How To - Starter Rebuild

Parts Needed, Tools Needed, Step-By-Step, Inspection, Disassembly, Inspecting For Wear, Cleanup, Brushes, Reassembly, Bendix & Spring Replacement, Bench Testing, Reinstallation, OH!

Topic:                           Rebuilding a Wetbike Starter (Hitachi s108-66b)

Expertise Required:      Intermediate

Estimated Time:            About 2 hours for total rebuild, 1 hour for quickie

Before You Begin           So, what starter is used on wetbikes? Hitachi 108-66b That info is useful, but you won't find this starter in any rebuilder's book. If you are just looking for internal parts, Suzuki is the best bet. The brushes, brush plate assembly, bendix, and bendix spring assembly are still available. 

Parts Neeed:                You will need the following parts (potentially):

      • Your brain
      • (1) - 10-3012-722  Brush Assembly (lower brush plate)
      • (2) - 10-3012-724  Screw (long)
      • (2) - 10-3012-725  Screw (short)
      • (2) - 10-3012-726  O-Ring (for long screws)
      • (2) - 10-3012-727  O-Ring (for short screws)
      • (2) - 10-3012-723  O-Ring for starter body
      • (1) - 10-3014-140  Bladser (starter bellows) (pic of homemade one)
      • (1) - 10-3012-730  Kit - Thrust Washer (probably not needed but handy to have)
      • (1) - 10-3012-729  Kit - Stopper Set (spring, sleeve, clip)
      • (1) - 10-3011-290  Pinion Assembly

Tools Needed:             You will need the following tools:

      • Workbench or Table - preferably with a Vise
      • 12mm socket or wrench to get starter removed
      • Hand-Impact tool with both Philips and Flat-blade sockets
      • Wire brush small enough to clean O-Ring surfaces (plumber brushes work best)
      • Drill press or handheld drill to spin armature to clean up contacts
      • Crokus Cloth or 3M pad to clean contacts - do not use emery cloth
      • Dab of waterproof grease for the o-rings
      • Big Mama soldering gun - or - small propane torch for brush plate connections
      • Bead Blasting machine (if you plan to repaint parts)
      • Slide-Hammer style bushing puller (very small size) for bushings
      • 3lb Ball Peen Hammuh
      • Mica Cutter (if you can find one) pic1 pic2 pic3

 Step-By-Step:             Here's step-by-step instructions on how to get it done:

      • Disconnect battery
      • Disconnect wire running from solenoid to wiring harness (on 50hp bikes this is behind the cover with the 4 10mm screws) (on 60hp models it's behind the black snap-on cover - be careful not to damage that cover when removing as they are No Longer Available - NLA)
      • Remove lower starter bracket bolt (works well for me to stand on the right side of the bike and reach under the carbs with a ratchet. Note: Battery ground strap SHOULD be connected to this bolt. If it wasn't make sure you do that upon reassembly
      • Remove one of the upper starter mounting bolts
      • Remove the other - but use one hand to "catch" the starter so that it doesn't crash to the bottom of the hull
      • Work starter around to right-side of the bike and pull it straight up. I don't think it'll fit if trying to remove it from the left side (especially if the intake fairing is installed)
      • Head to the workbench.

Inspection                 Take a minute or two to visually inspect the outside of the starter. Things to look for are CRACKS on the mounting flanges, heavy corrosion on those surfaces as well, and wear on the bendix's teeth.

      • Also, take a screwdriver and scribe a line on both the top seam and the bottom. That'll aid in reassembly.
      • Finally - inspect the starter bellows for air worthiness. Make sure it's not leaking - replace if necessary. This one is comical


      • Take a 10mm socket or wrench and remove one of the bolts holding the starter relay
      • Remove the other side. It's the breather for the starter bellows
      • Disconnect the 10mm nut from the stud on the starter that's holding the braided wire from the solenoid. Then the solenoid should be free - set it aside.
      • Place starter in vise if you have one. Leave plenty of room to get Hand-Impact-Driver onto the screws without getting your fingers pinched. If you are gonna replace the bendix or spring/stopper assembly - now is the time to do it.
      • Take a second and use a screwdriver to scrape out any excess paint and/or corrosion from the two slotted (flathead screwdriver) screws. If you can, do the same for the phillips-head screws too.
      • Hand-Impact Drive - Take time and get the proper socket that fits tightly into the slotted screws. I have one that I have to "hammer" into place. Nice tight fit and it keeps from stripping these soft screws out.
      • Use the Hand-Impact and remove the slotted screws first (very important).
      • Follow the same procedure and remove both of the phillips screws. Note: these may be severely corroded and might protest all of the way out. Or . . . they might break.
      • If any of the screws break and/or get the heads stipped out, don't panic. You can drill them out easily. Use a drill bit that is just big enough to drill down so that the head falls off - but not big enough that it's gonna hit the material on the bottom mount. Once you do it once, you'll get the hang of it.

      • While still in the vise, remove the bottom cover. Once it slides off - be sure to capture all of the thrust washers (should be at least one) that go between the armature and the lower housing. Set the cover and washers aside.
      • Slide the middle section off (the one with the field coils) and set aside. Note that there are O-rings between these parts. It's best to use new one, but if the old ones look ok, that'll work. However, getting the grooves they ride in cleaned up and painted is MANDATORY. If you don't you could get water in the starter and/or get corrosion started in a hurry.
      • Here's what most look like:

Inspecting For Wear      At this point, it's time to put on some gloves and start looking at the damage. Be ready for anything - corrosion, rust, water, burned-up-grease, smoked insulation, etc.

      • If your starter got really hot, it could have baked the insulation off of the coils - like this one.
      • If you removed the bendix previously - you can slide the armature out and put the thrust washers aside. If you don't need to remove the bendix, don't. Getting them off is easy - getting the new ring/stop collar on correctly is difficult.
      • Inspection time. Start with the armature and look for any burned spots on the contacts (bottom copper bars). Also look to see if there's any evidence of damage and/or contact between the armature body and the field coils. This armature's done.

Brush Plate - have a look to see if all of the brushes are wearing evenly. Also pay special attention to the little spring coils that hold the brushes in. They have a tendency to rust/break from excessive heat. If the brushes look really worn and/or any of the springs are broken - replace the entire plate. It's inexpensive.

Field Coils - look closely to see if signs of overheating are there. The insulation is pretty durable, but gets brittle and turns to dust if overheated.

Bottom Housing - This is where all of the funk ends up. Everything from brush dust to cocaine-looking, bleu-cheese type of stuff. You will need to spend time cleaning this thing thoroughly. If you bead blast it, you'll need to take extra care to get all of the beads/media removed

Bushings - if you feel excessive play in the upper bushing, it's time to replace it and the seal. Not sure exactly where to find replacements yet. Last time I checked Suzuki didn't list them. Next time I have a starter apart I'll have to measure them up and get some replacements.

Cleanup                     Upper Housing - take a few minutes and run a tap through the 2 holes the long screws go into. You'll see why later.

      • Mount the armature in a drill press an turn it on low. Use a piece of 3M cloth and clean up the contact surfaces. If your surfaces aren't nice and flat, then you should do this step in a lathe and cut them flat again.
      • Also take the time to clean out the Mica between the contacts. If you don't have a proper cutter, then you want to use the back side of a razor knife (square edges) to clean out the grooves. The idea is to cut a square groove rather than a U-shaped groove. Here's an old unit I use to cut mica.

Here's what it looks like with clean contacts.

      • Moving on the the lower housing - degrease this thing completely and then take a wire brush and clean off the 2 mounting pads that the starter plate bolts to. Nice-clean aluminum is what you want

Main body - if everything looks good (except for the brushes), then you're good to go. If your starter was burned-up it's time for some new field coils. If there is severe corrosion, then it's time to completely disassemble this unit, beadblast everything back to bare metal, reassemble and repaint outside (after assembly). Take extra time to make sure the O-ring grooves are clean. Then use a DAB of grease on the o-rings and reinstall.

Brushes - What Now?      So you found that your brushes are worn. If all 4 are worn, the fix is to replace the entire brush/plate assembly. If only 2 of yours are worn, you can just replace 2. My experience is that it is just as easy to replace everything as it is to just replace 2. Your mileage may vary.

Here's one with fairly new brushes. However, look how they're mushroomed out (lots of heat). I took a little time and squared them back up and was good to go.

Reassembly                 Put the upper mounting plate in the vise with the bottom facing up. If your armature is till in the upper mount, skip next step.

      • Put a tiny dab of lightweight machine oil on the shaft and slide armature into position - don't forget those thrust washers. I said a TINY dab of oil. If you use too much, it'll run down and contaminate the brushes. Same thing with WD-40 or other penetrating oils.
      • Install field coil assembly onto armature. Use a brand new slightly-greased o-ring here. Use the mark you scribed prior to disassembly to line things up. Then begin feeding the brush assy down onto end of armature. Now, use a couple of screwdrivers to hold the brushes back while you push it down. Take your time and try not to nick any of the brushes. That is . . . don't force it - just fenagle it.
      • Take a moment to look at those wires/ends of the field coils. Make sure they're not gonna get so close to the housing that they'll short out. Maybe a little liquid 'lectrical tape is in order.
      • Install the thrust washers onto the armature shaft. Again - use a DAB of grease - but not so much that it will sling out all over the place.
      • Now put a DAB of oil on the shaft and slide the lower housing on. Don't forget abotu the other slightly greased new O-Ring here. Use the scribe marks to position correctly.
      • Step 6 - I always use new fasteners and O-Rings on these starters. There are 2 different sizes of O-ring and I put a rub them with my greasy fingers prior to assembly (less than a DAB of grease). I start the 2 shorter screws first and snug them down lightly - then install the longer screws.
      • Tighten-down the 2 longer screws (flatblade) by hand first - then the 2 shorties. Now, take your Hand-Impact Driver and "set" the screws. Looking for 1/4 to 1/2 turn when using new screws and O-rings. Don't break them off, but get them seated snugly. Don't hit your finger/hand with the 3lb hammer either.

Bendix and Spring Replacement  My least favorite part of a starter rebuild. Flip starter around in the vise that that the top is up (sounds weird huh?)

      • Slide new bendix in place followed by the spring and retaning cup. Say a few kind words now. sealed 
      • Use a small hammer and get stopper ring started onto shaft. Figure out which deep well socket size will be necessary to hammer if down all of the way.
      • Start cussin', tapping, holding, and whatever it takes to get that damned ring into the slot. Now, try to figure out how to clamp it back down enough so that the stopper can get popped-back up into positon.

I really don't know what the proper procedure is. I'm assuming the starter rebuilding guys have a special (pneumatic) tool for it.

Bench Testing              Re-install the solenoid making sure that the braided cable has enough clearance. Don't want it shorting out or anything.

Now, hook up a batter directly to the starter. Touch the small wire coming off of the solenoid to the hot (+) side of the battery. Initially, let it spin for 4 or 5 seconds. I do this 3 or 4 times - trying to let the new brushes seat themselves onto the cleaned (and squared) armature. The brushes are square and the armature is curved, so it takes a few revolutions for the brushes to wear-in.

Reinstallation               Paint that starter if you want to. However, you will want the lower mount to be cleaned-off on both sides. That way the battery ground strap will have a nice clean plath.

      • Before dropping the starter in, take a minute to clean the terminals to the point that you see clean copper or aluminum. SHINY - that's what you want. I have found that the little plumber's brushes work great. You can get them at Lowe's or Home Depot and they come in several sizes (from 1/2" up to 1 1/2"). Much easier to work with than standard wire brushes.
      • Drop the starter in, hook up the battery ground strap to the lower starter mount, and away you go.

Oh By The Way . . .       Even after going through all of the above I have had starters that just wouldn't operate correctly. They either spun slowly or would disengage prematurely.

I dunno why - but sometimes a wetbike will just make you look stupid.





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