Re: Starter Motor Tight on rebuild

Previously K Glassborow wrote:

Hi

I was with Lucas for 22 years and many of our low output DC motors and of course starters used sleeve bearings both ends, a tap on each side at each end while operating off load helped with freer running. It was a standard tweak to meet the maximum amp draw at no load. You need a little free end play, that wavy washer might be too restrictive? The comm end journal doesnt look great, is that just the pic or corrosion? Aim for 10-20 thou end play and it should be better.

Many thanks for the info. End journal needs to be cleaned up for sure as does the armature. I haven't done any of this as yet.

Previously peter_shand wrote:

Hello Mike

Can you clarifiy 'a real handful' can it still be turned by hand? or do you have to grip the gear with pliers?

When these motors are put together the thrust washers push the armature towards the drive end cap, against the drive end 'snout' that carries the drive end bush. This causes the snout to wear into the laminations that make up the armature.

I have seen this on every starter motor i have rebuilt, this wear WILL eventually let the armature windings contact the drive end cap, wearing through the insulation thus degrading motor performance. It will also contribute to the motors 'stiff to turnness'

The photo shows the wear evidence in the rotor laminations. the further photos show the contact between the windings and drive end cap.

Peter thanks for all the pics, a great help. A 'real hand full' is me having the armature gear end gripped in the palm of my left hand, and turning it, very tight although it will turn. I was looking more for the armature to be revolving just using my index finger and thumb, perhaps a false dawn so to speak? The pictures you have included match the wear I have on the windings and in the end caps. Does this mean the armature needs to be replaced? I did try the original motor before I stripped it and it was turning over using a car battery and HD starter leads. It was about the same in that you needed a very firm grip to turn it by hand. The motor came with a very tatty Mk3 bike which has been imported from the States so I know very little about any past history. Although I do know it was kept outside under a sheet so the elements have got to it for sure. But like I say it did turn with a good dose of power through it.

I would really like to convert to roller or needle bearings. What are the bearing numbers you have used so I can order some. I have access to a lathe and vertical mill to machine the head assembly casing (06-6312) and the Drive end casing (06-6313) if needed.

I would imagine that the thrust washers won't need to be used if I convert to bearings?

regards

Previously peter_shand wrote:

Re reading your reply

The stiffness you describe is normal for these motors when assembled. they do free off a little after being run. Four brushes, two plain bearings and an oil seal all make for a motor that is a struggle to turn between the fingers, especially when you only have a little gear to grasp!

The armature will be ok, I reinsulate the windings with the proper insulating paint made for doing just this.

I also strip the oldotted insulation from the frame windings, reinsulate and refit them to the overhauled frame (shotblasted and painted) the photos show this in progress.

The drive side ball race i used is a 6203 2rs, the non drive end roller bearing size depends on the condition of the shaft, if its in poor condition the shaft has to be ground down to a size of the next suitable bearing, or the shaft has to be sleeved.

the drive end cap has to have a filler piece (alloy plate shaped to fill the reccess) bonded into it, this provides enough metal to allow the cap to be machined to fit the 6203 brg.

After getting the Motor up to scratch you will need the sprag sorting out, heavy duty cables, lucas solenoid, and an AGM battery.

Get that lot done and you can remove the kickstart!

Peter again many thanks. Is it possible you could attach a pic with the filler piece bonded in. Also what bonding solution did you use?

What I haven't added in is that I have bought a donor starter motor which has the 4 brush plate holder and 4 field coils in place. I've also manged to get hold of two new end caps. so what I am looking to do is put bearings in each end to help make it more efficient, which looking through your notes and pics, will help me do this.

I have the heavy duty start leads, suitable solenoid and just purchased an AGM battery so hopefully this will be the last operation to get it sorted, and the sprag of course.

Previously peter_shand wrote:

Previously mike_steer wrote:

Previously peter_shand wrote:

Re reading your reply

The stiffness you describe is normal for these motors when assembled. they do free off a little after being run. Four brushes, two plain bearings and an oil seal all make for a motor that is a struggle to turn between the fingers, especially when you only have a little gear to grasp!

The armature will be ok, I reinsulate the windings with the proper insulating paint made for doing just this.

I also strip the oldotted insulation from the frame windings, reinsulate and refit them to the overhauled frame (shotblasted and painted) the photos show this in progress.

The drive side ball race i used is a 6203 2rs, the non drive end roller bearing size depends on the condition of the shaft, if its in poor condition the shaft has to be ground down to a size of the next suitable bearing, or the shaft has to be sleeved.

the drive end cap has to have a filler piece (alloy plate shaped to fill the reccess) bonded into it, this provides enough metal to allow the cap to be machined to fit the 6203 brg.

After getting the Motor up to scratch you will need the sprag sorting out, heavy duty cables, lucas solenoid, and an AGM battery.

Get that lot done and you can remove the kickstart!

Peter again many thanks. Is it possible you could attach a pic with the filler piece bonded in. Also what bonding solution did you use?

What I haven't added in is that I have bought a donor starter motor which has the 4 brush plate holder and 4 field coils in place. I've also manged to get hold of two new end caps. so what I am looking to do is put bearings in each end to help make it more efficient, which looking through your notes and pics, will help me do this.

I have the heavy duty start leads, suitable solenoid and just purchased an AGM battery so hopefully this will be the last operation to get it sorted, and the sprag of course.

Hello Mike Again

The filler piece i cut out of some scrap alloy plate, though i did use a small cnc mill to do this it can be done with a hacksaw and files. to bond it in the drive end i used regular (24hr to you and me) araldite but any of the engineering epoxy glues will work just as well. dont be alarmed if the recess you machine in the cap for the bearing just breaks into the hole that carries the shaft for the intermediate gear, the final size just allows for the bearing to fit (40mm dia rings a bell)

The donor motor you bought, was it meant for a harley davidson? or is it a four pole modded norton frame? if the input connection is in line with one of the core irons it is a two pole frame that has had another pair of field coils added. if the input connection is between two core irons it is a four pole frame (aka harleys)

the two to four pole frame will work just as well as the pukka four pole frame its just that packing the field coil leads into the space under the brush plate can be a nightmare, space is very tight.

One of the photos shows a WPS (prestolite copy, chinese possibly) starter originally made for a harley, modified by me into a mk3 starter Note the quality of the rotor is far superior to the original prestolite item plus they have balanced it as well! also the non drive end cap already has a roller bearing fitted. I,m pretty sure these are the starters (modified to fit norton mk3s) sold by a couple of vendors over the pond.

what condition is the primary drive in? MK3'S with a working electric start you must run a chain primary as the sprag assembly needs oil to survive, dont be tempted to run a belt. If you are fitting new engine sprocket, sprag, and drive gear (from AN) that will sort the sprag as the new components are made to a closer tolerance than original.

If you are going to use the original bits the drive gear needs sleeving to close up the clearance to stop the sprag crunching itself.

A word about primary chains, No one makes decent triplex chain anymore. Unless you can source some old stock triplex you have to use an Iwis Duplex chain. works just as well and the bonus is its a bit lighter than the old triplex.

Engine. Unless you are planning to ride at WOT all the time (like a race bike) dont be tempted to fit a performance cam (PW3, 4S, SSS etc ) you will only wear the valve gear out faster and make more noise.

Two good modifications that i can recomend are a single carb and electronic ignition

Regards

Peter

Peter again many many thanks the information and pics are a fantastic resource for anyone. It looks like the motor I have is in fact an old Norton starter motor that's been modified to the four brush 'system'. Just to finish off before I start the bearing conversion to both end caps is that a nylon washer in the drive end cap I see in one of the pics. If you remember I was asking if the thrust washer setup I had was correct with the flat washer and the curved one (see pic on my initial posting). Firstly do you do away with both washers if the bearing set up is used or do you still need to put a protective washer over the armature shaft at the drive end to protect the windings?

Secondly I take it with the large bearing in the opposite end the oil seal will not be needed, I can't see it in the machined end cap?

regards

Previously peter_shand wrote:

Hello Mike

No its not a nylon washer, it is actually a fibreglass washer (or something similar, a bit like printed circuit board material without the circuit if you know what i mean) it came with the WPS starter and is a spacer used to take up the end float at the non drive end. You have to turn the armature shaft down to fit the 6203 brg at the drive end. when you do this make a thin shielding plate to slip over the shaft to stop swarf cutting the winding insulation to pieces, thin plastic will do, plenty of stuff suitable in the recycling bin! Turn the journal down so the brg is just a nice fit and stops a couple of mm shy of the windings.

The curved washer is not needed, just a spacer to adjust the float. I cut mine from actual circuit board material,

The oil seal is taken care of in the bearing itself '2RS' -- two rubber seals.

Take a close look at your four pole frame and the connection of the field coils to the frame itself. There will be two ends of the field coils that are soldered or spot welded to the frame. Original prestolite frames are spot welded, WPS frames and the like are soldered. both are good if done properly, The two to four pole frames i have seen unfortunatley have not been. The last one i overhauled for a client had the field coil to frame connection drilled for a small nut and bolt (like 6BA !) This is a high amperage connection and it has to be done properly.

Just had a look on the SKF bearing website and the needle roller i used for the non drive end is a HK 0912

This is 13mm od 12mm long and 9mm id necessitating the end cap boring out to 13mm and the shaft grinding down to 9mm.

Regards

Peter

Again many many thanks. Just to finish off, on completion does the armature need to rotate clockwise or anti clockwise to turn the engine over (looking at the motor from the gear end)?