Pop off pressure recommendation

[97explorer717]

97 GTX what I'm seeing says 23 to 43. That's a awful wide variance. My understanding is lower Popoff is richer and high is more lean...? I'm messing with the Springs now. Was at about 23 with original spring. Last one I tried I'm at about 32. That seems to make more sense to me being in the middle. What's ideal?

 

[etemplet]

If you have genuine mikuni parts.... the real stuff including the black spring your pop-off will be 37-38psi. I tried everything from 23psi to where it is now at 38psi The ski seems to like 38psi. 33 wasn't too bad but as I stated, if you are genuine MIkuni... it takes all the guess work out of it. Good Luck !!

 

[JeremyD615]

As long as both carbs are close to the same and they are within the specified range, you normally don’t have to mess with them. What size needle are you using and which spring? I know you’re supposed to have the 1.5 needle and seat from the factory, but I’m not sure which spring it came with.

 

[97explorer717]

As long as both carbs are close to the same and they are within the specified range, you normally don’t have to mess with them. What size needle are you using and which spring? I know you’re supposed to have the 1.5 needle and seat from the factory, but I’m not sure which spring it came with.

You're correct about the seat. I couldn't find any information on the spring except for OEM part number. Looks to be the black spring. Technically the spring in the carb is good. I was just going to put the new one in it. Reading through some forums it looks like it's recommended leaving the original spring in. I was just thinking it was a good idea to change out the 22-year Old Spring. Also I have four Springs that came in the kit. Was just thinking maybe a different pop off might be better or worse.

 

[LikeabossTM]

You're correct about the seat. I couldn't find any information on the spring except for OEM part number. Looks to be the black spring. Technically the spring in the carb is good. I was just going to put the new one in it. Reading through some forums it looks like it's recommended leaving the original spring in. I was just thinking it was a good idea to change out the 22-year Old Spring. Also I have four Springs that came in the kit. Was just thinking maybe a different pop off might be better or worse.

I knew I'd read about spring color somewhere. If you have a match it wouldn't hurt to try replacing it if it's that old, testing your pop off afterward of course.

 

[JeremyD615]

Yes, you generally want to reuse the old springs, even when you have new ones in the kit... As long as you replaced both at the same time, and you used OEM parts, you should be fine though. I will say though, it you have a bog or hesitation after reassembly, that’s the first place I would look to fix it. Don’t throw the old springs away!

 

[etemplet]

Make sure your seats are genuine mikuni and the correct size. Whenever I'm doing carbs for the first time, I buy new seats and needles. You never know what you are gonna find in there and I'm not playing with this stuff any longer. Once and done.