The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: lawnmowerman on 18.05. 2010 19:01

Title: My A10 SR now on the road - well sort of.............
Post by: lawnmowerman on 18.05. 2010 19:01
Hi All

I bought my SR last November in a newly rebuilt state but not registered. Having gone through the usual ordeal with DVLA I finally got the V5 with the correct details in April - just as well being as the weather here has been awful so I have been waiting for some decent weather for the first ride out.

During the winter months I went over the bike with some spanners and checked all the nuts and bolts (some were only finger tight) and got an MOT certificate. I decided to fit twin goldie silencers and they sound awesome!

I have now taken her out about five times - only short journeys of about ten miles. As the engine is newly rebuilt I have been taking it easy and everything seems OK - no oil leaks, plenty of power and a lovely sound. On the first couple of trips she started easily and did not miss a beat but on the later trips seemed a bit difficult to start and when she did start only started on one cylinder. There were also times when she started misfiring under load. I fitted new Champion N4Cs which did not seem to make much difference and sooted up quite quickly. On the last trip out I tried turning both fuel taps on as it sounded like fuel starvation and it did not miss a beat.

A mate of mine who is a Manx Norton engine specialist recommended NGK so I checked the NGK website and ordered some BR7EIX 6664 as recommended by NGK (what are all those letters and numbers?) I fitted the plugs today and I thought I would take the tank off and flush it out. There was loads of paint overspray and peeling paint in the petrol when I tipped it out into a bucket ? wouldn?t have taken much effort to mask off the filler hole when it was sprayed! I filtered the petrol, refilled the tank and shook it around and I heard something rattling inside. I fished around and pulled out a piece of debris which looked like a chunk of resin shaped like it was in the front right hand bottom corner of the tank (see pic). Looks like it may have been the last remains of a tank of petrol which had evaporated away and left a solid chunk of residue which had set solid ? probably came loose when I started riding the bike over a few bumps. Can?t think what else it could be unless anyone else has some ideas.
While I was at it, I removed the taps (see pics) to clean out the gauze filters. There was muck on the gauze but more worryingly I could not blow through one of the taps. I shoved a bit of wire through the tap and cleaned it out and I found that the hole through the tap was only about 1/8? when fully open. I refilled the tank with clean fuel and tried the taps and just got a trickle from both of them ? no wonder it takes so long to tickle the carb. Has anybody else got this type of tap and can anybody recommend a UK supplier who sells angled taps with a better flow rate?

The weather man says it is going to be 25 C later this week so I will be out for a run to see if there are any improvements.

Title: Re: My A10 SR now on the road - well sort of.............
Post by: bsa-bill on 18.05. 2010 20:43
I think your debris that looks like a piece of resin could well be debris that IS a piece of resin that has broken off  - either because the tank has been repaired with a resin based filler or it may have been sealed with tank sealer.
Taps might be suffering from encounter with same bits of resin ??

Have another look in the tank see if you can see if it's been sealed, let us know what you find

All the best - Bill
Title: Re: My A10 SR now on the road - well sort of.............
Post by: beezalex on 18.05. 2010 21:06
Yup, I've had the same problem with those types of repro taps.  Not only do they swell up and close the fuel hole but both sets I got (before I finally gave up) had significant burring around the holes through the cylinders which was tearing the rubber.  You can make them work okay if you take them apart, clean up the burrs and enlarge the holes with an exacto knife.  Eventually, however, they will swell and fail again. 

Personally, I like the original style cork push-pull petcocks.  You can always replace the cork in those and they flow well.
Title: Re: My A10 SR now on the road - well sort of.............
Post by: chaterlea25 on 18.05. 2010 22:17
Hi Lawnmowerman,
As far as I know NGK BR7EIX 6664 are resistor type plugs, the "R" in the number is significant
These are not suitable for magneto ignition bikes!!
Ordinary NGK  B6 or B7's are what you need
John O R
Title: Re: My A10 SR now on the road - well sort of.............
Post by: lawnmowerman on 19.05. 2010 09:11
Bill, I have looked at the bottom of the tank under where I believe the piece of debris came from and it is difficult to tell if it has been repaired from the outside as the tank has been resprayed and it looks perfect. I do not think that the piece of resin was actually doing any thing to seal the tank as it was only gravity that was keeping it where it was and if there was a leak it would have shown on the outside by now (I hope). Perhaps it was an earlier repair which was fixed by a braze on the outside before the tank was resprayed. Do you think there is too much to be petrol residue from evaporation over the years that the bike was standing prior to restoration. The PO may have added upper cylinder lubricant to the fuel or, like I did back in the day before I knew better, a capful of Castrol R just for the smell.
I held the piece of resin up to the sun today and it is a translucent amber colour, slightly flexible but will crack, not crumble if broken. It smells of stale petrol and I set fire to a piece and it burns quite well with loads of black smoke. I have heard stories about carbs being bunged up with petrol evaporation residue and I thought it may be that on a larger scale.
John, thanks for the plug info. It is particularly worrying as I went on the NGK website before buying and my bike is listed and that is the exact plug that is recommended. The bike starts up OK on them but I have not tried it on the road yet. Any plug experts out there?
Alex, I tend to agree - I never had too much trouble with the old cork taps originally fitted to all british bikes. OK they did leak after a while but not too difficult to change the corks. Anyone know a good UK supplier?

Ride safe
Title: Re: My A10 SR now on the road - well sort of.............
Post by: bsa-bill on 19.05. 2010 10:05
If the tank is not leaking then your probably right, I stored some cork inserts in petrol once and after about a year the petrol had evaporated and left an amber coloured jelly so maybe your resin is just that with a few more years added as you say.
Funny thing is I washed the corks and jar out and stored them again in petrol, this has been in the jar for around seven years now and is still petrol, I wonder if there is a difference in petrols or maybe I have the jar sealed this time.
The tap problem is one I know nothing about as yet but I do have this type to fit on my project so I'm all ears (eyes to be more precise)

Enjoy your run, weather up here is great this morning (warm), I've a few jobs to get done in the garden, then I should get to the Flash get it road going, get back to the project get it finished by which time it will probably be cats and dogs, the emergency budget will have put petrol out of reach and the old boss will temp me back out of retirement with riches to supplement my pension which will no doubt go downhill with this lot in charge .

mustn't grumble   

All the best - Bill                             
Title: Re: My A10 SR now on the road - well sort of.............
Post by: lawnmowerman on 19.05. 2010 10:29
Thanks Bill. Looks like I do have petrol residue but on a larger scale than you had in your jar, At least I can burn it on the fire after that "austerity" budget next month. I am definitely going to change my taps as the hole seems far too small and as Alex said, the holes seem to close up after use and restrict fuel flow even further. I wonder if a full flow brass ball valve similar to a washing machine tap design which is petrol proof could be used?

John, I have just spoken to NGK UK tech advice and they are saying that the BR7 EIX  stock no 6664 is the recommended Iridium plug for the SR but if the mag is not up to spec then starting problems may be experienced with the inbuilt resistor. The standard plug is B7 ES stock no 1111.
While I was at a classic bike jumble last Sunday I was tempted by some Spitfire Multispark units which I have fitted. The manufacturer was there demonstrating them and they looked quite impressive - without the units a single spark and with it, something like an African  thunderstorm. Whether it performs the same under operating conditions is another story. Only time will tell.
The bike starts OK so either the mag is good or the multisparks are having an effect. I also bought some snake oil...........

Title: Re: My A10 SR now on the road - well sort of.............
Post by: brackenfel on 19.05. 2010 13:17
Hi Jim,
A word about spark plugs.. A while back my A10 (before I tore it to bits to fix "the odd thing or two") started fine, ran rough and then I had only one cylinder.. Thinking the worst I checked compression etc, then found I only had one spark....  Luckily I had an old plug, swapped it and then had sparks on both cylinders...
Didn't think much about it as I then started the dismantling process..

A month later I decided to give the Laverda SF1 a run.. Started fine , up the (steep) drive ok.. Then started to misfire & a run up the road and I had a 375cc single on my hands.. Again, thinking "bloody carbs" I went back to the garage & checked.. I found that I had no spark on one side... Sound familiar???
An "old" plug substitued and normal service resumed..

NB BOTH plugs were NGK, both had less than 50 miles on, BOTH were brand new....

Maybe something to consider - to think I used to moan about Champion but recently I've found them to be pretty good...


Title: Re: My A10 SR now on the road - well sort of.............
Post by: MG on 19.05. 2010 13:52
I think I have expressed my exaltation about NKG's VX plugs in several other, similar threads already...  *smile* wink2

However, the one thing that kills plugs rather quickly, whatever make or price, is short distance riding. The plugs have to get hot, taking the bike out for a short run around the corner and back home or quickly trying/adjusting the carbs and putting the bike back into the garage half-warm is what causes failure in no time.

Just a point to consider.

Cheers, Markus
Title: Re: My A10 SR now on the road - well sort of.............
Post by: brackenfel on 19.05. 2010 21:52
Hi Markus,
I'm sure you're right as both bikes would have had this treatment.. Interestingly though the "old" plugs don't seem to mind as much.... *conf*

Title: Re: My A10 SR now on the road - well sort of.............
Post by: lawnmowerman on 21.05. 2010 20:17
Just put another 20 miles or so on the bike and cleaning out the fuel taps seems to have done the trick - the previous misfiring problem must have been fuel starvation.
I have noticed a couple of things. Firstly I seem to have some drips of oil from the tacho cable above the nut on the cable where it joins the angled connector on the side of the timing case. Is it a case of "it's a BSA sir - they all do that" or should there be some sort of seal.
Secondly I seem to have a problem starting. I usually put the A/R lever to full retard when starting and it eventually starts on one cylinder and the other one cuts in when I turn the lever to full advance. When I started up outside the pub tonight with the back end facing the open bar door I got a really loud backfire which bought a few screams from the girls at the bar.
When I got home I tried starting on full advance which produced the predictable kickback but it seems to start ok on the midway setting halfway between full advance and full retard without breaking my ankle. Not sure how many degrees the lever produces but I get no pinking on full advance. Will using too much retard cause the starting problems I am experiencing?
BTW I have just changed to NGK Iridium IX plugs so could they be more fussy than the old Champion N4Cs when starting?
Any thoughts appreciated.

Title: Re: My A10 SR now on the road - well sort of.............
Post by: a101960 on 21.05. 2010 22:41
Starting on one cylinder used to be a problem on my bike and more specifically it was the drive side cylinder. I changed the HT lead even though it looked O.K. doing that cured the problem. One other suggestion. As a rough guide make sure that the pilot adjust screw is about one and a half turns out. That is about the right setting for first or second kick start.

Title: Re: My A10 SR now on the road - well sort of.............
Post by: trevinoz on 21.05. 2010 23:26
         If you pull out the tacho drive shaft you see [or not] a very small o ring on it which should seal it to the housing.
I don't like this set up so I counter bored the housing base to accept an o ring which is a nice tight fit between the housing and shaft. This is A65 practice I believe.