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Post by oilman on Apr 17, 2015 17:56:16 GMT -5
I have a S2 with S2U-0 carbs. Apparently needle jet should be 220 0-2. But I have 214 0-2. Jet needle is stock 4EJ4.
How do I know if the needle jet is right? The chart on mraxl's carb tuning page only goes into saying an 0-2 needle jet is
O-2 = 2.610mm. There are other things at play aren't there? Not sure so thought I would ask.
I had an extra set of carbs with 220 0-2's in em but electrolosis means one jet ain't comin out. The others look a little rough.
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Post by mraxl on Apr 17, 2015 18:14:11 GMT -5
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Post by oilman on Apr 17, 2015 22:36:45 GMT -5
Sweet! Thanks Mraxl.
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Post by oilman on Apr 18, 2015 15:23:10 GMT -5
The 214 jet is a little different.  |
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Post by oilman on Apr 18, 2015 16:32:39 GMT -5
Installed. The 214 sticks up 1.36 mm higher (from the carb inlet floor when installed) than the 220. Sounds like a fair bit. Who knows how that effects the needle to jet relation ship.
Managed to get that 3rd needle jet out of the old carb. But the top got mutilated at some point in the past. Probably by me. So I guess I just need to watch ebay till one comes up. Or buy an entire carb.
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Post by mraxl on Apr 18, 2015 17:08:43 GMT -5
If you could trim 1mm from the bottom of the jet seat you would be good to go. The "hood" that sticks up into the bore is called the primary choke. The extra length there is not a problem but the extra thickness of the seat area (2.47) will cause a problem.
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Post by oilman on Apr 18, 2015 18:23:30 GMT -5
Hmmmm interesting, very interesting. I saw the primary choke height on your carb page. And wondered what that was all about. So when I fully insert the 220 I get a height of 3.11mm into the bore. The 214 fully inserted sticks up 4.07mm. Your page suggests primary choke 4mm. Do I measure just the part that stick up into the bore? I should measure the two for where that upper .... jet for lack of the right word. Where that sits. It may be unlikely. But I'm just wondering. Someone could have reemed the carb casting when they decided to use this 214 jet. You know how it goes. Improvise, adapt, overcome!
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Post by mraxl on Apr 18, 2015 19:31:35 GMT -5
Hmmmm interesting, very interesting. I saw the primary choke height on your carb page. And wondered what that was all about. So when I fully insert the 220 I get a height of 3.11mm into the bore. The 214 fully inserted sticks up 4.07mm. Your page suggests primary choke 4mm. Do I measure just the part that stick up into the bore? I should measure the two for where that upper .... jet for lack of the right word. Where that sits. It may be unlikely. But I'm just wondering. Someone could have reemed the carb casting when they decided to use this 214 jet. You know how it goes. Improvise, adapt, overcome! The problem with the 214 is that the jet doesn't sit flush in the bore. This disrupts air flow and affects needle position relative to the norm.... it would run leaner than with 220's and same clip position. The height difference of the primary choke is no big deal. It affects WOT, providing a richer mixture. Exaggerate the seating of the needle jet... what if it was 20mm into the bore instead of 1mm? It is easier to see what the problem is. |
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Post by oilman on Apr 18, 2015 20:00:26 GMT -5
@ Mraxl Maybe I'll see if my camera will macro down that far. But everything is at work and I'm off till Tuesday.
What I'm seeing with the parts I have is the 220 sits way down into its bore. The 214 too, but not so much as the 220. Neither sit flush.
All I was trying to get at with my last post was, this is all old stuff. So who knows for sure what mods, if any, have been done.
I'll try and do some more reading on primary choke heights over the weekend if anything can be found.
Thanks for your help so far. I know much more now than I did before. That's always a good thing eh!
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