Other How to test carb spring weight?

clayne100

clayne100

Location
Tualatin, OR
Anyone know how to test carb spring weight? I don't think color is as reliable as it once was. IE a 95 gram spring. Is that the weight of the spring or the spring force at a set compressed length? Thanks.
 
Vumad

Vumad

Super Hero, with a cape!
Location
St. Pete, FL
If you have several springs, if I recall correctly, the 115 is the longest, the 65 and 80 are the same length, the 95 is in the middle and coiled backwards.

The weight is the strength of the spring. Check the mikuni popoff chart for the amount of psi you get from a given spring and needle. Springs arent exact, so you should always test. Its also a good idea to always assume aftermarket springs are wrong.

Heres a pic. Google search mikuni spring sizes.
MikuniSprings.jpg
 
Dartman

Dartman

Location
usa
last 2 years the 95 gr springs from mikuni are 3-4 lbs less than they used to be
mukini springs are all over the place it seem anymore
 
catpower

catpower

Location
iowa
Dartman said:
last 2 years the 95 gr springs from mikuni are 3-4 lbs less than they used to be
mukini springs are all over the place it seem anymore
Click to expand...
Apsolutely, it's takes several springs to find a mate if running dual carbs. I've never gone by the specification found in the book.
 
Roseand

Roseand

The Weaponizer
Site Supporter
Location
Wisconsin
I had one 80 g spring be 18 psi and a 95 g spring be 20 psi with a 2.0 n/s, then another 95 g spring was over 30 with the same setup!!! I just cut it down to get the popoff I wanted. I was wondering why going from an 80g spring to a 95g spring didn't make a difference..
Always use a pressure gauge!!
 
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