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Replacing front sprocket only

10K views 30 replies 13 participants last post by  DME3 
#1 ·
I decided to clean out the gunk that piled up behind the front sprocket cover. Loads of gunk indeed!

Noticed the front sprocket looks like it's getting worn after 12.000 miles. Rear sprocket and chain look ok-ish.

Never had a bike long enough to have to replace the sprockets 0:)

So what do you guys reckon?
Replace the front sprocket only at this moment and ride another 12k miles?
Or replace all sprockets and the chain after the front sprocket is totaly worn out?
 
#2 ·
My understanding is that the conventional wisdom leans toward replacing the whole kit and kaboodle at the same time. One or two worn items will wear out the new piece(s) faster.
 
#5 ·
12k miles, that's about 20k km's right?

My front sprocket kinda looks like the one in your first picture.
Not totaly worn, but nearing end of life I guess.
 
#6 ·
I have always heard that we should change the front and rear sprocket when we are also installing a new chain. One of my son's is an adventure traveler with literally years of riding overseas with lots of dirt roads. Currently on a Suzuki DR650. He is just in the states for the winter after 6 months on the road in Russia, Siberia, and Mongolia. He routinely changes the front sprocket at less than 10,000 miles before he has to change the chain and rear sprocket at 20,000 to 30,000 miles. I do realize this is not the conventional advice but he has convinced me that it has not hastened his chain's demise. On a note from a couple months ago he was almost sure his chain was shot and was nursing it along. Decided to replace only the front sprocket again and to his own surprise the chain was not the problem. He is on a lot of dirt roads and worse so this is not an easy environment for the chain drive system.
 
#8 ·
Never adjusted chain slack realy. Maybe it could have been a bit tight when I took delivery. Slack now is a bit more than an inch.

I'll post up some pictures asap of the sprockets. Gives a clearer look of the state of them.
 
#11 ·
I noticed that dealers, at least in my neck of the woods, tend to overtighten chains, if they bother looking at slack at all. I keep the Triple's chain at about 35 mm too. So far only had to adjust it once in 10,000 km/6,000 miles. I clean and lube it frequently, which helps. Especially with very spirited riding over uneven roads its important that you dont limit suspension travel range by a chain, that is too tight.
 
#12 ·
At tech inspection for my last track day, I was told my chain close to being too loose. I had checked it the day before, and it was well within my acceptable range. I thought to myself, "that's just your opinion," but of course just nodded and kept my thoughts to myself.
 
#13 ·
Best to always replace chain and sprockets as a set IMO. Often a stretched chain will not grip the new sprocket teeth simultaneously but only one tooth at a time and will eventually 'bend' them over thus ruining the new sprocket. Consider also a worn chain breaking and punching a big hole in the crankcase; this will really make your day so having a high mileage chain is nothing to brag about. Even a well maintained chain should be replaced after 20K miles; you can get a nice SuperSprox kit with new chain and sprockets for around $200 which is a lot cheaper than damage from a broken chain. I have the 520 conversion with 2T larger rear sprocket which adds even more zip in top gear.
 
#14 ·
Considering risk over investment, I may replace the whole kit. Have you measured the stretching of the chain?
If the problem was the chain being too tight it will also definitely be worn. If you go for track days maybe it's a good idea to tighten the chain a bit for the track so you will have a snappier response, and then slack it again for road use. It does't take long and is a good compromise IMHO
 
#15 ·
I'm not sure that makes sense to me. Full suspension movement, unimpeded by an overly snug chain, is probably more important at the track than it is on the street. But, as I've said before elsewhere, I'm no expert.
 
#18 ·
Didn't check chain stretch, but slack is ok as per the manual. But since the slack in the manual starts at 13mm, the chain might have been to tight the first couple of thousand miles.
I usualy keep the slack at about 30mm, but since this bike is dealer maintained I don't check it as often as I did on my Ducati's... Didn't check it at all as I recall untill I replaced my rear tire after 10.000km.

I'll ride on for a couple of thousand miles to wear the front sprocket completly and install a new chain and sprockets afterwards. And order an extra front sprocket to replace it when it starts to wear.
 
#22 ·
I just got one of those, too. I had been putting it off far too long.

Using a paddock stand that lifts the rear through bobbins attached to the rear swingarm results in the bike being in the same suspension loaded position as if the rear wheel were on the ground. Actually, it might be better, because the bike is vertical and not leaning on the side stand.
 
#26 ·
I ended up replacing axle block sliders on my STR with aftermarket sliders and I cannot see the markings on the sides anymore. As you can visually see the whole length of the chain with this tool, this is probably a little more accurate than just counting the markings on the sides. However, I didn't want to spend big $ on chain alignment tool, so I bought a $14 manual tool instead from Amazon and it worked like a charm.




http://www.amazon.com/dp/B000GTVOJQ/ref=pe_385040_121528360_TE_dp_2
Thanks guys! Looks like I should probably also consider one of these alignment tools before my next chain adjustment.
 
#29 ·
In a perfect world, an alignment tool would just confirm the accuracy of the swingarm/slider block markings. ;)
 
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