SU carb

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SU carb


Post by Freak » Sun Oct 19, 2008 3:00 pm

Anyone know of a good website where I can find diagrams / tuning instructions for an su carb on a panhead? Bike is running good, spitting back through the carb on occasion, think it may be too rich? Any help appreciated.

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Re: SU carb


Post by john HD » Sun Oct 19, 2008 5:17 pm


please take the time to log in or register. you will get more replies and it only takes a couple of seconds to do so.

we have to approve all posts by "guests" due to the large amount of spam the board has recieved lately.

thanks for understanding!


ps, i think carb backfiring is a lean condition caused by air leaks or undersized jets, i'm sure more folks will chime in soon....

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Re: SU carb


Post by panhead » Sun Oct 19, 2008 5:19 pm" onclick=";return false;

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Re: SU carb


Post by Frankenstein » Tue Oct 28, 2008 10:22 pm

If you're running the 1 3/4" H, HS, or HD series, the TL or SM needle are a good starting point. Also, the stiffer dashpot spring used in the Jaguar HD 1 3/4" gives better response than the weaker spring used in the H or HS series commonly found on older Triumph and Volvo cars. Only add a drop or 2 of oil to the damper chamber in the piston, just enough to keep stuff from rusting. If you can find one, get the High flow float lid offered by Revera Engineering for the H and HD series float chambers. I used to run the stock float bowl dry on WOT runs :lol:
If you've got one of those new fangled units with the floatbowl directly on the bottom of the carb, none of the above applies, sorry. :(
Btw, I ran SU's on my 49, 62, and 65 pans for 20+ years, till my leg wouldn't fit around them anymore. Can be a good carb.

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Re: SU carb


Post by Panacea » Wed Oct 29, 2008 3:39 am

I ran an SU on my 49 for about ten years, easiest starting pan I ever saw. I never used the tickle pump. Mine did have the bowl built into the bottom of the carb, I do have one out in the garage with a seperate bowl, I suppose it was desighned to work at all different angles since the float bowl is adjustable for different angles,depending on the intake manifold I suppose...Mike

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Re: SU carb


Post by Freak » Thu Oct 30, 2008 1:27 pm

Thanks for the input. I'm not sure which SU I have, I cleaned the bowl up last night, but I didn't think to look at the numbers. I just got this bike a couple of weeks ago, and I guess I didn't pay close enough attention when the guy kicked it, I know the heads were cold, and it started in 2 kicks. Cold starts are taking me more like 15 or 20..... I think its the SU tickler thing......I'll just keep experimenting, thanks for the input tho', it was helpful !

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Re: SU carb


Post by scav-pan » Wed Dec 12, 2012 10:28 pm

Hi Frankenstein
I'm running ( or about to run) AN HIF6 SU With a BBX needle and yellow spring, in Your opinion would this be ok. I' m running it on a Pan with stock heads, but with a Morris Magneto. When i used to run a SU setup like this on my Shovel, i used to hold the piston down with the piston damper by unscrewing the piston damper out of the suction chamber and holding it on the top part of the piston, that would increase the amount of fuel allowed into the chamber when starting it from cold, it used to start first or second kick, but i didn't run a mag on the shovel, so any info on pans with mags and An SU would be helpful, also any advice on what spark plugs to run with this setup ( preferably NGK or Accel, i can get in uk) Thanks in advance
Scav- pan

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Re: SU carb


Post by scav-pan » Wed Dec 12, 2012 10:35 pm

This is a great source of info for SU carbureetors
SU Carburetters | SU - The SU Carburetter Company" onclick=";return false;
Scav -pan

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