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2003 Kawasaki Ninja 500r
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Discussion Starter #1
I've been fixing up my first EX500 (gen2). I have no experience with the bike but I'm thinking about some small mods which could make a difference. One of them is sprockets. Stock is 16/41 and I'm curious if 17/41 also works well, especially for highway trips. I think the ER-5 uses a 17 for the front.

On gearingcommander.com, I saw that the stock 16/41 combination with 104 link chain is apparently hard on the front sprocket. The same link of the chain hits the same tooth on the sprocket 161 times per mile. For comparison, a 17/41 combination only hits 19 times per mile. The rear sprocket only gets same tooth/same link something like 8 times per mile.

Soooo...if it's true that same tooth/same sprocket frequency is bad, with 16/41 it seems that preventatively changing out the front sprocket might help preserve the chain and rear sprocket longer, since it's so cheap and easy anyway. On my bicycles I've noticed that my aluminum front sprocket wears faster and if I don't change it when it shows wear, it stretches the chain quickly, which wears the rear gears.

So my questions are:

1. If you've tried a 17/41 combination, what did you think? Is it bad around town? Or too minor to notice?

2. Is there any proof to the same-tooth/same-sprocket theory causing fast/uneven wear? It seems logical but maybe it's just a myth.
 

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The larger the front sprocket the less the chain needs to bend, and more teeth in contact with the chain rollers at any one time - both of which should help reduce wear. Shouldn't change the wear on the rear sprocket though. Keep the chain properly adjusted and lubed and it (and sprockets) will last a long, long, time.

Adding a tooth to the front sprocket usually drops RPMs by about 500, which can help smooth-out highway cruising. I added 1T to my SV650 and it definitely helped. If the engine has ample torque in the low and midrange (like the SV) you won't notice much reduction in acceleration. The less torque available the more noticeable it will be. Depends on the engine, rider, and conditions, but the EX500 should be good with adding a tooth. EX250/300s not as much for some.
 

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In theory, its best to select sprockets with an odd number of teeth because with even numbers one tooth will always engage an inner link while the next tooth will always engage an outer link, causing uneven wear. In practice, the difference is negligible and obviously the Kawasaki engineers weren't worried about it when they specified the stock gearing.

Modern o-ring chains have changed the game because they no longer stretch (i.e. increase in pitch) like conventional chains did back in the "good old days". That has drastically reduced wear on all parts of the drive train. The bottom line: run whatever gearing you wish, maintain the chain properly, and don't worry about it.

I've only run my EX with stock gearing but a few years ago I bought another Kawasaki (a KL 250 Super Sherpa) that had an extra tooth on the countershaft sprocket because the previous owner used it as a commuter bike. When I returned it to standard gearing there was a slight but noticeable improvement in acceleration. Being an enduro bike I was not concerned about gas mileage or high revs on the highway because 99% of its use was in the back country.
 

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one tooth will always engage an inner link while the next tooth will always engage an outer link
:confused: I'm confused. How would a sprocket engage anything other than the rollers on the inner links? Then the outer links are just pins running through the rollers connected with plates.
 

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Going to address just the gearing change aspect of this question and not the sprocket wear.

I did a bunch of math on this very subject last year when I was contemplating what sprocket size to change to as I wanted the engine to spin just a little bit slower at 70-80mph. I personally wound up going with a 16/40 combination, which is a 2.5% gearing change, which was actually not as much as I wanted. That change only drops engine RPMs at 70mph by about 150. A 16/39 would be a 5.0% change, which would drop RPMs at 70mph by 300rpm. A 17/41 combination is a 6.0% change, giving an RPM drop at 70mph of about 350 (this is all assuming 70mph in 6th gear).

Far as acceleration, I did notice any difference in off the line of back road twisties performance. I may soon change the rear out to a 39 or take the front up to 17 and the rear back to stock at 41.
As an additional note, I was still able to use the stock length chain at 104 links, can't comment on any other combination.

For those reading, it is important to remember that gen2's had stock gearing of 16/41 while gen1's had 16/42.
 

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:confused: I'm confused. How would a sprocket engage anything other than the rollers on the inner links? Then the outer links are just pins running through the rollers connected with plates.
My explanation kind of sucked but I expect you have probably seen high mileage sprockets with wear on the sides of the teeth due to sprocket/chain misalignment. On a sprocket with an even number of teeth, every other tooth will show an impression of an inner link worn into the side of it. On sprockets with an odd number of teeth, all teeth exhibit identical side wear because the positioning of the inner links advances one tooth each revolution, thereby equalizing the wear. An interesting phenomenon but not worth worrying about assuming the system is properly aligned.
 

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@[email protected] I see what your saying now. With an even numbered sprocket, any specific tooth will only hit 1/2 the rollers. Where as with an odd numbered sprocket, any specific tooth will eventually hit all the rollers. Interesting stuff, something I have not thought of before.
Actually I have never seen a sprocket with any noticeable wear. I just change mine out because it's the thing to do. Maybe the next time I get new ones I'll see if I can find some wear with a micrometer.
 

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2003 Kawasaki Ninja 500r
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Discussion Starter #9
interesting cocktail party blather, but totally meaningless
lol...I was hoping fog would chime in. What can I say, I've got cabin fever. ;D

Seriously, though, the sprocket wear is a curiosity spurred by all the data on gearingcommander. But I like doing the math on ratio combinations. I went ahead and ordered a 17 for the front to experiment with.

Thanks, everyone, for your thoughts above. Saabnut, it looks like if you go with a 17/41 you'll end up with an 8% drop in rpm and I'll have a 6% on gen2. Also, just noticed you have 146,000 mi. Incredible. I recently saw an '03 that was pretty much ruined by 2,200 miles from sheer neglect. What a waste.
 

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Thanks, everyone, for your thoughts above. Saabnut, it looks like if you go with a 17/41 you'll end up with an 8% drop in rpm and I'll have a 6% on gen2. Also, just noticed you have 146,000 mi. Incredible. I recently saw an '03 that was pretty much ruined by 2,200 miles from sheer neglect. What a waste.
I actually have a full gen2 suspension swap on my bike, so I'd get the same change you'd see. The gen2 wheel and tire combo has a slightly smaller overall circumference than gen1, hence the slightly taller stock gearing on gen2's.

Thanks, it's been no small feat though. I don't abuse my engines, but I can't say I'm necessarily kind to them either. My past two engines got between 60k-70k miles before they were ready for an overhaul. Current engine has about 35k (since install, true mileage is a complete mystery as the bottom end was free off craigslist and the top end was pieced together from my personal stock) and while it runs well enough and the bottom end isn't making strange noises, I'm not thrilled about the oil consumption and the blow-by is more than I'd like, so I'm rebuilding a good spare gen1 motor I've had sitting on the shelf for some years now. Yes, I could pull the current engine and do a top end, but why when I can leave it running for now and take my time doing a full engine rebuild. I've finally got all the parts I need to replace the bottom end bearings, new rings, valve seals, etc., so that will be done over the course of the next month and I'll install it sometime this spring or early summer.

As for my mileage, I'm on track to hit 150,000 by May or June, which will be a momentous occasion for sure. Keep an eye out for a write-up when I hit that mark. I'll dive into further detail on the maintenance when putting in mileage which far exceeds the manufacturer's intentions.
 
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