BritBike Forum logo
BritBike Sponsor BritBike Sponsor BritBike Sponsor
BritBike Sponsor

BritBike Sponsor

BritBike Sponsor
BritBike Sponsor BritBike Sponsor BritBike Sponsor
Home | Sponsors, Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons, "OLD" BritBike Forum | DVD- Manuals & Parts books | BritBike Stickers & Decals
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
Photo posting tutorial

Member Spotlight
duck28
duck28
NJ
Posts: 30
Joined: July 2006
Show All Member Profiles 
Shout Box
Search eBay for motorcycle parts in following countries
Australia, Canada, France, Holland, Italy, United Kingdom, USA
Random Gallery photo
Who's Online Now
194 registered members (737Captain), 1,870 guests, and 596 spiders.
Key: Admin, Global Mod, Mod
Newest Members
melramius, Bob Newton, Klaus, LiborP, BrianG
9851 Registered Users
Top Posters(30 Days)
Stuart 118
Lannis 117
NickL 89
Popular Topics(Views)
394,014 mail-order LSR
Forum Statistics
Forums33
Topics64,640
Posts625,384
Members9,851
Most Online3,995
Feb 13th, 2017
Like BritBike.com on Facebook

Follow BritBike here!
Previous Thread
Next Thread
Print Thread
Rate This Thread
#701028 - 07/07/17 1:03 pm Super Rocket Main Jet- what are you running??  
Joined: Aug 2008
Posts: 84
mikelucas Offline
BritBike Forum member
mikelucas  Offline
BritBike Forum member

Joined: Aug 2008
Posts: 84
Burlington VT
Currently my Super Rocket has a Concentric carb on it that runs and pulls very well. That carb has been on it since my dad bought it in 1977. But I'm feeling like getting a Monobloc and putting it back on the bike as it's the correct carb for the bike and it just looks nice to boot.

I've scoured the internet and only found a few suggestions, most of which go back to the early Roy Bacon, Eddie Dow, BSA bulletins etc. But like most people say it's going to be different with modern fuels. So I AM FULLY AWARE :-) that I will likely have to fine tune the main jet etc. But what I'm looking for is what are people "currently running" on their super rocket with modern fuels????

My goal is to order the carb with a main jet that is close to what most people are currently running with modern fuels and then order a few jets up and down so I can fine tune it from there.

Literature is showing anything from a 290-420 main jet and I know some of this has to do with the changes made to the engine and for some reason where the motor was shipped etc.

Yes every engine is a little different, no two engines are exactly alike. Here's what I have for a set-up currently

1958 Super Rocket
Later style alloy head with larger intake valves
357 Cam
Boyer ignition- (properly set-up and strobe timed)
I have access to high test non-ethanol fuel (not looking to start an ethanol thread here :-)
Standard factory style exhaust
air filter- with this new carb I was going to go with either the fully exposed cone or round style in chromed ring?

I plan on ordering the Monobloc 389 (1 5/32")

If there's something I missed here that's relevant let me know.

Can't wait to hear where people are having success, I'm sure there has to be a general range/average of what works well in this set-up with modern fuels.

So let's hear it, what's your jet size?? And/or anyone have any relevant trial and error stories?

Thanks in advance-Mike


Last edited by mikelucas; 07/07/17 1:05 pm.
Support Your #1 BritBike Forum!
Membership Type! Free
Member
Premium
Member
Premium Life
Member
Vendor
Member
Site
Sponsor
Recognition No Premium Member Premium Life member (5 years) Vendor Member Site Sponsor Membership
Post commercial threads No No No Yes Yes
Custom title No Yes Yes Yes Yes
Upload avatar & photos No Yes Yes Yes Yes
Link avatar & photos Yes Yes Yes Yes Yes
Private Message Storage: 10 100 100 100 100
Length of signatures 255 600 600 600 600
Removes this very advert island between post 1&2 No Yes Yes Yes Yes
Price Free $12.90/year $105.00 No End
$55.00/5 years
$210.00/year
($17.50/month)
Email
Click on button >>
  Premium Member Premium Life member Vendor Member Site Sponsor Membership
#701060 - 07/07/17 9:34 pm Re: Super Rocket Main Jet- what are you running?? [Re: mikelucas]  
Joined: Feb 2010
Posts: 354
Red Lapierre Online content
BritBike Forum member
Red Lapierre  Online Content
BritBike Forum member

Joined: Feb 2010
Posts: 354
Upstate NY
Mike if I remember correctly
389/3732 (from Walridge)
Main 330
N Jet 106
Pilot 25
started with a 3 Throttle valve but changed to a 2.5
Needle position in middle.

Plugs have been a touch of black with some brown. Run great, starts easy. I went with manual advance not auto.
62 SR
40 over pistons

my BSA service sheet
Carb up to 59
Bore (in) 1 1/16
Main Jet 250
Throttle Valve 376/3.5
Needle Position 3
Needle Jet (in) .1065

Hope this helps
Red


57 A10 GF
61 A7
61 A10 GF
63 A10 SR
76 CB 125 Honda
76 FLH
2012 FLHTP
#701064 - 07/07/17 10:05 pm Re: Super Rocket Main Jet- what are you running?? [Re: mikelucas]  
Joined: Aug 2008
Posts: 84
mikelucas Offline
BritBike Forum member
mikelucas  Offline
BritBike Forum member

Joined: Aug 2008
Posts: 84
Burlington VT
Thanks Red,
Exactly what I'm looking for, hoping for a few others to chime in so we can maybe get a thread that becomes a useful resource.

I'll be reporting back once the carb gets swapped out as well.

#701455 - 07/11/17 2:23 pm Re: Super Rocket Main Jet- what are you running?? [Re: mikelucas]  
Joined: May 2013
Posts: 4,520
Allan Gill Offline
Allan Gill  Offline



Joined: May 2013
Posts: 4,520
Rotherham - S. Yorkshire
I set my fathers SR to run with a 930, it ran best with a 290 main jet. I beleive the main jet would have been about 350 for the monoblock. However in the AMAL manual they had various specs, some as high as 390 and 410. Some closer to 330.

Fuel shouldn't make too much difference to the jetting. I've found on a stock bike that going leaner is a big difference and going richer gives no benefit. Fuel and how it combusts will effect timing, if you still have the manual advance you can figure this out when on the road for where its happiest.


beerchug

Moderated by  Allan Gill, Mike Carter 


Home | Sponsors | Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons | "OLD" BritBike Forum | DVD- Manuals & Parts books | BritBike Stickers & Decals
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
UBB.threads™ PHP Forum Software 7.6.0
Page Time: 0.116s Queries: 15 (0.005s) Memory: 0.8150 MB (Peak: 0.9544 MB) Zlib disabled. Server Time: 2017-09-21 12:19:06 UTC