Another Troubled Engine thread.

[FilipinoAviator]

Hello everyone!

I recently bought another Ninja 250, it's a 1989 model that the owner claimed he was riding home one day and the motor started knocking really bad and he quit riding it (and bought a 2013 R1...) but swore it hasn't knocked the last few times he rode it around.

Bike has 16k miles.

Anyways, after a bit of reasearch on the forum, I thought it was just the cam chain tensioner. So yesterday, I pulled it out to clean it. The CCT was beautiful.

here is the video of it running-

https://www.youtube.com/watch?v=ouLqaIMhYGo

There's also a clanging noise coming from a loose exhaust shield when the bike gets revved up.

I changed the oil and filter to inspect for contaminants (still need to check the screen) but overall there hasn't been anything metallic in the oil or filter

After realizing the CCT was not the issue, I decided to pull the engine. I also have a wrecked 2003 ninja 250 that I planned on swapping engines with since I bought the 1989 knowing the motor was probably bad. However, I'd like to keep both bikes running.

With the engine out, I pulled the valve cover off to see that the valves had been adjusted before (marks on the adjusters from a poor fitting screwdriver, etc.) and nothing smelled burnt or out of the ordinary.

What do you guys think is wrong with the engine? Rod bearing on its way out? stretched cam chain?

[dcj13]

Is there a problem at all? Maybe one of the valves is set just a tad loose?

[csmith12]

Sounds like a cam chain to me, but why not swap the CCT out from your other bike temporarily to know for sure?

[FilipinoAviator]

Thanks for the quick responses djc13 and csmith12!

Both CCTs had about the same spring tension, but the 1989 motor is at least twice as noisy as the 2003 motor.

Should the CCT spring be easy enough to compress/hold in one hand? I read somewhere that some people had to use a vice in order to compress their CCT together. Neither of my springs were that forceful to compress.

I'll send an email to Kreiger about two manual CCTs and go that route if I need to.

[Motofool]

Originally Posted by FilipinoAviator

........... What do you guys think is wrong with the engine? Rod bearing on its way out? stretched cam chain?

Under some tension, 20-link length cannot measure more than 128.9 mm, according to the service manual.
The chain is a size 25 ANSI, which has 1/4" (6.35 mm) pitch and 0.130 in (3.30 mm) roller diameter.
Ten links in new condition should measure exactly 2-1/2".

The only function of the spring is to advance the non-return plunge as the chain wears:

http://faq.ninja250.org/wiki/Cam_cha...sioner_removal

Once the plunge go as far as the loose side of the chain allows, it should not go back.

Before the chain is too elongated, the tensioner hits a top by the rocker arm at the bottom of the well.

The noise may come from a worn clutch basket.
Pressing the lever should improve it.

A bad rod noise increases with rpm's and induces vibrations.
It has a tone that differs from cam chain noise.

[FilipinoAviator]

Originally Posted by Motofool

Under some tension, 20-link length cannot measure more than 128.9 mm, according to the service manual.
The chain is a size 25 ANSI, which has 1/4" (6.35 mm) pitch and 0.130 in (3.30 mm) roller diameter.
Ten links in new condition should measure exactly 2-1/2".

The only function of the spring is to advance the non-return plunge as the chain wears:

http://faq.ninja250.org/wiki/Cam_cha...sioner_removal

Once the plunge go as far as the loose side of the chain allows, it should not go back.

Before the chain is too elongated, the tensioner hits a top by the rocker arm at the bottom of the well.

The noise may come from a worn clutch basket.
Pressing the lever should improve it.

A bad rod noise increases with rpm's and induces vibrations.
It has a tone that differs from cam chain noise.

Thank you for the clarification of the CCT. After posting that, I found that exact wiki page and realized how much of a noob I am.

Today I pulled the CCT back out to make sure it was ratcheting properly, and it checked fine, so after putting that back together I gave it a valve inspection.

I found that 7 out of 8 valves were too tight. After adjusting those, now I'm going to stick the engine back in and see if that did the trick.

I'll play with the clutch on it. The cable was not set properly and when I first got the bike the clutch was locked up. After riding it around the yard with the clutch lever pulled in, the clutch finally freed up.

Thanks again guys! You all are awesome!!

[Motofool]

Originally Posted by FilipinoAviator

......... I found that 7 out of 8 valves were too tight. After adjusting those, now I'm going to stick the engine back in and see if that did the trick.........

Thanks again guys! You all are awesome!!

Please, verify that the rocker arms are OK:

http://n4mwd.blogspot.com/2013/06/ov...ts-during.html

Wrenching and learning,.....wrenching and learning,.....

You are very welcome

[Badot]

Sounds very similar to mine which I just tore down with the culprit turning out to be a rod bearing. Mine was loudest under light load at low to moderate revs and cleared up under hard throttle or hard engine braking -- if yours does the same, I'd put money on rod bearings.

[FilipinoAviator]

I should have taken a lot more pictures, but down at the hangar, I don't have running water so taking pictures with greasy hands becomes a fiasco.

SOME of the locknuts were wayyy overtightened (probably the ones that had to be adjusted last time someone was in there) but I made sure to torque the locknuts appropriately since they were easy to get to with the engine out of the bike. I checked and poked around (swabbed a magnet too) to see if there were any broken bits or chunks of metal anywhere, nothing turned up thankfully.

The engine is stuffed back into the bike. After I get some coolant in the system, I'll fire the bike up and we'll see what happens!

[FilipinoAviator]

Here is a new video of the bike running after the valve inspection.

http://www.youtube.com/watch?v=S700JYGyESI

After the bike was warmed up, I rode it around (sounds like hell) and it seems to have plenty of power, but I do need to dial the carbs in. One of the next weekends I'm going to just swap in the 2003 powerplant and put this motor in my wrecked 03 (and let others tear up this engine).

It sounds like it's coming from the right side of the bike. The clutch acts like it isn't fully disengaging (but doesn't fully engage until the last 3/4" of lever movement), which may also be a source of racket.

Yay for buying used bikes!

[spooph]

use a screw driver as a stethoscope to pinpoint the noise. Sounds like a loos cam chain to me, but the screw driver will help a lot!

[jkv45]

That sounds like valve clatter to me.

I guess I'd recommend checking the valves again.