'06 Ninja EX250 - Carb/Engine questions...

[plasmagrid]

Folks,
I don't want to double post. I searched the forum and didn't really see an answer to my thought in mind. Kinda new to what I am doing so please bare with me.
Over the weekend I adjusted my valves (completely out of spec.), Exhaust at .05mm and intake at .03mm, add a K&N filter and removed OEM airbox. Changed the plugs and at .027 (old ones had no anodes, surprised it ran for 5yrs). Also put a filter on the crank vent. I turned the air/fuel mixture screws all the way in and then turned them out 2 1/2 turns. I ended up at 5 turns out, which seems a bit much to me, so that when I blip the throttle is does not hang nor dip on idle. Heck this is the first time since I owned the bike that I can actually idle without choke after 30secs., I also don't have oil leaking on the engine anymore from that darn OEM airbox. I used to have to warm the bike up for 15mins just to start to ride. However, when I ride now I get this very light pulsing/hesitation sensation throughout the ride (all gears) So what I am looking to find out is
1. Does this signify a carb. clean and rebuild?
2. Does any needles need to be shimmed?

Any pointers to posts and ideas/thoughts would be greatly appreciated.

[jkv45]

Originally Posted by plasmagrid

Folks,
I don't want to double post. I searched the forum and didn't really see an answer to my thought in mind. Kinda new to what I am doing so please bare with me.
Over the weekend I adjusted my valves (completely out of spec.), Exhaust at .05mm and intake at .03mm, add a K&N filter and removed OEM airbox. Changed the plugs and at .027 (old ones had no anodes, surprised it ran for 5yrs). Also put a filter on the crank vent. I turned the air/fuel mixture screws all the way in and then turned them out 2 1/2 turns. I ended up at 5 turns out, which seems a bit much to me, so that when I blip the throttle is does not hang nor dip on idle. Heck this is the first time since I owned the bike that I can actually idle without choke after 30secs., I also don't have oil leaking on the engine anymore from that darn OEM airbox. I used to have to warm the bike up for 15mins just to start to ride. However, when I ride now I get this very light pulsing/hesitation sensation throughout the ride (all gears) So what I am looking to find out is
1. Does this signify a carb. clean and rebuild?
2. Does any needles need to be shimmed?

Any pointers to posts and ideas/thoughts would be greatly appreciated.

5 turns out tells you something isn't right. Did you remove the idle mixture screws and clean the passages, and reinstall the screws with a spring, washer, and o-ring? Did you pull the Pilot Jets and clean the tiny cross-drilled holes that plug easily? Are you running a fuel filter?

You should sync the carbs and check for vacuum leaks.

You need to isolate the throttle position where the issue is the worst (1/4, 1/2, 3/4, WOT) to know which circuit needs adjustment.

Shimming the needles to richen the midrange is pretty common, so most likely you would feel an improvement in the midrange/mid-throttle position.

[Tylorwashere]

Something that screwed me up on my most recent carb rebuild was the throttle cable. It was just a little too tight and was causing my adjustments to not have any effect. After I noticed and corrected that I was able to adjust my carbs without issue.

Just a thought

[ducatiman]

Engine demanding 5 turns indicates to me the fuel portion of the pilot circuits may be partially occluded ( plugged )
Could be at the actual tiny jet orifice or further in the circuit, dunno
Nevertheless, I’d suggest a look see
Have pilot screw and bowl orings on hand, replace automatically while you are there, just another suggestion

[Cgswss]

First, I have to get on my soap box. By elimating your airbox, you have left your self with a lot of tuning issues. That said, I would say almost for sure that you need to pull the carbs and pull out the low speed jets. Now I know everyone will cringe at this, but I use an E string to pass thru to make sure the holes are open. With the low speed jets out, put the straw from the carb cleaner in the port at the front of the carb that is off center. You should be able to get carb cleaner coming out the hole where you removed the low speed jet

Because you have removed your air box, “normal” advice is of little value. You should be looking for” tuning with pod filters” and getting advice from others that have a streetable bike with pod filters