In the past couple of days I've noticed a clunking noise from the front sprocket area when going off/on or on/off the gas in 1st and 2nd gear. It's small or large throttle openings, but only when going from completely on/off or vice versa. Also the chain has been making more clicky noise than usual. I adjusted the chain slack and lube it during xmas break. As far as I know its the stock chain and sprockets, the sprocket sizes are oem for the SF. I got her used in Nov 13 so not sure on the age of the chain.

I have found these probable causes from the what I have read here and online, but I'm looking for your input.

1. Chain needs cleaning and lube
2. Chain slack is off
3. Rear wheel needs to be aligned
4. Chain and Sprockets need to be replaced
5. Outputshaft bearing needs replacing


What should I be looking at to determine the correct actions here? I guess definitely check 1-3 as those are easy to determine. It's actually 5 I'm worried about so what signs are there to determine that is the issue?

cheers

 

Check the chain guard. It can be rubbing on the chain or debris stuck in there.

 

Grease the splines on the countershaft to make sure they aren't wearing excessively.

Look at the countershaft sprocket for hooking, the chain can shift back and forth between the hooked area front to back.

 

I took a quick ride during my lunch, the "clunking" noise only happens at low speeds where I assume there is little tension on the chain, as I also hear snap from loose to tight when getting on the throttle.

I'll check everything and take some pics to share here.

 

Last time I checked the slack I did with me on the bike and my brother adjusted it to the spec in the manual. However, I just saw the manual again and it says to check it with the bike on the sidestand. Would this mean the chain is looser than the spec? Either way I'll check it again with the bike resting on the sidestand.

 

Adjusted to the factory spec while sitting on the bike, the chain will be too loose.

 

Yep, too loose so the noise might be the chain slapping the swing arm... but it is better to be a shade loose than too tight. The chain will not fall off unless it is worn out junk.

I will say the best way to know you have good adjustment is to either weigh the bike down or pull the back wheel down with a tie down through the wheel over the seat until the counter shaft, swing arm pivot and rear axle line up, then adjust until there's a small amount of play, maybe an inch or so in the chain. Then release the bike and check the chain play unweighted to see how much should be there to keep from making it too tight. I know I would hate to have to tear down an engine to replace a damaged counter shaft bearing or have to put new bearings in the rear hub.

 

Ok, so I checked the sprockets and slack. The nut on the front sprocket was really loose. No not finger loose, but it nearly turned itself once I put a socket on it. The splines look good. I loosened the chain all the way to get some grease on the splines before tightening the nut.

The chain was just a tad looser than spec when resting on the sidestand. I set it back to middle of the spec.

What do you guys think of the sprockets after 20k kms, assuming they are the stock ones from the factory. I know, I know, I need to clean and lube my chain jeje.

 

Doesn't look horrible from what I can see. If the teeth show any signs of hooking or if the valleys where the rollers contact are getting oblong rather round then it's time for replacement. Try pulling the chain away from the back of the rear sprocket-if it moves more than 50% of the depth of the tooth then the chain also needs to be replaced.

 

On the 1st picture it looks like the top cog about to engage the chain is missing. Is this a 15 cog with the original chain length and rear sprocket?