05-21-2009, 05:55 AM #1
Pop-off with dull silver spring is higher than it should be?
I'm doing my first carb complete rebuild on my GP1200R
I bought mikuni original parts, everything from 4tecperformance.
I'm reading 54-55 psi on all three carbs (I used lots of lubricant CRC 6-56 and plugged the pump to the inlet and closed all outlets)
According to the table posted in this forum my 1.5 N&S with a dull silver 95g spring should read 43psi
Am I missing something?
I have read there are new platinum springs which replaced the previous gold ones... How similar is the platinum color compared to the dull silvers? Could I have the wrong ones? To me, these look dull silver and the arms are level with the adjacent surface.
I'm doing this to my GPR (single piped, 150psi, riva arrestors, 1200cc, nonported):
a. pilot 110
b. main 125
c. N&S 1.5
d. Spring 95g
1 turn lows
1 1/2 highs
Would the 55 psi run lean on my engine???
05-21-2009, 06:38 AM #2
- Join Date
- Aug 2007
- Bridgeton nj
if all three carbs are the same and you have no air leakage, it probably your air gage that's off, I had the same problem with the gold and the dull silver spring, the silvers were around 48lb and the golds was around 51lb not much difference but there was a big difference when installed, the needles are mainly opening with vacuum pressure in the carb against the springs not fuel pressure
05-21-2009, 09:32 AM #3
I just redid the popoff on my carbs, and was getting a little to much pressure as well. Assuming your gauge is correct, you will have to trim the springs a little and fiddle with them if you're shooting for an exact psi.
05-21-2009, 06:20 PM #4
Are you sure your arms are flush with the body?
05-21-2009, 06:27 PM #5
05-21-2009, 07:49 PM #6
I have some of those 50+psi dull springs too.... The way to tell the difference is that the true dull silver springs are shorter than the gold springs (and gold springs in disguise). So, if you have a true gold spring laying around lay it side by side with one of your "dull silver" springs. It should be very obvious.
05-21-2009, 08:13 PM #7
05-22-2009, 08:51 AM #8
Got a second set of dull silver which look just a littlebit shorter and measure 38 to 39 psi .
The mikuni rebuild kit came with a set of shiny silver which are a much more larger size and measured 50+ psi
Now thats really confusing....
05-22-2009, 11:49 AM #9
05-22-2009, 02:01 PM #10
Ooohhh, so thats platinum... Now it makes sense
Ill try the 38 psi dull silver,
how much can I bent down the arm?
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