The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: wole on 13.12. 2016 18:49

Title: 1960 a10 superocket hard starting
Post by: wole on 13.12. 2016 18:49
Hi all my superocket is a pig to start. In the past someone  I think has rebuilt it with a racing mag and proberly high lift cam and hc pistons. I am going to measure the lift of cam. When I have this measurement can the cam be identifiyed?. Also what cr pistons would give me Easy starting.thanks wole
Title: Re: 1960 a10 superocket hard starting
Post by: KiwiGF on 13.12. 2016 19:15
Does it not fire? Or is it just very had to kick it over?

My a10 gf is easy to kick over with a 356 cam and 7.25 cr Pistons.

I've kicked over an original a10 gf with 6.5cr and 334 cam and in comparison to mine could hardly feel the compression it was so easy to kick over!
Title: Re: 1960 a10 superocket hard starting
Post by: wole on 13.12. 2016 19:49
Hi it is fairly hard to kick over as I am 67 on full advance it kicks back. if slightly retarded it will not fire. I just have to kick it over on full advance until it does start
Title: Re: 1960 a10 superocket hard starting
Post by: Bsareg on 13.12. 2016 20:10
Sounds like a weak mag. Do you have a good spark when retarded?
Title: Re: 1960 a10 superocket hard starting
Post by: RichardL on 13.12. 2016 20:18
Could be the mag, but spark strength is easy to check. Also, could be that ol' devil pilot jet gunked up. My guess is that the first few kicks are not a problem but it gets harder as exhaustion sets in.

What's the plan for measuriing lift, dial indiacator on the end of the rocker arm?

Richard L.
Title: Re: 1960 a10 superocket hard starting
Post by: RichardL on 13.12. 2016 20:20
Here are the cam profiles: http://atlanticgreen.com/images/356-357.jpg
Title: Re: 1960 a10 superocket hard starting
Post by: Topdad on 14.12. 2016 11:01
have you checked the timing .if so what was the figure btdc. my cr is 8.25 ,spitfire cam whilst good comp not that hard to crank ,I'm nearly 67 ( jan ) ( *whistle*date can be provided for any donations ) 
Title: Re: 1960 a10 superocket hard starting
Post by: muskrat on 14.12. 2016 11:06
G'day wole.
Are you 100% sure the timing is correct? With manual advance/retard loose wire = advanced, tight wire = retard.
Cheers
Topdad beat me to it.
Title: Re: 1960 a10 superocket hard starting
Post by: wole on 14.12. 2016 16:01
Hi I have set timing to the Manuel. Which I believe is 3/8 Btdc fully advanced
Title: Re: 1960 a10 superocket hard starting
Post by: chaterlea25 on 14.12. 2016 18:06
Hi,
+ 1 on all the previous suggestions,
As you are losing spark strength when you retard the mag, one or two pointers that may help
Very few mag guys have the proper strength magnetiser to remagnetise the mag once its assembled
Some were also fitting sub standard capacitors that are not up to the job ??
Check the points for blackening ? clean them and see if starting improves ?
I think you will find that 3/8in. BTDC is a bit too much with the fuel we have to cope with now a days
I would bring it back to nearer 5/16in.

I have a Super Rocket in a similar state of tune, manual mag etc, I found it runs and starts better at 35 degrees before TDC (if my memory is correct??)

John

Title: Re: 1960 a10 superocket hard starting
Post by: RichardL on 14.12. 2016 19:07
Never having had to (gotten to?) start a manual.advance bike, I made the assumption that if the timing can be advanced to the point of kickback, it could be retarded to the right spot for starting. Wouldn't this make the setting of timing at full advance less critical, since it can be backed off manually?

Richard L.
Title: Re: 1960 a10 superocket hard starting
Post by: Bsareg on 14.12. 2016 19:41
Auto timed mags open the points when the armature is around max magnetic flux density,   on manual mags retarding  ignition brings points away from the most efficient fluxes density causing reduction of ht voltage at the plug
Title: Re: 1960 a10 superocket hard starting
Post by: Triton Thrasher on 14.12. 2016 19:46
With manual advance/retard loose wire = advanced, tight wire = retard.

Should be, but it's not impossible to have the opposite.
Title: Re: 1960 a10 superocket hard starting
Post by: wole on 14.12. 2016 21:02
Yes I agree with richard. I can adjust the timing to where ever needed.but if I retard it even slightly it does not fire
Title: Re: 1960 a10 superocket hard starting
Post by: Bsareg on 14.12. 2016 21:07
Retard your ignition and look at the colour of the spark, should be blue with an audible  snap. A pink spark will be useless under cylinder compresstion
Title: Re: 1960 a10 superocket hard starting
Post by: Rocket Racer on 16.12. 2016 03:22
When it is running does it idle nicely with clean pick up (so you can eliminate mixture). A poor mag will also often not cope with a low idle. It might pay to see if your mag will support a low idle for testing purposes.

my 60 SR runs a TT carb and still starts 1st kick (most of the time  ;) ) but does have an electronic bt-h mag
my manual ignition on my b33 will chuff away at a rediculously low idle like a clock.
for the single I retard just below kickback.

I don't believe the mag or compression should be an issue, so something isnt quite right
Title: Re: 1960 a10 superocket hard starting
Post by: worntorn on 16.12. 2016 16:14
Hi all my superocket is a pig to start. In the past someone  I think has rebuilt it with a racing mag and proberly high lift cam and hc pistons. I am going to measure the lift of cam. When I have this measurement can the cam be identifiyed?. Also what cr pistons would give me Easy starting.thanks wole

The 357 cam or any high lift, big overlap cam will make the engine easier to kick over than the same CR engine with a smaller cam, ie 356. This is due to compression that is lost at kick over speed and low speed with the increased overlap.

Glen
Title: Re: 1960 a10 superocket hard starting
Post by: wole on 18.12. 2016 11:18
Hi all thanks for your replies. From what you are all saying it seems like a spark and timing issue. I am going to look into this problem in the week after Christmas while I am off work. Just an update the mag is a racing mag overhauled by Dave Lindsey from the Midlands. I think I can rule out timing as it is manual so it can be moved to where ever you want it. The plugs are new n3c. I did have a problem it started firing on one which turned out to be a faulty new plug cap.I fitters new pair of ngk caps.I don't know if they are resisterized or not? Back to my first question.do you think high lift cam or hc pistols could cause hard starting. I was thinking about a electric start conversion but reading about it my bike would have to be in a 100% starting condition with a auto advance fitted or they don't electric start very well and I would be back to square one about two grand lighter0
Title: Re: 1960 a10 superocket hard starting
Post by: chaterlea25 on 18.12. 2016 17:33
Hi Wole,
The plug caps will have some writing on them something like 5k, you do not want these
You need non resistor caps NGK non resistor caps are black, but black does not guarantee non resistor
check that the plugs are non resistor as well
Some carbon brushes are also high resistance,
Mr lindsey is not without his faux paus, one mag from him had insulating varnish where the earth brush runs *ex*
Have you cleaned  and checked the points gap as I asked?
If the gap is out of spec then the mag will not spark at its best
If the mag spark strength falls immediately  you move away from full advance then theres a problem
Sort this and the bike will be fine

John


Title: Re: 1960 a10 superocket hard starting
Post by: muskrat on 18.12. 2016 19:01
G'day wole.
Get a pair of these,
http://www.ebay.com.au/itm/NGK-LZFH-NON-Resistor-Spark-Plug-Cap-Cover-Black-90-8710-/281561932902
The wife and neighbors might winge about TV reception when you start the bike *ex*.
Do as John said, then get a fresh set of eyes to check your timing.
Cheers
Title: Re: 1960 a10 superocket hard starting
Post by: wole on 18.12. 2016 20:37
Hi thanks just orders new caps f the neighbours  *smile*
Title: Re: 1960 a10 superocket hard starting
Post by: edboy on 20.12. 2016 01:36
just my tuppence worth on this story.
remove the points and check they are good condition. a sideview is not good enougth.
Title: Re: 1960 a10 superocket hard starting
Post by: JulianM on 05.02. 2017 13:04
Hi guys,

This sounds like a typical mag problem to me, I even had it on my Scrambler, (which by the way starts very easily now, If you have a strong leg - 777cc and 11:1)

When the mag is timed internally to the points it needs to be assembled so that the points are just opening about a nano second after the point of maximum flux, Flux is the point that the magnets have generated their max voltage in the coil,   This is a little funny as it needs to be at two places at the same time with a manual advance.  Advanced and retarded,  get this wrong and the spark will be too weak at one place or the other. Especially if the mag is a little tired.
Easiest answer is to give it to a good mag guy to check it over and tell (ask) him to make sure it sparks correctly at both full advance and retard.  And test it by hand when you collect it.   Or put it on the bench and mess with it until it works. That's what I did and it's lovely now.

Out of interest, after my initial struggle I fitted a brand new BTH batteryless K2F type magneto and this would not run the bike at all, Tiny little spark and nothing, only a very occasional pop.  The spark was so weak and small there was no way in my opinion it was going to run my engine. 700 quid wasted.  The original K2F Wader mag now works very well.
 
In essence, If you are strong enough and kick it with a good lot of body weight behind you, and kick it right through the full stroke from Just past TDC then you can start anything. High compression, twin carbs, and fast cams. 
Just also check that the bike is not wet sumped, this makes for one hell of a diference in kicking power needed, and therefore harder also for the engine to "catch"

Good luck,
Julian


Title: Re: 1960 a10 superocket hard starting
Post by: KiwiGF on 05.02. 2017 19:24
http://www.metservice.com/towns-cities/masterton guys,


Out of interest, after my initial struggle I fitted a brand new BTH batteryless K2F type magneto and this would not run the bike at all, Tiny little spark and nothing, only a very occasional pop.  The spark was so weak and small there was no way in my opinion it was going to run my engine. 700 quid wasted.  The original K2F Wader mag now works very well.
 


I have a BTH mag fitted to my A10, but just with flat top Pistons, it works fine but like you I noticed the spark is much weaker looking than a standard mag, I've been told this is normal and is because the voltage is higher. I wonder if there was another problem that caused it not to work on your engine, for example I had real problems getting the timing right, as the BTH timing pin method did not work due to sloppy tolerances etc.

Ps please send the BTH mag to me rather than toss it  *whistle*
Title: Re: 1960 a10 superocket hard starting
Post by: Klaus on 05.02. 2017 20:16
Hi guys,

This sounds like a typical mag problem to me, I even had it on my Scrambler, (which by the way starts very easily now, If you have a strong leg - 777cc and 11:1)


Julian

Oh thats sound good you have over 750 cc on a A10 engine??????
I m intressed to know whats inside this engine.

cheers Klaus
Title: Re: 1960 a10 superocket hard starting
Post by: Greybeard on 05.02. 2017 20:57
...Oh thats sound good you have over 750 cc on a A10 engine??????
I m intressed to know whats inside this engine.
Start here:
http://www.a7a10.net/forum/index.php?topic=6024.0
Title: Re: 1960 a10 superocket hard starting
Post by: Klaus on 05.02. 2017 21:57
Thank you, thats what I m looking for *loveit*
Title: Re: 1960 a10 superocket hard starting
Post by: worntorn on 14.04. 2017 04:57
Wole never did finish this one off . Hope he solved the starting problem,and if so, please let us know what the fix was. I don't see plug gap mentioned anywhere above, however I was reminded today that a few thou here can really make a difference, especially with a mag.
I've fiddled and fettled away at this 63 SR and now it runs very nicely, however starting was still difficult now and then. I've been suspicious of the new carb. I've even pondered fitting ei and forsaking the old mag.
Finally remembered today  that mags do not do well with a widish gap at kick over  speed.
28 thou is the spark plug gap which I have been using on the points coil and Ei bikes for a long time now. It's been forty years since
I last relied on a Lucas mag for sparks, so much has been forgotten​.
A while after fixing the mag ((easycap) the plugs were changed and that is the gap I set them at.
Narrowed the gap to 19 thou as the book advises (18min, 20 max) and it now starts in a single kick every time, hot or cold.
Amazing how well things go when one follows the strunctions, as my 3 year old granddaughter calls them.

Glen
Title: Re: 1960 a10 superocket hard starting
Post by: muskrat on 14.04. 2017 10:27
Yes a common male problem. "If all else fails, read the instructions".
Only with Boyer going from 30 to 25 helped.
Cheers
Title: Re: 1960 a10 superocket hard starting
Post by: Black Sheep on 15.04. 2017 06:58
One other thing. N3 plugs are a bit on the hard (cold) side for a SR. N4 would be more appropriate. I would suggest NGK B7ES which I have used successfully for many years. For whatever reason, my bikes (and Land Rovers) just don't get along with Champion plugs. I have had them fail in less than 20 miles (N3 in this instance) but have never been let down by an NGK.
Title: Re: 1960 a10 superocket hard starting
Post by: duTch on 15.04. 2017 09:43

  *ex*choke gag*ex*
Quote
"If all else fails, read the instructions".
...have to admit, when I buy things (not BSA), these days I've started flicking through the accompanying reading material...doesn't usually last long but at least I tried- but usually have to come back to it *rant*

  I've been having better luck with B6ES for a while, but depends on circumstance
Title: Re: 1960 a10 superocket hard starting
Post by: Greybeard on 15.04. 2017 10:02
...these days I've started flicking through the accompanying reading material...doesn't usually last long but at least tried- but usually have to come back to it *rant*
If it's written in Korean/Chinese/Japanese pidgin English, good luck!
Title: Re: 1960 a10 superocket hard starting
Post by: duTch on 15.04. 2017 13:25
 
 I don't care what Lingo it's in, best I can do is have a shot- worst can happen is I might learn a word or two in another lingo, there's lots who come who are canned for not speaking 'English' but can speak a multitude of others