.

Full gallery of install images below: