Ninja 250 Issues. Please help.

P

PaulTersigni

New member
So I have been out of the country for a year and when I came back I had some trouble starting up my ninja 250. Now I expected this considering I didnt really do my due dilligence before I left since it was sort of a last minute thing so I got what I deserved there. After draining the carbs a few times and continually running new fuel through them and after having checked the spark plugs to make sure they were not fouled and ensuring the battery was charged I was able to get the bike to start. That is not my issue.

Now that the bike is running I have had a slew of old problems come back and haunt me along with some new ones. On this bike I have already had to replace the clutch due to damage, but last year after I replaced the clutch the bike was running fine. Now however when i put the bike into first on a stand (so the rear tire is lifted of the ground) the rear tire just slowly spins, even if I release the clutch entirely (or for that matter if I dissconnect the clutch cable; which I have,) the tire just keeps spinning and the bike doesnt stall, which is obviously a problem. In addition to this the rpms on the bike dip before heading up if i twist the throttle quickly and even when they are up and I hole the throttle steady they bounce around with a variance of about 1000rpm rather than just holding their place. Sometimes if i twist too quickly the bike will even stall. I have tried adjusting the idle to remedy this issue to no avail.

I should mention that I also have a full yoshi pipe and the airbox has been swapped out for a K&N filter on my bike. Before you ask, yes I installed a factory pro stage 2 jet kit and had it tuned perfectly last year before I left.

Dumped a whole bottle of seafoam in there to no avail, still bogs right down to a stall if I open the throttle quickly. This is beginning to annoy. Does anyone have any other suggestions, the help from experts is always appreciated. Thanks again guys.

Then I took off the carb ad took it apart. Everything inside looks clean as a whistle and shiny and nice. So now Im really getting frustrated. I have no idea why the bike was bogging down to a stall in low rpms ONLY when i twisted the throttle. If i used the choke it went up smoothly and fine. If i turned the idle screw it went up just fine, but as soon as I touched that throttle it would bog down and if i didnt let go it would stall. However if i managed to get the rpms to about 4 or 5 k then all of a sudden everything went back to being perfectly fine, until I released the throttle, and then once again I would be back to square one and it would hang on its way down. I also think the bike was running rich when I had run it with the seafoam but before I took the carb off because I hate the tell tale white smoke and flames out the exhaust at high rpms with the pop sounds.

So given all of this information does anyone have any idea what is up with my bike and how I can fix it. Thanks a bunch you guys are a lot of help. I could really use some.
 
The wifes 250 did the same thing when we bought it. The only way it would run was to run it with the choke on. Was crazy! I pulled the carbs apart and hit them with carb cleaner getting every passage, or so I thought, still ran like crap. I pulled the carbs off again and ultrasonic cleaned them. A bit extreem but I had one handy.. Put it back together and it was perfect. The idle circuit is pin hole small! I bought a set of welding tip cleaners at princess auto to clean the fuel passages and the jets. You have to run the wire down the idle air jet toward the front of the carb, you should see the tip pop into where the mixture screw hole is. Also look at the bottom on the carb throat by the butterfly, you'll see a few small holes. Use the tip cleaner to poke them as well, gum / varnish will block them effecting off idle performance. When I was done I put an aftermarket fuel filter on the fuel line for good measure.

I set the idle mixture screw to factory specs and it was good. In hind sight I should have opened them an extra turn, took forever to warm up. The 250 had a wierd coasting circuit as well. It was a '98 and there was a seperate diaphragm and spring assembly that, acording to the manual, enriched the carbs when you slam the throttle closed. I made sure that was spotless as well.

I've run bikes on centre stands as well and had the same tire rotation issues. Hitting the rear brake will stop it rotating.
 
PaulTersigni said:
So I have been out of the country for a year and when I came back I had some trouble starting up my ninja 250. Now I expected this considering I didnt really do my due dilligence before I left since it was sort of a last minute thing so I got what I deserved there. After draining the carbs a few times and continually running new fuel through them and after having checked the spark plugs to make sure they were not fouled and ensuring the battery was charged I was able to get the bike to start. That is not my issue.

Now that the bike is running I have had a slew of old problems come back and haunt me along with some new ones. On this bike I have already had to replace the clutch due to damage, but last year after I replaced the clutch the bike was running fine. Now however when i put the bike into first on a stand (so the rear tire is lifted of the ground) the rear tire just slowly spins, even if I release the clutch entirely (or for that matter if I dissconnect the clutch cable; which I have,) the tire just keeps spinning and the bike doesnt stall, which is obviously a problem. In addition to this the rpms on the bike dip before heading up if i twist the throttle quickly and even when they are up and I hole the throttle steady they bounce around with a variance of about 1000rpm rather than just holding their place. Sometimes if i twist too quickly the bike will even stall. I have tried adjusting the idle to remedy this issue to no avail.

I should mention that I also have a full yoshi pipe and the airbox has been swapped out for a K&N filter on my bike. Before you ask, yes I installed a factory pro stage 2 jet kit and had it tuned perfectly last year before I left.

Dumped a whole bottle of seafoam in there to no avail, still bogs right down to a stall if I open the throttle quickly. This is beginning to annoy. Does anyone have any other suggestions, the help from experts is always appreciated. Thanks again guys.

Then I took off the carb ad took it apart. Everything inside looks clean as a whistle and shiny and nice. So now Im really getting frustrated. I have no idea why the bike was bogging down to a stall in low rpms ONLY when i twisted the throttle. If i used the choke it went up smoothly and fine. If i turned the idle screw it went up just fine, but as soon as I touched that throttle it would bog down and if i didnt let go it would stall. However if i managed to get the rpms to about 4 or 5 k then all of a sudden everything went back to being perfectly fine, until I released the throttle, and then once again I would be back to square one and it would hang on its way down. I also think the bike was running rich when I had run it with the seafoam but before I took the carb off because I hate the tell tale white smoke and flames out the exhaust at high rpms with the pop sounds.

So given all of this information does anyone have any idea what is up with my bike and how I can fix it. Thanks a bunch you guys are a lot of help. I could really use some.
Click to expand...

Don't know about your other issues, but the rear wheel spinning in the air, is normal.
 
I'm having the low throttle problem aswell, but i'm finding mine to be quite mild. It will stall if i give it a quick twist; The RPM's will go up and then dip below idle speed sometimes causing the bike to stall. Fuel Injection ftw...

Although if i do rev the bike up to about 4k+ on the way back down its turns out fine. I thought i was the only one having this problem. I'll be heading to a shop sometime in the near future, maybe they'll have some insight on this issue.
 
Thanks for the tips guys ill give some new things you suggested a shot, and chilly if you could let me know what they say at the shop that'd be awesome.
 
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