Help me diagnose this clunking...video inside.

maverick31210 · September 24th, 2015, 08:30 AM

I noticed the chain...I suspect it's the chain anyway, would clunk when I rolled the bike around. Nothing really noticeable when you're actually riding though.

Anyway, I loosened the chain up a little bit and it's not even close to as bad as it is in the video now. It still clicks a little but nothing like that.

I'm trying to figure out what's causing it though. Chain slack is within spec, the rear wheel is aligned and I measured to confirm. I lube the chain like twice a week. The only thing I'm thinking is that it might be the age of the chain maybe? It's 12 years old. Bike has 8K miles so it was never replaced.

Ideas?

Link to original page on YouTube.

spooph · September 24th, 2015, 10:26 AM

That is most definitely an overtightened chain.

Inspect your chain carefully. I'm willing to bet you'll find that there are worn parts and tight parts which will translate into an overly tight chain adjustment, or an overly loose chain adjustment. Depending on the orientation of the chain, and where the tight and loose parts are, you'll adjust the chain one way, and half a turn later it will be incorrectly adjusted. Easy way to check:

1.) adjust the chain.
2.) rotate one full rotation - throughout rotation, check chain tightness specification. If it changes, your chain is worn and needs to be replaced.

You may ask "what wears on the chain" - the links don't stretch, the rollers which contact the sprockets wear out. They are essentially bushings, right? So they might wear out and become oval on the inside. When this roller lands on the sprocket, it doesn't always land in the same way, and can increase or decrease the tension on the chain by a significant amount.

I recommend you replace the chain and sprockets. (Sprockets because worn sprockets will wear out a new chain much faster).

The previous owner must have neglected that chain to a great extent.

Ghostt · September 24th, 2015, 02:14 PM

Time for a new chain and sprockets, 8k on a chain that wasn't maintained properly is no surprise.

It will make a nice winter project.

And this should have been posted in PreGen tech section @Alex please move.

greg737 · September 24th, 2015, 03:56 PM

here's something to consider in a situation like this:

The manufacturer specified chain-slack adjustment is a "protective" measure, and not just for the chain itself, but also for one item on the engine. This relatively delicate item is the large bearing on the counter-sprocket end of the transmission output shaft.

If you run a motorcycle with an over-tight chain it can cause this bearing to fail due to excessive load stress.

To determine if your EX250 has a problem with this bearing you need to take the chain off and spin the counter sprocket (with the transmission in neutral) to see if the output shaft bearing (located just behind it) is making noise.

The bearing I'm talking about is "92045" on this drawing: http://www.partzilla.com/parts/searc...ION/parts.html

maverick31210 · September 24th, 2015, 04:17 PM

Quote:

Originally Posted by Ghostt

Time for a new chain and sprockets, 8k on a chain that wasn't maintained properly is no surprise.

It will make a nice winter project.

And this should have been posted in PreGen tech section @Alex please move.

LOL winter?

Chain and sprockets shouldn't take more than 45 minutes and 10 of those are cigarette breaks.

....unless I'm missing something here? I banged out the valves in a couple of hours, I don't see why chain and sprockets would take very long.

Alex · September 25th, 2015, 06:56 AM

/moved to pre-gen tech

September 24th, 2015, 08:30 AM	#1
maverick31210 Rides in shorts. Name: Laurence Location: Southern California Join Date: Sep 2015 Motorcycle(s): 2004 250 Posts: 62	Help me diagnose this clunking...video inside. I noticed the chain...I suspect it's the chain anyway, would clunk when I rolled the bike around. Nothing really noticeable when you're actually riding though. Anyway, I loosened the chain up a little bit and it's not even close to as bad as it is in the video now. It still clicks a little but nothing like that. I'm trying to figure out what's causing it though. Chain slack is within spec, the rear wheel is aligned and I measured to confirm. I lube the chain like twice a week. The only thing I'm thinking is that it might be the age of the chain maybe? It's 12 years old. Bike has 8K miles so it was never replaced. Ideas? Link to original page on YouTube.

September 24th, 2015, 10:26 AM	#2
spooph ninjette.org certified postwhore Name: Spooph Location: Golden, CO Join Date: Jul 2010 Motorcycle(s): '08 Ninja 250R Posts: A lot. MOTM - Oct '15	That is most definitely an overtightened chain. Inspect your chain carefully. I'm willing to bet you'll find that there are worn parts and tight parts which will translate into an overly tight chain adjustment, or an overly loose chain adjustment. Depending on the orientation of the chain, and where the tight and loose parts are, you'll adjust the chain one way, and half a turn later it will be incorrectly adjusted. Easy way to check: 1.) adjust the chain. 2.) rotate one full rotation - throughout rotation, check chain tightness specification. If it changes, your chain is worn and needs to be replaced. You may ask "what wears on the chain" - the links don't stretch, the rollers which contact the sprockets wear out. They are essentially bushings, right? So they might wear out and become oval on the inside. When this roller lands on the sprocket, it doesn't always land in the same way, and can increase or decrease the tension on the chain by a significant amount. I recommend you replace the chain and sprockets. (Sprockets because worn sprockets will wear out a new chain much faster). The previous owner must have neglected that chain to a great extent. __________________________________________________ My therapist has 2 wheels and a seat. If you are ever in doubt to my tone, please refer to my avatar.
	2 out of 2 members found this post helpful.

September 24th, 2015, 02:14 PM	#3
Ghostt in your machine Name: Scott Location: Summer Shade, Ky. Join Date: Oct 2014 Motorcycle(s): 98 Ninja 250/F12 aka ZX-2R "SERENITY", 91 Ninja 500/A5 aka ZX-5R "Phoenix", 84 Honda GL1200A "SIREN" Posts: A lot. Blog Entries: 25 MOTM - Jun '17, May '16, Mar '15	Time for a new chain and sprockets, 8k on a chain that wasn't maintained properly is no surprise. It will make a nice winter project. And this should have been posted in PreGen tech section @Alex please move. __________________________________________________ *violente et ignorantia* ZX-2R BLOG *Twitter and Instagram = Ghostt_Scott* *I'm not here to change your mind, just to inform.*

September 25th, 2015, 06:56 AM	#6
Alex ninjette.org dude Name: 1 guess :-) Location: SF Bay Area Join Date: Jun 2008 Motorcycle(s): '13 Ninja 300 (white, the fastest color!), '13 R1200RT, '14 CRF250L, '12 TT-R125LE Posts: Too much. Blog Entries: 7	/moved to pre-gen tech __________________________________________________ Montgomery Street Motorcycle Club / cal24.com / crf250l.org / ninjette.org ninjette.org Terms of Service Shopping for motorcycle parts or equipment? Come here first. The friendliest Ninja 250R/300/400 forum on the internet! (especially Unregistered)

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September 24th, 2015, 03:56 PM	#4
greg737 - Name: - Location: - Join Date: May 2009 Motorcycle(s): - Posts: A lot.	here's something to consider in a situation like this: The manufacturer specified chain-slack adjustment is a "protective" measure, and not just for the chain itself, but also for one item on the engine. This relatively delicate item is the large bearing on the counter-sprocket end of the transmission output shaft. If you run a motorcycle with an over-tight chain it can cause this bearing to fail due to excessive load stress. To determine if your EX250 has a problem with this bearing you need to take the chain off and spin the counter sprocket (with the transmission in neutral) to see if the output shaft bearing (located just behind it) is making noise. The bearing I'm talking about is "92045" on this drawing: http://www.partzilla.com/parts/searc...ION/parts.html