Author Topic: Super and Road Rocket ignition timing  (Read 2030 times)

Offline sprint

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Super and Road Rocket ignition timing
« on: 16.12. 2013 12:03 »
What is the ignition timing setting(s) for a 1957 Road Rocket and a 1960 Super Rocket?

Thanks

Offline Topdad

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Re: Super and Road Rocket ignition timing
« Reply #1 on: 16.12. 2013 12:45 »
Hi Sprint ,info I've got says S/R (frame nos GA) 13/32" BTDC and R/R 3/8" BTDC . There have been quite  afew posts about timing recently and quite a lot of variations and info so i'd sit tight for a short while until some of the gurus reply Regards BobH.
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Offline sprint

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Re: Super and Road Rocket ignition timing
« Reply #2 on: 16.12. 2013 12:53 »
Hi Sprint ,info I've got says S/R (frame nos GA) 13/32" BTDC and R/R 3/8" BTDC . There have been quite  afew posts about timing recently and quite a lot of variations and info so i'd sit tight for a short while until some of the gurus reply Regards BobH.

Thanks BobH.

That's part of the problem I have been experiencing that different books give different settings. So hopefully somebody may be able to give a definitive setting(s)?

Offline chaterlea25

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Re: Super and Road Rocket ignition timing
« Reply #3 on: 16.12. 2013 13:47 »
HI Sprint,
The settings now needed may be different from those quoted in different books
Dependant factors include compression ratio , which cam is fitted and so on
Modern crap petrol can/will cause preignition on the book settings
I have found that 35 degrees (5/16in) works well on alloy headed engines
as recommended by SRM
http://www.srmclassicbikes.com/technical/timing-figures

HTH
John
1961 Super Rocket
1963 RGS (ongoing)

Offline sprint

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Re: Super and Road Rocket ignition timing
« Reply #4 on: 16.12. 2013 14:25 »
HI Sprint,
The settings now needed may be different from those quoted in different books
Dependant factors include compression ratio , which cam is fitted and so on
Modern crap petrol can/will cause preignition on the book settings
I have found that 35 degrees (5/16in) works well on alloy headed engines
as recommended by SRM
http://www.srmclassicbikes.com/technical/timing-figures

HTH
John

Thanks John.

Would that also be suitable for a RGS with 8.25:1 CR and a 367 cam?

Offline chaterlea25

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Re: Super and Road Rocket ignition timing
« Reply #5 on: 16.12. 2013 19:10 »
Hi Sprint,
Assuming keyboard mashup on the 367?
357 and 8.25 are what I have on the SR and it goes really well at 35deg full advance *smile*

John
1961 Super Rocket
1963 RGS (ongoing)

Offline muskrat

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Re: Super and Road Rocket ignition timing
« Reply #6 on: 16.12. 2013 19:13 »
G'day Sprint. It also depends on the octane rating of the fuel you use. The higher the octane the slower the burn so 98 would need more advance than 91.
I use the old "advance till it pings then back it off a couple degrees" method. I run 35 degrees in the cafe but use 105 octane fuel and 9.5:1 comp, if I put 95 or 98 in her she pings badly. Any more advance and she pings her head off with the 105.
I think Orabanda worked out 32 degrees is best for his iron heads.
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Online Billybream

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Re: Super and Road Rocket ignition timing
« Reply #7 on: 16.12. 2013 19:20 »
Hi Sprint.
I also use 5/16" BTDC on my 1960 Super Rocket, this deviation is mainly to offset todays super market fuel. The manual advance and retard also gives a little comfort running this modified setting.
1960 Super Rocket, owned since 1966, back on the road 2012 after being laid up for 29yrs.

Offline trevinoz

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Re: Super and Road Rocket ignition timing
« Reply #8 on: 16.12. 2013 20:11 »
Eddie Dow recommended 5/16", which is 32 degrees, back in the 60s and we had real petrol then.
13/32" was always too much and it's hard to understand why BSA set that figure.

Trev.