Hey gents,

Would like some input on my bike.

03 Dyna FXD, TC88, had just a thunderheader and air cleaner on it, all california emission stuff removed. Bike ran pretty good, but would get a cough here and there, especially when colder temps (California cold so really not that cold), would do it here and there but really not that bad. I have heard that can be a "lean cough". Was told that by the previous owner (who installed the intake and exhaust) that it had the sportster needle in it. Based off the coughing, figured it may be on the lean side.

It needed the tensioners done, so I just finished that, decided to throw some S&S 509 cams in while I was in there. Figured I would need a rejet. I definitely had to use the choke/enricher to get it started with the new cams, and it wont idle without it until I ride a few miles, which I understand to be normal and about the same as before. I did get a few coughs here and there first couple rides. So, Im concerned its running lean. I check the plugs, the are pretty white with really no sign of tan/coco color which is worrysome.

The PO had drilled the plug for the adjustment screw, it was around 2 and 1/4 out. Went to around 3 and 1/4 out and actually hasnt coughed at all since then, but plugs are still white.

I am going to assume it has the sportster needle since thats what I was told and the carb has been messed with. Pulled the bowl yesterday and to my surprise it has a 50 pilot jet in it! And the main is a 180. I have read that 180 is stock, but my manual states that 190 is stock, but lots of the research I have done indicates 190 is pretty big. The bike runs pretty good, but concerned I am lean based on the plugs.

My questions: Is there a way to tell if I do have the sportster needle? What do you make of the 50/180 combo? What about the white plugs?

Thinking about grabbing a 185 and 190 main jet, and just trying them. I think the 50 pilot is plenty big but really not sure how the sportster needle would affect the pilot. All that I have researched indicates a 45/46 pilot with a 180-190 main and the stock needle shimmed up should be pretty good ballpark for intake, exhaust, and mild cams. But how would that change with the sportster needle? I definitely do think I would want to go back to a 45/46 pilot if I think it was running lean, and that it would cough a little until I adjusted the screw.

Any input? Thanks guys!

 

SO! What is wrong with "white" spark plugs? Have 132,000 on my bike and the front plug is always "white" while the rear plug is usually "white/light brown" sort of a 50/50 coloring. I blame this on Mr. Newton.

This is also the reason HD recommends changing the plugs at 5,000miles.

When flying piston engine aircraft it was common practice to "lean to 50 over", that is at altitude lean the engine via EGT to max temp then go 50deg under the max temp" with the mixture control which would be over lean on the engine. (You may have to think about that a moment to make sense)

IMO don't think "reading" plugs is as telling today with the modern pump gasoline, because of the corn and other additives mandated for pollution control.

If the bike is running good and there isn't any backfire or hesitation I would leave the jets alone, just my opinion for what it is worth. Remember you are in California and will have to pass that emission test.

There is more than jets to be changed, there are needles, emulsions tubes, springs, and float settings that all effect mixture.

 

Thanks for replying! And i have read the same, white plugs do not always mean running lean. Right now it does seem to run pretty well.

California bikes are sold with emissions equipment but are not subject to any testing so most of them "loose some weight".

Like i said, the needle has been changed to the common late 80's sportster needle and the jets changed slightly too.

If it were running slightly lean, what symptoms would I expect to see?

 

The Sportster needle is just a different taper. I believe it starts adding fuel earlier than the stock needle as it rises. Its a common mod when rejetting modern Sportsters..If it is running slightly lean it would be just like it comes from the factory. A lot lean down low it would take a long time to warm up and spit back thru the carb at lower rpm with aggressive throttle application.

 

What d24112 said.

Wonder why California doesn't test bikes? Only intelligent thing they do

 

That is my understanding as well, it was meant for a CV carb that didnt have an accelerator pump so its a taper that allows more fuel in the mid range. I have also read its a somewhat common upgrade for any CV carb, or some simply shim the factory needle up. What you are describing as lean is what it would do, but since I adjusted the mixture screw it hasnt done it. Maybe i'll just ride some more and see how it acts before changing anything as maybe I am closer than I thought. Like I said the reason for asking is it would cough randomly as it would warm up, and once in a great while when riding after warmed up, this was before the cams so I could only imagine it would be worse with the new cams and dont want to damage anything.

Ha ha, ya I'm not too sure but would speculate it has to do with the amount of bikes compared to vehicles and the somewhat cumbersome dyno testing of bikes. No complaints here, they already make me smog my diesel truck which is a complete joke. Might as well tell me to hand them $60 rather than lie and say they are doing a test. And not to mention the crazy registration costs. My 03 dyna cost me $128 this year.

 

Just a shot in the dark here but happened to me so will share just in case .. This same thing happened to me right after changed my Intake Seals and thought if anything would put me a Bit Richer with less air leaking from the Intake .. Then it really started acting lean , Back Firing on Decel and needing the choke to even start it when warm .. Then noticed a slight gas leak from the Fuel Valve Shut Off (Petcock) Turned out the Fuel Valve was screwed up not allowing enough Gas Flow .. All is Well Now ..

 

Just as an Addition I have a 2005 88" with a K&N High Flow A/C Vance & Hines 2:1 and Andrews TW21 Cams and Run a #48 Low Speed Jet and a #190 High Speed ..

 

Thanks for chiming in! The bike was actually running pretty well after I adusted the mixture screw, but I'll keep the petcock in mind if it starts doing anything weird. Thanks for listing your jets, I have read that is a good setup for a mild cam. Since I have the 50 pilot jet in there already, as well as the sportster needle, Harley stocks a 185 main so I am going to grab that tomorrow and replace the 180 thats in there and hopefully that will just richen it up ever so slightly to ease my mind ha ha.

Based off what everyone was saying, I pretty convinced I am actually good where I am but trying this other main jet will be easy. Definitely going to look closely at how it runs and fuel economy to see if I can get an idea what its doing. If you have ever checked your plugs, are the usually white? Understand that may be normal, curious of your experience.

Thanks!

 

If you have ever checked your plugs, are the usually white? Understand that may be normal, curious of your experience.



My Plugs are usually a Grayish Color .. Usually Ashen White on a Carb is Lean on EFI is not so critical as the newer ones with EPA 14.7 A/F white is normal running stock .. This perfect Tan/Light Brown is pretty hard to achieve all the time although I do get it sometimes but as long as the Electrodes are not snow white or burnt or Totally Black is not as critical as some make it out to be, especially with EFI ..