What is the pop off pressure for a 94 xp 657x engine?

[holorinhal]

Does any one know what the pop off psi should be for makuni sbn38 carbs on a 657x engine for 94 xp?
I am rebuilding the carbs and I tested the old popoff and it poped at 10psi. Manual said 21psi but not lower than 12psi for an xp?
It ha the dull silver spring init and the kit came with a dull silver and a longer shiny silver spring. Should I test the new needle and seat with the same size spring or try the longer shiny spring?... Thanks

 

[Bills86e]

18 suggest you re-use factory springs. specs are:
1994 XP 657X 270500196 270500195 BN-38I (SB) MAIN-132.5 PILOT-75 1.5 270500130 16 - 21 LOW- 1-1/4 HIGH- 0 SHAFTS IN LINE

Leak-down test your carbs after you re-assemble them. Just pump them up to a few psi lower than PO and if they hold 3-5 minutes U R good.

 

[Gary pope]

OK I just did this and my carbs, and it held approximately 15 psi for five minutes, one question I do have is could run in the wrong oil in it cause it to run real poorly?

 

[mikidymac]

The wrong oil won’t necessarily make it run poorly unless it’s fouling plugs but it will shorten the life of the engine.