Jet combination? GS550

[ajgs550]

Having a little trouble finding a good combo for jets. Does anyone else have a 70's GS550 with Emgo pod filters and a MAC 4-1?

My bike is a 78 GS550, with a complete engine rebuilt.
I bumped my Pilots up to 17.5, and my mains to 100. I seem to have a dead spot at mid range and rough idle. I also have very slow warm ups. I think the slow warm ups may be due to my pilot fuel screws (they are one turn out).

Any advise?

thanks

 

[drejal]

I've got a 79 550, with the emgo pods, and a "p.o. designed" awful cut up exhaust. It's not a 4-1, but I'd say it's pretty free flowing

I believe I'm running the 17.5 pilots, but using a 102.5 main. It's strong through the rev range, but is running just a tad rich in the mids. I'm just too lazy to pull off the carbs AGAIN and adjust the needle right now. (actually the needle is 2nd notch from bottom, so it just needs to go back to the middle I feel)

If I'm not mistaken, my pilot fuel screws are about 1.25 - 1.5 turns out (depending on what the plug chops told me it needed) Warms up right away. Mine idled a bit rough before I did the valve adjustment and intake o-rings. Purrs now.

Hope I could help a little

 

[ajgs550]

GS550 Jets

GS550 Jets

thanks for the info! Sounds like I am on the right track. I'm going through the carbs again the right way and putting in an o-ring kit, a few were so-so, otherwise everything else in new oem parts (floats . . . everything).
I have attached what my new plugs looked like after riding for about 5 miles or so and cutting the engine when I came in the garage, any thoughts out there? It looked to be lean on 2 and 4, and rich on 1. Can I tune these in with just air and fuel mixture screws?? Any wisdom?

Thanks!