Cleverchimp

Stokemonkey installation

version 1.0; the most up-to-date version of this document resides at http://cleverchimp.com/products/stokemonkey/support/installation/?v=1

Requirements

This guide assumes that you have already reviewed Stokemonkey’s compatibility notes (http://cleverchimp.com/products/stokemonkey/compatibility/?v1) to assure that things will fit, and are prepared to address any side issues like shifter/throttle ergonomics that your bike may present. It also assumes that Xtracycle’s FreeRadical product is already installed.

You will need the following items:

• Crank puller and crank bolt wrench
• Pedal wrench
• Metric hex wrenches in the common bicycle sizes (ball-head T-handle type recommended)
• 8- and 10-mm wrenches (or adjustable crescent)
• Needle-nose pliers or fourth-hand tool
• Cable cutter
• Grease

In some cases you will also need the following items, or find them useful:

• Bottom bracket installation and adjustment tools
• Chain tool
• Rubber mallet or similar
• Utility knife
• Hacksaw for kickstand length adjustment due to balance of battery

Important things

• Never, ever work on Stokemonkey while the battery is connected! Don’t let the silence give you a false sense of security: we still have all our fingers, but more than once have found ourselves wrestling large powerful bicycles as parts fly because we forgot it was live! Charge your battery while you install Stokemonkey, and forget about hooking it up until you are finished.

• The wires between motor and controller are delicate. Never pull or bend them sharply. Take care to keep them clear of any moving parts during and after the install!

• Many people are surprised to discover that the external case of the motor rotates in use. This is expected behavior. The motor has no internal moving parts: the motor rotor is the case.

Procedure

1. Remove the existing cranks and install the replacements. Confirm that the left-side chainring is far enough out for the lower run of the motor drive chain to clear the chainstays, as indicated in the diagram at right (shows right-side clearance, but the same test applies to the left).

   If there isn’t sufficient clearance, you must create it by any or all of the following means:

   • Removal of any right-side bottom bracket spacers
   • Addition of left-side chainring spacers
   • Substitution of a longer bottom bracket spindle
   • Substitution of an alternative left-side spider with higher chainline
   • Substitution of a bicycle frame with narrower chainstays.

   Stokemonkey requires a left-mounted spider and chainring of approximately 44 teeth. More teeth will result in greater range and lower top speed; fewer, the opposite. Cleverchimp provides quality compact-MTB replacement cranks for square-taper bottom brackets. You may substitute a tandem-specific left spider or even a spare right-side spider on the left side if desired. If you use a right-side spider, you will need a second right pedal, and must apply a thread-locking compound to the pedal threads to prevent it from unscrewing in use.

2. The mount is pre-assembled for clarity and packing ease. Disassemble the clamp by removing the 6 large bolts, leaving the set screws alone, and study how the tension cable is assembled before loosening the rear cable retainer bolt to open the loop. Leave the front cable retainer bolt tight.

   Assure that the contact areas of the clamps and tubes are clean and free of grease. The bolt threads, however, should be well greased.

   Attach the lower clamp plates to the Xtracycle’s top stay as shown, square with the bike. Do not tighten the bolts — just take up the slack in them. You should be able to adjust the position of the clamp on the tube easily.

3. Put the chain loop on the motor freewheel, and fit the axle into the steel bracket, with the mount slots facing up and the motor wires pointing down as they exit the axle. Some motors are provided with a special slotted washer. This is a spacer. It belongs between the inside face of the sprocket-side mount arm and the shoulders on the axle. Tighten the allen bolts in the ends of the axles lightly to fix the motor in the bracket; these button-head bolts can be damaged easily with too much tightening!

4. Clamp the motor/bracket assembly with the top clamp pieces, and fix with the 4 long bolts to the lower clamp pieces in place on the Xtracycle, like so:

   Again: don’t tighten — just remove the slack from the bolt threads. Put the chain onto the left-side chainring, and nudge the motor bracket in the clamps to make the chainline roughly straight. The motor will be offset to the left side:

5. Turn the bike upside down so the motor’s weight removes the slack from the drive chain.

   Nudge the whole assembly as required so the motor clears all adjacent members, with the motor body approximately 1cm (3/8”) from the rear of the seat tube, and correct drive chainline (in a single plane with the gears). A rubber mallet or block of wood and hammer may be helpful in nudging the assembly into position without having to loosen the clamps too much. Rotate the pedals backwards to turn the motor and check for quiet, straight engagement of the chain with the driven and driving gears. Check also to assure that the whole assembly is square, with the motor sides parallel to the seat tube.

   Lightly tighten the clamp bolts and check again. This is an iterative process of loosening and lightly tightening the clamp bolts enough to allow adjustment while assuring that the chainline and clearances are correct when the clamp bolts are tighter.

   As you lightly tighten the clamp bolts, aim for uniformly square gaps between the clamp plates. High precision is not required — just eliminate readily visible departures from the square and the straight.

   When the assembly is in final position, tighten all 6 clamp bolts firmly until they begin to chirp. Then tighten the set screws in the top of the clamps by 1/2 turn. (The start position should have the set screw points just touching the tubing, and the tightening should leave the points driving only slightly into the tubing.)

   Check the drive chain tension with your fingers. There should be no slack in the chain, but it shouldn’t bind at any point of the rotation, either. This is the ideal chain tension that we will strive to achieve at the end of installation, and again at service intervals to address wear and relaxation of the tension cable assembly.

6. Turn the bike upright, and check the drive chain tension again. The weight of the motor alone may have led to enough flex for the drive chain to have sagged a small amount; this is normal. The goal of the next steps are to remove any chain sag, and help maintain correct chain tension as the bike flexes in use.

   Loop the tension cable assembly around the seat-stay bridge as indicated:

   Several loop variations are acceptable as long as the cables clear the motor body, and the loop is not subject to slipping down the seat stay under tension. The tension cable should ideally be anchored around a point perpendicular to the line between the motor axle and the steel bracket’s clamped tube. Pinch the cable housing ends together and hook the front cable span with the cable yoke fastened to the rear cable span. The cable yoke should be cinched up to touch both ends of the cable housing:

   Push the rear cable end through the retaining bolt on the mount arm. Pull it taut with pliers or a fourth-hand tool, using the bottom edge of the mount arm for leverage if necessary. Take care not to mangle the cable for at least an inch below the retainer bolt. Tighten the retainer bolt when all visible slack is gone from the cables, the housing loop conforms tightly to the chainstays, and the chain tension feels too tight. Be careful not to over-tighten the cable retainer bolt; you can easily damage the cable. If you need to replace, it’s ordinary brake cable.

7. Firmly grasp both sides of the motor drive chain with your hands, and squeeze tightly together repeatedly, watching for any slippage of clamps or tension cable. Your goal is to test the tightness of all fasteners and stress the assembly enough to leave the tension cable and the chain feeling slack. This process is somewhat analogous to stress-relieving a spoked wheel as a means of achieving stable spoke tension.

   Retension the cable by loosening the rear retainer bolt and pulling the cable taut again.

   Repeat the chain squeezing and cable tensioning steps until the squeezes no longer leave the chain feeling slack.

   Check the cable tension again after the first few dozens of miles of use; retension the cable further by sliding the yoke down the cable spans as shown, and gently tightening the yoke bolt to hold it in place.

8. Cut the cable a few inches below the retainer bolt, leaving enough length for any future re-tensionings. Cap the cable end to prevent fraying. Note that the cable and retainer bolt may be positioned either on the inside or outside face of the bracket arm.

   This completes the mechanical assembly.

9. Mount the throttle on the handlebar. Twist the throttle to assure smooth action and a quick return to the off position. Do not overtighten the throttle set screw, lest it interfere with quick return to off. Cut your throttle-side grip short, so the combined length of the throttle and cut grip is no longer than the normal grip width. Leave a small gap between the throttle end and the cut grip edge on the bars, to prevent the grip end from rubbing on moving parts of the throttle, interfering with its motion. Review safety and compatibility notes for more discussion of the importance of assuring free throttle action, and recommended control layouts.

   Route the throttle wire cleanly toward the rear of the bike. We suggest wrapping it around the rear brake cable housing.

10. Remove the Snapdeck and install the controller bag as indicated, connecting all the wires through the velcro-closed bottom edge of the bag to their color-matched or pin-exclusive mates emerging from the controller. Assure that all wires are secured with zip-ties as required to stay clear of any moving parts.

This completes the installation. Refer to "Getting started with Stokemonkey" (http://cleverchimp.com/products/stokemonkey/support/getting_started/) for first-ride information, high-level tips, and basic troubleshooting.