Author Topic: which cam to use?  (Read 3511 times)

Online bsa-bill

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Re: which cam to use?
« Reply #15 on: 17.08. 2010 09:03 »
Hi Rocket Racer  - 357 fitted into my 59 A10 all right, looked close but had room enough.
Have read this before about cam through, could be a batch were cast just within tolerance, fair old difference between 356 and 367 though I've gone back to 356 for now at least until the rebuilt engine frees up.
Good luck with it
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline Rocket Racer

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Re: which cam to use?
« Reply #16 on: 17.08. 2010 09:17 »
I'm hoping it'll work nicely with alcohol fuel, some light genuine bsa pistons in the 8.x:1 (comp yet to be measured) big valves, a pair of 10TT9 carbs (a '55 type twin port head) and on castor oil... Cant wait to have it going! -but not a road bike...

Another set of '55 A10 cases I have that also had a 357 fitted had evidence of rough dremelling to get the cam to fit by a previous owner
A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
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Offline muskrat

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Re: which cam to use?
« Reply #17 on: 17.08. 2010 10:55 »
G'day RR,
                it seems strange about the cams. A 357 fitted in my "51 plunger and the A7SS cases with clearance.
I did have the same prob with the LJ crank going into '57 cases.
8 : 1 comp wont be enough to get the full benefit of methanol. It doesn't start really working below 10 : 1, 12 is better. At your comp you would be better off going 100 - 115 oct avgas.
Running my '57 A7SS at over 12 : 1 with 2 X 32 concentrics I would get 12 MPG !!! That's when I could keep the barrels on and SJ crank in one piece.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline Big Nick

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Re: which cam to use?
« Reply #18 on: 17.08. 2010 17:58 »
has anyonr tried the megacycle one ?
1932 500cc rudge
1936 500cc cotton pyton
1952 M20 with B31 motor
1952 Plunger A10
1954 New Hudson Autocycle
1962 A10
1982 BMW R100

Offline lawnmowerman

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Re: which cam to use?
« Reply #19 on: 17.08. 2010 19:48 »
G'day Muskrat - reckon your A7SS might run on diesel at over 12:1  *smile*

Must go like s*** off a shiny shovel and well worth the expense of 12 MPG and the risk of a broken ankle when kicking her into life.

Jim
1959 A10 SR
1938 Wolseley 14/60
1955 Ferguson TEF20 tractor
1965 Ferguson 135 tractor
1952 Matchless G80 rigid
1960 BMW R60
1954 Matchless G80S
1955 Ariel 500 VH
1951 Sunbeam S7DL
1960 Matchless G12 with Watsonian Monza
......and loads of lawnmowers

Too old to Rock and Roll but too young to die  (Jethro Tull 1976)

Online chaterlea25

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Re: which cam to use?
« Reply #20 on: 18.08. 2010 00:18 »
Hi All,
I finish the SR with the flat topped pistond and 356 cam and it now has 4-500 miles on it
It is a really sweet motor very quiet mechanically and just what I hoped it would work out like *smile*
BUT compared to my own SR it is a pussycat *ex* *ex* Very much the opposite of mine
The exhaust notes are very different, mine has a much sharper growl and the goldie "silencer" twitters lovely *smile* *smile*
There is a fair difference in performance etween the 2 bikes
I wont be detuning mine anytime soon *ex* *ex*
"Now wheres that shorrocks blower I had" ???? ???? ???? ????
Cheers
John O R
1961 Super Rocket
1963 RGS (ongoing)

Online orabanda

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Re: which cam to use?
« Reply #21 on: 19.08. 2010 12:32 »
As a guide to useability, compare the performance graphs on my thread of today (dyno testing SR engine).

You will see that when compared to the 356 cam, the 357 has less bottom end, and a top end that gets going, when the 356 has signed off!.
Bear in mind that the Sr has slightly higher compression, and a bigger carb; however, the characteristics of the different cams is evident.

Dio you need more acelleration, or low down rideability?

Richard

Offline Rocket Racer

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Re: which cam to use?
« Reply #22 on: 19.08. 2010 22:13 »
Those dyno charts were very interesting, thanks for posting them! I'd love to see a dyno of Muskrats A7  *respect*
A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
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Offline muskrat

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Re: which cam to use?
« Reply #23 on: 20.08. 2010 14:21 »
Well done Richard. That's real horses at the back wheel.
Might have to do that. A bike shop up in Nowra just installed a dyno. The old A7SS racer is now the A10 Cafe so not running methanol and high comp. Just a few more little things to sort out, like keeping the oil inside the rocker box.. Will post when done.
What about yours RR ?
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Online orabanda

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Re: which cam to use?
« Reply #24 on: 20.08. 2010 14:42 »
Still running in the RR; can't see it being ready until October (I have so many bloody bikes to choose from it takes a while to get the miles up!).

For example, two weeks ago I finally got up 1,000 km on this "rocket", and it also had it's turn on Ray's dyno.

At the risk of being branded a heretic, but in the interests of all things mechanical, check out the results: almost the same power as the iron head GF's, similar torque, and 2/3 the weight: Yippee its party time - turn the throttle and hold on!

However, I only get 70 km to a tank!

Any decent run out of town, and i strap extra fuel on the rack at the back.







I am also ckocking up the km's on this bike below: 400 km to go, and then it gets the tune-up on the rolling road!



Richard

Offline andy2565

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Re: which cam to use?
« Reply #25 on: 20.08. 2010 15:01 »
great bikes the xt's love em ,i got a 78 tt500,the only japanese bike i like,and i got enough to build a xt flat tracker in the future.
had an xt when i was travelling in OZ,
near wolves uk,will keep riding as long as can stay upright,tribsa,tt500,2xJAP grasstrackers+jawa.gold flash.triumph metisse,and others.

Offline muskrat

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Re: which cam to use?
« Reply #26 on: 20.08. 2010 15:17 »
Sorry Richard, I meant Rocket racers chair.Yes those 400's go, I had a 360 years ago. My XT is awaiting time and money. I threw points & condenser in a while back. 1st kick it backfired and I had 3 days off work !
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Online orabanda

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Re: which cam to use?
« Reply #27 on: 20.08. 2010 15:24 »
Muskrat,
I got a 360 too.......





This was my first 360, from a looong time ago....



Richard

Offline Rocket Racer

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Re: which cam to use?
« Reply #28 on: 20.08. 2010 22:46 »
The intention is to dyno the chair asap...I've got the bottom end assembled, still have to check valves have clearances, paint barrels, have ordered fresh wire circlips as the several new sets I had were only loose fits!! a number of other loose ends too, so wont be this month sadly.
The motor has the "heavy" early type lj crank, a 357 cam, big valves and med comp light BSA pistons. The inlet ports on the head are asymetric, so my engineers making manifolds as the top studs are mighty close to the ports. I'm hoping we'll have a pair of 10TT9 carbs and on alcohol although purely to keep the running temperatures down as chairs work fairly hard. Don't know how well it'll run but its going to look fabulous wink2
I'd been working in Oz but am now back home so its progressing again...
I'm always intrigued by dyno numbers as they appear to be mainly useful to see how the motor creates power rather than the numbers themselves which seem to vary dramatically from dyno to dyno. My old Norton atlas race bike which was claimed to put out 49 hp stock in road trim, in full race trim on race gas put out 49hp on a dyno after fettling... yet we keep seeing A10;s that are claimed to put out 33 -45 hp based on trim, putting out 22 to 28 hp. I appreciate the rear wheel vs crank argument, but I know my atlas wasnt twice as powerful as an A10...
I'll see if I can find a copy of the atlas dyno...

Sorry Richard, I meant Rocket racers chair.Yes those 400's go, I had a 360 years ago. My XT is awaiting time and money. I threw points & condenser in a while back. 1st kick it backfired and I had 3 days off work !
Cheers
A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
New Zealand