Author Topic: Pushrod question - problems starting new engine  (Read 9034 times)

Online bsa-bill

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Re: Pushrod question - problems starting new engine
« Reply #15 on: 13.02. 2011 11:14 »
I asked a similar question here and the answer was that the plug lead that fires is the one nearest the (fibre) heel of the points
So if your setting the timing with the points at about 10 to 11 o clock ish the heel will be around about 4 to 5 o clock and the lead providing the spark is the rear one (furthest from the barrels), this is generally the lead to the timing side plug but as iansoady  states this depends on how you time the engine.

This is interesting for me as your describing much of what went on when I rebuilt the RGF, one problem was that the cam-ring had moved outwards of it's locating peg and rotated (probably taking the points opening away from the maximum flux position of the maggie, ( don't ask me  about this as I'm way past my comfort zone, others here are much more knowledgeable about it)
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

Offline Duncan R

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Re: Pushrod question - problems starting new engine
« Reply #16 on: 13.02. 2011 11:22 »
Thanks Bill,

I will check that - not sure what I would be looking for though! Anyone got a photo or diagram of the cam ring postion?
Anglo - Indian A7SS (Actually is a 650)
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Offline Alan @Ncl

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Re: Pushrod question - problems starting new engine
« Reply #17 on: 13.02. 2011 19:07 »
Hello Duncan
I am currently in a very similar position to you and have a thread running on this too in the Amal and Carb section, to which the guys have responded admirably, as usual.  Sadly though, I am still stuck but you may want to follow that thread too (engine wont start) if you have not already done so.  

To definitively establish which mag output was driving which plug I took a resistance reading from plug tip down to earth with the engine on TDC.  If you get about 4 kohms, that is the one that is firing as the circuit goes up the plug core, along the lead, through the carbon brush, through the brass segment on the HT slipring and back to earth through the mag secondary winding.  This also shows up any unwanted resistance (for example, I found my new rubber plug cap was not properly screwed onto my new ignition lead).  The other plug circuit will show infinite resistance of course as the other brush is on the fibre portion of the slipring.  I then checked which cylinder was on compression by blowing down a bit of tube that is a tight fit in the plug hole.

Hope you have better luck than I have had so far and I will follow your progress with great interest.  

Alan

Offline Duncan R

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Re: Pushrod question - problems starting new engine
« Reply #18 on: 13.02. 2011 19:29 »
Hi Alan,

Thanks for info - yes I am watching your thread! I will have a chance to look at the bike again tomorrow, if I find anything I will certainly post it straight away.

Its so frustrating, my engine was in a bad way and I have just spent a small fortune getting it put right and now the bloody thing won't start. At least my legs have recovered from all the kickstarting! I am sure it is something stupid that I have overlooked.

Best of luck and hopefully we can both post some good news shortly.

Cheers

Duncan
Anglo - Indian A7SS (Actually is a 650)
Kawasaki ZZR 1100
BMW R80GS
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Online bsa-bill

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Re: Pushrod question - problems starting new engine
« Reply #19 on: 13.02. 2011 20:47 »
Quote
Anyone got a photo or diagram of the cam ring postion?

Will try and get a photo tomorrow Duncan, from memory (and this is dangerous ground) looking at the points end of the maggie with the cover off there is a screw on the outer case about 10 - 11 o clock, this should be about where the thickest part of the cam ring is ( well one of two obviously ).
The camring should be flush or just in from the maggie end casing as the cover actually holds the cam ring in, they can come off their locating pin if the bike is run with the maggie end cover off.

This is what had happened to mine (although can't remember running the bike with it off) result was it would with extreme difficulty start and then run quite well until I stopped it , then noway would it go again, and sometimes plugs would wet but mostly not, other issue were also contributing.

But keep at it you will get it going, started both my bikes today with one kick, further more the RGF which used to be tight to kick (to the point of being solid at times) is now much free-er, started it today in my slippers  wink2
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

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Re: Pushrod question - problems starting new engine
« Reply #20 on: 13.02. 2011 23:14 »
Hi Alan & Duncan

This is a quote from Trevinoz regarding my spitback and backfire problems

"Jim,
         It is difficult to get an accurate resistance measurement of the secondary winding between the slip ring and earth because the secondary wire end is loosely pushed into the slip ring without a positive connection.
I suspect that there is always a bit of an air gap and the spark jumps it.
         Trev."

When I tried a meter between the slipring and earth via the secondary winding I got variable unstable readings - only by pressing the probe hard against the slip ring did I get any reading at all.
Probably due to the way the wire is connected as Trev says.
You may not be able to measure the 4k secondary mag winding from the plug cap to earth via the slip ring if this is the case.


Jim
1959 A10 SR
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Offline Alan @Ncl

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Re: Pushrod question - problems starting new engine
« Reply #21 on: 14.02. 2011 00:20 »
Yes to Jim.  I saw that post from Trev too and agree that if you do not get a resistance reading, it does not necessarily demonstrate that you are on the wrong side (I remember too seeing that you were getting very high and erratic readings).  But if you test both plugs this way and do not get a sensible resistance on either, I think it probably does suggest that there is a problem as sparks should not be having to jump internal gaps or bad contacts.  In my post to Duncan I was assuming a healthy mag in which you were trying to find which output went where, whilst also checking the resistance was about right?

Meanwhile, good luck again Duncan. At least I have not spent big bucks yet so while disappointed so far, at least I have not made a big financial investment.  For now though it seems we are clearly 'comrades in adversity' (with sore legs and feet).  And as for Bill, getting it started in his slippers; well I am just green with envy!

Alan

Offline iansoady

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Re: Pushrod question - problems starting new engine
« Reply #22 on: 14.02. 2011 12:02 »

To definitively establish which mag output was driving which plug I took a resistance reading from plug tip down to earth with the engine on TDC.  If you get about 4 kohms, that is the one that is firing as the circuit goes up the plug core, along the lead, through the carbon brush, through the brass segment on the HT slipring and back to earth through the mag secondary winding.  This also shows up any unwanted resistance (for example, I found my new rubber plug cap was not properly screwed onto my new ignition lead).  


That's a good tip.
Ian.
1962 Golden Flash (arrived)
1955 Velo Viper/Venom (departed)
2004 Triumph Tiger 955i (staying)

Offline Duncan R

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Re: Pushrod question - problems starting new engine
« Reply #23 on: 15.02. 2011 13:46 »
Finally got some life out of it, but only on one cylinder. I retimed it but had to resort to loosening the mag and tapping the pinion bolt as the self extracting thread is shot, whilst doing this the cam ring fell out! looking at photos from the web I put the ring back with the whole at the bottom and the thick part of the cam  in line with the screw that holds the sliding catch for the points cover - is this correct?

It starts quite easy on one cylinder now (timingside) It was only running for a few seconds like it was running out of fuel, then discovered a blocked fuel tap which I have now cleared and it runs on one , I am getting no back fires from the unburnt fuel in the dead cylinder and good spark from both plugs.

I am now wondering if the cam ring is in the wrong postion?















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Offline iansoady

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Re: Pushrod question - problems starting new engine
« Reply #24 on: 15.02. 2011 13:56 »
Hi Duncan,

Unless I misunderstand, there should be two "thick parts" opposite each other so as to open the points twice for every revolution. You haven't by any chance got a cam ring from a K1F such as fitted to a Velo have you? You should see the points open twice for each mag revolution - these should be 180 degrees apart and should be the same gap.

But I expect you know this.....

Still, good progress - congratulations.
Ian.
1962 Golden Flash (arrived)
1955 Velo Viper/Venom (departed)
2004 Triumph Tiger 955i (staying)

Offline Duncan R

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Re: Pushrod question - problems starting new engine
« Reply #25 on: 15.02. 2011 14:05 »
Hi Ian,

Sorry, yes there are 2 thick parts (for want of a better description!) plugs are sparking alternatley. I will check the points gap on both cams to see if there is any diffrence. Are cam rings supposed to be that loose ? It fits in quite snug but you can twist it inside the housing
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Offline Alan @Ncl

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Re: Pushrod question - problems starting new engine
« Reply #26 on: 15.02. 2011 14:14 »
Hello Duncan
Can't remember if yours has a manual advance with moving camring but attach a pic of my old mag with a fixed ring (if any good).  There is a locating peg top right about 1 o'clock so only one place it can go.  On the pic, the ring is not driven fully in (and slightly out of line too I think) but you can see that where the camring starts to thicken, lines up with the brush holder holes.  Also the two lube holes are nearly in line (slightly clockwise) from the CB housing securing screw and pillar.

Don't think it should turn that freely but then again, I only know the fixed camring type.

Alan

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Re: Pushrod question - problems starting new engine
« Reply #27 on: 15.02. 2011 14:20 »
they twist if they are cable advance and retard but for an automatic advance /retard should be fixed, I would take it off again and check the locating pin, might need knocked through a bit ( this is what happened to mine - and same symptoms exactly)
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

Offline Duncan R

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Re: Pushrod question - problems starting new engine
« Reply #28 on: 15.02. 2011 15:43 »
Hi Alan and Bill,

I think it might be in the wrong postion - on the cam ring there is 3 cutouts no.1 is quite big (possibly for the manual control) no.2 is about half the size and 3rd is quite narrow and is cut at an angle, am now thinking the small cut out must fit over the locating or stop pin as that would give a tight fit and not allow the ring to twist in the housing. My mag is auto by the way. Sorry for the crap technical descriptions!

Thanks to all you guys for your help, it is very much appreciated.

Duncan
Anglo - Indian A7SS (Actually is a 650)
Kawasaki ZZR 1100
BMW R80GS
BMW R1100GS

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Re: Pushrod question - problems starting new engine
« Reply #29 on: 15.02. 2011 16:09 »
Here's a pic (I hope) of a bog standard  K2F manual camring. One hole, 2 cut-outs. The square-cornered wide notch is the one that goes at the bottom and allows ring rotation against the stop pin for adv/ret, the V-shaped one is for the end of the actuating hook on the A/R cable. Suspect your third notch been cut specifically to locate against the peg as required for use as a fixed ring. You ideally want a fixed cam ring and it wants to stay put when in its housing. If the small notch holds things together decently with no fretting and chatter then it will at least work, but it should normally be a tight fit, while the manual one obviously has to rotate quite easily.
Bill