Here is some information from the Yahoo FT500 Owners Group. The complete PDF with pictures is located at the bottom in the attachment section.
Replacing the Starter’s Pinion Shaft Bushings
Instructions for replacing the two starter pinion shaft bushings are given. The project requires the starter solenoid assembly be removed; and one or both of the pinion shaft bushings be extracted and then replaced. Although removing the left-side engine case is not required, it is also an option1. Replacing the inboard bushing requires deepening the inboard bearing seat with a tapered end-burr chucked into a Dremel-type rotary tool.
Replacement of both pinion shaft bushings are much simplified in this new version of the instructions compared to the earlier version. Credit for these new instructions is entirely due to Bob McBride, member of the FT500 Ascot Owners Group. These new instructions allow replacement of both pinion shaft bushings in a matter of a couple hours. The only specialized tool(s) required are that the mechanic has access to a high-speed rotary tool (Dremel or pneumatic) with two bits: a small tapered grinding stone, and a tapered metal-rated end-burr.
Basically, these newer instructions have the mechanic use a rotary tool with stone to grind a pair of detents in the old bearings to allow their extraction. Then in replacing the inboard bearing, the Dremel with end-burr is used to grind flat the base of the bearing’s seat. The new bearings are then pressed-in. The parts are cleaned up and reassembled; and that’s the end of the project.
The cost of the replacement bearings (both caged-needle type) are small. In year 2008, a new set of bearings cost a total of about $10 for both (~$5 ea).
Overview
In the FT500’s electric starter, a pinion gear slides onto the engine’s ring gear to engage the starter motor at the initiation of starting the engine. A number of FT500 owners have found that after 25+ years of operation, one or both of the bushing-type bearings holding the pinion gear’s shaft have become severely worn. This allows radial play in the pinion gear’s shaft. The symptoms indicating pinion bushing wear are that the engine’s starter will engage and the engine will turn over a crank or two, then suddenly halt. The sudden halting of engine rotation is probably due to the teeth of the starter pinion gear riding up on the ring gear’s teeth and then the two gears jamming. Subsequent inspection inevitably reveals a worn pinion gear bushing.
There are two bushings supporting the
pinion gear’s shaft: an inboard bushing and an outboard bushing. The inboard bushing most often is the one that wears excessively. The inboard bushing is in the left-side engine case and is on the engine-side of the pinion gear shaft (see drawing at right). The outboard bushing is in the starter solenoid assembly’s cover: on the pinion shaft’s end away from the engine. Both pinion shaft bushings are plain shaft bearings: i.e. bushings. Their replacements are caged needle bearings. Exact replacement bushings are no longer readily available. The replacement bearings are standard sizes.
1 Replacing the inboard bearing requires abrading metal with a burr. Although steps can be taken to avoid introducing metal and refractory particles into the engine (packing rags etc.) if a worker wishes to completely avoid the possibility of debris getting into the engine, the left engine case should be removed.
Replacing the Pinion Shaft Bushings 1 GRN Rev. 3 April 08
Honda FT500 Ascot
Inboard Pinion Shaft Bushing
Pinion Gear Shaft
Outboard Pinion Shaft Bushing

Honda FT500 Ascot
Inboard: HK1210; Outboard: HK0910. The replacement bearings can be ordered from a local industrial bearing supply store. Look in the Yellow Pages under “Bearings.” Call up one and tell them the part numbers above, and you’ll most likely have them in two to three days. Common bearing manufacturers are “Ina” and “Timken.” They use the same part number.
PinionShaftBushing
Inboard Outboard
ReplacementPartNumber
HK 1210 HK 0910
The most common cause of the worn pinion bushing(s) is thought to originate with the starter solenoid’s lock-cam mechanism. When the starter is first engaged, a lock-cam in the solenoid assembly locks the pinion onto the ring gear. This insures the pinion’s correct operation during the starting procedure. When the starter button is released, the lock-cam normally releases as well, and the pinion gear can then be rejected from the ring gear because the engine is running. However, as all FT500s are all currently over 20 years of age, the lubrication for the lock-cam’s shaft has typically dried out. In many cases (if not all), the lock-cam eventually starts to stick during the starting process. If the lock-cam does not release when the starter button is released, the engine will start and the pinion gear will not be rejected but will instead hold onto the ring gear. Although the pinion gear’s one-way clutch limits the rotational speed of the pinion gear’s shaft, tremendous loads are still placed on the pinion gear’s shaft. Usually engine vibration will quickly shake the lock-cam free and thus the pinion gear can be rejected off the ring gear. But still, severe pinion shaft bushing wear can be expected in short order.
An important side-line of these instructions on replacing the worn bushings is to strongly encourage overhauling the starter solenoid mechanism if it hasn’t already been done. If the bushings are replaced and the solenoid assembly is not overhauled, the fundamental problem is simply masked for a short time. Bearing wear will continue to be severe, if not outright destruction of the starter’s gears. Instructions for overhauling the solenoid assembly can be found on the same web-page as these instructions. And without a doubt, overhauling the solenoid assembly is the easier of the two tasks. The starter solenoid assembly can be disassembled, lubricated and re-installed in not much more than an hour: it is a simple job.
There are two ways to approach replacing the inboard pinion bushing: 1. the easier of the two is leaving the left-side engine cover in place and taking steps to minimize particle debris contamination of the engine; 2. removing the left-side engine cover. This procedure details the easier method. However, just for reference for those who decide to remove the left-side engine cover the following instructions are given.
Only for those who want to remove the left-side engine cover. To remove the left-side engine cover, the gas tank and seat must first be removed to de-couple the wires’ mini-connectors running from the alternator area. There are two mini-connectors that must be de-coupled: the alternator-wires’ mini-connector and the neutral-switch wires’ mini-connector. The starter solenoid assembly must also first be removed as there are two bolts inside the engine case that must be removed to allow the engine case’s separation from the engine. The starter motor remains attached to the left-side cover during the removal of the left-side cover. As a result, the starter motor bracket on the right-side engine cover must be removed, allowing removal of the starter motor while still coupled to the left-side engine cover. The main power connector to the starter motor must be disconnected.
The inboard replacement bearing is 1 mm taller than the original. This requires using a Dremel to remove a metal step in the base of the bearing seat that the bearing fits into. The step in the bearing’s seat is 2 mm tall. A skilled mechanic might attempt removing only 1 mm of seat, but it is much easier to remove the entire 2 mm of seat and then only drive the replacement bearing in flush with the surface of the engine cover. Using an oversize drift (often a wood dowel) larger than the bearing diameter will keep the bearing from being driven deeper than flush.
Detailed instructions on how to perform the bearing replacement follow.
Replacing the Pinion Shaft Bushings
Detailed Instructions
Honda FT500 Ascot
Tools required
Metric wrench set (sockets preferred) 8mm to 17mm with 100mm extension shaft Allen key 4mm
Flat-bladed screwdriver
Phillips screwdriver
Mallet and 3⁄4 inch round wood dowel
Rotary Tool (Dremel-type or high-speed pneumatic) Small tapered, pointed grinding stone
End-burr (rated for metal removal), tapered Paper-clip, one end straightened to use as a “poker.”
Tools Needed
Tapered Grinding Stone
End-Burr rated for metal removal
Optional Tools
Compressed air to blow out debris is nice but not essential Pliers, needle-nosed
Materials
Old newspapers to catch oil, & rags or paper towels
Q-tips for cleaning out grinding debris
WD-40 (or equivalent)
Replacement Bearings (Outboard: HK 0910; Inboard HK 1210) Grease (for general reassembly)
Engine oil change and new oil filter
High Speed Rotary Tool
Replacing the Pinion Shaft Bushings 3 GRN Rev. 3 April 08
Time required
Honda FT500 Ascot
About two hours for an average shade-tree mechanic not including the oil change.
Disassembly Instructions.
1. Remove the starter solenoid assembly by taking out the three 8mm bolts holding it to the left-side engine case. Using the flat-bladed screwdriver, gently pry the solenoid assembly free from the engine case. It will eventually spring free, because there is a weak coil spring
pushing the starter pinion shaft outward. Use the
directions in the Starter Solenoid Maintenance instructions (located on this web-site) for reassembly. Remove the solenoid from the starter solenoid assembly by removing the 4mm Allen head bolt. The solenoid is held in place with an O- ring, so gentle twisting and pulling allows it to pop free. The solenoid assembly is now free and can be put aside for work later.
2. Once the starter solenoid assembly is “in hand,” the pinion shaft bushings are now exposed for replacement. The inboard bushing is visible (see picture) in the left-side engine cover. When the pinion shaft is pulled out of the solenoid assembly’s cover, the outboard bushing is visible in the solenoid assembly’s cover.
Extracting the Old Pinion Shaft Bushings
1. In the case of the inboard bushing, think of it as a dentist extracting a tooth. Pack rags and/or paper towels around the area to minimize the contamination of the engine with metal shavings and stone debris. Caution: don’t get in too tight with the packing! You’ll see why the first time you contact a rag with the end of the rotary tool!
2. Using the rotary tool (Dremel or equivalent) with pointed, tapered grinding stone, grind out two detents in the pinion shaft bushings. Try to get the old bushings completely separated into two semi-circles, but avoid grinding into the case holding the bushings. Use the drawing below as a guide.
Old Bearing Sectioned with Dremel
3. Take a flat bladed screw driver and break the bushing halves in two and extract the bushing halves. Use fingers or needle-nosed pliers, if pliers are available.
Grind detents in bearing with cutting stone
Replacing the Pinion Shaft Bushings 4 GRN Rev. 3 April 08
Installing the Replacement Bearing(s)
Honda FT500 Ascot
Outboard bearing: simply drive the replacement HK 0910 bearing into the vacated bearing seat with a wood dowel used as a drift and a mallet. As an alternative to a wood dowel, the pinion shaft itself can be used in a bind.
Inboard bearing. It is necessary to first remove the step in the base of the bearing’s seat.
1. Prepare the area with rag and/or paper towel packing as in the “bushing removal” step above. Same caution is in order for not getting the packing material in too close to the work area.
2.
left as a guide, grind away the step with the rotary tool with metal-rated tapered end-burr. Insure the oil hole/groove is open and enlarge with the pointed stone in the Dremel. Poke a paper clip into the oil hole. Clean everything 3. Once the Inboard bearing’s base-step has been removed, seat the replacement HK1210 needle bearing into the modified bearing seat with a dowel and mallet. Do not overdrive! Only drive the bearing in flush with the top surface. Using an “oversize” dowel will insure that the bearing is not overdriven.
Using the drawing to the
Make sure oil hole/groove is open and make deeper.
ID 12 mm
OD 16mm
9 mm
16mm
Reassembly
Reassembly is largely the reverse of disassembly, but a few tips may be helpful.
1. Clean all worked-on areas as best as possible to remove metal chips and grinder debris. Use rags, washing material (WD-40 works well here), Q-tips, and compressed air if it is available.
2. If you haven’t already done so, please perform the solenoid assembly maintenance before you re-install the solenoid assembly.
3. Change engine oil and filter to complete the procedure. It is probably a good idea to run the engine at idle for perhaps 15-20 minutes before performing the oil change. This is to flush any remaining grinding debris down into the oil sump and filter. And it wouldn’t hurt to inspect/clean the oil pickup screen in the oil sump when the oil change is performed You have to remove the oil sump to get at the oil-pickup screen.
End of Pinion Bushing Change Instructions.
Replacing the Pinion Shaft Bushings 5
New Inboard Bearing
Remove this step with Burr on Dremel
11 mm

