Carb Needle Info

[MotorHead67]

Now that my motor is up and running, it's time to start tuning the carbs. I'll be using an air/fuel ratio meter to size the needles. I've downloaded the Haystack program to help determine the needle size but it doesn't deal with the .125 needles in my HD8 carbs. Does anyone out there know of a similar program for the HD8 carbs?
Any suggestions?
Oh, I should mention that the motor (BJ8) has been modified with more compression, a mild cam and headers and I do want to stick with the SU's.
Thanks,
Mike

 

[Dave Russell]

Hi Mike,
I could send a jpg to you if I had your email. It's too big to attach to this message & I don't have a web site. It contains data on about 55 .125 SU needles. Email me if you want it.
rusd@velocitus.net

 

[MotorHead67]

Perfect!
Sent an email.
Thank-you.

 

[GregW]

Hi Mike,
There is a book called "How to Build & Power Tune Su Carburettors" that may help. Since you've modified your engine a little, standard needles may not work through out the RPM range. This book has a couple chapters on reprofiling needles. Of course, getting 2 needles exactly the same could prove to be a challenge but that’s half the fun. A little trivia: I have an old Nisonger catalog that has a pair of complete new SUs for $150. /ubbthreads/images/graemlins/cryin.gif

 

[Keoke]

Greg, that is not a catlog it is a wish book!--Keoke /ubbthreads/images/graemlins/laugh.gif

 

[GregW]

Hi again,
There is a windows version of Haystack. www.winsu.co.uk/ The guy who wrote it says a new version should be ready “early 2005” which will support twin carbs. Put it in your favorites and check back.

 

[MotorHead67]

Thank-you Greg. I think Moss has that book. I should have ordered it months ago.
I went to the web site you mentioned and left an email.
I now have a list (thank-you Dave) with the stations on the needle listed in thousanths so I should be able to compare needles by percentages.

 

[John Loftus]

APT Performance appears to have the Des Hammill SU book along with lots of SU parts.

https://www.aptfast.com/

For .125" needles, have you tried the SUNeedle program? https://www.triumphclub.co.nz/su_carbs.html
Also more SU needle programs at
https://www.teglerizer.com/sucarbs/

Cheers,
John

 

[MotorHead67]

John,
Moss didn't have the book (as you probably know) but I was able to order it from Amazon.
I've been searching and surfing tonight and it seems that the SUNeedle program and Haystack are one and the same. Seems there's nothing out there for the .125 needles.
I guess I'll start with the 'UN' needle (factory 'rich') and work from there.
I also did my first test of the A/F ratio meter just to get my feet wet. Wonderful tool.