Starting & Starter Problems
New starters, substitutions, fitment problems.
Bosch; Valeo; Denso..... Starter motors. Overhaul?
Converting to/from Bosch, Valeo, Denso.
Starter relays, starter solenoids, notes, advice, etc.
© Copyright, 2012, R. Fleischer
For more information:
BASICS: How the starter circuits & associated parts function
The starter motor is a powerful electrically operated motor. The starter motor may have to provide upwards of 1/2 to 1 horsepower in quite mild temperatures with modest compression engines,...& even much more when the engine is quite cold, & has thick oil. The starter motors in our Airheads, like all vehicle starters, are not very efficient motors. The Valeo is more efficient than the Bosch.
Quite a lot of amperes might be needed under some rather common conditions. Starter motors of any kind for our motorcycles are, at best, 60% efficient due to magnetic field losses, friction losses, etc. 745.7 watts is DEFINED as ONE horsepower. If the system is a nominal 12 volts during cranking (typical, with good battery, wires, and connections, as read at the starter terminals), then 745.7 divided by 12 equals 62 amperes. Due to the efficiency losses, & the need for many more amperes to BEGIN engine rotation, it is NOT uncommon to require 150 amperes OR MORE from the battery.
I said that starter motors are not very efficient. BUT, what does 'not efficient' MEAN? The power rating of the most powerful of the three Bosch units used on the Airheads was 0.7 KW. 0.7Kw is 700 watts; divided by 12 is 58 amperes. Not bad, eh? BUT, notice that the starter is also rated at
320 amperes. That is the supposed maximum drain under a severe load. That is equivalent to 3,840 watts....and
is equivalent to a bit over FIVE horsepower. The battery, cold day, thick oil, so-so starter, ETC., may need
to provide a LOT of power!
There must be a means of switching on/off the large amount of current to the starter. A heavy-duty solenoid-operated switch is physically located on the starter. It is a fairly large round cylinder with electric terminals of the bolt/threads type, and this cylinder is mounted on the starter motor. This massive switch obtains +12 volts electrical power from the battery via a large diameter copper-conductors-cored cable. The starter motor is grounded to the engine aluminum case. The transmission is bolted to that engine case, so the transmission is electrically the same as the engine case. The battery's other connection (-) is to a hollow bolt at the rear right side of the transmission...that bolt secures the speedometer cable in place, provides venting for the driveshaft & transmission & provides the place for grounding the large diameter black-colored battery negative wire...which is, in essence, connected to the starter motor body and starter solenoid switch body....providing the -12 volts from the battery. Thus, the battery provides both + and - current to the CIRCUIT. As you have learned in Basic Electricity, you must have a "complete circuit". Anything in this circuit, that is not in good condition, can be restrictive to electric current flow. That is seen rather too often in poor wire connections to the battery.
There is NO FUSE. THAT is common to all vehicle starter motor primary circuits.
The starter solenoid itself is activated by a rather modest current delivered from a small starter relay. That small starter relay is located along the top frame backbone. With the ignition key ON, and assuming any KILL switch is in the RUN position, pressing the starter button will cause the starter relay to close its contacts, which sends +12 volt power from the starter relay via a fairly thin BLACK wire that goes to the male SPADE terminal on the starter solenoid unit. The starter relay is, therefore, a small relay that sends electricity to another much larger relay, called the solenoid (solenoid relay). The electricity causes a substantial magnetic field in the solenoid coil.
The physical center
of the coil has a large round piece of steel that is moveable.
Somewhat nerdy, and rather unknown by most:
The "coil" in the solenoid is actually a dual coil, with two ends connected, so it is a three terminal coil. The reason is that the current just described is INITIALLY applied to the section of the coil that draws a fair amount of current, and is called the 'Pull-in Coil'. This very substantial magnetic field moves the large steel slug. One end of the steel slug has insulated contacts or a contacting strip which is pushed towards large copper contacts & the pressure causes those contacts to be jumpered or think of it as being pushed-together. Once jumpered, the large battery cable at the solenoid can now pass a very large flow of electricity into the starter motor. At the same time, the pull-in wiring inside the solenoid switch disconnects, as it is no longer needed, and there is then no excessive heating by the pull-in coil current. The second coil of the dual coil is a STAY-IN coil that draws less current and will not overheat. Its purpose is to keep the solenoid piece pulled-in and the massive switch in contacting (shorted) position; so long as your finger is still pressing the starter button. In your Airhead, the starter solenoid is simply a high power electro-mechanical switch. The starter motor now receives a large current flow, and begins to rotate, suddenly, and powerfully.
A mechanical device called, generically, a 'Bendix' or Bendix drive, is on the starter motor shaft so it too begins spinning. It is located on the rear of the starter motor on the starter motor shaft. This device, via spinning forces & guide grooves, moves suddenly and very quickly rearward... with quite considerable force. As it moves towards the rear it engages its teeth into the engine flywheel teeth. The teeth of the Bendix drive, & on the flywheel gear, are shape-designed to enable quick meshing at high levels of force. The flywheel is called a Clutch Carrier in models from 1981. The teeth are actually part of a steel gear, of very large diameter, and with specially shaped teeth. That is called the Ring Gear. It is heat-shrunk or otherwise fastened securely onto the outer diameter of the flywheel. Engagement of the rotating Bendix drive teeth and the ring gear teeth, causes the engine to rotate. It is the inertia and centrifugal force (centripetal if you are a purist) that 'throws' the Bendix drive backwards, to engage the flywheel.
Early Airheads were equipped with Bosch starter motors without speed reduction gears and they contain field coils. Late model Airheads had a Valeo brand of starter motor which has permanent magnets instead of field coils like the common Bosch has. The Valeo starter motor has a planetary type of reduction gear inside its nose, which allows the starter to develop higher rpm and hence higher power. Early Valeo starters had problems with the magnets coming loose (they were epoxied to the housing).
Types of Bosch starters, differences, flywheel teeth differences, etc:
There are at least THREE types of Bosch starters used on the Airheads as original equipment.
I say at least three,
because there are some rare instances of other models used on
The number of teeth on the starter's Bendix gear & the engine flywheel, are always, on early Airhead models, 8 teeth on the starter with 93 tooth flywheels. The later Airheads had 9 teeth on the starter used with 111 tooth flywheels.
Thus, the early Airheads had a 93/8 gear ratio, which is 11.625; and, the later Airheads 111/9 ratio is 12.33. This later higher ratio enables the '9 tooth' Bosch starter to develop a fractional amount more horsepower, mainly because it can spin faster. The stock Valeo starter also uses this ratio, but contains a planetary gear set that enables the Valeo to internally spin even faster, developing a bit more horsepower than the last of the Bosch designs that BMW used.Bosch starters, details:
Valeo starters were installed on later motorcycles; all are 9 tooth; early ones were troublesome; the
glued-magnets came loose and 'locked-up' the starter. See www.euromotoelectrics.com for fixes or updated new ones; or, see your favorite independent BMW repair shop, such as Ted Porter's Beemershop.
Problems starting BMW Airhead motorcycles can often be traced to a bad battery or its connections, but there are other possibilities:
1. Poor contacts on the starter relay under the fuel tank. This can be sometimes be repaired by opening the can and burnishing the contacts. It is possible for you to hear this relay's faint click, and yet the contacts are not making electrical connection. Very rarely, the relay has corrosion INSIDE the base. In many instances YOU CAN repair the relay.
Commonly, the starter relay has faint corrosion on its EXternal male prongs, & in its socket (on models having a socket). Cleaning external connections will cure the No-Start-NO-Click. A permanent fix is to JOIN, very cleanly & neatly, & insulate afterwards, all the RED wires (usually 3) at the socket. The reason joining the EXTERNAL red wires works is because there are two terminals on the relay for these wires, and the jumpering occurs INSIDE the relay, thus any problem with the EXTernal spade connections will act like the relay is not there.
2. Poor solenoid (located on the starter motor) internal contacts. A replacement is best; but I will have more to say later, herein, about how you might be able to repair one.
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.
4. Early Valeo starters had a nasty habit of the glued-in-place field magnets coming loose & jamming the starter. Some have rebuilt them using Saturn car starter parts. Better to change to a Bosch like the earlier Airheads had...or, get an updated Valeo, or EnDuraLast, or Denso, ETC....which are the easiest things to do. BE SURE you read the rest of this article, where, near the end, photos show some things to know.
5. You CAN change the original Bosch Starter to a late model improved Valeo. You may have to do a SMALL amount of metal work (just simple filing), described later in this article. Be SURE to get the appropriate 8 or 9 tooth starter. Same, regarding metal work & 8 or 9 teeth, if converting to the Denso ...or any other....starter. I check this metal interference fit even if just replacing with the original brand of starter, or even if just overhauling the original starter.
6. A more expensive solution is to install the modified Denso starter that is available from numerous sources. I am not convinced it is worth the large cost. Distributed/Sold by Motorrad Elektrik, www.motoelekt.com; and possibly available from such as Ted Porter's BEEMERSHOP, etc. These are modified-nose versions of the DENSO-made starter used on Toyota's, etc. Possible interference problems with this starter, & need for some mild metal filing/grinding, is shown with photos, at the end of this article. A MINOR possible problem.
7. http://bmwmotorcycletech.info/electricalhints.htm has further information on problems with the starter circuits. There is more information, such as for the /5 problems, also in that long article.
See also: http://bmwmotorcycletech.info/startingprobs.htm
WARNINGS!.....>>Fitting a starter motor; breaking nose castings; ETC.
Failure to properly fit ANY starter, squarely and solidly/securely, to the cradle in the
motorcycle can lead to a broken starter nose.
The Bosch starter MUST have the forward plate affixed and tight to the bracket and engine. 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 with the heavy Bosch.
Do NOT "assume" anything. Never install a starter motor, any brand, without carefully checking how well it fits into the engine case cradle. This caution applies to the original starter, and any replacement. THE END AREA OF THIS ARTICLE HAS DETAILS ON EASY FIXING OF ANY INTERFERENCE PROBLEM.
If the starter motor bearings are quite bad, that can cause tilting of the armature, not good for the starter nose, and not good for the starter Bendix drive, flywheel teeth, etc.
Other problems include a bad starter ring or fitment on the flywheel/clutch carrier, & too tight a clearance between the Bendix gear and the ring gear. These are rather rare, IMO.
If your bike kicks back (or, backfires backwards), that can be VERY hard on the starter, and the problem needs immediate attention.
Some engine cases, especially early engine cases, may need some filing to ensure a proper fit. Further down this article are some of the interference problems found on starter fitment, but these are not necessarily the same fitment problems found with starters back in the seventies.
Later model Airheads (AFTER 1984) use a starter relay with a diode inside. Some folks have substituted a 0-332-014-118 relay (03-32-014-118), and some HAVE used a DF005 'Blazer' relay from AutoZone stores (which has two 87 terminals & no 87a terminal). 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; & with late models with 2 diodes in the relay, so ask ON THE AIRHEADS LIST about it. Complications, if any, are easy to deal with, so don't be discouraged with my remarks here.
BMW has an SI on retrofitting the Valeo starter on 1985-1988 bikes that came with Bosch starters. BMW says that the original starter relay contacts are not up to the larger current draw of the Valeo SOLENOID COIL. It is my belief that the original relay will usually be OK most of the time; HOWEVER, you certainly do not want its contacts to stick together. If you want to install a relay with larger current capacity, see this document, which I have here in pdf format for you: http://bmwmotorcycletech.info/Retrofitting Valeo Starter-2383.pdf ...OR, install a common relay as in the prior paragraph. This is applicable to 1985-1988 models officially; so if you install a Valeo in earlier models, ALSO pay attention! That SI does not have ALL the information...but I do:
If the original starter relay is 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. I have heard of sticking relay problems, but maybe only rarely, since I began working on Airheads! So, it is likely a 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 much more likely to be only with 1985-1988 models; due to a change in the relay internals construction that is NOT mentioned by BMW. It is possible that lengthy starting can tend to overheat the relay contacts.
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 & the Valeo solenoid coils under
actual starter use; they are NOT excessive & are just about equal! The inductive kick-back voltage
is also comparable. This 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 & burnish
the contacts. It is my belief that the problem, if there really is one (per BMW), that it is confined to SOME of the 1985-1988 models.
Bosch Starters used on BMW Airhead motorcycles:
Be sure to use the Bosch (or other) starter with the proper number of teeth to match your flywheel or clutch carrier!!!
If you decide to use some starter from a car, salvage yard, etc....be SURE the starter has the correct direction of rotation, and will fit. If a Valeo, be sure the field magnets are secured. I cannot recommend you go to a salvage yard, except in an emergency situation, or you are hardly able to pay the INexpensive price for a new starter from such as the company's I have previously mentioned.
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, reasonably rugged, reliable, but less powerful than the "permanent magnet high rpm with planetary gear type" like the Valeo. A property of the Bosch field coil type is that as it 'sees' a heavier & heavier load (cold engine, thick oil, high compression engine, etc), it draws more & more current, producing more & more power. Still, the ultimate power from the Bosch starters under most conditions is less than the Valeo, which spins faster, & has the planetary gear reduction drive inside. I consider it a tossup as to which is better, considering all factors. The Valeo parts are less rugged, but that appears not to be any big factor, even over many miles, at least with the updated type with the secured field magnets.
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 had NO reports of
any loss of magnetism. I suggest ignoring this 'supposed' problem.
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 with the heavy Bosch. When installing a Valeo in place of a Bosch, you do not use the the plate nor bolt. The Valeo installation is ~ 6 pounds lighter than the Bosch. Do NOT throw away that mounting plate, someone, or you, may want it. When installing ANY starter be especially careful that the starter is properly & squarely mounted, you want to avoid breaking or otherwise cracking the nose (the casting that is the rear part over the flywheel) during operation. Be sure the mounting cradle, nose area, etc., is CLEAN of filth and there is NO proud metal, etc. See later on that subject in this page!! This caution on fitting INCLUDES the original starter!
The Valeo Starter & some Bosch information:
The magnet failures on the early Valeo's are well-known. Using epoxy to glue magnets may have its place in this world, but there were lots of failures, especially in Airheads where the starter is subject to so many repetitive heat-cool cycles from engine heat. I do NOT like the ideas of epoxies being subjected to constant wide temperature changes, their expansion-contraction rate is different than the surrounding metal. The starter in an Airhead does, remember, sit right on top of the engine, inside a cover! The constant heating/cooling cycles can crack or otherwise ruin the bond of the glued magnet. Valeo addressed this problem (in 2001) by changing the type of glue & reshaping the side of the magnet that fits against the starter shell. Late manufacture Valeo starters are adequate & seem reliable. BUT: 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 (rare, never seen one), work fine in cars. The proper aftermarket Valeo's with the updated magnets, bonding, & clips, are available fromwww.euromotoelectrics.com and from such as Ted Porter's http://beemershop.com. Watch out for cheaper made & cheaper construction "Chinese" starters, being sold, UNbranded, in place of a real Valeo.
You may run into information leading you to think about using a Saturn or some other automotive
Valeo 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.
NOTE!.....it is possible to miss-fit a starter, and the nose cone does NOT break immediately. That is rather common for the broken nose situations.
Here is a link to an article on working on the Valeo starters: http://largiader.com/tech/valeo/. Use only the images and text for them. The article does not get into some deeper technical matters, but will be useful to you if you have not taken a Valeo apart before, & want to do maintenance to fix loose magnets, or replace worn planetary gears, clean/lubricate, etc.
Going from a Valeo to a Bosch and vice-versa:
BE SURE you use the proper number of teeth on your starter motor, to match your flywheel! If you decide to change your failed Valeo to a Bosch: Brand New Bosch's are very pricey & probably not available. If you want a Bosch, and yours is not, you can try to find a cheap good used one, & rebuild it if needed. Generally you need only a set of brushes & bushings (bearings) & a solenoid assembly. If the Bendix drive is questionable, replace it. The solenoids can often be rebuilt, 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 & use the forward bent metal plate when using the Bosch.
The 'Bendix' drive should be clean & lightly lubricated. Some use a silicone grease due to its general non-hardening & wide temperature range. I have some mixed feelings about the use of silicone's on fast moving parts, & maybe a lightly laced moly grease is better...I am NOT sure about this. Starter rebuilders may have ideas. I personally have used a faint coating of common wheel bearing greases, and this works fine.
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 & hardly noticeable, ...to more moderate. The problem comes about because the starter nose machining is NOT EXACTLY the same between the Bosch & the Valeo starters, & BMW was, perhaps, a bit more careful about machining the engine case when the Valeo was installed as the stock starter. It is my belief that when BMW shipped Valeo starters on the later Airheads, that the machining on their Valeo nose might be very slightly different. I have not made enough measurements to prove this.
I strongly suggest that ANY time you replace or even re-install, ANY starter, that you
CAREFULLY check its fitment!!
There have been instances of a starter poorly fitted, & the
nose broke! Remember, the forces are HIGH.
I THINK that most metal interference problems will be seen only when installing a Valeo in place of a Bosch, but I am not 100% sure about that. There were instances of the Bosch having problems with broken nose cones in the seventies models. Best to check, find any interference ....and using a common file, or simple rotary grinder, fix ANY potential problem.
My advice here is generic, & assumes you will check fitment of any & all starters, that includes the Bosch, the Valeo, and the Denso....and no matter what HAD been fitted. This includes refitting the same starter! I think that anytime you remove & replace even the same starter that was in the bike....that you should check for the proper fitment. This is particularly so if the nose cones have been breaking. They should NEVER break.
I suggest your CHECK the fitment before you remove the old starter....and then, 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 teeth. On some Airheads, BMW may not have cleaned up 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 might not fit perfectly, may not want to go fully downwards at the nose
area & the Valeo threaded bolt holes (or even Bosch unthreaded ones??) may not
line-up perfectly. Inspect carefully, & 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, & then the Valeo (Bosch?) SHOULD fit/mount correctly.
The Denso fitment problems:
It was reported to me that the Denso aftermarket starter, such as sold by
Motorrad Elektrik, etc, does not, or may not, fit perfectly. I obtained a photo. The installer noticed TWO problems with metal interference:
1. Light interference with the solenoid to a rib on underside of the starter cavity cover (sorry, no photo on that).
2. Interference at the mounting ear on the back cover. In the photo, below, you can see that the ear has been ground down so as to give about 1-2 mm of clearance between the crankcase and the starter ear.
Overhauling the Bosch Starter Motor & Solenoid Switch:
Bosch starters are used in a variety of makes/models of vehicles. Sixties & Seventies
VW's, for one example, use similar starters to the ones in Airheads. They vary some,
but are mostly the same. So, it is not difficult, even at some auto-parts stores, to get
parts. I do, however, suggest you get them from
or Ted Porter, http://beemershop.com
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 (there are two windings) should be considered as 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. IF THE SOLENOID CONTACTS ARE REALLY WORN OUT, IT IS BEST TO REPLACE THE ASSEMBLY, ALTHOUGH NERDS LIKE ME HAVE MADE NEW CONTACTS & CONTACT PLATE. Most of you will just replace a solenoid switch as a normal matter when overhauling a Bosch Starter. But, for those of you that wish to try to fix or improve such a switch, I include the details here. See the photo, below.
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 mass will work. It is the MASS of the tip that
is important. A very large soldering gun (perhaps the 275 watt size) might work OK.
You undo the 2 screws as shown; 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 & 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....& the mating contacts held to the solenoid with a funny 'nut'. I usually don't bother disassembling further on the plunger side.
Clean the contacts in the cap & at the end of the plunger. You can use a very small
rotary stainless steel or brass cone-shaped brush, that you can put in your drill press
or electric drill. They remove very little material if used BRIEFLY and with not too much
pressure; this takes only a few seconds at modest rpm. Other methods will also do,
such as a flat end of a piece of doweling or other tool, covered in 220 grit sandpaper.
Use what you want to, but do not make deep scratches....you want a smooth clean
surface of maximum contacting area. You MUST keep the contacts FLAT & square to
the assembly, so maximum contact surface will be obtained.
There are 4 thin solid copper wires that have a thin enamel coating for insulation. The paired wires (push the insulation back a bit if you need to, to see it is a pair) go to the SPADE terminal that has a black wire to the starter relay. You've already marked the case and cap so you won't mix them up, right? There is one wire that is spot-welded to the metal end case; that's the ground wire for the HOLD-IN coil. The single wire next to it is the one that goes to the starter & one of the large solenoid switch contacts. You did note where the wires went when you removed the cap? If you goofed & did not mark the cap & 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, & the wires go to the correct terminals! You can assemble the cambric ring & the wires to the cap, & lift the cap a wee bit, & 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 pegs) to the plunger side of the solenoid unit carefully, using #1 eyeball; 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 & 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 (#30) on the solenoid. Connect the - terminal of the battery to the starter body...such as a nose mounting ear. If you get a small spark from this, you miss-wired the solenoid!
Hold the starter strongly...it will tend to jump around as it starts!..... using a jumper wire or screwdriver, etc, momentarily connect the SPADE terminal to the + battery connection at the solenoid (#30). The solenoid should clicking strongly & loudly & the starter should run.
Another test is that you can use an ohmmeter instead of #1 to #6. Disconnect the battery.
With unit NOT attached nor connected to the starter motor:
Moderately low ohms: terminal 50, the male spade terminal, to the case. LOW ohms: Terminal 50, the male spade terminal, to the solenoid large terminal that goes to the starter motor.
Overhauling the Valeo:
I was going to write up how to do this, but a fairly decent article with photos is on Anton Largiader's website, so here is the direct URL:
Valeo starters can be purchased fromwww.Euromotoelectrics.com. They have parts for Valeo, and Bosch, & many other things. I highly recommend them over Ace Houston Warehouse, which is mentioned in Anton's article as well as the one you are reading, well above this area. Another quite good source is: http://www.beemershop.com
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 URL spelling for euromotoelectrics
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: photo of the metal interference problem. Clarifications & editing throughout article.
11/23/2009: reference to Anton's site for the Valeo overhaul, euromotoelectrics in that same area, etc.
04/25/2010: Add photo and information on the Denso problem
05/24/2010: Fix typo regarding forward plate that IS used with Bosch, NOT Valeo. Clarify minor details.
05/12/2011: Fix typo where word alternator should be starter. Add dividing line at one place to clarify a new discussion section that was confusing. Fix a couple of mis-spellings. Remove hyperlink to 'thisoldtractor site (that has removed the starter motor overhaul information).
08/04/2011: Fix note, DF005 relay now confirmed as substitute.
11/14/2012: Clean up article, separate sections needing such, add some minor details, fix whole article so will display a bit better on Chrome and Firefox, and on somewhat smaller screens.
08/11/2014: MINOR changes
02/16/2015: Extend, somewhat, the warnings
04/04/2015: Add information/section "How the starter circuits and associated parts really function:". This is the same section I expanded-upon, located in article startingprobs.htm. Expand testing. Fix wrong description on wire connections inside the solenoid assembly.
07/21/2015: Re-work section on starter/flywheel teeth vs model #, for more clarity. Cautions added 11/15/2015.
01/14/2015: Clarity. Metacodes. Left justify. Narrowing.
03/14/2016: Update again, due to problems with displaying differently, weird colors, etc., on SOME browsers.
05/14/2016: Fix typos/errors in paragraphs on watts versus horsepower and current drain.
©copyright, 2012, R. Fleischer
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Last check/edit: Saturday, May 14, 2016