Starter

Hi
MY starter has crashed.
Total crushed. It has for unknown reasons joined the engine around an had enough .
I must now get me a new one. So far I've found that it's just one option (I am considering not the original as an alternative).
It is: 06-4791B.
Is there anyone out there who has experience with this one.
Vidar

I was tempted to do the same however I am having my original starter rebuilt and upgrded by Old Britts. I am back to kickstarter for the time being but I will report back on how things turnout I.e cost $ and the 4 brush upgrade plus bearing in place of the bush.

Hi
It was an orginal starter with the same upgrade that you now are waiting for, that crashed for me, but I dont now why it happend .
Vidar

Vidar
Before fitting a new motor
I would want to find out why it broke. Can you describe in more detail what actually happened? (I understand we are talking about an 850 mk3)
The failure modes for the starter system on MK3,s that I know about can be:-
1. The sprag 'flipping' resulting in the starter failing to engage.
2. The sprag 'crunching' and locking the drive gear to the engine sprocket (if the engine starts and runs this can destroy the starter motor as the huge increase in revs just explodes the motor)
3. Using a belt Primary drive run DRY (this wrecks the sprag as it requires lubricant, resulting in 2 above, this has been known to happen at speed, causing A LOT of problems ) If you have to use a belt, make sure it is running in oil.
4. Anti-backfire device set too tight (correct torque setting to slip at 50 ftlbs)
5. Corrosion. The water proofing as standard is non-existent. This is not helped with the motor situated under the Amal carbs. The petrol from them when tickled washes the lubricant out of the bearings (especially the brush end) leading to corrosion. Silicone RTV used on assembly is an effective cure for this ( Wynns black gasket maker is a black RTV just right for this application)
5. Motor leads/wiring/battery/solenoid. Original motor leads can be upgraded for better ones. Battery also.

We have a member in the local owners club that has one of the 06-9147B starters and it works perfectly. Please be aware that if any of the above 1.2.3.4. conditions are still prevalent you could still suffer premature failure.

If any other forum reader has anymore failure modes please tell me as i would like to avoid them if at all possible.
Regards
Peter

None of the above listed specific cases happened to me.
I started up normally and drove. Suddenly everything locked up.
Engine and the wheels stopped suddenly. I thought the engine were totally destroyed.
I managed to stop and started again with the chiken. The engine worked perfectly normally.
The starter was dead
When I got home and opened the primary _, everything was ok there, except starter which was totally crushed. All gears ok. bearings were ok.. the Sprag was ok, so was also the backfire device. I also checked the torque on this and it was exactly right either way.
I wonder, can the starter got power so it joined the engine until it became too much?
Vidar

Vidar
Sounds like a variation of 2. Can you explain the damage to the motor? a photo or two would be greatly helpful in diagnosing what has gone wrong. Do the rotor windings look to have expanded? (this will be evident as they will probably make removing the rotor from the motor frame very difficult)
I have just been rebuilding some of these motors for clients. Motor frame dissmantled, shot blasted, internal/externally painted, two pole frames converted to four poles and brushes, end caps with rolling element bearings, drive end cap reinforced to take the new 6203 in the drive end and a needle roller in the brush end. A couple of these motors were in particularly bad condition (Corroded, rotor windings touching the end cap, bearings seized, rotor com worn.
I have also converted a couple of WPS Harley davidson starters to fit the MK3 both for myself and a client.

As for the availability of new motors you can buy the Dynodave Hitachi based motor, available from dynodave in the USA, Holland norton works in The Netherlands, Norvil in England and probably elsewhere, Colorado Norton Works supply a motor that looks like its based on the Harley motor mentioned above. Andover Norton List a new replacement motor so you have a bit of a choice, it all depends on how deep your pockets are as none of them are cheap (you are talking a few hundreds of pounds/dollars/euros. delete as applicable)
Regards
Peter

vidar hjelm johansen said:

I wonder, can the starter got power so it joined the engine until it became too much?

Click to expand...

Yes, it can happen if the solenoid contacts stick, or perhaps the starter push button switch jammed on?

For the starter to lock the engine and overspeeded to destruction there must have been a problem with the sprag/drive gear/engine sprocket as it is only supposed to drive in one direction.

dobba99 said:

For the starter to lock the engine and overspeeded to destruction there must have been a problem with the sprag/drive gear/engine sprocket as it is only supposed to drive in one direction.

Click to expand...

Yes, you're right. Even if the starter motor did continued to operate, the sprag would still have had to lock up to stop the engine.

I'm thinking the large crank starter gear (064371) could potentially engage the starter drive if, for some reason it began turning with the crank?

Pointing to a problem with the needle roller bearing inside the drive gear possibly?

dobba99 said:

Pointing to a problem with the needle roller bearing inside the drive gear possibly?

Click to expand...

Possibly the needle roller seizing or breaking up, or perhaps loss of end play on the gear which might cause it to turn with the crank?

It is a great mystery. I have tried to think through all of the mentioned scenario.
Ale parts are ok except the starter. needle bearing too and the sprag.
But the engine was blocked on a brutal manner.
Vidar

dobba99 said:

Vidar
Sounds like a variation of 2. Can you explain the damage to the motor? a photo or two would be greatly helpful in diagnosing what has gone wrong. Do the rotor windings look to have expanded? (this will be evident as they will probably make removing the rotor from the motor frame very difficult)
I have just been rebuilding some of these motors for clients. Motor frame dissmantled, shot blasted, internal/externally painted, two pole frames converted to four poles and brushes, end caps with rolling element bearings, drive end cap reinforced to take the new 6203 in the drive end and a needle roller in the brush end. A couple of these motors were in particularly bad condition (Corroded, rotor windings touching the end cap, bearings seized, rotor com worn.
I have also converted a couple of WPS Harley davidson starters to fit the MK3 both for myself and a client.

As for the availability of new motors you can buy the Dynodave Hitachi based motor, available from dynodave in the USA, Holland norton works in The Netherlands, Norvil in England and probably elsewhere, Colorado Norton Works supply a motor that looks like its based on the Harley motor mentioned above. Andover Norton List a new replacement motor so you have a bit of a choice, it all depends on how deep your pockets are as none of them are cheap (you are talking a few hundreds of pounds/dollars/euros. delete as applicable)
Regards
Peter

Click to expand...

I can vouch for Peter's Harley Davidson starter motor conversion, he did mine and the difference is stunning, the motor will spin the engine like a modern bike.

sam