Anyone know anything about ninja 250's?

[Steel]

So I'm fixing up my freinds 250 she just picked up as a first bike because i promised i would (oh the things we do for the fairer sex). When we went to look at it, it didnt seem all that bad, but once i got it back and started tearing into it... it didn't seem all that good . Looks like the last owner had no clue about what he was doing and took everything half apart. Nnng.

Anyhoo, I got it started (after putting the choke cable back on... the previous owner had no idea why it wouldn't start) and what worried me the most is that bike makes a motherfuckin RACKET when it runs. Granted the carbs are out and doesn't want to hold an idle, and i couldn't run it for more than ~30 seconds seeing as how the coolant system was taken apart, but when it was running that beast had a HELL of a ping to it. I was thinking piston slap at first, but it's a little different, and ruled out the valves whacking the pistons as well considering it did run for more than 5 seconds like that. It's only got 12,xxx miles so i also want to rule out the bigend bearings being toast. Can anyone explain to me what a normally running 1992 250 is supposed to sound like?

Oh yeah, also, the clutch isn't disengaging either. Sticky plates methinks. Any weird clutch oddities on these bikes that anyone knows about before i go tearing into the tranny case?
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[jeffcoslacker]

If they run with a weak cylinder, the odd power pulses make everything in the clutch basket and gears (especially with a draggy clutch) rock back and forth rapidly in backlash (especially with a twin)...sounds like it's coming apart, but may be ok. Listen carefully to the camchain area (center top of head) and camchain tensioner (rear middle of cylinder block) for a broken chain adjuster or chain flutter...

Coolant in the head deadens a lot of top end noises also, so you probably also hear that with no coolant...

I wouldn't worry so much about the clutch until you get it running..sticky plates will free up with use...you can rock the bike back and forth in gear with the clutch pulled in and usually get them to break free. Is that a hydro clutch? I don't know...may be out of fluid or has air if so...does it have a cable or a hose and cylinder?

If it only wants to run on choke, check for air leaks around carb to head boots, you may find why it's odd firing....

[Steel]

Naw, definitley a cable clutch, i dont think hydraulic clutches were used very much way back then.

Welp i suppose i'll be putting coolant in there come saturday, and seeing how it is then. I might run it for a while then and see how it sounds after it warms up, and try to free up the clutch as well.

[caddydaddy]

The engine makes a little bit of ticking when running, which is just the valves. But the clatter you mention doesn't sound right! Have the valves been adjusted by you, or ever? That will cure a lot of running problems.
As for the clutch, is it adjusted correctly? The clutches do stick when the bike is cold and first started up after sitting for a while. Are you saying they stick with the bike being on the center stand and the rear wheel turns when the engine is started? If so, that is normal, until the oil warms up. It also helps to put fresh oil if you haven't done so already. What does also help is to hold the clutch lever in for about 10 seconds before engaging first gear.


Also, check out the FAQ section of the Ninja 250 riders club forum.

http://faq.ninja250.org/wiki/Main_Page

[Steel]

Oooh, that page is great!

I'll see if i can get a recording of it running next time i do.

[jeffcoslacker]

From that 250 site:

The negative part of all this is that when the tensioner goes, the cam chain can slap around within the engine, tearing off bits of the plastic that are there to help guide it and protect the metal... which then float around in the engine until they get stuck somewhere or do damage. The chain can also jump teeth, in which case the timing is off and the bike runs terribly, or you have that unhappy valve-to-piston contact. So, if you have a (usually consistent) ticking coming from the upper right side of the motor, and you know the valves to be correct, you should replace the cam chain tensioner.

I guess it runs down one side, rather than down the middle like most I'm used to...

anyway they say it's not a common failure on this motor, but if the location of the noise matches, it warrants looking into...

What was the reason for the partial disassembly? I hate to see that on a bike someone buys...usually means they tried to fix something and gave up, or screwed it up worse...nobody takes apart a motor that runs fine...

[caddydaddy]

Yeah, I hope someone didn't try and fix something and screw it up either! 12,000 miles on a Ninja 250 is low mileage, so that's not from normal wear!

[Steel]

No, the guy replaced the stator, and took apart the fairings and such. It doesn't look like the motor was torn into... that's MY job :-D

Ive heard that tese weird little 180* phase twins make a hell of a racket while they're running normall, but i dont have a basis of what's too much racket... my sv makes a racket too, what with the 90*v, straight cut cam gears, loud pipes, and intake honk, but i'd know if it didnt sound right.

AH well. At the very worst, if the motor is toast, i'm pretty sure any motor from like 87-06 will fit.

[caddydaddy]

Originally Posted by Steel

No, the guy replaced the stator, and took apart the fairings and such. It doesn't look like the motor was torn into... that's MY job :-D

Ive heard that tese weird little 180* phase twins make a hell of a racket while they're running normall, but i dont have a basis of what's too much racket... my sv makes a racket too, what with the 90*v, straight cut cam gears, loud pipes, and intake honk, but i'd know if it didnt sound right.

AH well. At the very worst, if the motor is toast, i'm pretty sure any motor from like 87-06 will fit.

The engines aren't that loud, in fact, they're pretty dang quiet! I have people jokingly ask me if my bike is running. At highway speeds, I hear wind noise over the engine, even though it's running at over 9,000 RPM!

And the 250 engine is pretty much the same for all years up through 2007.