Jetting help

[Ordo]

I've already done a search on this. But I need some help before morning gets here. I have an 85r with fmf fatty with answer silencer, boyesen rad valve, k&n airfilter with outerwear and no lid. And the engine is stock as well as the carb. Run pump gas with mobile 2t oil mixed 32-1. I live north of Kansas City at about 586ft. I just want to get somewhere close on the rich side so I can work up. And that way I don't have to buy to many jets.

[Dammit!]

It's safer to start off too rich and then go down. I'd probably start at about a 160 with those mods.

[TeamGeek6]

Jets may not be enough, most of the operating range of that carb is controlled by the main needle and slow jet. The main jet mostly controls wide open throttle. If you want a couple of mains to play with, i have a pile of too-bigs from 142 - 155 and nothing to put them in.

[Ordo]

Finally fired it up tonight and it is sputtering just off idle throught the rest of the throttle. I put a 160 main in and I'm not sure where to go from here. It seems rich but do I need to change any thing else besides the main.

[TimSr]

The mods you mention are all pretty minor, and Id bet youll probably end up around stock or even lower than stock, if the FMF Fatty is a low to mid range pipe. I highly doubt youll need to mess with the pilot if its stock. Either way its important to get your main jet dialed in first, before messing with anything else, because it affects the entire throttle range. You need to run some wide open plug tests. There are tons of threads already in this forum on running plug tests and how to read them that will show up in a search. People unecessarily worry about starting out too lean, when it takes some real work to melt a piston. Its not goin to happen running a plug test. Get it warmed up, put in a clean plug, and run a plug test, and go by your plug reading.