The Bosch and Valeo Starter
motors!
overhaul; converting from a Bosch to a Valeo
(and vice-versa);
STARTER RELAYS, STARTER SOLENOIDS, ETC.
©
boschvaleostarter.htm
article 16-A
Problems with starting can often be traced to:
1. Poor contacts on the starter relay
under the fuel tank. These can be repaired by opening the
can and
burnishing the contacts.
It is possible for you to hear this relay click, and yet the
contacts are not making electrical connection.
2. Poor solenoid (on starter motor) internal contacts.
A replacement is best; but I will have more to say
later, herein, about how
you CAN repair one yourself, in most
circumstances.
3. The starter itself may have worn brushes, worn bush/bearing, poor drive gear
assembly, or an armature that needs undercutting
at
the commutator and truing on a armature lathe. It may
also be heavily grunged-up with dirt/filth. On
some BMW's, the starter
is the ground return for the headlight
relay coil, another complication.
4. Early Valeo starters had a nasty habit of the field
magnets coming loose and jamming the starter. Some have
rebuilt them
using Saturn car starter parts. Better to change to a
Bosch...or, get an updated Valeo, which is the easiest thing to
do, and
not expensive, from
www.euromotoelectrics.com
5. You CAN change the original Bosch
Starter to a late model improved Valeo (see 4.). You may
have to do a tiny bit of metal
work, described later in this article. Be SURE to get the
appropriate 8 or 9 tooth starter!!!
Starter relays:
Some later model Airheads use starter relay
with a diode
inside. Unconfirmed information is that some have substituted
a
0-332-014-118 relay, perhaps a DF005 'Blazer' relay from AutoZone
stores. The Bosch starter relay uses two #87
terminals,
and may sub to Bosch 03 32 019 150 for 1977+ bikes. That is a common Bosch
accessory use relay. Connector,
if you need one, is 0 334 485 007, while
the spring loaded terminals are 1 901 355 917. It is
certainly possible to substitute
almost any common 20 or 30 ampere 12 volt relay for the starter
relay on
Airheads, but there are some
complications,
such as with the /5;
and with late models with diodes in the relay, so ask ON THE
AIRHEADS LIST
about it. Complications,
if any, are rather easy to deal with, so don't be discouraged
with my remarks here. MORE information on starter relays
later
in this article!!
There is an aftermarket starter available,
the most prominent being a modified nose model.
Distributed/Sold by Motorrad Elektrik,
www.motoelekt.com; and
possibly available from such as Ted Porter's excellent BEEMERSHOP.
These are modified nose versions of the DENSO-made starter used
on Toyota's, etc.
Types of Bosch Starters:
There are at least THREE types of Bosch starters used on the airheads
as original equipment:
Bosch starters up
through 1974 were 8 tooth 0.001.157.007, rated 0.5 hp and 290 A. The /6
bikes for 1975 and 1976 used
an 8 tooth 0.001.157.015 rated 0.6 hp and 320
A. The 8 tooth starters are used ONLY with the
93 tooth flywheels; and are
for all practical purposes, interchangeable.
For 1977
and later, the starter
has to be 9 tooth, for use with the 111
tooth
flywheels (or more properly called the clutch carrier from 1981).
The starter is 0.001.157.023, rated 0.7 hp and 320
A.
Solenoids, unconfirmed, seem to be the same as EARLY air-cooled
VW.
When overhauling a Bosch, I usually replace
the
Bendix, the bearings, the brushes, undercut the armature and
make
sure it is round and semi-polished, and replace the
solenoid assembly. Your choice on what you do.
NOTE: The "Airheads
Beemer Club" had an account with Ace Houston Warehouse, a
wholesaler/importer/remanufacturer, ETC.
The Club account is #700.
Call Bob Spencer at 1-800-392-3332 or e-mail to acehoutx@flash.net.
Mention account 700.
The Valeo starters are available. Per information I
received from a fellow Airhead, the part was
D6RA15, Valeo changed it to
432586. This is supposedly a brand
NEW starter. There was no core charge, but they will might
pay shipping to get your old
one.
I do NOT know if this is the latest updated Valeo with the safety
clips for the magnets!! They may still rebuild Bosch
starters, last price
I got was $200 and a $100 core charge and shipping (core charge
refunded).
Bob Spencer thought that
the Bosch starters MIGHT be put back into production at some
point. Quite frankly, I don't have a good reason to
deal with
these folks.,....and I have had NO dealings with them. I
consider the prices a bit high....and I think their stock of
starters may
be getting thin anyway. NOTE! The above is supplied as a
courtesy.
I
HAVE
had dealings with John Rayski at
www.euromotoelectrics.com and
I CAN recommend him for Bosch
starter (and other parts) and for Valeo starters (yes, brand-new
updated Valeo's) (Snowbum has purchased a
Valeo from him)....He has the
proper Valeo starters with the updated magnets and clips; his prices are good, he
offers
free shipping
(on some orders...and can be quite a savings on a
heavy starter)....and he is knowledgeable
about the use of these
in our airheads. He is the same person who makes and sells
the EnDuraLast alternator
conversion for BMW airheads and for MotoGuzzi's. He can supply you
with proper spark plugs
and a lot of
other things. Look at his website:
www.euromotoelectrics.com
Although I
have a wholesale account with John, I am no longer in the
business of supplying parts and services,
except in a rare instance. I prefer you go to such as Ted
Porter's Beemershop
www.beemershop.com
or direct to euromotoelectrics.
Be sure to use the Bosch with the proper number of
teeth. The Bosch starters
have a bent metal plate at the forward end,
using
one bolt to the timing chest wall. This supports the starter to the timing
chest wall, needed on the Bosch. When
installing a Bosch in place of a Valeo, you do not use the the plate nor bolt, and
the Valeo installation is maybe 6 pounds
lighter than the Bosch. When
installing a starter be
especially careful that the starter is properly and squarely mounted,
you want to avoid
breaking or
otherwise cracking the nose (that casting that is the rear part
over the flywheel) during
operation. Be sure the mounting
cradle, nose area, etc., is
CLEAN of filth and proud metal, etc.
See later on that subject
in this page.
The Airhead Bosch starter uses ELECTROmagnets, not permanent magnets, for the field coils.
Bosch does make a
permanent magnet starter, but I have never seen one in the
Western Hemisphere.
The Bosch electromagnet starter is very old-fashioned technology,
rugged, very reliable, but less powerful
than the permanent
magnet type like the Valeo. A nice property of the
Bosch field coil type is that as
it 'sees' a heavier and heavier load (cold
engine, thick oil,
etc),
it draws more and more current, producing more and more
power. Still, the ultimate power is less
than
the Valeo, which spins faster, and has the planetary gear
reduction drive inside. I consider it a tossup as to
which
is better, considering all factors.
It has been theorized that the Valeo permanent magnet type MIGHT
loose some magnetism over TIME and USAGE.
However,
they
have held up surprisingly well....and I have NO reports of this
problem. I would suggest ignoring the idea
of this problem.
The Valeo Starter, and some Bosch information:
We all know about the magnet failures on the
early Valeo's. Frankly,
epoxy-gluing magnets may have its place, but there
were lots of failures,
especially in airheads where the starter is subject to engine heat by direct
contact. I do NOT like the
ideas of epoxies being subjected to
constant wide temperature changes, their expansion-contraction rate, AFAIK, is vastly
different than the surrounding metals. The starter in an airhead does, remember,
sit right on top of the engine, inside a cover!
The constant heating
and cooling cycling can crack or otherwise ruin the bond of the magnet glue.
Valeo addressed
this
problem (in 2001) by changing the type of glue and reshaping the side of
the magnet that fits against the starter shell.....and
late manufacture Valeo
starters are adequate and seem reliable.
There is an aftermarket
type of Valeo housing available
with a modification to help keep the magnets
from moving,
spring-type separating pieces (clips). Valeo permanent magnet
starters....as well as permanent magnet starters from many
other
manufacturer's, even Bosch, work fine in cars.
The proper
aftermarket Valeo's with the updated magnets,
bonding, and clips, are available from euromotoelectrics.
In the past I have been outspoken in that I personally
preferred the Bosch electromagnet type for our airheads. However,
I am
open-minded on the latest Valeo starters....and think them now OK....so, if you are making a decision between
overhauling your
Bosch, or replacing it with a Valeo.....or; replacing a Valeo
with a Bosch....I no longer have any especially
strong preferences for the
Bosch over the Valeo (or the aftermarket Denso, for that matter).
For sure, overhauling your
existing Bosch starter is going to be much cheaper than replacing
it with a brand-new 'anything else'. The stock Bosch
starters are perfectly adequate.
NOTE: For starters, or for
parts for rebuilding, etc., see
www.euromotoelectrics.com, John
Rayski...as noted above.
This is for both Bosch and Valeo. John knows the in's and out's of
all of them, and has a stock of all the pertinent Bosch
and Valeo parts;
and has Valeo starters of the correct type in stock. You
MUST tell him if you need a 8 or 9 tooth starter.
The Bosch is a common starter for many starter repair shops, easily worked
on...but some may not have the parts for the
starter used in our
airheads.
You may run into information leading
you to think about using a Saturn housing
when rebuilding an original troublesome
Valeo. Unless you
are trying to save the absolute maximum amount of money, I recommend you
get a new upgraded version
Valeo from
www.euromotoelectrics.com
Or get them to fix you up otherwise.
Going from a Valeo to a Bosch:
If you decide to change your failed Valeo to a
Bosch: Brand New Bosch's are pricey and probably not
available. Try to find a
good used one,
and
rebuild it. Generally you need only a set of brushes and bushings (bearings)
and a solenoid assembly.
If the Bendix drive is questionable, replace it. The solenoids
can often be rebuilt too but I do NOT recommend it, although I
have
the information in this article. You may have to undercut the
armature, farm this out
or do it yourself, it is not difficult. YOU
MUST obtain and
use the forward bent metal plate!
Keep the Bosch 'Bendix' drive lubricated. I like to use a
silicone grease due to its general non-hardening and
wide
temperature range. But, I have some mixed feelings about the use
of silicone's on fast moving parts, and
maybe a moly containing
high temperature more common grease is better...I am NOT sure about it. yet. Starter
rebuilders may have ideas. I've not had
problems using my lubricants.
NOTE!: This is applicable to
1985-1988 models:
There is a POTENTIAL
problem, not commonly known, and there is even a BMW SI (Service
Information,
in other words, a Bulletin) on it, and the bulletin is 12-013-9
(2389). If the
original starter relay is the
61-31-1-244-019 (that's a BMW number, not a
Bosch number!), it contains a diode, and has other properties that
BMW thinks
do not match
the Valeo starter, & the relay contacts might stick.......and the starter
continue to run!
BMW says that the proper relay is 61-36-1-391-397, which has a higher
current
carrying
capacity, and a stronger spring to help the contacts open.
If you have to replace the -019
relay, BMW will supply the -397 relay.
It also has the diode
inside. Some have substituted generic 30
ampere relays.
NOTE that I have not
actually heard of anyone having this sticking problem due to the
starter-swap. I
have heard of it happening due to sticking relay problems, but
maybe only once
or twice since I began working on Airheads! So, it is a
very rare event. On the
other hand, it is my belief that if there IS a problem with
putting a Valeo into an
Airhead that came with a Bosch, that the problem is likely only
with 1985-1988
models.
To avoid
confusion, if you have a
pre-1985 Airhead, the
stock relays seem to
hold up just fine with the Valeo.
I
have MEASURED the current draw of the
Bosch and the Valeo solenoid coils
under actual starter use, and they are NOT
excessive, and are just about equal!
The inductive kick-back voltage is also comparable. The solenoid
coil current is the current
that passes through
the starter relay contacts. I would
not be
inclined to replace the
early stock relay,
although I might open
it and burnish the contacts. Again..it is my belief that
the
problem, if there really is one (per BMW) is confined to the
1985-1988 models.
When
retrofitting a Valeo to a BMW Airhead that had come originally
with
a Bosch starter, there can be an metal interference problem, which can
be
very slight
and hardly noticeable, to more moderate. The problem comes
about because
the nose machining is NOT EXACTLY the same between
the Bosch and the Valeo
starters themselves, and BMW was, perhaps, a
bit more careful about
machining the engine case
when the Valeo was
nstalled as the stock starter. It is my belief that
when BMW shipped their
own Valeo starters on the later Airheads, that the machining on
the Valeo
nose might be very slightly different. I have not made
enough measurements
to prove this, but it is unimportant anyway, as
I strongly suggest that
ANY time
you replace ANY starter, that you CAREFULLY check its fitment!!
There have
been instances of a starter poorly fitted, and the nose breaking!
MY ADVICE:
Whilst I THINK that this metal interference problem will be seen
only when
installing a Valeo in place of a Bosch, I am not sure about that.
So, my advice
here is generic, and assumes you will check fitment of either
Bosch or Valeo.
After
you remove the old starter, LOOK carefully at the area the
aluminum nose
of the old starter had
recessed into, just forward of where the gear mates to the
flywheel (or clutch
carrier from 1981) teeth. On some Airheads, BMW may
not
have cleaned up any excessive metal over the
last 1/2" or so of the round
cavity, at the top inside
edge. When you try to
install the starter (probably this
happens only with the Valeo, but I am NOT sure about that), you may find
some combination of the following:
The starter does not fit perfectly,
may not want to go
fully downwards at that nose
area and the Valeo threaded bolt
holes (or even Bosch unthreaded ones??)may
not
line-up perfectly. Inspect carefully, and use a
half-moon fine file, or a small
electric rotary tool of some sort, to make this inside area
smooth at the top, with
NO metal that is 'proud' (or of lesser diameter, causing a reduced
diameter).
You
can feel this with a fingertip, and usually see it with your #1 eyeball.
I have personally
seen this and had to remove about .020" (+-), on both sides, at that
top area. This is easy to do, and
then the Valeo (Bosch?) fits/mounts correctly.
The Valeo, btw, as opposed to the Bosch, has threaded holes,
so you use the bolts
you had from the Bosch, sans nuts, from the rear.
Photo regarding the
possible interference problem:
note the excess material at the left. Don't worry if
you remove a bit too much material!

Overhauling the Bosch:
I originally had information on how to
do that, but not enough photos, and dropped those instructions
when I
found that there were several
places on the Internet that you could already find instructions on
disassembling and overhauling the Bosch starter. Here is
one of them. You will have to scan down the page for the
information:
http://www.thisoldtractor.com/gtbender/loopframe_electrical.htm#solenoid_cross-reference_-for_bosch_starters-
That article has a list of substitutes
for the Bosch solenoid too. I will add the Bosch number
0331 302 077 to that list.
These Bosch
starters are used in a variety of makes and models of
vehicles. Sixties and Seventies VW's, for
one example. They vary some, but are mostly the same.
So, it is not difficult, even at some auto-parts stores,
to get
parts. I do suggest you get them from
www.Euromotoelectrics.com ,
so you can be sure of getting the
correct parts.
Not shown anyplace that I know of, is how to overhaul a
malfunctioning solenoid switch.
That is because most people will replace the solenoid. A malfunctioning solenoid
that has an open winding is
not repairable. However, most
of the time the problem is poor contacts inside; although poor
contacts at the
brushes of the starter can make the solenoid act
like it was bad. Below are
photos of a Bosch solenoid unit
as used on our Airheads.
I have removed the terminal end cap.
To do so, you need a large soldering iron with a big tip.
Even a 35 watt
iron with a big tip will work. It is the MASS of the tip
that is important. A
very large soldering
gun (perhaps the
275 watt size) might also work OK.
You undo the 2 screws as shown,
and then put a slight to modest amount of pressure on the end cap
(as if
trying to remove it), whilst you heat the solder joints until
they release. Go back and forth to the soldering places;
until the cap comes
off.
Clean up the solder holes. It is
VERY important not to mix up which wire goes to what
terminal
hole!!!...so watch them as you remove the cap. DONT
GOOF HERE!!! The easiest way to avoid this is to
mark the end cap and body before removal!
Inside you will see the flat switch
contacts recessed in the cap you removed....and the mating
contacts held to the
solenoid with a funny 'nut'. I usually don't
bother disassembling further the plunger side.
BEST way to clean the contacts in the
cap and at the end of the plunger: Use one of the very
small rotary
stainless steel (or brass) cone-shaped brushes, that
you can put in your drill press or electric drill. They
remove
very little material, and it takes only a few seconds at
modest rpm.
An acceptable other method is with
the flat
end of a piece of doweling or other tool, covered in 220
grit sandpaper.
You MUST keep the
contacts FLAT and square to the assembly, so maximum contact
surface will be obtained.
There are 4 solid conductor wires. The
paired
wires (push the insulation back a bit if you need to, to see the pair)
go to the battery terminal, and the single wire
goes to the SPADE terminal.
DO NOT mix this up!
You've already
marked the case and cap so you won't mix them up, right?
There is one
other wire that is
spot-welded to the
metal end case. The single wire next to it is
the one that goes to
the spade
terminal. You did note where the
wires
went when you removed the cap? If you goofed and did not
mark the cap and body, the
information here
will
guide you to the proper fitment of the
wires before you re-solder.
When re-assembling, you need to be sure the solenoid contacting
plate fits into its mating cap depressed area
portion, and the
wires go to the
correct terminals! You can assemble the
cambric ring and the wires to the cap,
and lift the cap
a wee
bit, and rotate the tang at the far end of the solenoid, to line
up the contacting plate with
the cap cavity.
Push against the tang
end, holding the cap end, on your bench top, to be sure the
contacting
plate actually moves
into the cavity for it. Assemble cap (align wires and pegs) to the plunger side of the
solenoid
unit carefully, using #1 eyeball, and
test that the solenoid plunger
mechanically works OK with your fingers, then
screw the
cap on with the two
screws (locate the pegs!)...and THEN solder the terminals.
Use ONLY a very hot
large tip soldering iron. Use standard rosin core
electronics solder. Be careful to assemble
correctly!
The solenoid should be tested with it mounted
and connected-up to the starter.
Do the testing on the repair bench,
before you install the starter into the engine block. You
will need heavy gauge wires. Connect the + terminal of the
battery to the
battery large
threaded terminal on the solenoid. Connect the - terminal
of the battery to a starter nose
mounting
ear. If you get a small spark from this, you
miss-wired the solenoid!
Hold the starter...it will tend to jump
around as it starts!.....and, using a jumper wire or screwdriver,
etc,
momentarily connect the SPADE terminal to the
+ battery
connection at the solenoid. The solenoid
should clicking strongly and loudly and the starter should run.

Revisions:
02/06/2004: add link to /5 article; minor other clarifications
05/30/2004: add NOTE on the starter relay changes
10/27/2005: updated in numerous places
04/22-2006: add red note on Valeo
installation needing special relay
11/28/2006: correct spelling in this URL: www.euromotoelectrics.com
11/29/2006: Change to 16-A, and do minor editing (16-B is being
written)
04/28/2007: Fix actual hyperlink for euromotoelectrics, display had been
OK, link NOT.
09/28-10/1/2009: Update hyperlinks, clarify
some details that were unclear; re-arrange article a bit for
additional clarity, add
all the information on the Bosch Starter solenoid overhaul.
10/17/2009: update with photo of the metal interference
problem. Clarifications and editing throughout article.