Need Help with Idle Mixture

[Lenny750]

Just installed a FactoryPro Jet Kit. Stock air box, but I'm running a Delkevic slip-on without a baffle. I guessed and went for the 120 and #15 jets and put the needle clip in the 4 slot with the nylon washer that came on the stock needle. Pretty much everything went well and the bike runs much smoother. The vibrations that started at 4,500rpm and just kept going are now limited to just 4,500 to 5,500rpm. Thinking of putting a thin washer under the nylon washer to raise the needle a little bit more to try to get rid of those last few vibrations.

The only issue I have is the Idle Mixture. I started at 3 turns out and went for a ride. It was good until the bike got warm, then it would bog down whenever I tried to leave a stop or give it gas at under 2,000rpm. Since it got worse as the engine got warm I assumed it was to rich and turned the idle mixture screws in 1/2 a turn. It got better, but not solved. So, I turned them in 1/4 turn. Still has some issues with leaving stops and throttle at low rpm. Should I just keep turning the screws in until it gets better? It seemed weird since everyone says 2-1/2 turns out is the right place, but I'm at 2-1/4 now and still seeming to run rich. Any suggestions?

Bike was a California model, but I took all of that stuff off. Not sure if that matters.

[92xjunker]

No where did I see a carb sync, which does cause vibration in the range you mentioned. Guessing at jet size is foolish, FP has a sheet with it, try following it!! Damn I wish you guys would do thing right, instead of just shooting in the dark. First you need a CLEAN carb set, then follow the install sheet. Adding just a can doesn't justify larger jets!!! Free flowing header with a can would!! It's bogging when hot is because you're running too rich..rant over...

[shpielers]

120s with stock header sounds way rich. I've heard most people use the OEM size jets when they don't have higher flowing exhaust just fine, and I believe 3rd position on the needle.

[arsenic]

No where did is see a carb sync, which does cause vibration in the range you mentioned. Guessing at jet size is foolish, FP has a sheet with it, try following it!! Damn I wish you guys would do thing right, instead of just shooting in the dark. First you need a CLEAN carb set, then follow the install sheet. Adding just a can doesn't justify larger jets!!! Free flowing header with a can would!! It's bogging when hot is because you're running too rich..rant over...

1) sync the carbs
2) you don't need bigger jets
3) yes 2.5 turns should do the trick, but it will be too rich if you're using bigass jets. Case in point.


Read it this time

[92xjunker]

And poof!!!! there it is...

[Lenny750]

I isn't like I was just guessing blindly guys. The sheet said stock jet size for street slip-ons with baffles and the larger jets for "race" baffles. I figured a race baffle would also include no baffle, so I went one size over stock. The needle was a guess though. I thought that the needle position and jet size didn't really factor into idle mixture. That is the only place with issues. It runs fine without stumbling or bogging down at anything over 2,000rpm.

Anyway, I'll change the jets out and move the needle down one slot tomorrow and see if that solves things.

BTW, I did clean the carbs. But, they were pretty damn spotless when I started. 11,000 miles in 9 years isn't going to dirty them much.

[ZukiFred]

Sitting and not running will gum up carbs as fast as anything else, and no one said anything about cleaning them, they said sync as in synchronize.

http://www.motorcycleanchor.com/katana/trinc/sync.htm

[kanatunawagz]

Sitting and not running will gum up carbs as fast as anything else, and no one said anything about cleaning them, they said sync as in synchronize.
http://www.motorcycleanchor.com/katana/trinc/sync.htm

actually.. mr junker did say to make sure they were clean...

First you need a CLEAN carb set, then follow the install sheet.

To the OP, these guys will get ya taken care of, they know their stuff. Just gotta understand, they get grouchy when us new guys show up with problems and ask the same questions. lol Lots of these bikes out there, so everyone and their grandmas show up with similar issues. Syncing the carbs it prolly one of the most important issues from what ive read, and i can agree first handed. Im guilty of that as well.

stick around, ask questions and you'll get it dialed in!

[92xjunker]

Sitting and not running will gum up carbs as fast as anything else, and no one said anything about cleaning them, they said sync as in synchronize.
http://www.motorcycleanchor.com/katana/trinc/sync.htm

Um, you might want to reread my rant there fred.

[ZukiFred]

Oh, so now I am suppose to read EVERYTHING before I coment...
So I was just a little off, one person did say to clean them.

[92xjunker]

I isn't like I was just guessing blindly guys. The sheet said stock jet size for street slip-ons with baffles and the larger jets for "race" baffles. I figured a race baffle would also include no baffle, so I went one size over stock. The needle was a guess though. I thought that the needle position and jet size didn't really factor into idle mixture. That is the only place with issues. It runs fine without stumbling or bogging down at anything over 2,000rpm.

Anyway, I'll change the jets out and move the needle down one slot tomorrow and see if that solves things.

BTW, I did clean the carbs. But, they were pretty damn spotless when I started. 11,000 miles in 9 years isn't going to dirty them much.

??????? Your first katana? Just because you can't see the dirt, doesn't mean they are clean. Stock header = stock jets. FP always states start with stock jetting, then go through their setup steps, idle, full throttle then midrange.

[skjeflo]

Anyway, I'll change the jets out and move the needle down one slot tomorrow and see if that solves things.

BTW, I did clean the carbs. But, they were pretty damn spotless when I started. 11,000 miles in 9 years isn't going to dirty them much.

If you aren't going to listen to those who have come before you and have WAY more experience with these bikes, at least only change one thing at a time. Then you will be on a path to narrow your problem down.

As for clean carbs...like ZukiFred said, sitting is one of the worst things you can do to these carbs. Along with ethanol gas going to crap you can have hoses deteriorate and drop chunks of rubber into your fuel, fuel tanks corroding and giving you tiny bits of rust etc. in you carbs. Also, rubber seals deteriorate over time, in use or not. A good cleaning takes time, knowledge and the proper tools.

So was your cleaning limited to a can or two of carb cleaner and maybe a brush? Or did you disassemble and dip each body for 24 hours in Berryman's and then use fishing line or small guitar strings to make sure the passages were clean?

Use the knowledge this forum has stored up, both in the archives and that which comes from those who know their stuff. Do that and your bike will be running well very soon.

[maniac1886]

+1. I thought my carbs were clean till I got in the pilot jets with fishing line. Not so clean.

[Lenny750]

So was your cleaning limited to a can or two of carb cleaner and maybe a brush? Or did you disassemble and dip each body for 24 hours in Berryman's and then use fishing line or small guitar strings to make sure the passages were clean?

I disassembled them and dipped them like everyone says to do. It wasn't much extra work to fully disassemble after getting the carbs out, so I figured why not. There wasn't much in there though. The cleaner only discolored slightly after 24 hours. I didn't use fishing line though, hadn't heard about that.

[arsenic]

Yeah, taking the carbs off and separating the set is basically the same thing.