Author Topic: Running out of puff  (Read 4097 times)

Offline Hubie

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Running out of puff
« on: 17.06. 2010 23:18 »
G'day all,

Have been reading with interest the problem child a10gf of a10sausage.   I note with interest how his bike is pulling strong uphill at 70mph.  My bike revs very cleanly and well throughout the range in the first three gears and will sit on 60 in top fairly well but try and give it any more wellie and progress is very slow to increase.  I know I have my carb jetted right but I am wondering why I run out of steam beyond 60.  The bike should cruise pretty easily at 70.

I have a mk1 concentric on it with a 230 main jet which according to what I have read is about right.  If I turn the air lever open while riding, it slows it down so the bike is not too lean, nor is it too rich.  Standard magneto with the timing properly set up.  It is a one kick start every day and runs fantastically except for when described above.

Any thoughts would be appreciated.

Cheers,


Dave.
1959 BSA Golden Flash
1956 Royal Enfield Super Meteor
1955 Royal Enfield 350 Bullet
2007 Harley Davidson Sportster 1200 Custom

The early bird gets the worm, but the second mouse get's the cheese!

Offline trevinoz

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Re: Running out of puff
« Reply #1 on: 17.06. 2010 23:33 »
Have you tried changing down to third and opening it up? If so, does it accelerate?
Do you still have the 24 tooth engine sprocket fitted? If so, top gear is now like an over-drive and your engine will probably struggle to accelerate.
Trev.

Offline muskrat

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Re: Running out of puff
« Reply #2 on: 18.06. 2010 09:32 »
I think Trev hit the nail on the head. With a tall primary even my fire breathing cafe has to go back a gear at 60 to accelerate quickly.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline Hubie

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Re: Running out of puff
« Reply #3 on: 18.06. 2010 13:14 »
Now that I have the rest of the bike sorted, will have to do some playing and see what happens.  Will post on my progress.

Cheers

Dave.
1959 BSA Golden Flash
1956 Royal Enfield Super Meteor
1955 Royal Enfield 350 Bullet
2007 Harley Davidson Sportster 1200 Custom

The early bird gets the worm, but the second mouse get's the cheese!

Online BSA_54A10

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Re: Running out of puff
« Reply #4 on: 19.06. 2010 13:00 »
Quote
Standard magneto with the timing properly set up.  It is a one kick start every day and runs fantastically except for when described above.

As BSA instructed for the fuel that was available when it was new or slightly further advanced to compensate for the light fuel oil that we get now days ?

Try changing the points to change the timing.
Rule of thumb .001" = 2 deg.
Close it down to advance
Open it up to retard.

A lot easier for experimenting than pulling the timing gear off.
Bike Beesa
Trevor

Offline a101960

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Re: Running out of puff
« Reply #5 on: 19.06. 2010 15:00 »
An interesting topic. I have an RGS  and the recommended ignition setting is 3/8 BTDC. At this setting there is no doubt about it, it goes very well, but it pinks under load. I use 99 octane petrol. Backing off to 5/16 reduces the the tendency to pink, but also reduces performance. What is interesting is the fact that the road test published in the 'Motorcycle' magazine back in the sixties comments on the tendency of the engine to pink even on 5 star petrol. Now,I have no wish to burn holes in my pistons, or to knock out my bottom end, so I run my engine on the 5/16 BTDC setting. It would seem to me that the price of of opting for more go is a shorter engine life due to the stress imposed by more advanced ignition. I am not one of those people that enjoy stripping down and rebuilding engines. I just want to ride the bike. The late Bob Currie wrote about how BSA twins did not like pool petrol, and how they tended to run on and pink. http://tetraboost.com/ is one product that is available that can provide genuine leaded fuel. But be aware this is not a cheap option. I have tried using this product, and I could not determine any real difference (at 3/8 BTDC). The engine still pinked under load.

John

Offline muskrat

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Re: Running out of puff
« Reply #6 on: 19.06. 2010 21:00 »
G'day John,
                   that stuff sounds great, but down here any lead additive is illegal (bloody tree hugers). They are even taking standard unleaded off the market and replacing it with E10. I use Nulon octane boost and a smig of R30 oil.
 Try going a little richer with the carb settings eg. from #3 1/2 slide to a #3, raise the needle 1 notch. You may need a hotter plug, from B7ES to a B6ES, but you will be able to advance back up to 3/8". Worked with mine.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline bonny

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Re: Running out of puff
« Reply #7 on: 19.06. 2010 22:51 »
what is the speed an a10 in standard flash tune will sit comfortably at on the road with out shaking itself to bits ? 

Offline trevinoz

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Re: Running out of puff
« Reply #8 on: 19.06. 2010 22:58 »
Bonny,
               That will depend on how well your engine is balanced.
             
                          Trev.

Offline bonny

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Re: Running out of puff
« Reply #9 on: 19.06. 2010 23:03 »
Bonny,
               That will depend on how well your engine is balanced.
             
                          Trev.
only had a few quick blasts on my a10 before i dismantled it for restoration , but it seemed to be smooth enough trev.

Offline a101960

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Re: Running out of puff
« Reply #10 on: 20.06. 2010 00:02 »
Muskrat, my friend. There is no doubt about it. Tetraboost is good stuff, and it is legal in the U.K. as is leaded petrol. Yes that is right leaded petrol can be legally sold in the U.K. It is bloody hard to find though, because it is expensive due to the high tax rate imposed on it. I do not know how the Ausie customs operate, but in the U.K. as an example you cannot operate a radio transmitter without a license. However you can legally buy and own one as long as you do not use it. That in its self is no deterrent. There is a whole sub culture  here in the U.K. that buy transmitters and set up radio stations. The authorities then hunt them down, but it is a losing battle. When the operators are caught the equipment is confiscated. So, what do the operators do? they go on air again with new equipment. As I say, weather your customs could impound Teraboost at the point of entry I do not know. Do not mention tree huggers to me. All these self righteous enviromental barstewards are very good at complaining. How many of them are prepared to give up their cars or live without gas or electric power? And Interestingly enough, unleaded petrol is a greater health hazard than leaded petrol. Why so? Benzene and tuoline. Both substances being highly carcinogenic. You don't even have to ingest the stuff by breathing it in Benzene can be ingested by contact.On that cheery note I will say good night.

John

Offline Hubie

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Re: Running out of puff
« Reply #11 on: 20.06. 2010 00:24 »
It's a bit wet here at the moment but that will give me some time in the garage to close up the points a little and raise the needle one notch.  I already have the timing more advanced as it was actually coughing and choking under load from being too far retarded.  I have since sorted that and I am not after a race bike, I'd have bought something else for that.  I just want it to perform the way it was designed to. Will see how it goes.

Cheers,

Dave.
1959 BSA Golden Flash
1956 Royal Enfield Super Meteor
1955 Royal Enfield 350 Bullet
2007 Harley Davidson Sportster 1200 Custom

The early bird gets the worm, but the second mouse get's the cheese!

Online chaterlea25

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Re: Running out of puff
« Reply #12 on: 20.06. 2010 02:13 »
Hi All,

BSA_54A10,

""""Try changing the points to change the timing.
Rule of thumb .001" = 2 deg.
Close it down to advance
Open it up to retard.""""

I believe you are mistaken with the quoted information above!!
Opening the gap advances the ignition
the cam has to open the points gap further so it must start sooner, ie advance

HTH
John O R
1961 Super Rocket
1963 RGS (ongoing)

Offline Hubie

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Re: Running out of puff
« Reply #13 on: 20.06. 2010 08:58 »
Timing is nice, the bike pulls like a 13 year old boy in third up to 60mph with a bit more left.  I think Trev is right that my engine sprocket is too big.  The only reason for my scepticism was putting a 22 tooth gearbox sprocket on my meteor up from 20 and it transformed the machine.  I might get myself a 22 tooth engine sprocket (up 1 from standard) and that should do the job. 

Might also try out that extralube zx1 stuff from a post by a10sausage just to see how it goes.

Cheers

Hubie.
1959 BSA Golden Flash
1956 Royal Enfield Super Meteor
1955 Royal Enfield 350 Bullet
2007 Harley Davidson Sportster 1200 Custom

The early bird gets the worm, but the second mouse get's the cheese!

Offline Hubie

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Re: Running out of puff
« Reply #14 on: 21.06. 2010 06:11 »
Also on this topic, does anyone have a 22 tooth 2 lobe engine sprocket they want to part with??

Cheers,

Hubie.
1959 BSA Golden Flash
1956 Royal Enfield Super Meteor
1955 Royal Enfield 350 Bullet
2007 Harley Davidson Sportster 1200 Custom

The early bird gets the worm, but the second mouse get's the cheese!