Is this symptomatic of dirty carbs?

[CmichRider]

Hey guys, so as I am starting to get the bike ready for the next riding season, I'm noticing some odd stuff with the bike. Last year I had problems with a fuel leak and odd running, so I took the bike down to its carbs and semi-cleaned them.I checked the jets and made sure they were clear and removed any debris and wiped the inside of the carbs clean; needless to say, not very thorough. I put washers on the needles also.

Right now the bike does start, it is rideable, but I wouldn't call it great. It is difficult to start even with full choke, and once choked, RPMS go up to 5-7k, if I try to turn the choke down very soon after, the whole bike dies. At this time, if I quickly throttle the bike, it dies. If I let the choke run at 5-7k for a few minutes, I can lower the choke, but it goes down to 1-2k and then jumps up to where it should be for the appropriate level of choke. My throttle response is slow and the tach is slow to come back down, but does not hang very long.

This is the typical dirty carb, correct? I have no hesitation taking the carbs out and doing a thorough cleaning, but if I do, I am trashing the airbox and putting K&N pods on, mostly because of the extreme difficulty I had reinstalling the carbs last year. The rubber carb to airbox boots were super stiff, even after heating them. I almost think that some bits of the rubber may have gotten into the carbs with all of my swearing and fighting with them.

[CynicalC]

With k&n pods you will need to rejet. Give the carbs a thorough cleaning, and check for any vacuum leaks.

Check this out for making it easier to access the carbs.
http://www.ninjette.org/forums/showthread.php?p=462353

I had a similar problem with my revs hanging after I cleaned the carbs. I took them back apart and double checked everything, when I put them back on it had solved itself. Purrs like a kitten now.

[CmichRider]

The rejetting is the only thing that makes me apprehensive about going to pods. I don't want to be trying to manage two different issues at once instead of one, but it would make working on the carbs so much easier.

I think I might do the airbox mod, but that still wouldn't make it any easier to attach with the carb boots I have, would it? I had a problem with their stiffness the first time, not necessarily that I was running out of room. Once I got one side on, the other would come off because the boots just weren't pliable. Hose clamps helped that.

[choneofakind]

The airbox mod makes it easier because there's more space to work with. pod's will still be easier.

I say clean them and make sure they run right. Then go to a pod filter and rejet.

[CmichRider]

Got the carbs out today, only took about 45 minutes, which is probably half the time it originally did. A lot of that time was spent wondering where I put my screwdriver and hex key set. I'm gonna wire through the passages this week my best, and buy some spray carb cleaner and clean these up the right way.

[CmichRider]

Starting taking them apart today, first thing I noticed was the mostly-clogged idle air screw holes. There was a pinpoint of light I could see through, but after running a brass wire through it I realized just how clogged it was. I probably opened it up to 10x the space it had before. That might be the majority of my problems right there..

[CalvinAmI]

I have the exact same symptoms as you... like EXACTLY.
I am a beginner at motorcycles but am about to pull my carbs off and clean them.
I plan to replace the airbox with the K&N pods and rejet PLUS shim the needles, but I SUCK at getting all the info together to order my stuff =)
I need to get my ducks in a row and get all the parts in so I can tackle it as one project. Are there any pics of how exactly to clean our carbs?

[choneofakind]

Originally Posted by CalvinAmI

Are there any pics of how exactly to clean our carbs?

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

^^ 2 methods of cleaning the carbs in that link. Both methods include a link to some great pictures for reference to cleaning/working on the carbs.



For removing the airbox, you'll need:

• R-0990 (or similar pod filter(s) of choice)
• breather for the crankcase (more info on what size in the faq.ninja250
• 108, 110, 112 main jets
• ten #4 (or 3mm, whichever you find) washers. That makes 5 for each needle.
• 40 pilot jets just in case you end up turning the 38 pilot jets out 3.25 turns or more
• patience in taking out the airbox and jetting

There's your list!! Now go work and have fun learning about your bike!!!

NOTE: faq.ninja250.org is a great place to go for tons of info on how to work on your pregen. I joke about it being the ninja bible.

[CalvinAmI]

^^
You rock =)
Looks like i've got some reading and tinkering to do =)
Thanks again!

[CmichRider]

Put the carbs back on today and noticed it wasn't seeking for an idle anymore, and after warming it up, it seemed to only need a few adjustments with the idle-mixture (slow throttle response and hanging idle). I took it for a ride and it rode great from 4k-13k. Pulled nice and hard. Until after about 20 minutes, I went to go stop at a light, pull in the clutch, RPMs drop to 0 and the bike dies completely. I killed the battery trying to restart it. Had to jump it and limp it home. I noticed surging and bucking, and at 3/4 throttle it was bogging, and then a sudden surge of power that almost got me off the bike (wasn't expecting it...).

Seriously...wtf is wrong with my bike now?

[choneofakind]

Are your diaphrams damaged?

are all your vacuum lines sealed properly on the nipples they attached to on the carbs?

[CmichRider]

I paid careful attention to the diaphragms and did not notice any damage, no tears or rips, but a little indentation in one corner, it didn't look to be enough to cause any problems though. Vacuum lines are all seated completely, but the spring clips on one or two of them are missing, still snug though. I'm more worried about it just up and dieing on my in the middle of nowhere, when this happened, I was only a block away from my house.

Could these problems just be coming from a weaker battery? I was just looking at some model numbers and it looks like the battery in my bike, while still 12V, is 3AH instead of 6AH like the stock battery (or acceptable replacement). Not sure if that would have an impact..

[Tony B]

Sounds like prodding around with wire might have dislodged some dirt that's now somewhere else ! Note, if you read any how-to type articles on carb cleaning, and/or the factory manuals, it will always tell you NEVER to poke wire through carb orifices, it's easy to damage the tiny drillings.
Best way is to find someone with an ultrasonic cleaner to do the bodies for you ...

[CmichRider]

I was following the how-to posted on another ninja250 wiki, which mentioned using copper wire because it is softer than the other metals in the carbs, so as to not damage anything. The wire I used just came from speaker wire, and was soft as could be. I think that there's a good chance that the small defect I saw on the diaphragm could be causing the bad mid-range. In retrospect, while I believe I adjusted the floats correctly, I wasn't entirely sure, since they had to be in such a right position to be adjusted. I'm sure that could be contributing. I'm not sure if anyone around here does ultrasonic cleaning, I only heard of it for the first time a couple of weeks ago on here. Does it work well?

[Tony B]

Originally Posted by CmichRider

I'm not sure if anyone around here does ultrasonic cleaning, I only heard of it for the first time a couple of weeks ago on here. Does it work well?

Yes !! Companies that specialise in carb rebuilding all use ultrasonic cleaning as part of the process. I'm sure there must be someone local to you, try googling it

[AlanDog]

So your original post sounded like my bike... before I adjusted the valves. Have you had the valves adjusted (recently or ever?) Now that the valves are adjusted, the bike idles fine, before it would either die or I'd have to keep the choke on for 10 minutes (and have it rev to 5k at stop lights). My valves were totally off--7 out of 8 were actually touching (no clearance).

[AlanDog]

Also, since the valve adjustment, the bike has a stronger midrange and is smoother at low rpms. Although at first it seemed the top end was a little weaker it's about the same.

[CmichRider]

Ok, so some updates.

I worked on the bike from 2pm today until it got dark. What did I accomplish? Well I got those carbs the cleanest they ever will be, save straight from the dealer. Made sure that carb cleaner came out of every orifice and where it was suppose to, as per the guide. Replaced the slightly pinched diaphragm with a spare I had from another set of carbs- anyone need diaphragm? Haha.

Killed the battery multiple times today. I'm going to go buy a stock replacement tomorrow. Oh, and don't forget to turn the gas tank to ON after reinstalling the carbs, or else you'll be cranking til the battery dies...ask me how I know.

I also synced the carbs as best I could using the yardstick-tubing method.

I need to mess with the idle mixture screws, but I cant manage to get in there without burning my hand, and I don't have a screwdriver small enough. Right now the bike stays idling, but has very sluggish response to throttle and it hangs like none other.

Oh, and it sounds like a helicopter. I assume that's because I adjusted the valves on the loose end, correct?

Also, the only thing I could find related to ultrasonic cleaning, was a dentist.

Edit:

Also forgot to mention, tested for spark and it was good in both wires. But the left wire does not sit flush on the valve cover, it is a good 3/4 centimeter above it, the right wire sits about where it should. When I unplug the left wire, the bike does not change in tone or running, but it dies when I unplug the right plug, I am sure this is a problem, but what exactly is it?

[davenay67]

Originally Posted by CmichRider

When I unplug the left wire, the bike does not change in tone or running, but it dies when I unplug the right plug, I am sure this is a problem, but what exactly is it?

If the engine does not change when you remove a HT wire then the engine is only running on 1 cylinder. No wonder it sounds bad and idles badly.

In this case your left cylinder is not firing. Find out why the HT wire is not sitting on the spark plug.

[CmichRider]

Right, i'm surprised it is able to run on 1 cylinder. The plug I took out of the non-running cylinder was black, slightly wet. This is "normal" condition for a plug that is not sparking as it should, correct? I am 90% sure that the one cylinder is not firing as it should be, the header from it is warm but not nearly as burning hot as the other. I synced the carbs, but when I did it it probably meant nothing since only one cylinder was firing correctly.

[davenay67]

Originally Posted by CmichRider

Right, i'm surprised it is able to run on 1 cylinder. The plug I took out of the non-running cylinder was black, slightly wet. This is "normal" condition for a plug that is not sparking as it should, correct? I am 90% sure that the one cylinder is not firing as it should be, the header from it is warm but not nearly as burning hot as the other. I synced the carbs, but when I did it it probably meant nothing since only one cylinder was firing correctly.

You're getting some spark, judging by the warm rather than cold header pipe. At this point I would be looking to determine if the misfire is because the HT lead is not seating correctly on the spark plug, or whether you may have a faulty coil.

When you push the HT lead onto the spark plug you can feel it positively engage with the top of the spark plug.

[CmichRider]

I can feel the wire engage the plug, but it still isn't seated correctly. That makes me think that the spark plug isn't seated all the way down in the threads.

[davenay67]

Originally Posted by CmichRider

I can feel the wire engage the plug, but it still isn't seated correctly. That makes me think that the spark plug isn't seated all the way down in the threads.

That's an interesting thought, and could explain the intermittent firing.

Is the spark plug cross-threaded by any chance..?? If it were me I would use something (pencil, small plastic rule, tape measure, etc) to gaugee how far down from the top one of the spark plug is in one cylinder and then copmpare that measurement to the other cyclinder....that would confirm if the spark plug is not seated all the way in.

[CmichRider]

Measuring it was exactly what I was going to do, only I tried the other wire on the "bad" plug and it went down flush with the valve cover. The bad wire does not go down all the way on the good plug. So its not a problem with the way the plug is fitting, its a problem with the wire itself. I looked inside and compared it to the good wire, but I couldn't see a difference at all.

[davenay67]

In that case I would put the 2 spark plug wires side by side and see if one of them has a longer reach from the tip to the rubber lip that seats on the cylinder head cover. could it be that the rubber lip has slid up the HT wire somehow..??

In any case, if the spark plug boot is reaching the spark plug and is seating OK, then I would really start to suspect the ignition coil on the mis-firing side of the engine.

[CmichRider]

I went ahead and got new coils+wires off ebay. Figured it couldn't hurt, and I got a decent deal. So that's what is going on now, just waiting for those.

[CmichRider]

She lives! The lil ninja is up and running great. Better than when I got it. Smooth all through the rpms and idles like a dream.