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No acceleration

Hi, I am new to riding and this forum. I just bought a 2007 ninja 250 and after riding it around a little bit today it did not want to take the throttle and after getting to about 3000 rpms it would die. It was idling in neutral fine but just couldn't give it any gas. Any ideas why? Thanks

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4,752 Posts
Was it running fine before buying it & did you get it this week or months ago or what?
I would load test the battery & check the air filter or install a new one. I'm assuming a stock airbox. Also, fresh fuel???
The motorcycle needs a good, fully charged battery to start & run right. don't assume a battery is good, even if it's new. test it.


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Just bought it Sunday with 1900 miles, guy said he had a tune up within the last 100 miles although that could've been months ago I just don't know. Do you think gas filter could be a problem or carbs? It was riding great when I test rode it and took it to get inspected then started having issues on my way back from inspection.

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4 Posts
Valve Clearance Adjustment

I recently adjusted the valve clearance and I thought I would share my experience. I'm not a pro with wrenching but given enough time I usually don't make things a lot worse.

The Bike : 2004 ZZR 250 ( Model EX250H ). Very similar to the 250 Ninja in the States.
11,000 km ( 6,835 miles ). I have had the bike for two years and cleaned the carbs when I first got it. It had sat for at least three years before that.

The Issue : Long bizarre warm-up after starting. Bike starts fine, but only with full choke when engine is cold even if air temp is 25 C ( 77 F ). If engine is warm it starts fine. After starting ( from cold ) it revs quite quickly to 3,000 / 4,000 or higher. I would ever so gently nudge the choke lower, revs would drop to 2,000. Just a red one too far and the revs dropped to 900 and bike would sometimes stall. If I got it to settle at 2,000 and walked 10 feet away the revs would climb back to 4,000. Back I go to massage the choke a little bit lower, step way and away it goes to 4,000 again. This can go on for ten minutes. When I finally take the choke off completely the bike settles into a lumpy idle of 1,100. Well, I take off riding, blipping the throttle when slowing down for stop signs.

For sometimes as long as a half an hour the bike may stall at a stop sign and not restart that quick. After the bike is fully warm it comes to a idle of 1,600 and runs like a clock.
Spec for idle speed is 1,200. Seems quite low to me.

The Problem : This process is a complete pain in the kester.

A Note : The Maintenance Chart says the valve clearance doesn't need to be checked until 12,000 km ( 7,500 miles ). After my experience I'm thinking sooner. After I cleaned the carbs the bike seemed to work fine - good response, decent mileage - just the warm-up issue.

I never did synchronize them. More on that later.

To adjust the valve clearance you have to remove the cylinder head cover. To do that you remove the forward fairings on both sides and the gas tank. I suggest you remove the radiator and the supporting bracket.

I had read that one could just unbolt the bracket, leave the rad hanging by the hoses and skinny the cylinder head cover out. I had no such luck.

Say Willy, how do you drain the coolant without making a sizable mess ?

Don't ask me, I can't do it.

So now you are looking at the camshafts - 4 in total - 2 on each cylinder - each actuating 2 valves.

I checked all the clearances and they were all too tight. Some were so tight that the
saddle under the cam was tight against the cam at all times and the adjusting screw, lock nut and saddle didn't wiggle at all. I thought, initially, that the ones that did wiggle were the problem. Not so. As Kopcicle has said on this forum you should be able to hear some valve noise from a properly adjusted engine. He and others are the ones that lead me to valve adjustments in order to solve a idle / warm-up / carb problem.

Kawasaki makes a valve adjustment tool for this bike. I have read elsewhere that the
adjustment is perfectly doable without the tool.

I wouldn't want to try it. On some valves I had to take the tool out of the way to be able to get the feeler gauges into where the had to be. Perhaps the feeler gauge from Kawasaki that is specific to this task would have been as valuable as the adjustment tool. I'll never know an I'm not going to buy the gauge. What I do know is that it took me a fair bit of time to make the adjustments on 8 valves. One time bandit was the feeler gauges. Mine were labeled in both English and Metric. Using the wrong blade ( a 0.12 [in] instead of 0.12 [mm] ) is going to mess up your day. Be careful. I checked, second guessed myself and checked again. I've read elsewhere that separating out the blades can solve access problems by not having the handle of the feeler gauge get in the way. I didn't have too much of a problem with that. If you separate blades tie something onto them so they don't drop into the engine. I've also read that bending the tip of the blade to an angle helps to get them into place easier. I didn't want to try that with a borrowed set of feelers.

I did have two other problems - one I had a fix for that I'm pretty comfortable with, the other, not as much, but both were further time bandits. One problem I don't have is lack of a service manual. They are worth the money, but not infallible and I'll get to that shortly.

The problem, the one with the comfortable fix, was not being able to see the marks through the viewing port on the alternator cover ( left side ). The smaller upper one with the black cap is the viewing port and you should be able to see a "1T" ( for cylinder 1 - left side ) and a "2T" ( for cylinder 2 - right side ) stamped into the crankshaft at some point as you rotate the engine. I could only see the bottom half of the characters. There looked to be two places that there was a "2" stamped into the metal. The "1" I only found once. Now I could blame bad eyes and bifocals, but I won't. The larger black cap spins off to get at the nut that you use to rotate the engine ( counter-clockwise - 14 mm socket ). Both these covers are on the left side of the engine, you can only see / access them with the fairing off and you can spot them in the coolant mess photo.

So Willy, what's the trick to getting the covers off without messing up the plastic at the long curved bottom slot in the covers ? A large flat blade screwdriver isn't a great answer. Use a coin clamped in a needle nose vise grip. A Canadian Twoonie ( $2 coin ) works great. You don't have a Twoonie ? I can get one to you for the low introductory cost of $8.99 US ( plus shipping and handling ). Just PM me.

The reason you need to rotate the engine is that the valve adjustment must be made with the piston at TDC ( Top Dead Center ) at the end of the compression stroke. The Service Manual was very clear and explicit about this. There is an arrow cast into the the crankshaft that can be seen through the viewing port that shows the correct ( counter - clockwise ) rotation of the engine.

So how did I do this without being able to see the marks through the viewing port ? I took out the spark plugs, put a long stiff wire through the spark plug hole to rest on the top of the piston and rotated, watching the cam lob position. You can see where the intake has closed ( end of intake stroke ) and watch the wire come up ( compression stroke ) and stop before the wire starts to drop (power stroke ).

Of course the two pistons do not reach the top of their compression stroke at the same point in the rotation of the crankshaft. Hence the "1T" and "2T" marks in different places. You will have to rotate the engine again to set the valve adjustment on the other cylinder.

Now for the problem with the uncomfortable fix. It is not possible to adjust all four
valves ( 2 intake and 2 exhaust ) of one cylinder when the piston is at TDC at the end of the compression stroke even though the Service Manual says you have to. The cam lobe for the exhaust valve is positioned in such a way that the adjustment tool hasn't enough clearance to get down to the adjusting nut. The Manual say I should be able to do it. I tried every way I could think of. Maybe someone can point out my error. I went many times over making sure I was at TDC at end of [compression] stroke, not at TDC at end of [exhaust] stroke.

My solution was to set valve clearance on the intake valves as the Manual said ( TDC - compression stroke ) and the exhaust valves on both cylinders with the piston about 3/4 of the way up on it's compression stroke. This was just before the cam lobe got in the way of getting the tool down onto the adjusting nut. As I said, I am not totally comfortable with my solution.

I buttoned up the cylinder head cover to the head, making sure to align the rubber gaskets at the top of the spark plug wells. Another glitch in the Service Manual was that they say the cylinder head cover is set on with a silicone sealant and the gasket itself will need to be replaced. That is after scraping the head and the cover. No silicone was found by me ( I didn't take the ridged rubber gasket off the cylinder head. Who needs to look for trouble. )

The cover buttoned up real nice. I torqued it up just right but since I didn't have a torque wrench I went with the German method. Installed the gas tank. Started it up in the garage and it make a fair clatter, like cutlery in a dryer at 3X speed. Worked the air out of the coolant system. Warmed the bike up real good.

Bonus information :

Shut her down and got the gas tank off, rigged up a bit of a fuel supply ( turkey baster tube ). Hooked up my home-made vacuum gauge and started the bike to be able to synchronize the carbs.

Now the gauge uses vegetable oil so it doesn't react as fast as if you used water but it would react faster than the mercury gauges that a shop uses ( I would be surprised if they used real mercury these days, but who knows ). Now I don't think the carbs were that far out of sync. But by excessive and rapid movement of the adjusting screw I was able to quickly get them out of sync. Small fine adjustments and patience resulted in getting the levels ( sync ) real close.

The synchronization adjusting screw is in between the two carbs and there is no way you would get at it with the gas tank on.

That works out because there is no way to get to the vacuum lines with the tank on. The two lines come from the right side of the carb bodies on the engine side of the carb close to where the butterfly valves are inside the carb. Easy to find ? Sure. Easy for me to be sure they are the right lines ? Not so much. They are the only one I could figure were the right ones. The one from the right carb runs to the coasting enricher system on the left side of the left carb. The line from the left carb runs to the fuel tap ( petcock ). So I'm now confident that the carbs are synchronized. As I said I don't believe they were far off in the first place.

2nd Bonus Information :

The gas and vacuum lines on the bike are held on with a circular wire clamp that is bent up and formed into a small circle at the ends of the wire. The circle ends sit about an 1/8 of an inch apart when the clamp is in it's proper place. Don't worry about moving this clamp down the rubber line past the bump in the nipple it is attached to. It's a pain in the kester to do, takes too long and most importantly is unnecessary. Just pull the line off the nipple. The clamp expands and pops over the bump. Putting it back on is just as easy. Just push it on and it will pop over.

So did the valve adjustment solve the main issue ?


I let the bike sit overnight. Fired it up, about 1/2 choke, came to 2,000, didn't race up to 4,000, crept up slightly as it warmed up, I was able to adjust the choke without having to split hairs. After only a couple of minutes was able to take the choke off and ride away. No stalling. Rode out about 50 km ( 30 miles ) and tweaked the idle down to 1,500. Rode back home as a happy camper. The valve noise was considerably less when the bike was running outside than what it was the night before in the garage. After the test run it seemed even better still ( less noisy ).

The Valve Thread Sticky in The Mechanics Corner is a good thing to read through. A lot of tips, info and reasons why valves are important.

Bottom line - if valve adjusting was a little bit more fun I would recommend it to everyone.
Before I did my valve adjustments I had the same issues as you the bike would not idle at a set rpm it would climb as high as 4k

the valves were so out of spec not even the thinnest feeler would fit. the bike has 17k miles on it. Anyways did that after I had to fish a tool I dropped on the timing chain side and it idled better but I think the throttle cable needs to be lubed I have to hold it closed like 1 MM which it will idle at 1500 as soon as I let it go that 1MM is enough to send the bike around 2-3K.

Th choke I don't know how others are but how hard should it be to move?

Having said that I need to replace the clutch perch any idea on how to get the left grip off?
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