#45 pilot and #180 main. Is this what the rejet kit comes with and what would be best for a 2003 1200 C? I have read more times than once that the #45 prevents the stumbles and backfires.

 

Is 45/180 right? Sorta. Depends. Absolutely. Not really. Too little information to tell you that. Is your bike stock? Did you change the AC, exhaust? Do you have performance cams or head work?

To answer the 45 jet question - 90% of the time, combining a 45 slow jet, aftermarket AC, and tweaking the mixture screw will go a long way to eliminate a lot of the popping/farting through the carb. Changing the stock main jet won't do anything for that. Slow jet controls everything at idle and off-idle. Its not until you are rolling and on the gas hard that the main jet picks up and plays a roll.

If you buy the Dynojet kit (recommended), you'll get everything you need sans the 45 slow jet. But the dealer or any Harley bike shop or shop that works on CV carbs will have one. The DJ kit instructions provide you everything you need to get the bike set-up and running well. You'll get the different jet sizes to choose from plus a new emulsion tube, as well as an adjustable needle jet, and new slide spring.

You can change a couple jets, tweak the mixture screw, and be good to go in a lot of cases. Many have done this for years with a degree of success. The up side is cost savings now. The down side is it's trial and error. If you don't get it right the first time, or upgrade/change pipes or other engine goodies down the road, its back to the drawing board.

I like the piece of mind the DJ kit provides. It is proven effective technology. Plus you get a box of extra jets along with fool-proof instructions you'll to adjust your setup as your bike evolves down the road.

Footnote: Why doesn't the DJ kit come with a slow jet? In many applications, the DJ kit alone is enough even without the slow jet upgrade. But the slow jet will run about $5 so worth it to get one along with the jet kit.

 

Benson,

As far as I know, the bike is stock. Factory pipes, Ham Can cover, etc. Of course, I dont know jack about HD's, so take my info for what its worth. When the guy cranked it up for me, it ran pretty strong. I am buying it from a Car Dealer, it was a trade in for a new truck. Less than 2k miles, so I am guessing it is stock. I did hit the throttle while it was idling, and that 1200 sure has some power. I just hope that is is a good bike for Daily transportation. I dont want to have to tinker with it all the time, other than the normal maintenance.

 

Could be stock. Despite the lean factory setup, Sporty have a lot of power. That said, if it were mine, I'd put a SEAC on it. While I had it in the operating room, I'd do the jet kit. Sure it might have been jetted by the previous owner. But only way to know 100% for sure is to open the carb. And if you are in the carb, might as well jet it yourself. Especially since you had stumbles and backfires. Even if it were jetted previously, it didn't fix the problems.

Afterward you'll have even more power. More importantly, you'll know it was done right because you did it yourself.

 

I haven't ridden the bike yet, I just listened to it run, etc. I told the guy I will be test riding it before I give him the rest of the money. I hope to find someone who knows a little about HD's to go with me and ride it.

It doesnt stumble when idling or when revving it, but the only way to know is to ride it at speed. I dont reckon there can be a whole lot wrong with it with only 2000 miles. I dont know how long the lean run stuff with the EPA has been going on, but I was hoping that the 2003 model year was excempted.

 

I have a 03 1200c, 45 slo, 180 main, straight pipes and se a/c
runs good. minimal farting, maby need baffles for the pipes

 

ride it and take notice of how much throttle you give it and when it bogs then find out what jets you have and change them accordingly. if it bogs with a little gas step the slow jet up a little if it bogs with more gas, change the main. I just rejetted saturday after a dyno and it definatley runs better and has more power in the midrange