Weber Tri-Power questions

theman1990

Active member
Looking for any advice on triple weber's. Have read quite a bit on here already and have some pretty good ideas on what needs to happen. Thinking progressive link with 185 jets in all three? Any advice on how to get bellcranks for the carbs?
 
Looking to experience the 'enjoyment' of multiple carbs, eh? Jetting will be based on your engine set up and it's a bit of trial and error. I found it REALLY helpful to install a wideband 02 to get proper jet sizing. Prior to that, I was just stabbing in the dark. Offy linkages are available from Exeter auto supply http://www.exeterautosupply.com/ and weber linkages/jets are available from Pierce manifolds http://www.piercemanifolds.com/default.asp as well as Redline http://www.redlineweber.com/
Somewhere on here is a table of various member's set ups on jet/air sizing. My guess is that 185s are probably a little fat for a stock 200. I don't remember what I have but they are in the 185 to 195 area, if I recall. Again, it depends on your engine set up. One of the things I learned is not to use too much spring tension to keep the outer carbs closed. You want the linkages to slide nicely without excessive pressure, just enough to keep the butterfly closed. Too much makes it harder to drive and can cause the linkage to twist a bit. I also found it easier to use a cable gas pedal vs a rod actuated one. Good luck & have fun...

One more thing. I tried running with all 3 idle and progressive, running on all 3 nonprogressive, and idle on the center only progressive. Mine runs best when idling only on the center with a progressive linkage like the way (I believe) Offy designed it to work.
 
Here is the number for the carb arms.. http://www.piercemanifolds.com/product_p/99005.316.htm. i am about 50' above sealevel and currently run a .180 mains in the center and 165 in the outers. .65 idle jets on all 3. The AFR looks good with this jetting. I also idle off the center carb.....i use the comp 260 h cam and headers also. I do recommend a wide band AFR meter tonhelp with tuning and monitoring. I do have to jet up to a 185/190 for the center in the winter here which is upper 30s/lower 40s. Use the progressive setup for a street....... street/strip engine.
 
All above advice is solid. Depending on how much head work was done and overall build that jetting is a good start. I run 195 in all three. Idle is around 13.8 but Wide open in 12.6-8 using a F.A.S.T. Dual wide band a/f ratio.. Progressive linkage.
 
Well I'll have a relatively well worked large log head w/ decent compression and the dual pattern cam so I think we'll start with the 185's or so. What idle jets are y'all using? They only matter in the center carb, right? Any other changes to the carbs?
 
.65 idles in all 3....had to add a little stiffer return spring to the end carbs......
 
Main jets don't have to be the same as air. There are 2 books on tuning weber carbs that are a decent read for the inner workings on how each adjustment affects the rest of the set up. One is by Haynes and I don't recall the other at this time. If I can find it in my 'Library' I'll post it.

The second book is titled "Weber Carburetors" by Pat Braden, HPBooks
 
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