first time carb setup issues

[randallscott]

Howdy everyone. i am working at getting my 78gs750 tuned and running right. i have done the following ;new petcock, new points + condensors, new coils,plug wires + caps, new plugs, coil relay mod,new air filter + airbox reseal, carbs completely disassembled, dipped + new orings from mr.barr, including intake orings, carb sync with morgan carbtune, valves ckd + adjusted to spec, and attempted to adjust pilot circuit with colortune. new battery. cleaned up bullet connectors, adjusted timing + points gap.
my problem is with cylinders #1 + #2. started with colortune on #4- everything went as described in literature. same with #3. #1 is running rich (yellow flame) and adjusting the pilot fuel needle has no effect, all the way in/all the way out, still rich. #2 is not firing at all. very good spark, pipe is cold. again adjusting pilot fuel screw has no effect. when i crank throttle to 4000 rpms i get a little bit of fire in #2. very little.
seems #2 is not getting fuel at all. is the carb completely blocked,(is this even possible?);stuck valve?bent valve?
i appreciate any and all advice that anyone can provide. im not sure how to proceed- redip carb?compression ck? HELP! thx for your patience with this long winded post!! cheers, randy.

[SqDancerLynn1]

You could still have a carb problem ? Have you checked the compression and adjusted the valves ?

[robertbarr]

Compression test first. I'd also drain that one carb to see how much fuel you get out of that bowl.

[Guest]

Compression test for sure. How was the bike running before you started the clean up? sure sounds like a carb problem. When you took the carbs apart what did the tips of the fuel mixture screws look like? did you make sure there wasn't a tip broken in the carb? how did your float adjustment go? believe me, I know the pain of repeated carb tear downs. But all is good, after the 10th or so time you get real fast at it.

[Nessism]

I concur with checking the fuel screws. Assuming the fuel screw tips are all there and nothing is stuck in the hole, I'd set them to 7/8 of a turn open, set the air screws to 1.5 turns. When you cleaned the carbs did you make sure the pilot jets are open by holding them up to a light to make sure the orifice is open? I've seen lots of plugged pilot jets, even after soaking in carb dip.

Good luck

[randallscott]

no compression in #2

well i bought a compression tester-1 and 4 were ok- threads are hooped in 3, and 25 psi in 2. put some oil in plug hole and 2 went up to150psi!!! so im pulling the head, which ive never done before. guess ill have to get some gaskets. i hope things aren't too messed up in there. plug hole threads in 2 are pretty bad too so i reckon ill put some helicoils in while im at it. i'm all excited about doing this! wish me luck guys. im sure ill be asking more questions in the near future. cheers, randy.

[BassCliff]

Hi,

It's possible that you've got a stuck ring. Sometimes you can just ride it hard and the compression will improve. Try that before pulling the motor apart.


Thank you for your indulgence,

BassCliff

[Guest]

I managed to save/rethread a cylinder with a tap and some grease to catch the shavings. Moved it ahead just slightly and then removed and cleaned off the metal shaving and then did it again with new grease, took only a bit of time and the threads were fine without droping any shavings in. Might be worth a try before ripping things down, but then again ripping stuff apart is always a good time too. Best of luck.