In the last few days, I've been getting to know a lot about the 087A carbs on my '76550K. I know I ask a lot of questions here, but you guys are generally helpful, and I feel like I must be doing something wrong. Anyone care to help me figure this out?
Problem:
1/8-1/4 throttle hesitation, seemingly caused by one or more fouling plugs.
Setup:
#1: For the first few weeks, I was running all new stock jets in cleaned carbs. New points, timing was set, UNI air filter, and an older MAC 4-1. Tank is clean, petcock is brand new and has the filter screen. New NGK D7EA plugs, and new plug caps. Although, when I went through the carbs, I stupidly didn't pull the needles because I thought it would upset the sync between the carbs.
^ With this setup, the bike would run very rich, sputtering at small throttle openings, but felt good after 1/4 throttle. It got worse as the bike warmed up, and removing the air filter completely fixed the sputtering.
#1.5: I left everything the same as above, but synced the carbs and installed a Dyna S ignition. Igntition was static timed, and I have no reason whatsoever to suspect that it isn't working well. Sputtering seemed to get *slightly* better, but was still present, again, especially when the bike was warm. Again, removing filter fixed the low end hesitation, indicating an over-rich situation.
#2: Everything the same as above, but I checked the needles. Stock 272304 needles, 4th slot from the top. Totally stock. BUT, the #4 needle had some damage on the tip, and the bottom of it was all black. This was also the cylinder that was running the richest. Problem solved. I had some Keyster D26 needles, so I put 4 brand new needles in and set them at the 4th slot from top. I should note that they're about .5mm longer, so I anticipated a slightly lean condition, if anything. Ran the bike for a day, and it seemed better. It sounded and acted a little lean, but the plugs were grey, or even slightly dark. But the revs hung a bit more than before, and the exhaust had that 'fluttery' sound. For the most part, the sputter was gone. Seemed to be *barely* present when the bike heated up, as before.
Until the next day, when the sputter got just as bad as before. I pulled the plugs and #3 is now completely black. Blacker than black. The other plugs vary from very dark grey to basically black.
If the other plugs had been grey or whitish, but plug #3 was black, I'd suspect something amiss with the needle I just installed. But why would they all be running rich-ish? Could one carb misbehaving affect the others somehow? Mechanically, this setup SHOULD run stoic or a little lean.
When it stops raining I'll pull the needles out again and check on carb #3 (with the fouled plug), but I'm just looking for some advice here.
I just had another thought- Would pulling the slides out from the top change the carb sync drastically? You obviously have to disconnect the linkage, but it can only go back together the same as it was- shouldn't be much, if any change, right?
Thanks for any advice, and sorry for the long post- I'm at my wits' end!
TF
