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New Bike Investigation (Carb)

The screw looks good, I don't intend to replace it, I wouldn't mind having one of those easy finger adjustable screws but don't think it's worth the money right now, there was a little funk on the tip but it cleaned right off and the hole in the carb body looked clear, gave it a shot of carb cleaner just for giggles, the O ring and washer in good condition. Once again fired up the engine and after it was warmed up wound up with the screw four turns out to get the best idle. More turns out had no effect so I'm thinking the needle is doing nothing and there's nothing to do but wait for my new jet to arrive. I'll suffer the embarassment of the occasional pop 'till then I reckon. Thanks to all for the replies. And thanks to the Dr. for the post merge too. :D
 
2003FXDX said:
More turns out had no effect so I'm thinking the needle is doing nothing and there's nothing to do but wait for my new jet to arrive. I'll suffer the embarassment of the occasional pop 'till then I reckon. Thanks to all for the replies. And thanks to the Dr. for the post merge too. :D
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The important function of the idle mixture screw comes into play from about 3 1/2 turns open to the closed position. The circuit will only flow so much fuel for the idle speed correction. If you have to open it more than the 2 1/2-3 turns, then the slow jet is too small and the next size should be installed to achieve the correct adjustment.
 
:bigsmiley12: Got it! New Jet is on the way. I was apparently wrong about reading the thread pitch and diameter size on this site. I finally found it again (link below, bottom of page), 6mm dia. x .75mm pitch. A size not in my set anyway.
Keihin CV Carburetor Part Numbers
 
Update: The new #46 jet is installed. After warming up, It seems to run smoother a slow speeds/rpm's (my neighborhood has a 25 mph limit). I found the best idle at about 2 & 3/4 turns out on the screw. Went for a ride and once, slowing for a stop sign, it popped back through the carb again. I rode it a while (10 miles +/-) and adjusted the screw and idle speed again, wound up about three turns out. Once again I had one little pop through the carb while slowing and doing a "rolling stop" and turn at a sign. After a short ride with no further issues I turned it out another quarter, now at 3 & 1/4 turns out. on the return ride home, no popping, no problems. I'll leave it like it is for a while and see how it goes. I seem to be averaging around 40-41 mpg so far. Does that sound reasonable?
 
2003FXDX said:
Update: The new #46 jet is installed. After warming up, It seems to run smoother a slow speeds/rpm's (my neighborhood has a 25 mph limit). I found the best idle at about 2 & 3/4 turns out on the screw. Went for a ride and once, slowing for a stop sign, it popped back through the carb again. I rode it a while (10 miles +/-) and adjusted the screw and idle speed again, wound up about three turns out. Once again I had one little pop through the carb while slowing and doing a "rolling stop" and turn at a sign. After a short ride with no further issues I turned it out another quarter, now at 3 & 1/4 turns out. on the return ride home, no popping, no problems. I'll leave it like it is for a while and see how it goes. I seem to be averaging around 40-41 mpg so far. Does that sound reasonable?
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Good thread to follow..

Lots of Good advice given here... and YES on the 40/41, I never got more than 36 on my 2000FXDS 95" and after stage one and slightly modified carb..

You are looking good and Did you replace the slide? That may be a part of the pop.. If it only does it on occasion,,, it might be liveable.. Is that POP only on decel?

You have a good grip on the thing.. May I suggest replacing the carb bowl screws with allen head bolt at 5/8 inch long instead of the stock phillips headed ones..(me strip off the heads and replace on a regular basis).
Makes it easy to change out the jets and an occasional cleaning of the bowl.... While carb is on the bike..

Just My Way :D

signed....BUBBIE
 
Looks like you got things pretty much sorted. Fuel mileage and performance is about right. My Sporty worked this way just by following Glider's setup exactly...only had to screw out 2 turns (2 1/2 was highest RPM and most responsive, turned in 1/2 for better fuel mileage "crisper throttle response accelerating" and knowing I am still a "little" rich). No deaccel popping, but a slight "gurgling" sound, if I deaccelerate and close the throttle rapidly. :D
 
My internet connection has been spotty for the last few days so I apologize for not answering your questions sooner Bubbie. No, I did not replace or otherwise modify the slide though I might buy a replacement just for the heck of it, to play with later. As far as when the Pop through the carb happens, it seems to be only on a slow speed deceleration scenario, like right after a slow speed down shift to stop or make a turn. Over the weekend I tried a couple of different combinations including the stock main (190) jet with two #4 washers and the .46mm slow jet. This setup seems to be lacking in mid range acceleration compared to the adjustable needle with the DJ tube and main jet (180). Perhaps I need a larger main or another washer under the stock needle but I'm going to be short on time to mess with it for the next week so I'm sticking with the DJ needle, tube and jet for a while. After my last ride with no pops as as good or better performance at all speeds as I've had to date, I think I have it as good as I'm going to get it with the parts I have. Time to let it be for a while! Thanks to all for the help and suggestions. :cheers

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Update: My hats off to Bodeen :cheers , Although I didn't find any manifold leaks the first time I checked, I became convinced my engine should run better after listening to several other HD's idling during the last week or two. I checked again and hit the right spot this time I guess. There's no doubt, I have a manifold leak! I'll fix it and update again in a couple of days. I suppose the odds are against being able to cure it by just tightening the bolts... I'll order a new seal kit. Is it worth the extra money to get silicone instead of rubber seals? First chance I get I'll pull it apart and inspect what I have. Then I guess I get to start all over again with the jets, oh boy!
 
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Another update on my situation in case anyone cares or might find the info useful in a future search. I have been experimenting with different jet/exhaust combinations and have decided the best results overall are with the stock needle with two #4 brass washers under it combined with the stock 190 main jet/tube and a #48 (.48mm) slow jet. With the 48 slow jet I finally have good results with the idle screw ending up around 2 1/2 turns out. I also found the bike runs better with the stock mufflers on since the manifold leak was eliminated. On a leisurely 140 mile ride through the country back roads yesterday I scored 46 MPG, best yet. One problem though, it's too quiet! I put the SE II slip ons back on and though there is no noticeable difference in power they are just a bit too loud for me and the engine seems to idle smoother with the stock ones. I have ordered some Smartpartz Quiet baffles for SE II's to try as a compromise. I'll report back after I get them installed and tested. I've read good things about them but mostly on their web site so we'll see. If they don't work out I'll be selling the SE II's and trying something else.
 
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