Topic: In the Ballpark-Carbs

[hdpredator]

i'm currently in the process of the engine rebuild on my full resto.  nothing to ask here, but considering the riding season here in minnesota is kinda short, i'm hoping for some advice to save some time when i move on to the carbs.  here's the scenario:

i've a 1974 CB550K.  the carbs have no model number stamped on them (as is correct according to the chart i found here).  i'll be running a uni foam filter, stock airbox, and a mac 4-to-1 exhaust on the air side.  on the fire side, dyna s ignition and accel coils with the larger gap on the plugs.

in scouring the posts, what i've put together is running one or the other of the formentioned items wouldn't require a rejet (from stock), but the whole shebang on the same unit would and i haven't found anyone with my same setup.  thing is, i've no idea how far to go.  i've talked to some kawa/suzi gurus around here and they say two sizes (stock: #100, new: #110) and moving my clip setting down a notch.  well, i figured i'd see what the honda experts have to say.  i know it's going to be trial and error on my part getting them synced and tuned properly.  but i'd hate to destroy a piston(s) because of a lean mixture.  just hoping you guys can help me get in the ballpark.

thanks for reading and your help in advance, and just in case you didn't know, a few things i've learned during the resto:
1. anti-seize apparently didn't exist before 1978 (and everyone used breaker bars to tighten things)
2. mother's mag & aluminum polish is a wire brush in a can...awesome
3. the top of the line biodegradable, non-corrosive, non-toxic, non-everything is exactly what the description sounds like: water.  the best degreaser is mineral spirits.  $6 a gallon at walmart for the odorless stuff (great for working in the 1-stall garage at an apartment complex)
4. if something seems like it went together way too easy, try looking under the bench for the rest of the parts
5. whoever decided bearing retainers should be made of tin or paper machete should be punched in the neck
6. it IS the smaller spacer for an all balls steering bearing kit
7. wheel lacing isn't that difficult as long as you realize if you have to force something, it's in the wrong spot
8. wheel truing is another story
9. you haven't mastered the english (or any other) language yet (example:  i was in the navy for six years, stationed in spain for three of them.  i can cuss and swear fluently in both english and spanish.  apparently i can cuss and swear fluently in italian, german, sweedish, swahili, and zulu as well.  and now the neighbor kids can too)
10. regardless of how pure your intentions of getting the bike running so you AND your wife can go riding TOGETHER, 5 hours a night in the garage isn't enough to excuse you from dishes, laundry, vacuuming, etc.  if you don't believe me, just ask my wife.
11. the only thing that cuts the bead on a rotted crumbling weather-checked tire is a hacksaw, not a wire cutter, tin snips or harsh words.
12. EZouts and bolt extractors have worked very well...for about half a dozen people in the history of the planet.  they were patient.  i wasn't.
13. titanium bits are expensive.  but try drilling out a broken off EZout without one.  see #12.

thanks again -curtis

[TwoTired]

i've a 1974 CB550K.  the carbs have no model number stamped on them (as is correct according to the chart i found here).  i'll be running a uni foam filter, stock airbox, and a mac 4-to-1 exhaust on the air side.  on the fire side, dyna s ignition and accel coils with the larger gap on the plugs.

I had a 75 CB550K (uni foam filter, stock airbox, and a mac 4-to-1 exhaust) with the 022A carbs.
#38 slow jet, #100 main, and stock needle (I don't remember the needle clip position, sorry).  Ran great.  I believe I had to adjust the Air bleeds a little to get the low speed throttle response peppy.

If you are worried about lean, check your spark plug for deposits early and often til you establish trends.

Cheers,

[hdpredator]

thanks, two.  the #38 and #100 came with the k & l rebuild kits i've got.  i read that stock came a little rich and that adding a 4-to-1 could be done without a rejet, but i didn't know if throwing the accel coils on there would require a little more.  the manufacturer's instructions say to widen the gaps on your standard plugs and that a rejet MAY be necessary.  don't know if it's legit or a liability disclaimer from accel.  either way, as soon as i toss this chingadero back together, plug checks will definately be in order.  thanks again. -curtis

[TwoTired]

If the K&L kits came with slide needles, carefully measure them in comparison to the stock ones.  Sometimes, aftermarket manufacturers get it wrong.

The Mac 4 into 1, depending on the sample, may reguire a larger main jet for WOT operation.  The Mac isn't really a performance exhaust, but a cheap replacement for rotted, leaky, exhaust systems.  Their quality control process doesn't ensure that each exhaust flows properly, only that it doesn't leak.  If it flows to a performance boost, it was an accident during manufacture.

Widening the gap on your plugs is an artifact of having a higher coil voltage potential.  The wider gap should improve completeness of the fuel burn for better economy, and help extend the usefull life of your spark plugs.  Seems unlikely jetting would be effected.  But, a colder plug might compensate for mixture effects from longer spark jumping the arc.

My bikes have all had standard ignition.

Cheers,