ninja 250 dropped a valve

reignman

reignman

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My sister has a 1990 ninja 250 that has been had been having some issues. was extremely hard to start and barely idled when it did. decided to check valves and find a broken rocker arm on one cylinder. i replaced the rocker arm and adjusted the valves and it was starting and idling much better! went to ride it to test it out and fill it up with fresh gas and when accelerating i heard an awful noise that sounded like when the key is turned once a car is already started. limped the bike home where the investigation has begun.

i tested the compression and the left cylinder has about 120 psi...the right was 0. pull off the valve cover and see that the valve collets missing, the rocker is displaced and the valve has dropped.

clearly that is the issue causing the massive loss of compression. my question is what all do i need to repair/replace? the valve is bent, the collet broken (luckily i retrieved all the pieces) and the rocker is pretty deeply scored. there is also a small nick out of the top of the piston but i dont really think that will cause any issues? there are also a couple chips in the top portion of the cylinder wall and the edge of the cam lobe is scraped off. im really just trying to get the bike running again for her and get rid or it so i want to spend as little as possible. I know that at a minimum the valve rocker and collet need replaced but im not sure if the other parts are fine or not. what do you guys think?
 
I bent a valve on my old Ducati. It was cheaper to find a used head than buy even just a valve for that, let alone everything else. I just swapped a used head on and rode it for another 2 years.
 
1990? Well I would just sell it like it is or trash it. Buying a used head and changing it requires a lot of work and you would not get much money anyway for such an old bike. Who knows how much scrapes are in the engine and what got damaged in addition (piston, cam, crankshaft ....) I would not invest into such a bike. If it would be a rare or expensive bike of course but a 250 Ninja.

Just my 2 cent.
 
Dreamdemon said:
1990? Well I would just sell it like it is or trash it. Buying a used head and changing it requires a lot of work and you would not get much money anyway for such an old bike. Who knows how much scrapes are in the engine and what got damaged in addition (piston, cam, crankshaft ....) I would not invest into such a bike. If it would be a rare or expensive bike of course but a 250 Ninja.

Just my 2 cent.
Click to expand...

i agree its not worth a whole lot, even in mint condition. but its worth next to nothing as it is. seriously, the scrap metal might be worth more than what it could be sold for as is lol. but its worth a whole lot more than nothing if i get it running and just get rid of it. recouping some money is better than none

my question is just whether the damage to the parts i cant easily and (relatively) inexpensively replace like the cam and cylinder wall are enough to keep it from running properly when/if i replace the valve
 
I didn't notice the cylinder damage the first time. Somehow missed that in the post.
Mine didn't have any damage like that but it also wasn't running when the valve bent. I had just tried to start it.
Is the damage only in the combustion chamber? If so you can probably put it back together ok...
 
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That little chip, the valve, rocker, and the scrape on the bottom portion of the cam lobe. The rest of the cylinder looks fine not scored or anything
 
If you can do all the work yourself and pick up the parts cheap it may be worth while. I would clean up any rough/marked parts with some wet&dry emery paper be careful not to let any fall into the motor [ place a kerosene soaked rag on top of piston] and make sure to clean all parts well afterwards ,but if you have to pay for labour etc forget about it and put the money towards another bike.
 
I did the same repairs to my first bike a 00 ex250 and I was into it for 300 bucks. It's not a hard job either. You should be able to find all the parts you need from a motprcycle junk yard. They sold a bunch of those bikes.

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Parting it out seems like way to much work to make twenty dollars here and there until we recoup some money. I'd rather just have it running get rid of it quick and get it out of my garage
 
If the rest of the bike; bodywork, tires, chain and sprockets are in great condition, get a head on ebay and fix it. If it isn't haul it to the boneyard. Most of those things look like they took a trip through a cornfield.
 
I agree with whoever said try to fix it cheaply, clean it up as best you can, and sell it (that sounds like the route you are going).

My first bike was a Ninjette, and while not mighty in the horsepower department, they are formidable little bikes. I bet you could fix that bike up and it would probably make a fine little commuter for someone. I probably wouldn't take it across state lines or cross country, but in and around town, why not? They're good on fuel, and cheap to insure.

If the rest of the bike isn't in bad shape, fix it and sell it to someone as a cheap first bike that they'll probably wreck anyway.

EDIT: As stated previously, if you can do most of this work yourself, it will probably be worthwhile. Otherwise, not so much.

You situation reminds me of what I consider two of the problems facing modern society, namely - Folks can't (and don't want to learn how to) fix their own stuff. And second, as a result of the first (and other factors, of course) we live in this society where everything (even people sometimes!) are disposable.
/soapbox rant
 
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