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NEW BUILD: Yeti AS-R 7 with CYC X1 Stealth

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    NEW BUILD: Yeti AS-R 7 with CYC X1 Stealth

    Sold my Polygon Cascade 3 with a BBSHD to a friend on short notice. I need a bike, motor, battery, and charger. I know what the BBSHD feels like on a hardtail, I like it but want more. Preferably full suspension. The bike is what I need first, after I know my bike then I can get a kit to fit it. I must also build the entire bike on a strict budget, of less than $2500.

    Within a few days, I found a bike on craigslist, it is a 2009 Yeti AS-R 7. It has been used for downhill racing, but the owner had kept it up and upgraded it regularly. it also came with a box of spare parts like new rotors, shock pump, bb removal tool, new derailer, and cassette, and 4 sarm chains.

    PRICE: $800
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    knowing what the BBSHD felt like, and having installed it. I wanted a different kit, Not that I didn't LOVE the BBSHD but I am an experimentalist and wanted to try something new. Plus, the 73mm BBSHD was out of stock from LUNA. So I started doing research. there were a few options, but many are either discontinued or out of stock or something else. Finally, I stumbled across the CYC X1 Stealth from HERE: It has a torque sensor and the controller is an ASI BAC 855. It was also a bit more powerful than the BBSHD. It also had the benefit of being very programable. (Or Is It a benefit? We Shall See.)
    Rated voltage
    36-72 DCV (nominal) (10-20s Batteries)
    Rated torque

    Max. rated power

    Max. torque (at crank)
    > 5 N.m.


    150 N.m.
    Overall efficiency
    > 90%
    Anodized Black
    Weight (motor & controller)

    Total weight with crankset & bb
    2.7 kg

    4.5 kg
    Bracket materials
    Crank arm length

    Q factor
    165mm or 170mm

    Control method
    Motor sensor
    Hall & temperature sensor
    11/53 option with 32T bike chainring

    11/63 option with 38T bike chainring

    Motor SPECS:
    Motor Type

    BLDC Out-runner
    No-load Motor kV

    Stator lamination


    N45UH (> 180°C)
    Efficiency (at 2 N.m.)

    > 93%
    Rated rpm (at 2 N.m.)

    > 9000 RPM
    Epoxy sealed

    Black epoxy potted stator
    Gear Box SPECS:
    First stage reduction ratio

    1:6 Stealth Gen 2 Quiet Planetary Gearbox
    Second stage

    219H chain
    Overall reduction ratio from motor to crank

    1:28.9 (11/53T)

    1:34.4 (11/63T)

    PRICE: $902.10 WITH Shipping

    After I bought the bike I realized the Battery I was planning wouldn't work. It would have to be underslung and impact resistant. so that left the wolf pack as my only option. since they weren't in stock for standalone orders I had to special order one, this was possible because I had bought a BBSHD before.

    PRICE: $650 for BATTERY + $67 for Charger (both with shipping)

    Once I had everything in hand it was time to build the bike.
    First I brought the bike into the Basement and flipped it upside down for easier access to the BB. the BB and surrounding areas had some interesting cable routing to accommodate the full suspension. it also had tabs to bolt a chain guide onto.
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    Once I removed the front chainrings, crank arms, and pedals it was time to get the motor mounted. To remove the BB I had to use a 16 Spline bb removal tool, which is what the motor uses as well.
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    the cable routing became more manageable after removing the front derailleur. The cable you see above that loops up is for the front derailleur and so was lost when I removed it.

    to mount the motor I had to first disassemble the Bottom Bracket. to disassemble the Bottom bracket I first removed the two black lock rings you can see lying on the far right and left. then the steel shaft slid out and the two black bb casing parts came apart.
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    mounting the motor was slightly tricky. First, I had to line the spacer and motor bracket(1) and then screw the right side of the bb in tight. once that was done the other side was easy. instead of using the spacer provided I used the chain tensioner that came with the bike to space it out. (2) It worked perfectly. I tightened both of the sides down tight with a 16 spline bb tool. (3)
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    to finish mounting the motor I had to insert the axel of the motor.

    then on the other side, I tightened down the lock ring by hand.
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    the next thing to do was put the drive train in place.
    first, I had to remove the cover of the moter side gear.
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    then I put the drive freewheel on.
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    then I reinstalled the motor side drive cover and the locking ring you can see in the center of the freewheel.
    Click image for larger version  Name:	PXL_20220614_215231477.jpg Views:	15 Size:	363.4 KB ID:	153244​ .

    Then I bolted on the crankarms and put the bike chain on.​​
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    Now I had to mount the battery. since I was mounting it on the down tube and underslung I had to remove the cables running along with it.
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    ​then to mount the battery​, I didn't have water bottle mounts so I had to get two pipe clamps and hold the battery and mounting bracket on permanently.
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    now with the motor and battery mounted it was time to do the wiring.
    I didn't get pictures of the wiring process but here is the final resulting cockpit.
    I like the left thumb throttle better than stock, or twist. the reason is that on a bumpy ride either one of them can be triggered by hand motion, however, the left thumb is very difficult to accidentally trigger.
    I also had to extend the motor to battery connections, the stock connecter is very short.
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    Here is a close-up of the display buttons, brake, and throttle.
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    And finally, POWER ON!
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    Since the building of the bike, the controller became bricked. I blame it on myself for interrupting it while changing settings, but the fact remains that the controller quit. however, I have had a very good experience working with CYC on un-Bricking it. they are helping me even though I did not buy the kit directly from them. Electrify bike, the ones that I bought it from have been very responsive and unhelpful. right now the controller is on its way to Hong Kong to be reprogrammed by CYC and hopefully fixed.

    Thanks for reading my very long and very boring build report.
    Attached Files
    Last edited by DaveK; 07-09-2022, 08:47 AM.