Thanks Dennis!

Question about the Pilot jets... I've removed all of the pilot jets... is there additional stuff to remove? Does the brass seating that it screws into come out?

I've given it a good soak in carb cleaner, sprayed it out, taken a tooth brush to the dirty stuff, and blown out all of the passages with the compressor.

 

Not sure that brass comes out. I think they are pressed in. Once the jet is out the opening should be large enough to get it clean. I like to squirt a little carb cleaner in every opening and watch that is squirts out somewhere. The tiny ones are the hardest to get clean. Usually the biggest problem with carb cleaning is getting the pilot jets clean but your putting new ones in so your good there.

 

The main jet has a brass emulsion tube that it screws into. That is removable, using a 7mm socket and a careful hand.

 

hello, newburt here wanting to add my .02 since i'm also running a naked 600 hurricane. mine's an 88. just getting my project bike on the road after saving the ole' thing from a dubious future last fall. full mechanical fresh and detailing over the winter. she's buck naked and running a Kerker can with stock headers.

she was running pretty strong in the lower gears to 11K, with a few dips here/there in the power but fell on her face above 75/80mph. seemed to be starving for air, or maybe fuel.

i researched (again) any possible downside to running gravity feed and found nothing so i moved into the carbs. they were spotless, with new needles/jets/float valves, etc. thx mr PO!. all was super clean but i carb-cleaned the circuits anyway, then checked float heights where all was well. jetting was found to be stock, and i set the a/f mix screws to 2 1/4 turns.

i found this thread and started looking into the possibility of modifying the intake system. did a quick test with the rubber runners removed, leaving just the two holes in the airbox and she ran terrible at all rpm's. while further disassembling the airbox, i noted that the foam wrap around both perforated steel tubes (under the singe cover in the airbox) had disintegrated and had turned into a semi-solid sheet of compressed particles. not wanted that mess upstream of my airfilter, i cleaned all the stuff off and did a test run with rubber runners and un-wrapped perf tubes. better, but not great.

thinking that it would be best to have a good supply of somewhat stable air entering the airbox via the rubber tubes, i re-wrapped the steel perforated tubes with a scotchbright pad (luckily a perfect fit). and i also wanted to reduce the possible "ram air" effect at higher speeds i also stuck a piece of scotchbright pad in the frame holes, just ahead of the rubbers.

wow, all better! she zings easily and very quickly to 12K in the first three gears, then shifting into the top three at around 8000, i'm now at 105 and steadily rising but no more road. i have every confidence she'll hit 125 (indicated) which is not bad considering there's not one fairing on the bike and i'm not tucked much.

no more flats spots that i can notice all the way to 12K, and idles at 1000rpm's. am pretty happy. if anyone is having tuning problems i'd recommend checking the foam wrapping around the perforated steel tubes inside the airbox, that was my main source of trouble. easily corrected once found, but i've never seen them mentioned before.

 

The reason you haven't heard anything about this is that it should have no effect at all on how the engine runs. The flow to the air box is more restricted in your configuration. Many people put additional holes in the top of the air box to draw more air.

My guess is something else you did improved the problem. I also notice that you said you are running gravity feed. This can result in fuel starvation at higher RPM's and is why Honda added the fuel pump in the first place.

 

I've posted it before but the best way to fix the ram air effect on a naked bike is a way I found a long time ago on custom fighters

Originally Posted by Mustapha dump
The main cause of issues when the fairings are removed is the float chambers seeing a slightly lower pressure than the airbox sees when moving at speeds above 45mph or so.
The ZX series of Kawasaki sportsbikes suffer from this problem very acutely.
What you really need to do rather than restricting the amount of air entering the airbox, is to enable the float chamers to see the same pressure reference as the airbox.
The easiest way to accomplish this is to find the two Tee pieces between carbs 1&2 and carbs 3&4 which are the float chamber vents, on some banks of carbs on the Hondas it is one large Tee piece between the 2&3 carbs as all 4 carbs are linked across the top.
Once you have determined the float chamber vents, attatch a short length of rubber hose to the Tee piece, and then run it into the airbox through a hole drilled in the underside just large enough to pass the hose through tightly.
Face the open end of the hose towards the front of the bike under the airfilter, if needs be slash cut the hose at 45 degrees and face the cut upwards and forwards.
By doing this the float chamber vent will be fed by the air entering the airbox which then ensures that the pressure in the float chambers is equalised with the airbox pressure, once this is achieved the air passing through the venturi will suffer a slight pressure drop, as this happens the air pressure in the float chamber becomes slightly higher than that in the venturi directly above the needle jet/jet needle, and this higher pressure in the bowl then forces the fuel up the needle jet/emulsion tube and introduces it to the airflow through the venturi where it is then atomised and carried into the cylinder.

 

Indeed Ben. Well written advice.

I had these woes back when I modified mine to RAM-air. After fighting the ram air forever I ditched it and went back to normal. It wasn't until 2 years ago when I helped build a blow through carb turbocharger on an older Mustang that the float chamber reference line finally clicked. Mainly because under boost it blew all the gas out the ref lines.