Valeo starter overhaul

If your Valeo starter makes a screeching noise after starting the engine, it needs to be cleaned. Other symptoms of starter trouble vary, but inevitably the starter needs to be pulled apart for cleaning and inspection. If your starter has an electrical fault (not working, intermittent operation, etc), read Greg's article linked at the bottom of the page. If your starter has loosened magnets, read Alex's article. Contrary to what I've read on the web, I don't think the squealing problem is caused by the planetary gears as much as by the solenoid mechanism (plunger and pinion splines).

For reference, here are the internal parts, names used, and replacement availablity from BMW for the D6RA15 starter used on Airheads. BMW does not list any repair parts for the D6RA55 starter used on the Oilheads, but the brush sets and repair kit #4 will work. Differences are listed at the bottom of this page. At the time of writing this, replacement pinions, brushes, solenoids, etc. were available from BMW. Pinions and solenoids were about $120, and brushes were $10 to $20 depending on which kit you need.

1. Solenoid switch, 12 41 1 244 607

2.Clutch fork lever, 12 41 1 244 609

3. Starter pinion, 12 41 1 244 682

4. Repair kit, 12 41 1 244 611

5. Carbon brush set, 12 41 1 244 684

6. Spring washer, 12 41 1 244 623

7. Hex nut, 12 41 1 244 622

8. Repair kit screws, 12 41 1 244 613

9. Carbon brush set, 12 41 1 244 685

Tools needed:

Torx T25 or 4mm allen for removing the three motor housing bolts
Torx T20 for removing the solenoid switch
13mm wrench for removing the solenoid lead
8mm wrench for removing the brush assembly

Basic disassembly process

Remove the nut and washer holding the brush cable to the solenoid body.

Remove the three bolts holding the motor housing to the nose casting, and remove the T20 bolt holding the solenoid to the casting. The nose casting can be pulled away, and the motor body can be pulled away as well, leaving three basic parts: the casting, the motor body, and the steel plate frame. Note: there are weak rivets also holding the motor housing to the plate, but pry them apart and discard them.

Remove the remaining two T20 bolts so you can pull the solenoid switch and spring off. At this point you can slide the pinion towards the end of the shaft and remove pin holding the fork and plunger in place (it will probably fall out). Clean the plunger and the inside of the solenoid switch body.

If you are just trying to stop a "run-on squeal" you may not need further disassembly. By cleaning out the curved splines between the pinion and the starter shaft, and cleaning the plunger you can restore free operation. Be sure to flush with plenty of solvent and blow dry with compressed air. You may want to lube with a VERY thin coat of a moly-based grease, such as CV joint grease.

By removing the large circlip and prying the cover from the planetary gear housing, you can slide the gears out a bit in order to clean them better. Flush the gears with solvent and brush away all of the old grease that you can reach. Pack the gear housing with fresh grease (you don't need to use a lot), slide the shaft through, push the cover into place and reapply the large circlip.

Disassembling the starter shaft

If you want better access to the planetary gears or the pinion splines, you will need to remove the thrust ring from the end of the starter shaft as follows:

With a socket or equivalent, drive the outer ring down from its internal snap ring towards the pinion. In this picture I am using an item from a BMW toolkit to push it down.

Pry the snap ring away GENTLY (you may need to reuse it) and slide the thrust ring and pinion off the shaft.

Remove the large external circlip from the base of the starter shaft, and slide the shaft out through the planetary gearbox.

Reassembly is difficult at this point! After putting the retainer and the snap ring back on the shaft, you will need to push down HARD on the retainer and simultaneously squeeze the snap ring under it. The retainer and snap ring are partof the rebuild kit listed by BMW, but in truth I see very little advantage in removing these parts at all, because you can clean the parts well enough without it.

The remaining disassembly you can do is removing the brushes. I found this to be somewhat tedious and the brush holder assembly is fragile. By removing the two nuts on the end of the motor, you can pull the cover off and inspect the brushes and contacts. If you have had no problems, and the contacts and brushes look OK, I absolutely would not go any farther. If the contacts look badly arc-damaged or the brushes look too short, you will need to carefully study Greg's article before proceeding.

If you do a total disassembly of the starter, this is what you are likely to end up with (the solenoid body and nose casting are not shown here).

Some people prefer the Bosch starter instead; Greg's article below describes the basic differences in design. The Valeo is much lighter; about 2.8kg instead of 4.5 for the Bosch.

Differences between D6RA15 and D6RA55

Although the starters are very similar in construction, they turn in different directions because they are mounted facing in different directions on the bikes. So, the pinion and shaft differ in the direction of the splines and gear faces, and the commutator is wired differently. Of course the nose casting is different, and the reduction gear teeth are coarser on the 55, which makes every part in the drive line (commutator, gear housing, carrier/shaft, pinion) different. The 15 has a reduction ratio of 5.5:1 and the 55 is 5.6:1.

However, these parts are not likely to fail. The motor housing and the brush assemblies are identical, as is the solenoid switch, plunger, fork, and spring. The same rebuild kit (bushing, thrust ring, circlip) and brush repair kit will work on both. The bolt kit used on the 55 (if you want to replace the T25s with allens) will not work on the 15 because one of the 55 bolts is shorter.

Replacement

The D6RA15 has been renamed by Valeo to 432586. This is available from Ace Houston Warehouse for $155 to $175 depending on quantity. Contact Bob Spencer, 800-392-3332 acehoutx@flash.net and be sure to quote the Airheads Club account #700 to get the discount.

Parts not available from the dealer might be available from Tiedemann Auto Elektrik in Germany and from Euro Moto Electrics in Colorado. Euro Moto carries new magnet housings, which are not available from BMW.