Rocky Mountain Powerplay crank length

Rocky Mountain Powerplay bikes come with a mix of 170mm and 165mm crank lengths. Given their relatively low bottom bracket, the 170mm cranks results in frequent pedal strikes. The 165mm cranks are better, but I still had too many pedals strikes with them. Because the one-way chainring spider on the Powerplay requires a Cinch to connect to the crankarm, the crank alternatives are limited to Race Face or North Shore Billet. There are several options to reduce the crank lengths under 165mm.

Race Face 160mm:

Race Face recently released their Turbine crankset in 160mm, which are probably sufficient for most riders. It's both the cheapest and easiest way to do to a shorter crank. The cranks are $180-200 new:

https://www.raceface.com/products/turbine-crankset

If your stock crankset is a 24mm spindle you'll also need need to buy the 30mm spider lock ring (part #1347006) from Rocky Mountain ($40-50), along with a press fit BB92 30mm bottom bracket. The Race Face Double Row Cinch 30mm is my recommendation at $85:

https://www.raceface.com/products/bb92-double-row-cinch-30mm

In addition, if your stock crankset is 24mm, you'll need the Race Face 149.5mm spindle kit:

https://www.raceface.com/products/spindle-kit-cinch-149-5mm

North Shore Billet 145mm, 155mm:

If you want to go shorter than 160mm, the easiest solution, though the most expensive, are the Powerplay cranks from North Shore Billet in 145mm and 155mm lengths for $535: 

https://northshorebillet.com/products/talon-crankset-rocky-mountain-powerplays 

They're a direct upgrade. If your stock crankset is a 24mm spindle you'll also need need to buy the 30mm spider lock ring (part #1347006) from Rocky Mountain ($40-50), along with a press fit BB92 30mm bottom bracket. The Race Face Doubel Row Cinch 30mm is my recommendation at $85: https://www.raceface.com/products/bb92-double-row-cinch-30mm

Race Face Atlas 155mm:

A less expensive, but more difficult alternative is re-drilling Race Face 175mm Atlas crank arms to a 155mm. This can be done because the Atlas cranks aren't hollow, and the back side ribs don't extend very far, leaving a lot of aluminum around the new pedal hole. New Atlas cranks can be had new for $180, but can be found used for about $100:
https://www.raceface.com/products/bb92-double-row-cinch-30mm

Like before, if your stock crankset is a 24mm spindle you'll also need need to buy the 30mm spider lock ring (part #1347006) from Rocky Mountain ($40-50), along with a press fit BB92 30mm bottom bracket. The Race Face Doubel Row Cinch 30mm is my recommendation at $85:

https://www.raceface.com/products/bb92-double-row-cinch-30mm

The Atlas cranks will also need the 151.5mm RD151DH spindle, if it doesn't already come with the crank arms:

https://www.raceface.com/products/spindle-kit-cinch-151-5mm-rf151dh

Although the cranks can be run like this, I recommend added Race Face crank boots to make it look better for the nominal cost of $12:
https://www.amazon.com/dp/B00JNAK4OU

You'll need the following tools:

• Mill or drill press
• 1/2" drill bit
• 9/16-20 tap - left and right hand
• 13/16" end mill
• Dremel or angle grinder

You need to mark and center punch the location of the new hole on the back of the crankarms, 20mm up from the existing holes.

Then they need to be drilled with a 1/2" bit. This can be done using a drill press or a mill. It is not recommended to try and do it free hand. I found it easiest to fixture the crank arm upside down, though there are multiple way to accomplish this.

After drilling the new hole, flip the crank arm over and use an end mill to flatten the area around the new pedal hole to give a flat surface for the pedal to seat against. I used a 13/16" end mill. Since this is a drilling operation and not a milling operation, a drill press should be safe to use.

The new holes now need to be tapped. A set of 9/16-20 taps on Amazon are less than $30. Make sure to use plenty of tapping oil and make sure to use the left tape on the left arm and right tap on the right arm.

Once the holes are tapped the extra crank arm length can be cut off. I prefer to use a vertical belt sander to give the end of the crank arm a nice rounded shape, similar to stock. Note, part of the original pedal hole will still remain at the end of the crank arm.

Finally, install the crank boots.

I think it's pretty evident that unless you already have some of the tools needed (and some experience using them), it's probably cheaper to go with the North Shore Billet cranks. 

Additional information can be found in this thread on EMTB Forums:
https://www.emtbforums.com/threads/shortening-your-cranks.29059/

Yamaha YDX Moro torque specs

 

Yamaha Moro YDX display

The Interface X on the PW-X3 motor equipped Yamaha Moro YDX is Bluetooth enabled and can connect to smartphone apps, GPS devices, or bike computers. However, the display itself is horrible, with just a series of LED lights to tell you the assist level and battery level (in only 25% increments). The location isn't great either right next to the stem.

Yamaha also makes the Display A which is a plug-and-play upgrade. While it doesn't have Bluetooth, it shows the speed, assist level, and battery level in 5% increments. It also combines the assist buttons with the display itself, so it's fewer wires and an altogether more compact design.

To replace it, remove the right side cable cover, and gently pull the wire out until you get to the connector. With a bit of finess the connector will come out through the cable port. At that point just disconnect the Interface X, and connect the Display A.

Single speeds and half links

Single speeds often use 8 or 9 speed chains because of the significantly higher quality and the lower weight. However, it can be challenging when a half link needs to be added to achieve the property chain length. Every 3/32 half link I tried, and I think I've tried them all, is slightly too wide to be used in a multispeed 3/32 chain.

To do it right you want two of these:

KMC Z610HX master link
https://kmcchain.us/products/z610hx-c-l

And one of these:

Gusset half link
https://www.universalcycles.com/shopping/product_details.php?id=22297

The KMC master links in the link above is nickel plated and very nicely made, unlike most BMX style master links. They're slightly wider than a normal 8/9 speed connector link, so they play nicely with the half link, and the slight added width isn't a problem with the narrower multispeed chains since the difference is so small. They'll also digest any half link out there while still working nicely with a multispeed chain. 

The Gusset half link is another quality product. The entire thing is nickel plated, unlike most half links. They also sell it already joined to a set of inner plates, the reason being they can peen the ends of the pin for extra strength. Also, unlike other half links, the Gusset uses the superior bushingless design.

You want to use the two KMC master links to join the Gusset half link into your chain. Make sure the flat side of the Gusset half link faces away from the teeth. 

You can still use a connector link, but it cannot connect to the half link as the connector link simply isn't wide enough. When I run a connector link and half link together, I'll usually install the half link on the opposite side of the chain.

Vacuum bleeding a shock

WARNING: ALWAYS WEAR EYE PROTECTION. I’ve had suspension fluid sprayed in my eyes and it sucks. It can happen even if you do everything right.

Degas the Suspension Fluid 

Suspension fluid has a lot of dissolved air in it, and before bleeding this air must be removed for two reasons:

• Dissolved air makes the oil more compressible.
• It allows the oil to absorb any small air bubbles left after bleeding.

Fill the vacuum bleeder reservoir no more than halfway with suspension fluid. Close the compressed air valve, open the vacuum valve, start the vacuum pump and run it to -30 in of Hg, then close the vacuum valve and turn off the vacuum pump. The the fluid sit in vacuum for 15-30 minutes. The vacuum can then be relieved by slowly opening the compressed air valve.

Bleed the Damper

NOTE: These bleed instructions are for bleeding a reservoir shock with a bleed port and an IFP. Although the basics of the bleed procedure are the same, the details for other damper architectures are different, so be sure to familiarize yourself with those before bleeding. 

Preparation

• Service/rebuild the damper and assemble it without suspension fluid.
• Connect the appropriate bleed adapter to the bleed port on the shock, and position it so it’s the highest point of the damper.
• Install the IFP and the reservoir cap retaining clip. It is very important the IFP be retained inside the shock during the bleed process.
• Fill the vacuum bleeder reservoir no more than halfway with the desired suspension fluid.
• Set your compressed air regulator to 45 PSI.
• Connect the compressed air source to the vacuum bleeder.

Bleed

1. Close the compressed air valve, start the vacuum pump, and slowly open the vacuum valve. Once there’s a good vacuum, close the vacuum valve and turn off the vacuum. Be sure to close the vacuum valve before turning off the pump.

NOTE: What look like bubbles under vacuum are actually pockets of vacuum and will collapse during the pressure phase of the bleed.

2. Verify the vacuum valve is closed, and slowly open the compressed air valve. Oil should start flowing from the reservoir into the damper. Once the pressure is stable, cycle the damper several times by hand. It can also help to tap the damper to dislodge any bubbles.

4. Repeat steps 1-2 several more times (I usually do 5 cycles) to help insure all the air is evacuated from the shock. Any small bubbles which remain will be absorbed by the degassed suspension fluid.

5. Close the compressed air valve, and use the pressure relief valve to release the pressure.

6.  Disconnect the air compressor, open the compressed air valve, and set the IFP depth. The excess oil will be pushed back to the vacuum bleeder reservoir.

7. Disconnect the vacuum bleeder from the bleed adapter, then remove the bleed adapter and close the shock's bleed port.

8. Install the reservoir cap and pressurize the reservoir to spec.

Building a vacuum bleeder

A suspension vacuum bleeder uses alternating vacuum and pressure to bleed a damper. It's much easier than hand bleeding, does a better job, and is a less mess.

Bill of Material

A bleed adapter specific to the damper will be required to connect the vacuum bleeder to the damper. ANSO (https://anso-suspension.com) makes good bleed adapters at a reasonable price, and the list below reflects using ANSO adapters. If different bleed adapters are used, the "3/8" FNPT V-Style coupler" would need to changed to work with those adapters.

• 1/4" NPT 50 PSI pressure relief valve - $9 -  https://a.co/d/7lOzOpp
• 3/8" OD 1/4" ID polyurethane (PU) tubing - $9 - https://a.co/d/7cUTqff
• 1/2" NPT to 1/4" barb 90* fittings - $10 - https://a.co/d/fgpZFRI
• 3/8" spring hose clamp - $6 - https://a.co/d/gdm5f48
• 3/8" FNPT V-Style coupler - $9 - https://a.co/d/8DQBxJ5
• 1/4" NPT pressure gauge - $13 - https://a.co/d/f1TbRqJ
• 1/4HP 3.5 CFM vacuum pump - $55 - https://a.co/d/2L3zF0F
• Hydronix HF2-10CLWH12 filter housing - $23 - https://a.co/d/dYMTLSv
• 3/8" NPT 3/8" tubing push to connect fittings - $9 - https://a.co/d/auJHnwp
• 1/2" NPT mini ball valves - $13 - https://a.co/d/72oPZEk
• 1/4" FNPT air hose quick connect adapter - $4 - https://a.co/d/aGIQmXG
• 1/4'' NPT 1/4" barb fittings - $5 - https://a.co/d/cOngmrj

TOTAL - $165

Assembly

NOTE: Whenever installing a fitting the threads should be wrapped with at least three layers of Teflon tape. Be sure to orient the wrap so that tightening it doesn’t try to un-wrap it. 

Vacuum Pump

• Fill the vacuum pump’s sump with suspension fluid, roughly the same viscosity as you’ll be using.
• Remove the inlet fitting and replace it with a 1/4” NPT barbed fitting.

V-Style Coupling

• Install a 3/8” NPT push-to-connect fitting.

Quick Connect Coupling

• Install a 1/4” NPT barbed fitting.

1/2” Ball Valves

• Install the 1/2” NPT barb 90* fittings so they point away from the valve handle.

3/8” Push-to-Connect Fitting

• In one of the fitting, drill out the bottom of the fitting so a tube can extend all the way through the fitting.
• Meticulously clean any metal swarf out of the fitting.

Filter Housing

• Drill a 19/32” hole in the top of the lid and and thread in the drilled out 3/8” push-to-connect fitting. Teflon tape is not needed on the thread. The fitting will tap itself into the plastic of the lid. Keep threading it in until the bottom is just proud of the inside of the lid.
• Drill a 15/32” hole in the top of the lid, then thread in the pressure gauge. Teflon tape is not needed on the thread. The gauge will tap itself into the plastic of the lid. Keep threading it in until the bottom is just proud of the inside of the lid.
• Drill a 15/32” hole in the side of the lid and thread in the 1/4” NPT pressure relief valve.  Teflon tape is not needed on the thread. The valve will tap itself into the plastic of the lid. Keep threading it in until the bottom is just proud of the inside of the lid.
• Clean out any plastic shavings from the lid.
• Install the two two ball valves into the two threaded holes in the lid. The valve handle should face upward, and the barb fitting should face downward.

Putting it all Together

• Insert the polyurethane (PU) tubing through the push-to-connect fitting in the lid and feed it down until it sits about 1/4"-1/2” above the bottom of the reservoir. Install a zip-tie or clip to prevent the push-to-connect release collet from being depressed.
• Cut the PU tube to length. It needs to be long enough to go from the vacuum bleeder to the damper with some slack in the tube. However, the tube should be kept as short as practical to aid in bleeding.
• Connect the V-style coupling to the end of the PU tube. Install a zip-tie or clip to prevent the push-to-connect release collet from being depressed.
• Cut a length of PU tube to connect the reservoir to the vacuum pump. Put two spring clamps on the tube, warm up the two ends with a hair dryer or heat gun, connect them to the barb on the vacuum pump the barb on one of the ball valves on the reservoir; this is now the vacuum valve. Put the spring clamps in place.
• Cut a length of PU tube to connect the reservoir to the air compressor. Put two spring clamps on the tube, warm up the two ends with a hair dryer or heat gun, connect them to the barb on the quick connect coupling and the barb on the other ball valve; this is now the compressed air valve. Put the spring clamps in place.

Testing

• Test the reservoir to make sure it holds vacuum. Close the compressed air valve, open the vacuum valve, and run the vacuum pump until the pressure gauge registers 30 in. of Hg vacuum, then close the vacuum valve and turn off the pump (air can bleed through the vacuum pump when it’s not running so close the vacuum valve before turning off the pump). The reservoir should easily hold the vacuum for several minutes, if not hours. If it doesn’t, there’s a leak which needs to be found.
• Test the reservoir to make sure it holds pressure. Pressurize the reservoir to 45-50 PSI and close the compressed air valve. Set the air compressor’s regulator to 45-50 PSI, DO NOT pressurize the reservoir with higher pressure air and try to stop it at 45-50 PSI using the pressure gauge. Again observe the pressure gauge for any changes in pressure. If the pressure drops over the next several minutes, there’s a leak which needs to be found.

If the system passed both the vacuum and pressure tests, install it in its final position or install it in its stand/frame.

Andreani Thread

Many vacuum bleed adapters use "Andreani thread" named after the Andreani vacuum bleed machine. It's actually an 1/8" BSPP (British Standard Pipe Parallel) thread. 

Adapters from BSPP to NPT are available:

https://www.amazon.com/dp/B0CLHK1CP2

https://www.amazon.com/dp/B01LQU8FV8

NOTE: There is a British Standard Pipe Parallel (BSPP) and also a British Standard Pipe Taper (BSPT). Make sure you purchase the Parallel.