pop-off PLEASE help

[daverade]

so im figuring this all out.....here is what i got.....rebuilt bn-40i carbs yesterday, with mukini kits... my pop-off chart says from 23-43 psi...how close do the 2 carbs have to be can they be a few psi difference, and what is the "ideal" #, there full stock, we used the silver springs in the kit, what im having trouble with is one carb is popping at 30 psi or so the other at like 17psi...n&s are good, swapped it back and forth from carb to carb...how can i adjust it...is bending the tang a legitimate method?? and i know the tang is not supposed to be above the carb area..i took a straight edge and put it over the tang and its a little lower is it a problem??? please any imput is appriciated

 

[daverade]

and what gram spring is the silver one that comes in the mukini kits???

 

[seadoosnipe]

Pop off...?

I saw your thread a while ago but when I looked for it, it had fallen off the radar.

The ideal place to set the pop off on the 787cc is about 25 to 27 psi. The one you have below 20 psi will allow fuel to pretty much free flow into the engine...not good.

The tang (lever)...? This should be set flush to the check valve body base or no more than one mm over. It can't be below. So, adjust it back to flush, or just a tad past.

It's not recommended but I have cut my springs as needed to get the desired pop off setting. In the Mikuni carb manual we have, it states you can. In our BRP shop manuals, it states you shouldnt. Never stretch a spring. It's no good if you do.:cheers:

 

[daverade]

ok perfect.... i used a razor blade as a straight edge....on both carbs, they will hold the 10 psi for 30 seconds, no bubbles from N&S..also the diaphram will hold 4psi for 10 second... both carbs are popping strong at 27-28 psi .....i did it about 10 times on both carbs, because i dont want to do this again....now the only thing contradictory i see, is when i place the "straight edge over the tang, on both carbs its about .5mm below "flush" i can just barely see light, what is this gonna yield......thanks for the reply

 

[seadooya]

silver springs

Yo...theres 2- inna pack, ones a 95gm, others a 65gm. The 95gm is coiled counterclockwise. make sure the needles are wet (wd-40), when doing the test.

 

[daverade]

yyyoooooooooo, cool i used the 65 i think the silver one...i tried pm'n ya 100 times and it wouldnt let me....ok i got them on hit start and bbbrrraaaappppp... idling at 3200 need to get to the lake and set that up...both are popping off strong at 27-28 psi every time...

 

[daverade]

What happens if the "tang" is slightly lower than the metering chamber? Slightly seriously like a piece of hair

 

[daverade]

Bump.........