05 RX1 MPI S/C @10 lbs. lean at 6000 rpm ????

[rxboost05]

Nothing wrong with 13.8:1 Are the new springs stiffer or lighter than what you had stock? I'm assuming slides are all the way up at full throttle, how about where the stumble was?

Sprins are lighter. At 6500 rpms where the stumble was is where i am seeing the 13.8 to 1. At wot i am seeing about 11.9 to 1, and yes slides all the way up.

 

[rxrider]

Maybe off topic, but the Holtzman silver springs did cure my fat low end, with the stock springs AFRs were high 10s to low 11s, with the silver springs low end went 14+. Also my high end cruise AFRs got down from 14.5 to 13.3 with the silver springs. I had no mid range problem but the silver springs did cure both low end and high end cruise AFRs, 1/8 and 3/4 throttle.

 

[dynotechjim]

sometimes a rich burble will show lean on wideband I think because of O2 coming past sensor from misfire. Misfire usually happens richer that 10/1 and leaner than 17/1 or thereabouts.

one other issue we had with lean sneezing HD carbs was the sneeze can cause small tears in the slide diaphragm and prevent it's lifting at open throttle. Engine would run fine, just no HP at all. If a lean sneezing RX1 lost one carb diaphragm, you might not know it since the other 3 cyls would be carrying the load. Might be something to look for if you suspect you have a sudden 25% HP loss with no other problems.