The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Amal, Carburation, Fuel => Topic started by: Liakos1982 on 30.04. 2015 09:12
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So I have been troubleshooting some starting problems. My 58 10SR can take 10-15 kicks to start when cold, but after a ride to get warmed up, kicks on the first, guaranteed. I have a fresh magneto, so I have been trying different cold starting techniques but am running out of patience, so I need some help!
When A10 owners talk about tickling, flooding the carb, what exactly does this mean? I depress the carb until fuel flows out of it. But this does nothing to help start. Do I need to do this repeatedly?
Choke seems to make no difference either, opened closed no difference...
After numerous attempts to start the bike, I have removed the spark plugs, which appear bone dry.
If one was to make a diagnostic, methodical list of troubleshooting a hard starter, with a fresh magneto, what would you suggest?
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Hi , they sometimes can be quirky ( read pain in the idiot ) but really it should be a second/third kick at most . Tickling is just flooding as you appear to be doing ,re the choke mine doesn't really make any difference except when really cold and have in the past not had one without any starting issues . By the way you say new magneto I'd still check points for being clean and gap and also clean the slip ring with a clean cloth and check the pickups there are some dodgy ones about ,if you get a lot of black of the slip ring they may be to soft.
My starting ritual is this , petrol on, flood carb set choke about qtr open set the piston up on the kickstart for a good swing and kick away opening the throttle slightly during the kick . As soon as it starts choke progressively opened up . Take off cap on oil tank check return and away. That's my way sure others do it differently but it works for me and has done for many years , best of luck, Bob
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Are you giving it plenty of throttle after flooding it? Unlike most modern bikes they usually won't start with the throttle shut or only opened a little. About a third open works for me.
If it starts but stalls shortly after they usually need flooding again.
It's an art to work out whether to flood (tickle) the carb when the engine is halfway between hot and cold......flooding should not be needed when the engine is warm.
My bike does not need the choke, it has one but for some reason it makes almost no difference using it!
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G'day Liakos. This topic could describe my missus *ex* *ex* *bash*
Cold motors usually need a rich mixture, hot a bit leaner, hence ticklers and choke. You say that you tickle till fuel comes out but the plugs are dry *ex* The float height may be too low so after the initial flooding and a few kicks, it's now not getting enough. Take the plug leads off, tickle the carb, give her a few kicks and take the plugs out. They should be wet but not dripping.
Cheers
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On my '58 iron head I tickle until gas issues forth. Usually it will give a sign of life on the first kick and if I'm lucky and can catch it and have it running. If not, I'll quite often give it another tickle on the grounds that if it fired at all it used up all of the first lot. And yeah the choke seems to make very little difference so I usually don't bother with it. I guess I'm using some throttle as I kick. I'm on a concentric of some kind.
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I was to scared to say that .... in case it leaked back to "she who must be obeyed " Bob.
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Are you retarding the ignition too much, or is it automatic?
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It's automatic.
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Just a thought, but did you ever tried it without choke or tickling? If your mixture is a bit rich it may well need nothing at all when cold. *dunno*
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Ok! Thanks for all the help, I think I found a combo which works. I tickle the carb now, prime the motor, 3-4 strokes, find the compression stroke, re-tickle and presto, 1st kick she roars to life.
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Isn't that the same as sayng that it starts on the third or fourth kick?
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My plunger A10 ALWAYS starts first kick (like most of my A10's - but not all!).
356 cam
7.25:1 pistons
standard 276 carby
modified air cleaner (K & N insert)
31 degrees BTDC
tickle carby, choke fully closed and.........we have ignition!
https://www.youtube.com/watch?v=6--KI2_k344
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..., prime the motor, 3-4 strokes, find the compression stroke, ...
Isn't that the same as sayng that it starts on the third or fourth kick?
Would depend how many strokes to a kick / kicks to a stroke.... *conf*
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So I changed the spark plugs, and got a proper 1 kick, no priming!!! Yes! However, the brand new plug failed after a short ride 100km, max. Is there any reason why the plug would burn? I was running champion 4nc plugs they were purchased from de Groot in NL so they were correct for the aluminum block.
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You will have fouled the plugs. Do they have dry soot or oily black stuff on them?
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Sometimes new plugs just die.
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Sometimes new plugs just die
so true - but why considering the simplicity of design and the years that they have been making them
I sometimes wonder if there is some element of conductivity in the deposits left by modern fuel
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Sometimes new plugs just die
Yes that is oh so true, and even worse sometimes they are faulty straight out of the box. A while back I bought a new set of plugs for my car. The engine would rev freely with no load on it, but the car was undriveable due to the engine missing under load. I refitted the old plugs and it ran perfectly. Just because a set of plugs are new it does not mean that they good. At least I did not end up changing the coil, leads, distributer cap and other bits in an attempt to cure the problem. The plugs in question were Bosch. On my A10 I have always found Champion to be the most reliable plugs NGK plugs never seem to last very long for some inexplicable reason. Other people have had different experiences. It all seems to be a bit of a lottery to me. I would also suggest experimenting with the pilot mixture if the bike is hard to start when cold. I found that setting up the engine idle as described in the book was a bit suspect. The book settings were fine when the engine was hot, but the engine proved difficult to start when cold. A little tweak to richen the pilot and all was well. I have found this to be especially so if a colour tune is used. Start with the pilot screw at about 1- 1/2 turns and work from there. Well it worked for me anyway.
John
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I had a similar problem starting my bike from cold and I was getting frustrated and about to lose confidence in using it, however a friend gave me a tip which has made all the difference. He noticed that the bike had a concentric carb fitted and he said that when starting it I should keep the throttle closed, ie; no blips. I took his advice and now I tickle it, operate the choke lever a little, keep the throttle closed and kick. It seems to work, he doesn't know why this should be the case but it was something another BSA twin owner told him. Gus
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...when starting it I should keep the throttle closed...
I thought that was the standard advice when starting any engine. *grins*
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That may be so Graybeard but many riders blip the right twist grip when starting their machine! Gus.
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Sometimes new plugs just die
so true - but why considering the simplicity of design and the years that they have been making them
I sometimes wonder if there is some element of conductivity in the deposits left by modern fuel
In a word,
YES
Modern "fuel" which is not petrol is quite conductive at cylinder pressures.
Modern fuel can not be completely burned in our old cold air cooled engines which is another reason to starve the engine off because in the last few strokes the engine is running quite lean and will burn the crud left behind by modern fuel ( which is not petrol ).
Because our dinasaurs represent less than .00000000000000000000000000000000000000000000000000000000000001 % of spark plug sales now days, modern plugs are not designed for their benefit.
They are designed to be installed nto new era lean burn fuel injected engines which run too hot for glazed insulators.
have a close look at an old plug.
the insulator was nice and smooth with a shine on it.
Compare it to a modern plug & you will see the insulator is white and matt looking with no shine to it.
Thee new insulators pick up crud and form a conductive parth very easily
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Following Trevors theme of spark plugs, a few months back I was working on my triple and a mate who happens to be very clever who was helping me get it sorted, commented on my NGK plugs which I had bought and fitted without thinking. I cannot remember the exact discussion but the result was that I refitted the worn old champions and had an immediate improvement in starting the bike. Apparently current NGK plugs are designed for modern engines and if they foul will not clean them selves up...
My father in law has a 650 Benelli S2 which was also a very temperamental starter so I mentioned it to him and he swapped out his NGK's with new mexican champions and he couldnt believe the difference with starting.
After these two incidents I have bought champions for all my beesers *eek*
I had used NGK's for years but apparently they have changed the way the plugs are finished, something to do with the glazing *dunno*
Cannot claim its the root of all problems but amazing what difference plugs made in two old school engines.
Since fitting the champions I have not had to remove a plug for cleaning (famous last words that will no doubt bite me!)
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The thing you need to remember about Champions Vs NGK's it is apples Vs custard tarts.
Champions have a very very very wide range of not operating properly while NGK's have a very limited range of not functioning properly.
Go to any spark plug interchange site and you will see N3C's range from BP6 through to BP8 in NGK amd I have found that even BP5's work well to replace N3C's with modern fuel.
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The only time I've had plug troubles on the BSA's were on Chumpions. If it's tuned right the NGK's are fine.
Cheers
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In the past I'd not had any issues with NGK's but these issues occured with new plugs bought last year .
What I believe is that new NGK's are very prone to fouling (in some engines) and that once they do, they need cleaning. Whereas new (mexican made) champions don't have this issue.
My understanding is that NGK have altered the standard of the glazing and it can now cause problems in old engines.
All I'm suggesting is that if your plugs are fouling on start up and you suspect plugs, try another brand