Photobucket went down and took all the pictures.

But I'd bet you could search google and the 1000f section and find a diagram that's not lost in PB.

 

I see there are two lengths as someone posted they got a 140mm length that was too long. Not sure it will be easy to know if what I buy is 127mm or 140mm. I am testing resistance on my son's 06 coil to see if that would work; but length could still be an issue. I will just assume that a CBR 600 coil would be the right length since the engine is probably basically the same as the 87.

 

So Hamlin, Adding one washer to each needle did seem to make a difference. Mostly in cruising behavior. The bike seems to no longer 'kick' when I am cruising (once it settles out). Still a lot of missing, sputtering when I am accelerating in the 2k-3k range, but note that this occurs when cold and when hot. Another behavior that is only specific to this one carb rack (one reason I don't like these) is the idle stays high for some number of seconds after releasing the throttle. I know this is an indication of a vacuum leak; but that just seems so unlikely since I have gone through everything that could result in this; including using o rings to seal the throttle shafts; which by the way seemed to have zero impact, so perhaps one post I read that the theory of leaking throttle shafts being silly may be true. I was thinking it may be related to the very large main jet just letting too much fuel through that takes a few seconds to burn off; but the problem with that thought is that it would also need air and it could only get extra air if there was a vacuum leak, hmmm. The high engine speed makes shifting a little tougher and would make the bike unsuitable for my son to ride (as he would get confused and make mistakes). Note that the other carb rack doesn't do this; mounted with all of the same stuff. I have also swapped the slide diaphragms between carbs where the the set with the large main jets is now using some I repaired a bit (some were pinched) and this behavior has stayed with the carb bodies. I believe I also tried the 105 jets and stock needes in this set and as I recall the issue didn't disappear; but would need to confirm that.

 

I may consider using these needles with the two washers in the other carbs with the 105 main jets just to see how that responds. Guess I am now less convinced that I have a plug wire issue. Not sure it would cruise that well if that was the case. Also, I can twist the throttle to max while cruising and I don't feel any missing.

 

That's great news. As stated before, when you have non-OEM parts, it's always a bit of a dance to get it just right.

Do your throttle cables move freely?

 

Throttle cables are fine. Other carb rack doesn't do this, so more confirmation. It stays up long enough that I have twisted the throttle OFF to confirm that it is closed. Obviously the throttle is a little tighter now with o rings in the shafts; but this problem is not new since that change. In fact, I made that change to see if throttle shaft vacuum leaks was the cause. The number of seconds the idle stays up is not consistent; if it was, it would be easier to deal with. When I get this all figured out, my plan is to run the other carb rack but with the tuning stuff I figure out between the two. Other carb rack has been my baseline since it runs more consistent; idles much better. It is also cleaner and didn't go through the complete parts cleaner bath like these originals did. Supposedly also has 12k less miles.

FYI: I ordered a couple of more main jets for tuning since I was told that a 112 jet seems pretty large. I have a 108 and 110 set coming. But not expecting main jet to alter this behavior. So far it is remained with a 102 jet a 105 jet and a 112 jet. Best results in 112 jet so far.

 

Moved the needles into the other carb set (which idles at a consistent RPM and drops to normal RPM off the throttle) with the extra washer. Same basic issue; bike runs great for 5 minutes then starts missing while cruising. But twisting the throttle wide open from low RPM is smooth so long as I am already cruising. Twisting the throttle just a tough, misses.

I am going to try and move the floats so the float level will be swapped between the carbs and the 112 main jets into this set. Pretty sure the behavior will remain the same; this carb will run good for 5 minutes then start missing.

Very strange. You would think the carb behavior would move when the parts are exchanged; but guessing that will not be the case. We will see.

 

I keep raising the needle and problem in this set of carbs doesn't really seem to change. As the bike warms up; I start hearing 'pinging' in some cases where it is missing; but only occasionally. So the bike gets 'leaner' as it warms up? makes very little sense unless some part is failing on warmup. Still under max throttle it smooths out quickly (might stumble once or twice, but then goes). Engine revs up nice in neutral but sounds stumbly (if that is a word) when reved up to steady rpm. Still have to wonder if it is the crank position sensors that fire the sparker that mess up; but that isn't a good explanation for why max throttle smooths out fast. Still sounds like carb issue. I will try larger main jet with twp washers in needle (what I had in the order carb rack) and then consider float bowl changes. After that; I will start running out of ideas other than just replacing the rest of the electrical system, getting another used carb rack, or playing mix-n-match between the two carb racks; but no idea what I would mix and match. 108 and 110 main jets should be arriving soon; but since it pulls pretty good at max throttle, main jet seems unlikely to help. Bugging me that carb changes seem to have zero affect on the stumbling issue; no better, no worse with this carb rack. Since the other rack shows signs of vacuum leaks; I don't feel like I can make any progress with those.

 

I lowered the needles a step (like removing 3-4 washers) and it definitely hurt. and by hurt, I mean the same basic behavior but much worse. so I can't raise the needles much more than I had them (maybe one washer), so maybe the 112 jet with previous needle position.

 

Moved the floats from the carbs that cruised better (level was a bit higher), raised needles to MAX with one washer, installed 108 main jet that just showed up. Bike is pretty close. I had the 112 in there with the same setup and cranking the throttle would choke the bike. So folks were right that 112 is too large. Not sure why those were in the bike in the original carbs. I will do the stick coil mod soon, but I am now pretty convinced that Hamlin is right and the problem is just carb tuning with the wide open muffler on the bike. Silly me for assuming the original carb was already setup by someone for that exhaust. Seems that it was 'somewhat' setup for it, but not correctly. Not sure how smooth I should expect the throttle to feel at lower RPM when accelerating from a stop. It is pretty good if I go hard, but has hesitation if I go easy. But definitely not terrible.