New Owner needs a little help? (cut out when hot)

[bigwol]

G'day Bigwol, tappet clearances cold, iron head 10 in 16 ex, alloy head 8 in 12 ex.
I run my alloy head A7 at 8 and 12 but the alloy head A10 needs 10 and 14 to stop it happening.
Cheers

Many thanks Muskrat

[stu.andrews]

Hi bigwol, welcome to the forum. There are guys on here with a mine of information, so, keep asking!
I had my magneto reconditioned by a guy named Paul Lydford. He did a dynamo for me several years back & his workmanship is first class.
He lives in Shaftesbury, Wilts (1 Maple Close to be precise) but he has a business namely APL Magnetos. Phone no. 01747 852136. His normal turn round time is about 2 weeks. As far as charges are concerned, I can't help you on this as the work on my A7 was done as part of a warranty issue after buying the bike from a dealer. The dealer paid for the magneto to be reconditioned.
When cold the bike would start, run & tick over, but when hot, would tend to misfire & would not idle or start. It is the all too well known symptoms of a magneto condenser failing when hot. They seem to have a varied life span, mine lasted 51 years so, for once, we must congratulate Joseph Lucas!
Have a chat with Paul. He is very helpful. If you have not removed a magneto before & it has an automatic advance unit, then the securing nut is also the puller. Read about it before trying to remove.

Hope this helps

Regards


Stu

[bigwol]

Thanks for the welcome Stu. There is no sign of a missfire with my bike, just gradual loss of power till it stops. No coughing spluttering farting or banging!
The mag was refurbed for the PO about a year ago so should be ok. The guy who did it has been great saying if it turns out to be the mag he will sort it under guarantee. My next step is to have the carb off and see if there is any crap in there and clean it out, tank too if needed. If the tanks off i'll check the tappetts and compression and see where we go from there.
Good job i have some holiday coming up!
Dave

[raindodger]

Hello, Bigwol.

     Your problem puts me in mind of some trouble I had on a B31.  The hole in the fuel tank cap was blocked, it ran well at low speeds but ran out of steam when asked to keep up on a club run.   Clearing the breather hole cured the problem.  Hope yours is as simple.
Regards.
Raindodger

[bigwol]

Hello, Bigwol.

     Your problem puts me in mind of some trouble I had on a B31.  The hole in the fuel tank cap was blocked, it ran well at low speeds but ran out of steam when asked to keep up on a club run.   Clearing the breather hole cured the problem.  Hope yours is as simple.
Regards.
Raindodger

Hadn't thought of that one Raindodger, a mate of mine had the same thing happen on his Matchless G12. (Someone had put blue tack in the hole!) Will give it a look see. 

[bigwol]

Update guys.
Yesterday I got a few hours in the shed and looked the A7 over.
No sign of anything in the carb other than petrol. Same with the tank.
I did find the HT leads a little loose at the Mag and the rubber plug caps could be in better condition so will order new leads and caps but doubt they were the cause.
Checked the tappetts. Way too tight for 10 and 16 as for iron head. Re-set them and fired it up and wow, ran at way too high revs for tick over, i'd guess at 2000? Took carb back off, rechecked cable route but still the same. Seems it must have ran rough - because of the tappetts? (although there was clearance when cold of some kind) - so someone had not only wound the slide stop up but also the cable adjuster! Re-set throttle cable, stop and air screw and she ticks over like a watch. Was going to go for a decent ride this morning to see if I've cured it but of course it's peeing down!
Will keep you all informed, and thanks again to all who replied and posted suggestions, much appreciated.
Bigwol.

[duTch]

If you go out anyway, it won't get hot enough to stop anyway....(water cooled) .??
 But if it did that'd be a bitch= time for hot toddies!
 
Hope that's the prob tho', and good on ya for persevering, good luck& cheers

[trevinoz]

Bigwol,
                You should adjust the tappets as per the camshaft fitted, not the head material.

  Trev.

[bigwol]

Bigwol,
                You should adjust the tappets as per the camshaft fitted, not the head material.

  Trev.

Absolutely Trev, to the best of my knowledge it's a standard engine, and as it came from the factory. (Numbers match the old green log book)
I did about 60 miles round trip yesterday, stopping roughly mid way for a tea and a sausage sandwich, and it was fine. Not as hot a day as last week when i had the issues though.
Someone loaned me a copy of "BSA A7 & A10 Twins, Super Profile, by Owen Wright, a Haynes tome. Looking at the spec sheet in that from '58 A7 tappetts are 8 thou both inlet and exhaust and from '59 all models were fitted with the "sports" cams from the Shooting Star variant. Shooting Star model tappetts are listed as 8 thou in and 10thou ex. from '58. It's all very confusing!
I will run it as it is at the moment and see how she performs on hot days (assumming we get any more) and see if I have  recurrence of the problem. I may even try re-setting the tappetts as listed and see if it returns. I also have a Haynes on order and will try to get along to the local OC section meeting at some point.
I've had to fit a replacement light switch and for the life of me cannot see a way of wiring it so the side lamp goes out when the headlights are live. Couldnt follow the old wiring as the switch fell apart in the headlamp shell when the bacolite disintigrated! At least it's road legal.
I have to say it does ride nice!
Again thanks to those who contributed to helping me sort it out.
Bigwol

[bsa-bill]

scuse my ignorance chaps but why should the clearance at the tappets be differrent because the cam lifts higher, I know it is cause BSA said so.
Is it due not to the camshaft profile but because with that camshaft the engine might run hotter and isn't that why it has an alloy head to keep it cooler

[bigwol]

Still not had a chance to give the A7 a damn good thrashing to see if the problem has been cured. Took it in for MOT in the week, passed with flying colours - and promptly got a puncture which I just havnt had time to fix. 

[warmshed]

scuse my ignorance chaps but why should the clearance at the tappets be differrent because the cam lifts higher, I know it is cause BSA said so.
Is it due not to the camshaft profile but because with that camshaft the engine might run hotter and isn't that why it has an alloy head to keep it cooler

I think it has something to do with the cam profile rather than the max lift. The cam may also have quietening ramps etc, so follow manufacturer's recommendation when setting the tappets.

[ian davies]

Hi. Had the same problem with my A7. just did'nt want to start when hot so i fitted a Brightspark condenser, problem cured.Cheers Ian.

[bigwol]

Not having the best of luck with my first BSA guys, got the puncture sorted the other week, took it to work (about a 20mile run each way,) and she is noisy and has a fair bit of oil on the drive side cylinder. I suspect a big end on the way out so will not run her again until i've investigated. Are these a noisy engine? I was at a show the other week when someone started up what i think was a C15 and that sounded pretty awful too, the guy rode away on it and didnt seem that bothered. Maybe my AMC's are just quieter bikes!
When i get time - never seem to get any of that - I'll take the head off and see if the conrods move on the journals. Will keep you posted .....

[Butch (cb)]

Well if you run your BSA alongside a Triumph you shouldn't be able to hear yours.