Bike cranks but won't keep running

Working on seca 750 rh... Just installed another set of meticulous rebuilt carbs and now it will only barely start then it putters out. I did get a back fire and checked the new plugs and they look good except #2 cyl, was black and wet. Spark on all plugs also. Looking for any suggestions on where to go next.

 

What have you done as far as tuning?
Where are the mixture screws set?
I like to do a running sync each time I move the mixture screws.
Start lean at 2 turns out then increase 1/8 turn each time resynching until you find the sweet spot.

 

Valves adjustment, set mixtures screws as advised on this forum. That is setting the mix. screw on the butterflies -to see a little light through when looking at the side, and used a very thin feeler gauge. I'll try the way mentioned on the reply next. Thanks

 

Did you follow the "church of clean"? One person may think carbs are clean and another would say they are not. Just trying to get a feel for your definition, and I don't mean any offense by it. Most of the time, these bike will run well with a good set of carbs that are clean. The starter ckt jet in the float bowl must be clean and able to pass liquid through the jet.

Any back history on the bike that might make us think it could be something else. The battery is in great shape and is charged to 12.5v DC before you try staring the bike? Let us know how the troubleshooting goes.

 

You are describing a "bench synch" process, the purpose of which is to equalize the butterflys to make them all equal and allow the engine to start and run (no matter how poorly) under its own power. Immediately after that is accomplished (and an idle established) then you go right onto a running (vacuum-gauge) synch process.

Have you checked to make sure the carbs are receiving fuel? Fuel levels set properly? Compression check? Valve clearances checked?

 

Getting an issue with the coils clicking with no crank at times.. Compression check is all range from 90 to 100 for vacuum

Getting a fire up every time now. Adjusted the mixture screws as noted but still doesn't stay running to sync. carbs. Accomplishing a little at a time which sis a good thing.

 

For the follow up. The battery is at 11.4 v. / I do have the old one that is reading 12 v. DC and I am using a external fuel bottle at this time.