Jump to content

Needle Modification for L20b SU's


mtngoat

Recommended Posts

Just read threw this.  AWESOME work guys.   :thumbup:

 

I am going to be putting some 38mm flat top SUs on my lz22 soon and was trying to find some info on needle sizing.  NOTHING is out there.  Is there an online file on how to sand the needles?  I didn't see a link or where can a get a book on it?

Link to comment
  • Replies 82
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

The "how to" in this thread is as good as anything I've found on the interwebs ;) there is a DQ article mentioned earlier but it's rather short on detail imo You'll find that while the procedure is the same for modifying, you're profiles will differ because of your motor set. One thing you can probably count on is what regions to modify based on speed and throttle position... That should stay consistent.

  • Like 1
Link to comment

Just Joel and mtngoat

 

Did you guys do any modification to the throttle shafts and butterflys on your 38s?  In the DQ article listed above the mention 'thinning' out the shafts for less air restriction.  Anyone try it?  I am right now to try and get more air.  For the throttle shaft seals, did you go with the ZTherapy bearings or just some rubber at the ends?

 

How big is the gap between regions?  Want to start to mock up a chart.

Link to comment
  • 2 weeks later...

I made a new set of needles this evening and added the new profiles to the table under "Joel mod #3". Earlier, I described a rich condition in the lower rpm/speed range and I hope to correct this by leaning out the first six stations compared to my "Mod #2" set. I should have a chance to test them tomorrow if the weather cooperates ;)

 

Profiles2.png

 

  • Like 1
Link to comment

Hey Joel I'm interested in hearing how your new modded needles worked out. I haven't had the time to take mine apart to see what needles I'm running but according to my WBO2 I'm right in the same ball park as you between 11-15. I did have a problem last week with it running lean on the freeway but it turned out that the overflow lines had been partially plugged.

Link to comment
  • 3 years later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.