Sunday, March 13, 2011

Part 7 - Starter motor

An Ultima Thunderfire 1.75kW starter motor was ordered for the bike.

The chrome on the starter motor wasn't up to the same standard as the other components from Ultima.
You can see the copper layer in the circled area below. Not a big deal considering that it is hidden when the starter is installed but still surprising that it was shipped by the manufacturer with an obvious cosmetic flaw.

Before the starter can be installed, the starter gear assembly needs to be assembled to the starter motor. The starter gear assembly comes with the primary. The parts attach to the starter motor shaft in the order shown in the image below. Begin by sliding the spring stop over the shaft, followed by the spring, starter gear spacer, starter drive gear, starter gear bushing and finally the starter bolt. 

Parts required for starter gear assembly in assembly order

Starter gear assembly before fastening

Starter gear final assembly

Mounting points (click to enlarge)
Two 5/16-20 2" SHCS (grade 8 if you can get them) are required to bolt the starter motor assembly to the primary motor plate. The motor plate has an alignment pin to ensure correct alignment of the starter with the ring gear on the primary pulley. Looking from the back side of the motor plate you can see the alignment pin and the edge of the ring gear. Further out is the gold colored bushing that supports the starter drive gear when it extends outward to start the engine. This must be lubricated. The bushing is housed in the starter gear cover and should be removed before installing the starter so that you can see what you are doing. Slide the starter into place over the locating pin and fasten the 2 bolts. Everything is being mocked up to ensure proper fit so nothing is being properly torqued or loctied now. Unless this is the final fitment, you want to take it easy on the spinach and avoid tightening the bolts to more than snug - just enough to hold everything in place. Looking from the primary side of the bike you should see something like this:

Starter installed viewed from primary side

The starter gear cover can now be replaced which will leave you with the complete assembly. There is a single post on the starter motor that gets connected directly to the battery positive. This requires a heavy duty cable as there will be hundreds of amps flowing through the cable when the starter is engaged.

Battery cable set

Starter gear cover replaced

Starter installed

The hole diameter of the battery cable ring terminals is too small for the starter motor power stud. Nothing a drill can't fix but it is clear that the wrong part was ordered. Details details details. 


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