Time for a new cylinder head

scottsa · June 18th, 2011, 09:48 PM

Not exactly how I wanted to make my first post after lurking here for a while.

Shortly after I left the house today my 2002 lost all power and would not stay running without constant throttle. I immediately turned around and went back home and started trying to find the problem. After opening up the head I saw that the right intake rocker arm on cylinder one was sitting at an angle so I started to loosen the tappet screw to see what was going on when the side of the depression the tappet screw sits in (no idea what this is actually called) snapped. It was already getting dark so I haven't been able to get any clear shots, but here is the area that snapped, I will try to get some better pictures tomorrow.

051111DSC00003.JPG

I don't see any possible way to fix this so now I'm without my daily commuter while I search for a replacement head.

kkim · June 18th, 2011, 10:33 PM

http://www.ninjette.org/forums/showthread.php?t=70218

scottsa · July 5th, 2011, 08:04 PM

I was able to get a replacement head, got it mounted and the valves adjusted back to spec but now I have another problem. When I start the bike it now idles around 4-5k. I am putting together a list of potential problems so I can run through them to look for a solution, it is possible that the carbs could be the issue as they were bumped around a little while swapping around the heads and when I first attempted to start the bike after the swap the throttle body was "stuck" and was keeping the throttle from opening. Is it possible that this caused the butterfly valves to be out of position and they are now open too much at idle? Already checked the idle adjustment screw and it is backed out to the point where it is not even touching the throttle body now.

Any other suggestions for possible problem areas that I should check?

kkim · July 5th, 2011, 09:23 PM

Quote:

Originally Posted by scottsa

when I first attempted to start the bike after the swap the throttle body was "stuck" and was keeping the throttle from opening. Is it possible that this caused the butterfly valves to be out of position and they are now open too much at idle?

mind explaining that a bit more in detail? what throttle body?

scottsa · July 5th, 2011, 11:01 PM

Sorry probably should have said throttle plate not body, but I actually can't find a name for it in the parts fiche and I couldn't think of anything else to call it at the time. What I'm talking about is the part on the right side where the throttle cables connect to the carb. To borrow one of your pics it is the part that idle adjustment screw sits against in this photo.

DSC05866-1.JPG

It actually looks like this is hanging open slightly as I have found that if I twist the throttle closed I can get the idle back to the normal 1500 rpms, but I can hear a click when I do this, also the throttle will not return to this position normally and the throttle takes more force than normal to open until it clicks again and then returns to normal. I checked both cables and they do not appear to be binding so it leads me to believe something is going on with the plate or possibly the spring behind the plate.

kkim · July 5th, 2011, 11:30 PM

okay, some ideas...

have you tried disconnecting both cables and turning that plate by hand? it should snap back to a closed position due to that spring. by disconnecting both cables, you'll be able to see if it's the plate itself sticking or something to do with the throttle and/or cables.

have you tried spraying the plate with some wd-40 to possibly loosen it up?

are your cables properly adjusted with the correct amount of free play on both cables?

CynicalC · July 5th, 2011, 11:43 PM

Disconnect the throttle and throttle return cables from the carb to help isolate the binding. They both attach to a small bracket held on by one phillips head screw. Just take that off and work the carb by hand. My guess is that the binding is in the cables. Lube them and check inside the throttle assembly on the handlebars too.

scottsa · July 6th, 2011, 05:14 PM

Quote:

Originally Posted by CynicalC

Disconnect the throttle and throttle return cables from the carb to help isolate the binding. They both attach to a small bracket held on by one phillips head screw. Just take that off and work the carb by hand. My guess is that the binding is in the cables. Lube them and check inside the throttle assembly on the handlebars too.

Thanks Colin and Kelly, just got home from work so I will take the advice of both of you and disconnect the throttle cables to see if that lets the plate return to a normal position. Here is a crappy cell phone pic of the plate from mine.
IMG_0098[1].jpg

CynicalC · July 6th, 2011, 08:27 PM

http://faq.ninja250.org/images/b/b6/CARBURETOR.png

The screw (92009a) that holds on the bracket (11044) is what you want to take off. that'll let you pop the throttle cable off.

scottsa · July 6th, 2011, 09:25 PM

Got it sorted out, this was a case of looking for the hard answer before checking the easy solutions. The problem actually was the screw on the clamp holding the tube to the head was rotated to far towards the inside of the bike and what hitting the sync screw slightly and holding the throttle open slightly. Just loosened this back up and rotated it around a bit and problem solved.

Took the bike out for a bit of a ride and everything seems to be good now with the replacement head and the throttle. Hopefully I won't break anything else!

kkim · July 6th, 2011, 09:29 PM

June 18th, 2011, 09:48 PM	#1
scottsa ninjette.org member Name: Scott Location: LA Join Date: Mar 2011 Motorcycle(s): 02 Ninja 250 Posts: 11	Time for a new cylinder head Not exactly how I wanted to make my first post after lurking here for a while. Shortly after I left the house today my 2002 lost all power and would not stay running without constant throttle. I immediately turned around and went back home and started trying to find the problem. After opening up the head I saw that the right intake rocker arm on cylinder one was sitting at an angle so I started to loosen the tappet screw to see what was going on when the side of the depression the tappet screw sits in (no idea what this is actually called) snapped. It was already getting dark so I haven't been able to get any clear shots, but here is the area that snapped, I will try to get some better pictures tomorrow. 051111DSC00003.JPG I don't see any possible way to fix this so now I'm without my daily commuter while I search for a replacement head.

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June 18th, 2011, 10:33 PM	#2
kkim Join Date: Nov 2008 Posts: Too much.	http://www.ninjette.org/forums/showthread.php?t=70218

July 5th, 2011, 08:04 PM	#3
scottsa ninjette.org member Name: Scott Location: LA Join Date: Mar 2011 Motorcycle(s): 02 Ninja 250 Posts: 11	I was able to get a replacement head, got it mounted and the valves adjusted back to spec but now I have another problem. When I start the bike it now idles around 4-5k. I am putting together a list of potential problems so I can run through them to look for a solution, it is possible that the carbs could be the issue as they were bumped around a little while swapping around the heads and when I first attempted to start the bike after the swap the throttle body was "stuck" and was keeping the throttle from opening. Is it possible that this caused the butterfly valves to be out of position and they are now open too much at idle? Already checked the idle adjustment screw and it is backed out to the point where it is not even touching the throttle body now. Any other suggestions for possible problem areas that I should check?

July 5th, 2011, 11:01 PM	#5
scottsa ninjette.org member Name: Scott Location: LA Join Date: Mar 2011 Motorcycle(s): 02 Ninja 250 Posts: 11	Sorry probably should have said throttle plate not body, but I actually can't find a name for it in the parts fiche and I couldn't think of anything else to call it at the time. What I'm talking about is the part on the right side where the throttle cables connect to the carb. To borrow one of your pics it is the part that idle adjustment screw sits against in this photo. DSC05866-1.JPG It actually looks like this is hanging open slightly as I have found that if I twist the throttle closed I can get the idle back to the normal 1500 rpms, but I can hear a click when I do this, also the throttle will not return to this position normally and the throttle takes more force than normal to open until it clicks again and then returns to normal. I checked both cables and they do not appear to be binding so it leads me to believe something is going on with the plate or possibly the spring behind the plate.

July 5th, 2011, 11:30 PM	#6
kkim Join Date: Nov 2008 Posts: Too much.	okay, some ideas... have you tried disconnecting both cables and turning that plate by hand? it should snap back to a closed position due to that spring. by disconnecting both cables, you'll be able to see if it's the plate itself sticking or something to do with the throttle and/or cables. have you tried spraying the plate with some wd-40 to possibly loosen it up? are your cables properly adjusted with the correct amount of free play on both cables?

July 5th, 2011, 11:43 PM	#7
CynicalC ninjette.org certified postwhore Name: Colin Location: Bay Area Join Date: Feb 2011 Motorcycle(s): '96 EX250 Posts: A lot.	Disconnect the throttle and throttle return cables from the carb to help isolate the binding. They both attach to a small bracket held on by one phillips head screw. Just take that off and work the carb by hand. My guess is that the binding is in the cables. Lube them and check inside the throttle assembly on the handlebars too.

July 6th, 2011, 08:27 PM	#9
CynicalC ninjette.org certified postwhore Name: Colin Location: Bay Area Join Date: Feb 2011 Motorcycle(s): '96 EX250 Posts: A lot.	http://faq.ninja250.org/images/b/b6/CARBURETOR.png The screw (92009a) that holds on the bracket (11044) is what you want to take off. that'll let you pop the throttle cable off.

July 6th, 2011, 09:25 PM	#10
scottsa ninjette.org member Name: Scott Location: LA Join Date: Mar 2011 Motorcycle(s): 02 Ninja 250 Posts: 11	Got it sorted out, this was a case of looking for the hard answer before checking the easy solutions. The problem actually was the screw on the clamp holding the tube to the head was rotated to far towards the inside of the bike and what hitting the sync screw slightly and holding the throttle open slightly. Just loosened this back up and rotated it around a bit and problem solved. Took the bike out for a bit of a ride and everything seems to be good now with the replacement head and the throttle. Hopefully I won't break anything else!

July 6th, 2011, 09:29 PM	#11
kkim Join Date: Nov 2008 Posts: Too much.