Sunday, March 6, 2011

Part 6 - Motor, primary and transmission

The motor arrived on Friday. From time of order to delivery was exactly one week with free shipping (except for the lift gate fee that I elected to pay to simplify offloading at home).

The boxes - motor, primary and transmission

Motor: Ultima Black 113 ( 1850 cc ) EPA compliant
Transmission: Ultima 6 speed Black RSD hydraulic clutch
Primary: Ultima Drag style 85mm belt drive
Ordered from Jireh Cycles :

After everything was removed from the boxes, the motor was placed in position on the frame. All the mounting points lined up correctly but the motor ships without any mounting hardware. A quick trip to Ace hardware was required to get temporary 3/8" mounting bolts. Used 2" long bolts in front and 3 1/2" bolts for the rear mountings. A chromed motor mounting kit from Gardner-Westcott is on order for final assembly. The motor is very heavy (160lbs) so I suggest you get help lifting it into the frame. Naturally I did it without help.

Motor positioned in the frame

The next step was to mount the transmission. The transmission has 5 mounting studs. 4 of the studs go through the slots in the frame mounting plate. According to Mike at MMW, the 5th stud can be cut off. It's not needed. The slots let you move the transmission forward and backward so that the primary plate that connects the motor and transmission can be properly installed. At this stage the motor and transmission mounting bolts were left loose.

Transmission mounted to the plate behind the motor

Motor and transmission loosely mounted

The primary consists of a lot of parts so the assembly is more challenging than the motor and transmission which arrive fully assembled. The Ultima instructions are very clear. At this point I did a mock-up of the assembly just to make sure all the parts were in the package and that everything fit correctly. The primary will need to be disassembled in future and then re-assembled using locktite and the correct torque specifications.

Primary parts

The primary motor plate locates over a ring feature on the motor and a pin that extends out of the gearbox. With the motor and transmission loose with respect to the frame, the motor plate was used to jockeyed them into position creating the correct distance between transmission and motor. The primary motor plate is bolted to both the motor and gearbox fixing them with respect to each other. The entire assembly was them straightened with respect to the frame and the the motor and transmission were snugged to lock everything into place on the frame.

Primary rear plate connects the motor to the transmission

The front and rear pulleys and belt were installed next. It was a real battle to get the front pulley onto the splined motor drive shaft. I was worried that it might get stuck so didn't force it on the whole way - I need to disassemble this when mock-up is complete anyway.

Front and rear pulleys installed

Next up is the clutch. The clutch consists of a series (I lost count) of alternating steel and fiber plates which are held in place by the pressure plate
Clutch installed

The motor and transmission pulley caps cover everything up and provide an edge for keeping the belt on the pulley. The caps are bolted to the pulleys.

Motor and pulley caps installed

The last step is to line up the outer cover with the support shafts and bolt it into place. It's not really a cover in the traditional sense but that's what the manufacturer calls it! The outer cover caps have bearings in them which slide over the bosses on the pulley cover caps. This provides extra support for the pulleys.

Driveline installed



  1. Mos Def excellent.

  2. That primary drive is pretty wide. How well does your foot fit to the left side controls?

  3. The mounting plates on the frame were already extended outward to accomodate the primary. Clearance is good.

  4. Great pics and good pointers. You already sound like a pro.