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Request for advice - Miller dynamo problems

BlackLightning998

Well Known and Active Website User
VOC Member
Evening all,

Doesn't it always happen this way - getting the bike ready for Ace Cafe this Sunday (Black Shadow day) I knew I had had a problem on the dynamo side - not charging last time I ran the bike - anyway I took the end cover off to find the commutator has "eaten" itself with once copper segment disappeared completely and some serious chunks missing from the carbon brushes as a result.

I was advised to speak to Stuart Towner and sure enough he will be able to sort the dynamo for me - hurray, however the question for the Forum this evening is about running the bike this weekend.

I've got a 14AH battery - so fully charged there will be no problem riding the bike in daylight to and from the Ace - even though she's on electronic ignition it pulls next to nothing from the battery.

My question for the Forum is about leaving the bike safe and rideable for the trip. I don't want to leave the dynamo running as is, if something else breaks down and the dynamo seizes there could be bigger problems!! Removing the dynamo from the bike would leave the bike not oiltight - so seems sensible to leave it in place if I can and remove/disconnect the drive.

I've opened up the primary inspection cover, removed the assembly as follows on drawing M014 - nut (198), (dynamo lock washer PD23 is missing), dynamo drive plate (PD17AS), dynamo sprocket (PD15/1), dynamo oil thrower (PD28) and so only dynamo sprocket boss PD16 is left on the shaft.

Question - am I safe to button up again and run the bike with PD16 left on the shaft with no lock nut? Or should I use nut 198 to tighten up on the end of the shaft, although there doesn't appear to be any way of getting some purchase on the nut whilst holding and preventing the dynamo armature shaft from spinning.

Or should PD16 come off - if so, any bright ideas of how to pull it off?

If that's done, does that mean everything is off that needs to come off the primary drive side and I can simply replace the inspection cover and happily ride the bike?

Thanks all.

Stuart
 

timetraveller

Well Known and Active Website User
VOC Member
Years ago when I used to sprint in the production class I would take off the dynamo sprocket etc to reduce the power taken by the dynamo. Everything was taken off but the PD16 left in place. It never came loose so go ahead and enjoy the day. :)
 

johncrispin

Well Known and Active Website User
VOC Member
Dyno

Stu,
No harm in leaving the (bare) end of the armature shaft. The whole lot is Ok in situ, it is after all clamped in. I am going to try to make it up on Sunday, regrettably not on the Shadow, but I have a spare 12v Miller ( my spare) if you want to use it while STU T. fixes yours.
 

BlackLightning998

Well Known and Active Website User
VOC Member
Many thanks John...

Hi John,

Sounds like the PD16 can stay in place on the shaft for the run on Sunday - that's good news and I'll button it up again in the morning.

I think I can manage for the 3 weeks that Stuart says he needs - I intend doing the Bill Hancock Rally in York on 7 June so should just make it all back together for that. If I get stuck perhaps I could give you a call and take up your offer - very kind of you indeed.

What's driving my calculation is that the bike has a 14AH battery fitted and the ameter shows discharge at less than 0.5A when running so the electronic ignition system is clearly not taking much. On that basis, so long as I am riding in daylight, I should be OK for my runs out and about.

I've got the famous AA card if I get stuck.

Fingers crossed Stuart T. can get me all back together again even sooner.

Interestingly Stuart suspected that perhaps with headlight on the bike may be drawing too much as the dynamo is rated at 50W. I can't find a marking on the bulb but from it seems to only draw 2 to 2.5A when switched onto main beam. It's not the first time Stuart says he has seen the commutator cry "enough".

Cheers John, and thanks again so much, really appreciated.

Stuart
 

petermb998

Well Known and Active Website User
VOC Member
Hi Stuart
Don't forget the small amount of current you will use for your brake light.
If you have a spare battery and some were to fix it safely i would consider taking one with you. fully charged of course.
Hope to see you at the riders Rally.
peter
 

Len Matthews

Well Known and Active Website User
VOC Member
PD16 left on the shaft? Definately not. I wrecked the primary drive and damaged the crankcase of my outfit when competing at Cadwell. Like Norman, I decided that I didn't want the dynamo whirring round whilst out on the circuit so I removed the sprocket and oil thrower but omitted to put the retaining nut back on. After two laps of practice PD16 broke loose from it's taper and got carried along the top run of the chain and burst out of front of the crankcase. The chain was reduced to fragments and the clutch sprocket was in three pieces plus damage to crankcase and cover. End of racing that day!:(
 

timetraveller

Well Known and Active Website User
VOC Member
Following Len's comments I thought I would go out to my workshop where my old sprint engine, complete with Miller dynamo and PD16 lurks. No way I could get the PD16 off by hand but as soon as I put a puller on it, it came loose. It has been sitting there for more than 40 years since I sprinted and for the several years whenI was sprinting. I must have been lucky so listen to Len and see if you can get a small puller in there and take off the PD16 or somehow wedge the dynamo shaft and get a nylock nut on there. A question. Why would anyone want to continue to use a Miller dynamo? Is this a question of originality? They were unreliable 50 years ago and almost everyone changed over to Lucas regulators and then to Lucas dynamos (series'D's). With a total potential power output of 50 W they are hardly the thing to be using in modern traffic. Many a night I used to have to ride home without lights, only switching them on when other vehicles appeared. I remember one night passing a whole bunch of late night, unlit party returnees on a quiet country road who must have thought that they were about to be devoured by an invisible roaring, clattering demon as I hurtled past. Modern traffic conditions are not condusive to such youthful indiscretions!! :cool:
 

BlackLightning998

Well Known and Active Website User
VOC Member
Hi Stuart
Don't forget the small amount of current you will use for your brake light.
If you have a spare battery and some were to fix it safely i would consider taking one with you. fully charged of course.
Hope to see you at the riders Rally.
peter
Brakes, what are those - aren't they something that those modern, new fangled machines have to stop you!!

Seriously, cheers Peter. I'll now put a 3/8ths BSF nut on the end of the shaft with a little medium locktite if ||I can find a way of stopping the shaft spinning, charge the battery full and head off to enjoy myself with an AA card in my pocket!!

See you in York one way or another...

Stuart
 

BlackLightning998

Well Known and Active Website User
VOC Member
Thanks Len - and now for the next step.......

Len, thanks for the advice.

PD16 is on and the nut is now fully home with some "frequent" locktite, battery's on charge so all being well in a couple of hours I will take it for a spin.

Thanks to Bruce for sending details of the "little puller".

So the next question for the Forum is - how do you take the dynamo off if the PD16 collar is on a taper fit.

I'd have thought I slacken off the mounting cradle bolts and simply pull it/slide it towards the gearbox side - but I am guessing it is not that straightforward?

I would think that even the gentlest of tap on the end of the armature shaft will be exactly the wrong this to do and cause real damage given the tolerances of the arnature spinning in the housing.

I'm sure many members will have done this job many times - here I am once again as a spanner wielding novice not wishing to damage anything, later on I'll find time to read the books - but advice eagerly sought and gratefully received.

Thanks to all who've replied so far.

Cheers

Stuart

PS - Really looking forward to the Shadow Anniversary Event at the Ace Cafe tomorrow - weather is looking hot and sunny like last year - watch the Forum for some new pictures tomorrow evening.
 
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john998

Well Known and Active Website User
VOC Member
Removing dynamo.

Hello, I may have misunderstood, but you do not need to remove PD16 to remove the dynamo. You can pull it off after you remove the dynamo.
The dynamo is a wangle to get out, I think it comes out from the primary side best, but this depends on how the carb and oil pipes are set up.
I agree with Len do not risk running the bike with out removing, or fitting a lock nut.
The miller is an excellent unit, if you do not over load it, and have an electronic regulator. Mine has done 40 years for me with nothing more than the odd clean out. John.
 

petermb998

Well Known and Active Website User
VOC Member
Hi Stuart
To get the PD16 off the dynamo with out the extractor hold the Pd16 in a vice if you have one undo the nut or put it on the threaded shaft to protect the threads and tap with a hard faced or copper mallet.
I will now duck from the brick bats.

regards Peter
 

BlackLightning998

Well Known and Active Website User
VOC Member
Ahh - I think I have been mis-understanding the design...

Hi John/Peter,

I think I must have misunderstood the design, I thought the PD16 had to come off the shaft to allow the dynamo shaft to be pulled through the back of the casing with the dynamo - it seems from what you are saying that when I take off the bolts holding the dynamo clamp that the dynamo can be removed with the PD16 in place?

If that is the case then I can just take the dynamo and with it PD16 on the shaft to Stuart Towner who is going to do the repair for me and let him deal with it as he will have the special tools required I am sure.

What was obviously confusing me was that I thought that PD16 had to come off the shaft to allow me to pull the dynamo out the back of the primary chaincase.

Thanks John and Peter for clarifying.

Tomorrow night is the night!!!

Stuart
 

petermb998

Well Known and Active Website User
VOC Member
Stuart.
At last you are just about seeing the Light.
You might be best in looking at a Lucas E3L type dynamo,converted to 12 volts.
The fitting of the sprocket to the dynamo is better than the miller, more positive.
Have a look at the spares list drawing and compare them.

regards Peter.

PS you have still a lot to learn about Vincents. keep at it.
 

Len Matthews

Well Known and Active Website User
VOC Member
Sorry to disagree Peter but the Series D dynamo sprocket adaptor (PD33) is not as robust as the B/C arrangement. I've come across one or two that have split along the keyway and therefore wobbled about on the armature. What's more, the retaining bolt is only threaded 1/4" BSF as against 3/8"BSF on the Miller armature so it can tightened more securely.
 

BlackLightning998

Well Known and Active Website User
VOC Member
Now - how to go about re-fitting it and what about the oil leaks!!!

IMG_4750.JPG

Afternoon all,

Never done this attachment thing - so hopefully you'll be able to see the picture I have attached which is taken from the gearbox side and is of the location of the dynamo into the primary.

I'm shocked to say that when I took off the dynamo to go to Stuart Towner the drive end was plastered with this "gunk" that resembled the stuff you put on exhausts to stop it blowing and the housing you may be able to see from ther picture is covered in it too.

Now, the bike suffers from the well known problem of allowing oil to build up in the chaincase and then if I run the bike like that it will plaster itself all over the back of the bike. I imagine that at least part of the culprit is this dynamo fitting. When I drain the oil level back to the level plug I then get 200 or so clean miles with never a drop of oil - she ran to the Ace Cafe at the weekend and did not disgrace herself - a clean piece of tarmac under the bike all day.

I do know that there is a recognised mod for the primary drive side but I do not want to contemplate that just yet thankyou.

I would like to hear from any members who have experience in fitting the dynamo with a view to getting an oiltight seal. All suggestions gratefully received.

It transpires when I took my dynamo to Stuart yesterday that it is a hybrid with a Lucas body being grafted onto a Miller drive end - it is now resting with Stuart (well and truly fried, dynamo that is - not Stuart) and he is going to work his magic for me.

In the meantime John Crispin has been good enough to lend me a spare Miller dynamo and I'm going to try mounting that this weekend.

Further interestingly under the dynamo is a piece of horesehoe shaped steel shim which I guess has been used to lift the body of the dynamo up - this isn't shown in the drawings as standard (and the Lucas body is 3 inch too) - has anyone come across this being needed/being done before?

So I know about the tab washer, I'll use locktite and Dick S. helpfully described how I could lockwire the nut - anyone else got some helpful advice for a novice on how to go about fitting the dynamo to get a good job and hopefully minimise oil leaks?

Cheers

Stuart

PS Hope the attachment works......
 
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rapcom

Well Known and Active Website User
VOC Member
Oil leaks from dynamo

A shim to adjust the height of the dynamo is a routine part of the adjustment, if required. It would normally be a flat plate of suitable thickness, fitted between the crankcase and the dynamo cradle ET221. Putting a shim between the cradle and the dynamo is a bit of a bodge, as it is liable to move, and end up altering the fore-and-aft adjustment as well, while you are fiddling with the dynamo.
A nicety of fitting is to adjust the position of the oil thrower ring PD28 for minimum clearance against the crankcase, to minimize the gap which the oil escapes through!
A smear of a sealant of your choice between the dynamo and the rear face of the dynamo drive housing can help a lot, particularly if the cases are as rough as yours appear to be. The machining in this area is often very poor and inconsistent.
 

Vic Youel

Well Known and Active Website User
Non-VOC Member
Stuart,

My Miller needs a shim and it must be carefully placed too so that the dynamo does not tilt within the clamp. Also need to juggle the oil thrower/body clearance as well.....result is a few more oil drips. Not everything on a Vincent is a good design and certainly electrics seem to be an after thought!

Mine has several other oil leaks but it stops corrosion...... that well used one at the Ace on Sunday could do with more leaks I thought!

My chaincase does not normally fill up though.

Cheers

Vic:)

PS Comet is a better design in terms of leaks and adjustment..... but you need to undo the timing cover to remove the dynamo. Something I am reluctant to do with my new Maughan rebuild...... the dynamo electrics don't work but haven't done any measurements yet as to determining the cause.
 
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Len Matthews

Well Known and Active Website User
VOC Member
We've been here before about sealing dynamos. The primary chaincase needs to breathe so if you seal the end face of the dynamo it can't. Ask Hugo Myatt about the consequences! I'm surprised that a newly built engine has a problem of oil transfer through the drive-side mains. Taken as read bores and pistons are new, is the breather timing correct?
 

BlackLightning998

Well Known and Active Website User
VOC Member
I'm no expert but how does the primary pressurise?

We've been here before about sealing dynamos. The primary chaincase needs to breathe so if you seal the end face of the dynamo it can't. Ask Hugo Myatt about the consequences! I'm surprised that a newly built engine has a problem of oil transfer through the drive-side mains. Taken as read bores and pistons are new, is the breather timing correct?

Hi Len,
Many thanks for your reply - I'm finding your responses very helpful - I've said it before, it is such a shame that you aren't closer for me to bring the bike in and let an expert do it for me.

I'm an interested amateur - with an inquisitive mind. I haven't managed to get a copy of FYO yet as they are out of print with Russ (I'm on backorder). I plan to do some ATY, KYB and other reading before the weekend but have found the Forum rapid, helpful and convenient.

As the interested amateur, I can't fathom out why the primary will pressurise and need to breathe: my logic is telling me:

1 - There are no reciprocating parts to create pressure
2 - A properly machined dynamo face would lead to an effective (relative) seal
3 - Actually, wouldn't an effective seal help to stop oil finding it's way through the main bearings from a pressurised environment to a non-pressurised environment.

What am I missing - I have managed to get all MPH's from 1969 until today - is anybody able to point be to some reference points in there to read about the problem?

I've e-mailed Terry Prince who did the engine to ask his thoughts on the primary filling up. You are right that everything from the big end upwards was replaced in the engine, but he told me that the big end was fine and so was left - not sure what that exactly means in terms of it not allowing oil through though.

I've PM'd Hugo to ask him what his experience was that you mention so I can learn from that - have offered him the opportunity to post it on here so we all see it.

It seems to me I have two issues:

1 - Why is the primary "filling" up?
and
2 - Why is the oil coming out of the primary?

I think these are actually two seperate issues to deal with though although back to my amateur (puts tin hat on) logic viewpoint that a sealed primary might actually resist oil finding it's way in through the bearings from a pressurised environment.

The "gunk" on the dymnamo face plate and the back of the primary suggests that whoever did it, did not know about possible issues of preventing the primary cases from breathing.

Thoughts?

Stuart
 
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