Hey Everyone,

(some of you might know some of this background already if you've followed one of my other threads)

Should factory pilot jets have a clear path that can pass air/fluid from one end to the other?

I cleaned a carb on a hawk that had been sitting for 2 years. At first after cleaning, it still didn't run. I noticed that the pilot jets did not have an open path from the slotted end to the tip. In other words, if I blew, or tried to spray (compressed air or carb cleaner via a tube) directly into the hole in the slotted end, nothing came out the emulsifier end. I concluded this meant that the were internally still fouled.

I have a spare carb I bought off of ebay that has been jetted. The pilot jets in it do have a clear path from tip to tip, they can pass air/fluid all the way. I put them in and now the bike starts and runs.

My question is, am I correct that factory starter jets should have a clear channel from one end to the other that can pass fuel? I did not think to look at the spare set that I put in to see if they had a different number on them.

My bike is still difficult to start, and the choke doesn't seem to function correctly, so I am trying to figure out if a) the pilot jets I put
in are not OEM, and require some different tuning somewhere that I did not do, and b) whether the pilot jets my bike came with were fouled beyond repair, or they just don't work the way I think and are actually fine, and it was some other adjustment I should have made to get the bike to run with them.

Thanks,
Avram

 

Avram,

Stock pilots are #45. Some, but not very many, owners have put in #48s. Yes, you should have a very small hole in the end, and also the ones on the sides should be open as well. They are different, front to back. Don't get them mixed up. Use a small strand of copper wire to clean these out. You don't want to scratch or enlarge the holes.

 

Should the hole in the tip go all the way through to the slotted end?

I'm pretty sure the answer is yes b/c I just found from the person I bought my spare carb from that it had stock pilot jets. So I believe my original pilot jets are varnished *solid* inside. Forgetting about whether I'm damaging them, I tried putting a safety pin through, and it stopped half-way even if I pushed really hard.

 

I can't speak for the Superhawk (haven't owned it long enough), but on other bikes the pilots are the first to get gunked up. ~mike

 

Yeah, it goes all the way through.

 

Several people have commented, here and in other threads, to be careful not to mix up the front and rear pilot jets. However, from looking at the online microfiches it appears to be the same part for both front and rear. I understand that the main jets & their holders are different front/rear, but could someone please confirm that the front & rear pilot jets are the same part?

In this diagram the are both labeled 38. There are two 38's in the chart, part #'s 99103-MT2-0450 and 99103-KPS-0450 - but the first of those two parts has been superseded by the second one - it is not a front/rear distinction.

Thanks!

 

The front and rear pilot's are the same. The 175 main jet is for the front and the 178 is for the rear. The emulsion tubes are different though. That is what the main jet mounts to.

The needles are different as well. The one marked "A1UF" is for the front and the one marked "A1UE" is for the rear.

 

There can be a lot of hard to reach places within the carburetor body itself that will still be blocked by varnish, so even if the jets are spotless, it still won't run for crap.

Here's what I think you should do...
Start with the set of carbs I sold you, these have not been sitting that long and I'm willing to bet are a much cleaner as is. Remove the slides, jets & air mixture screw (if you have the special "D" tool). Take some carb cleaner and spray every orifice, then blow them all out with some compressed air. Every passage way has two opening, so when you blowing air through them you should fell it coming out somewhere else on the carb, if not repeat the procedure. Take the slides from your old set and put them into your new carbs... stock needle and all (remember the needles are different... see above post). Do not use the slides from the carbs I sold you unless you are going to be using the rest of the Dynojet kit. Those slides have been drilled to work with the DJ kit. Make sure the Pilot jets from the set I sold you are clean by holding them up to a light, the passage way should be clear, and re-install them in the carbs. Install your stock size main jets (175,178) into your new carbs. Re-install the air mixture screws, the order is; "screw, spring, washer, o-ring", slide it in as a set. You can replace the o-ring if you so desire, I never do unless they are junk. Set the mixture screw to 2 & 1/4 turns out from lightly bottomed. Install the carbs and go for a ride.

Sorry if any of this is redundant info... I'm not up to speed on your other thread.

 

The number 45 pilot jets are too lean for me. I still need to adjust the pilot screws, however I think 48s are perfect. 50s are too rich.

 

They definitely are much cleaner. That's a good point about hard-to-reach places - I assume you are referring to deep inside the channels where the jets mount, and perhaps on the path from the jets to the actual ports in the venturi?

Hmm... I wanted to keep your carbs intact b/c when all is said & done I hoped to sell them again. I don't plan on ever jetting my bike. I'm going to keep it mechanically stock as much as possible.

But my bike is tricky to start. Choking it will start it, but it stalls in like less than 1.5 seconds and then it won't start until I close the choke (when it's 50 degrees out). After that, it will fire, but I have to blip the throttle just the right amount at just the right time to get it past the 500rpm firing-with-the-starter-running mode up into the >1000 rpm running mode. Just a little too much throttle, or the right amount at the wrong time and it stops firing.

It's not crazy to think that could point to fouling in the path behind the pilot jet.

FWIW, the bike seems to run perfectly once its warm - no trouble idling or anything else - although I may well be cheating by having the idle stop **** set more open than should be necessary, if I am unknowingly compensating for a fouled pilot jet.