Author Topic: cam ring problem.  (Read 6798 times)

Offline emilios

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cam ring problem.
« on: 13.03. 2010 17:36 »
Hi..
I just got my fully rebuilt K2F magneto from FTW..
I dont know why but they didnt put new cam ring...and know as before i have a huge different between the two pistons..
I was trying today to set ingnition...
When i set one piston to fire at 32 degrees the other was firing about 50 degrees...
If i buy a new cam ring i will solve the problem or do i have to customise my own?
Did someone did customise a camring?
Thanks
1956 BSA A10 Plunger
1954 BSA B31 Goldstar Replica
1970 Honda cb750K0 project
Cyprus

Offline a10gf

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Re: cam ring problem.
« Reply #1 on: 13.03. 2010 17:46 »
Hi, before doing anything I'd suggest contacting FTW and ask for an explanation. Getting an even LR timing is definitely part of any full magneto overhaul.

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Offline alanp

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Re: cam ring problem.
« Reply #2 on: 13.03. 2010 20:24 »
Hi, I had a similar problem with one contact gap at .012 the other at .003. I've passed my K2F over to Paul Todd to rectify which will include a CNC machined cam ring and a replacement end housing where the fit of the end housing into the main body places the cam ring concentric with the armature.
Alan
Member of the 'Last of the Summer Wine Club - Jennycliff'.

Offline a101960

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Re: cam ring problem.
« Reply #3 on: 13.03. 2010 20:46 »
Are you sure that it is the cam ring that is the problem? It could be that the shaft is not running true due to housing misalignment. I had the same problem that you describe and that was the cause. I would worry about the quality of workmanship if I had a rebuilt magneto with a fault like that. I agree with a10gf get back to the repairer and find out how your rebuilt mag came to be so poorly aligned.

Offline emilios

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Re: cam ring problem.
« Reply #4 on: 14.03. 2010 16:31 »
I email to FTW and im waiting answer..
1956 BSA A10 Plunger
1954 BSA B31 Goldstar Replica
1970 Honda cb750K0 project
Cyprus

Offline emilios

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Re: cam ring problem.
« Reply #5 on: 16.03. 2010 19:17 »
Here is what FTW answer..

The timing on the cam is not ajustable I have used the same cam as you sent.
Lucas magnetos left the factory like that, it is usually because the cam housing has not been machined correctly and the bearing is not in the centre of the cam, 20 degrees on the engine is 10 degrees on the magneto this was normal for Lucas, the manufactures Triumph BSA etc demanded a cheap magneto and that is what they got. I have spent hours grinding the cams for my own bikes, but I can't do this with customers cams as it would more than double the price of the rebuild.


1956 BSA A10 Plunger
1954 BSA B31 Goldstar Replica
1970 Honda cb750K0 project
Cyprus

Offline a10gf

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Re: cam ring problem.
« Reply #6 on: 16.03. 2010 19:33 »
 *eek*

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Offline MG

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Re: cam ring problem.
« Reply #7 on: 16.03. 2010 19:34 »
Now that guy has a nerve!
I bet if you were located 2 miles away from him and not in Cyprus, the answer would have been completely different.

Lucas mags NEVER EVER had a deviation of 10 degrees on the cam. BSA specified a maximum offset of 4 degrees on the crank, if my memory serves me right.
That st...d "§%/("/§!$!$§ should be hit on the head with the crap he's delivering.

Sorry, but impertinent botchers like that upset me. If he is not able and/or willing to do it properly, he should be honest enough to tell you and not do it half-assed.

That's why I restore my mags myself...
1955 A7 Shooting Star
1956 A10 Golden Flash
1961 Matchless G12 CSR

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Offline a101960

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Re: cam ring problem.
« Reply #8 on: 16.03. 2010 20:16 »
I will do my best to be restrained in what I say. Emilios, FTW (who ever he is) is talking rubbish. I know that it is being wise after the event but you should have sent the magneto to somebody like Tony Cooper. The housing should have been replaced or machined and fitted with a bush. I am amazed how people like FTW are able to continue trading. I do not know how much you paid to have your magneto overhauled, but Tony Cooper charges around £160 and for that cost you would have had a Magneto that had been rebuilt with all new parts and the armature and cam ring set properly. I can only speculate that FTW has a day job working on a ranch as an understudy for John Wayne. I can only advise you to contact Tony Cooper with a view to getting a proper job done.

Tony Cooper Motorcycles
110, Olive Lane,
Halesowen,
West Midlands,
B62 8LT

Tel 0121 5592405
Fax 0121 5612410

Or this man: Shaun Hawker

http://www.hawkerelectrical.co.uk/

Online groily

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Re: cam ring problem.
« Reply #9 on: 16.03. 2010 20:48 »
Upsets me too - because it's total crap, like the job he's done. Disgraceful attitude.
A decently rebuilt mag should offer near-as-dammit identical points gap on both cylinders and near-as-dammit 180 degrees apart. Cam rings are available if there was actually anything wrong with yours, and one should have been fitted if there was. Might not be as good as a one-off grind to suit a particular mag, but hell of a lot better than what you've been left with. Without getting into a pissing competition, Dave Lindsley wouldn't send out a mag like that, nor would SRM - 2 people I have used in recent years, although like MG I prefer to do my own. Nor would Tony Cooper or Shaun Hawker, as A101960 says, although I've not used them myself.

Just because you're a long way away, I suspect you've been fed a load of bullshit. At least forums like this make sure that adverse publicity gets spread around, although it's no comfort to you. No-one would send back a mag in that state if he had a reputation worth guarding. All too reminiscent of Manosounds 'machine shop' a year or two back.

Now, assuming that at least the armature has been rewound (or proved good) and a new condenser fitted, you should at least have guts that are capable of working.
I reckon you'd be capable of sorting the rest of it out - they're actually not so hard to get to bits - it's the rewinds that are hard.

First thing I'd do is look at the state of the bearings. Is there any slop on the bearing at the contact breaker end when you wiggle the whole thing by the backplate? Ditto at the other end? If there is, either the bearings or the insulation washers that go between the outer race and the magneto body (drive end) or outer race and cb housing (points end) need replacing, or you need a shim - either behind the inner race of a bearing (awkward to fit) or more likely between the end housing at the cb end and the magneto main body (easy). If there is up and down play at the drive end, the oil seal in there won't last long and you'll have that messy problem too. I'd hope the man has replaced the insulators and oil seal and fitted shims, so there probably isn't any slack, but you never know.

Does the contact breaker assembly rotate dead in the middle of the magneto - ie can you see if it's running eccentrically when you rotate it? If you hold the mag body in a vice, and rig up a fixed pointer to just kiss the head of the screw that holds the points on as you turn it by hand from the other end, you'll see if it's more than a few thou out pretty easily. (Best to turn it with the sparking plugs on the leads and the plugs attached to the same vice as an 'earth' by the way.) If it isn't turning true, it's either because the bearing that end is not centralised because the housing isn't on dead square or because the insulator behind the bearing is askew or because there's too much end float for the lack of a shim. Slackening the small screws that attach the end housing to the main body of the mag, wiggling and retightening might help. It's not a shim problem though if the armature doesn't have any end-float when you push and pull it axially. Worst case, the outer race of a seized bearing has spun in the housing some time in its life and enlarged it so nothing will make it true again. But hopefully that would have been picked up even by a moron.

Assuming it is all dead square, with no slop in the bearings and no end float, are there still differences between the points gap for the left and right cylinder and in degrees? If so, all other things being equal, either the cam ring is worn or, in relation to the first point, the gap, the cone on the contact-breaker back-plate is a poor fit and the backplate isn't seating dead squarely on the armature. Hopefully the female taper on the armature is OK.

I would hope that FTW managed to produce a set of points that are in reasonable shape and that the backplate is indeed a good fit on the taper - and that the keyway in the armature and the raised key on the backplate are still OK. But I begin to doubt everything in light of what you say they said to you.

For any parts you might need except the armature, I find the easiest and fastest people are Independent Ignition Supplies (www.magneto.co.uk). They do all the little bits by return post, from pick-ups and carbon brushes and springs, screws, points, shims, bearings, insulators etc etc and I've been very happy with their service. (I currently have an order in myself for some condensers and other little bits.) Look on their site under 'Joseph Lucas K1F, K2F and KVF', which are all basically similar on the parts front, bar the slip rings.

Trouble is, you shouldn't have to be paying twice over - wish I could think of a way of getting your money back, or some of it. It's a bloody disgrace. But it reinforces something Dave Lindsley said to me recently when I sent him a manual K2F on behalf of a friend - 'Half the mags I do are mags that have supposedly been redone by other people and are completely useless'. He was very uncomplimentary, more so than a family forum allows me to quote! You get what you pay for I guess - he's not cheap - but he guarantees his work for 2 years and the finished result I saw looked better than new inside and out.

If you need a step by step guide to how to get the thing apart, I'd say there are a hundred people here happy to help you. The only hard bit (apart from rewinding and the condenser), is bearing inner and outer race removal and replacement. Which does need to be done with great care - and preferably a correct tool.

Meantime, are you going to hassle FTW for some of your money back? The reek of bad publicity could be a weapon . . .
 
Good luck anyway! Reckon I'm as irritated as you!
Bill

Online bsa-bill

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Re: cam ring problem.
« Reply #10 on: 16.03. 2010 20:56 »
Don't FTW give a two year guarantee ?,

All the best - Bill


All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Online chaterlea25

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Re: cam ring problem.
« Reply #11 on: 16.03. 2010 21:05 »
Hi All,

Of course all this is of little help to Emilios, as he is very much further away from the UK specialists than I am

I agree 20 degrees is way too much of a difference and this is NOT acceptable in any circumstance's
1)If this is the case the points gap must be radically different,
2)What are the points gaps?
3)on both cams?
4)Maybe the points rotor is not sitting correctly in the armature?
I had this happen when some of the epoxy from the armature leaked down into the taper???

Emilios can you check out the items above before you send the magneto back to the UK again??

I am assuming that this is a manual advance magneto?
If it is an auto advance have you wedged the auto advance open before you time the engine?

FTW advertise in Old Bike Mart and I'm sure other publications
10 or so years ago I had a couple of magnetos rebuilt by them, from complete rebuilds to armature only rewind and condenser.
On one rebuild I supplied a new "original Lucas" slipring to be fitted, this they did, but after a few hundred miles the pattern brushes had eaten away the slipring  *sad2* *sad2*
On contacting FTW they said send the mag back and they would replace the slipring
They did this under guarantee and covered the cost of the return postage as well as the slipring and labour.
The magneto's rebuilt by them have given NO other bother  *smile* *smile*
THe K2F timing diff is less than 2 degrees (maybe I'm lucky????)
As I said this was all some 10 years or more ago.

In more recent times I have had work done by Tony Cooper who is excellent
I can also recommend CMES in Bristol,  Sean Hawker is a sound guy and excellent services and parts
I had a vintage V twin magneto rebuilt by Moat House Magnetos, again 1st class
this was because there is an unwillingness by some companies to do shall we say "non run of the mill" magneto's

Happy St. Patricks Day to ALL     (17th March)
John O R




1961 Super Rocket
1963 RGS (ongoing)

Offline Josh Cox

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Re: cam ring problem.
« Reply #12 on: 17.03. 2010 07:59 »
If you would endulge me ( on with the devils advocate suit ).

By todays standards, just about every other part of these bikes are not particularly well machined, 60 years ago though, before CAD, it was top rate.

Read Orabanda's threads about his dyno experiences, and the maggies cams being "out" are common.

My maggie was adjusted by some 8 or 9 degree at rebuild ( machined the cam ).

Whilst you might be horrified by this guys response, if he put the same cam back in, machined and charged you double, would you be annoyed and feel ripped off.

This cam worked OK before the maggies stopped working ?.

These are not high performance machines, for example what is a new rice burner 650cc capable off, 120 HP compared to our 20 odd ?.

If you want to go fast, buy a rice burner.
Black 1953 Golden Flash Plunger

Offline MG

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Re: cam ring problem.
« Reply #13 on: 17.03. 2010 08:23 »
Josh,
you are absolutely right when you say that this old machinery can't be compared to modern standards in terms of accuracy and manufacturing tolerance.

But 20 degrees are way off. There's something seriously wrong with this mag. Any serious rebuilder would have noticed that and should have done something about it, even if it was rejecting this rebuild.
If it is the camring, well, that's an easy fix. Buy a new one at SRM and add 60 quid to the bill.
New bearings go without saying, so that shouldn't be an issue here, assuming they used insulation washers of correct thickness and adjusted the play correctly.
When I rebuild a mag, each armature is checked in the lathe. If it is not running true and this cant be fixed, I recommend to buy a new one. Makes no sense to refit one that won't run properly.

Either way, imho a fair solution would have been to inform the customer what is wrong and why it can't be fixed and send the mag back instead of spending several hours on it with questionable results.

All the mags I have rebuilt so far run with an offset of 0.5-0.8 deg on the crank, just by spending 20 minutes grinding the cam ring to fit. You would be surprised by the difference in engine performance when the ignition is correctly balanced.
And I'm sure that 20 deg deviation are a rather safe way to a major engine rebuild.

Just my 2 pence worth.

Cheers, Markus
1955 A7 Shooting Star
1956 A10 Golden Flash
1961 Matchless G12 CSR

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Offline a10gf

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Re: cam ring problem.
« Reply #14 on: 17.03. 2010 13:38 »
Quote
And I'm sure that 20 deg deviation are a rather safe way to a major engine rebuild
Yes, the mag may give a huge strong spark after the repair, but beeing detrimental or potentially destructive to the engine when put into service makes this 1\2 overhaul useless in real-life terms.

------------------

Emilios, how are the points gap in the 2 opening positions? Any difference there suggests a misaligned bearing cup and\or an eccentric cam housing, the camring itself (measure the thickness of the 2 lobes) could be fine. If this is the case, personally I'd rather opt to correct that first, then, if needed, eventually doing a small fine-tuning of the cam as the last resort. You'll end up, like many others, forced into having some mag expertise  *smile*
e

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