Super Jet pop-off leaks (no 'pop')? How to tell L spd. jet #?

[schicks]

When checking my pop-off presure the needle seemed to leak rather than 'pop' out at 15-18psi consistently. When I pushed the down on the spring and arm it would release the rest of the pressure. I was expecting more of a pop from the needle, any thoughts? i did plug the pulse and lubed

also, how do i determine what low/high needle adjusters i have? I pulled them out and didn't see any inscriptions on them.

I have a 701 ported, ada head 35cc domes, b-pipe, reeds are the major goodies, the thing hits hard through out the power band and I have zero complaints, but when i pulled the head the pistons had no wash (all black) and I want to richen this mixture up but not mess with the needle adjusters because it hits perfect. Should i richen the low and high speed jets (pilot/main)? at what increment?
Currently i am running: low/high speed adjusters ?, low/high speed jets 67.5 & #135, 2.0 n/s, 65g spring 15-18psi pop-off

 

[Scraggly]

did you plug the return off to?

 

[schicks]

yep, didn't help. is it suppose to give a complete pop and release all the presure at once?

 

[swannysxr]

Pull out neede and seat, check for debris. Should hold until pops open. may need replaced

 

[schicks]

needle/seat looked clean. cheap enough to try new ones. Any tips on reading the L/H speed adjuster sizes?

 

[DAG]

If the N/S leeks there is a ring around the rubber that needs replaced. It needs to pop and the seal completely off or you'll be chasing tuning issues. I dont think you can buy just the needle (if someone knows if you can please share) Main jet size is on the head of the jet while the pilot jet is around its body (really hard to see without good light).

 

[Vumad]

needle/seat looked clean. cheap enough to try new ones. Any tips on reading the L/H speed adjuster sizes?

There isn't a size on the H/L adjustment screws. You don't change them. If you screw them too far in or out, you change jets. Jets only come in ranges of 2.5. The screws are to get in b/t the 2.5 range b/t jets. The only reason to change screws is if you have a carb that doesn't have t-handle screws and you want them, in which case you buy the same thing with a T- handle.

Needle and seat can look clean but get a bit hard and not seal perfect. If they are not new, replace them. THey are only about $10 ea set

 

[tor*p*do]

make sure they are well lubed with wd-40

 

[kevbo]

When checking my pop-off presure the needle seemed to leak rather than 'pop' out at 15-18psi consistently. When I pushed the down on the spring and arm it would release the rest of the pressure. I was expecting more of a pop from the needle, any thoughts? i did plug the pulse and lubed

also, how do i determine what low/high needle adjusters i have? I pulled them out and didn't see any inscriptions on them.

I have a 701 ported, ada head 35cc domes, b-pipe, reeds are the major goodies, the thing hits hard through out the power band and I have zero complaints, but when i pulled the head the pistons had no wash (all black) and I want to richen this mixture up but not mess with the needle adjusters because it hits perfect. Should i richen the low and high speed jets (pilot/main)? at what increment?
Currently i am running: low/high speed adjusters ?, low/high speed jets 67.5 & #135, 2.0 n/s, 65g spring 15-18psi pop-off

Your needle valve is fine as long as it holds the desired pressure, they need to be wet in order to get the "pop". All you need to do is open the top screws 1/4 turn and ride it. If power declines noticeably then you were already rich enough.

 

[JetManiac]

When checking my pop-off presure the needle seemed to leak rather than 'pop' out at 15-18psi consistently. When I pushed the down on the spring and arm it would release the rest of the pressure. I was expecting more of a pop from the needle, any thoughts? i did plug the pulse and lubed

also, how do i determine what low/high needle adjusters i have? I pulled them out and didn't see any inscriptions on them.

I have a 701 ported, ada head 35cc domes, b-pipe, reeds are the major goodies, the thing hits hard through out the power band and I have zero complaints, but when i pulled the head the pistons had no wash (all black) and I want to richen this mixture up but not mess with the needle adjusters because it hits perfect. Should i richen the low and high speed jets (pilot/main)? at what increment?
Currently i am running: low/high speed adjusters ?, low/high speed jets 67.5 & #135, 2.0 n/s, 65g spring 15-18psi pop-off

You have stock dual 38 carbs? They come with 1.5 n&s, not 2.0.

You should swap the low speed jets to 75. That is a low popoff for 38s, suprised it hits good with low popoff and bigger n&s.

 

[schicks]

thanks chris, i just picked up a couple different L jet sizes to try out. Yes, stock dual 38s. I also bought a new set of 1.5 & 2.0n/s and will try various springs. Any tips or suggestions on where a good starting point would be with n/s? I have read/re-re-read and mostly understand the mikuni tuning guide as well as tuning posts. I may keep my exisiting needle/spring and start off with increasing the L jet first and see where its at because like I said, it hit good and had no hesitation or bogging through out the power band...but was running a little on the lean side.

i just added the ada head 35cc domes, b-pipe porting to 48mm, xscream waterbox, #zero flywheel to my ported 701

 

[JetManiac]

thanks chris, i just picked up a couple different L jet sizes to try out. Yes, stock dual 38s. I also bought a new set of 1.5 & 2.0n/s and will try various springs. Any tips or suggestions on where a good starting point would be with n/s? I have read/re-re-read and mostly understand the mikuni tuning guide as well as tuning posts. I may keep my exisiting needle/spring and start off with increasing the L jet first and see where its at because like I said, it hit good and had no hesitation or bogging through out the power band...but was running a little on the lean side.

i just added the ada head 35cc domes, b-pipe porting to 48mm, xscream waterbox, #zero flywheel to my ported 701

1.5n&s, 75pilot, 95g/43psi with oem f/a -no worries