'02 Ninja 250 - Little to no power in lower RPM range

[MrMistyEyes]

Hey guys!

I bought a 2002 ninja 250 a couple weeks ago, but it has a few problems. This was my first bike, so I didn't really notice any of the problems. After a little research, I thought I should clean my carbs. I took the carbs out and cleaned out the "pipe" area (sorry, I'm not familiar with all the nomenclature), and the float bowls. I cleaned the main jets, but couldn't get the pilot jets out, because I didn't have the right screw driver screw driver. Next, I went to clean the diaphragms, but one was ripped. A hundred bucks later, I installed a new diaphragm, and put everything back together. Now, it barely has any power at the low end, and I must have the choke almost fully turned on for the bike to run. Good new: it has a TON more power >8k rpms. My guess: pilot jets are clogged. I wanted to know if y'all had any more input.

TLDR:

• Cleaned everything in carbs except the pilot jets.
• Replaced a ripped diaphragm.
• Didn't tighten one of the boots enough and gas leaked pretty heavily, but it no longer leaks, because I tightened it.
• Now, it has little to no power in the < 5k rpm range. In fact, it is kind of hard to get it above that range without the bike dying.

[MrAtom]

Did you remove the idle-mixture plugs? There are two screws that are capped off from the factory on the bottom of the carbs. You can use either a hacksaw or a drill, but be a little careful with either tool. If you haven't, take those plugs off, take out the idle mixture screws and clean out those channels with some carb cleaner. Here's a guide on removing them:

http://faq.ninja250.org/wiki/Removin...re_screw_plugs

When you're done, put 'em back and tighten down those screws until they're just snug. Don't go Lou Ferrigno on them. Then back them out 2.5 turns and they'll probably run, but not too efficiently. Look at this for tuning them better to match your bike, your atmospheric conditions, etc:

http://faq.ninja250.org/wiki/How_do_...dle_mixture%3F

If you wanna get a little more advanced, you can check this out:

http://faq.ninja250.org/wiki/How_to_...e_your_jetting

Also, if you're annoyed by the process of taking the carbs out, you can shorten the process by doing this. I personally haven't (my bike's all chopped up already, so it's less necessary for me), but a lot of members have benefited from this:

http://faq.ninja250.org/wiki/Battery...r_carb_removal

Of course, if you're willing to spend more, other members have benefitted from @ducatiman He provides carb cleaning services, and while I haven't used him personally, his customers seem happy.

Best of luck! Report back with an update. Sorry to link-bomb you

[Ghostt]

If your Bike needs the choke to run after start & warm your pilot jets are blocked, it's that simple.

I strongly recommend that you PM @ducatiman
https://www.ninjette.org/forums/showthread.php?t=226815

Until you get the carburetors sorted out, all other tuning is irrelevant, and a total waste of time. Once the carburetors are sorted out, then check/adjust the valves, and replace the plugs, and service the spark plug caps.

Once those are done, then you can start dialing the engine in.

[Kestrel]

Hi MrMistyEyes,

Definitely take a look at the links posted by MrAtom to the Ninja250.org FAQ. Furthermore, here is the link which explains the proper procedure for cleaning the carbs.

http://faq.ninja250.org/wiki/Cleaning_the_carbs_2

If you are mechanically able to remove the carburetors (which pretty much everyone can manage), then cleaning them really isn't any more difficult. The CV carburetors used on the Ninja 250 are rather basic in their design, and fairly simple to renovate should it be necessary. The steps and pictures in the FAQ are very good, and tell you much of what you need to know about the cleaning process. While there are a few exceptions where trickier cleaning techniques are needed, for the vast majority of cases, it's something most owners can handle on their own.

[Ghostt]

The most difficult part of servicing the carburetors is proper cleaning, most importantly the fuel circuits/passages, the pilot jets, main jets and emulsion tubes, which all those need to be removed.



Beyond common problems...... comprehensive carb cleaning is not for everyone, there is much to go wrong in short order. We've seen many members endlessly chase their tails, break stuff, assemble and adjust stuff wrong.

With some of the fleet becoming old, the vast majority require much more than "cleaning". The potential for leakage must be addressed, any less attention is irresponsible, and yes, this may even require thowing money and parts at them (gasp). Consumables...carb innards are not forever items.

And certainly there is MORE... much more....to it than simply addressing the pilot jets while they are out and on the bench.

Please...you're screwing around with FUEL...if not absolutely sure of what you're doing...send them to someone who is.

This isn't ment to scare, just to inform you.

[HoneyBadgerRy]

It should be just the pilot jets, take them out, clean them, take the mixture screw out, inspect and replace if necessary, if not clean the pilot circuit, button the carbs back up, and set the mixture screws and idle.

[Ghostt]

I have no doubt it's the pilot circuit, I'm just saying that other issues may exist, or could go wrong.

If all else, go out and buy new idle jets, if they are that bad, keep in mind the size orifice of the jet, and tubes are very small, sometimes it's easier just to buy new ones, to save time and aggravation.



Sometimes you need more than a can of carburetor cleaner and a toothbrush.

[MrAtom]

Oh and one thing people forget to mention because it seems too obvious to most of them: DONT GET CARB CLEANER ON YOUR DIAPHRAGMS! it'll warp them and you can sometimes get them back to shape by putting them in front of a fan, it doesn't always work. I made this mistake my first time around and got lucky (I was more used to little weedeater carbs. The diaphragms in those can take a little more abuse).

[Ghostt]

I use the freezer trick

[MrMistyEyes]

Thanks for your replies, guys. I'll see if I can take some of your advice and put it into practice.