Strange noise

[Cursivealpha]

I've been hearing a noise on and off. It completely stops when I press the rear brake. My best description of the noise is that it sounds like a leaf rattling in a fan; just a very soft clicking sound.

Any help is welcome, I have no idea what I am doing. The bike is only at 450 miles, so I can't imagine it's worn through any parts already. I'll be taking it in for its first maintenance soon anyway to get it done before winter, but would like to have a better idea of what to mention to the dealership.

Thank you

 

[dmonkey]

Do you hear the sound while the bike is stationary with the engine idle, or only when the bike is in motion and does not have the rear brake applied? Applying the rear brake would firm things up at the rear of the bike.
Soft clicking sound makes me think you may be hearing the chain rolling or something in the spokes, but if it happens when the bike is stationary then it might just be a loose part vibrating. If you hear it while the bike is stationary, first place I'd check is the license plate.

 

[Cursivealpha]

It sounds completely fine while stationary. I had assumed it was just something rattling somewhere, but the rear brake silencing it threw me off. Maybe a loose caliper or something in the suspension?

 

[dmonkey]

It certainly could be something like a brake pad just skimming the brake rotor.

To troubleshoot I would put the bike on the center stand, engine off, in Neutral, and spin the rear wheel by hand. Then try again but apply the rear brake gently. See if those conditions reproduce it. Another thing to try, if you're comfortable with it, would be to start the engine, make sure the front tire is firmly on the ground and rear is in the air, put the bike in gear, and apply light throttle to see if you can isolate the sound with the bike running in place - with all your body parts clear of the drive chain.

 

[Cursivealpha]

I will try that.
Thank you so much!

 

[drjon533i]

Sounds like it might be due to the kick start lever being pushed back slightly by your foot. Pushing on the rear brake would pull it away and stop the sound. Mine would do that occasionally until I rotated the lever 1 notch.

 

[Daytripper]

Mine would do that occasionally until I rotated the lever 1 notch.

I had to do the same, my size 13's needed more space to operate the brake than most!

 

[Chinjab]

Sounds like it might be due to the kick start lever being pushed back slightly by your foot. Pushing on the rear brake would pull it away and stop the sound. Mine would do that occasionally until I rotated the lever 1 notch.

Yep, foot on the kick starter would be my guess

 

[Fishwishin]

Another vote for inadvertent contact with the kick starter while applying the rear brake.

 

[FizzBuzz3000]

I'm not a big person (5'8") and have had either my boots or jeans tug on the kickstarter lever multiple times before. I move it one notch back and it solved that problem.

That aside, I do wish they either made the bike not require a battery, or just didn't have a kickstarter all-together. It's a tad bit wasteful for a bike this small to have both as an option imo. You can start the bike without a battery, for instance. Just need to kick twice.

 

[dmonkey]

I'm not a big person (5'8") and have had either my boots or jeans tug on the kickstarter lever multiple times before. I move it one notch back and it solved that problem.

That aside, I do wish they either made the bike not require a battery, or just didn't have a kickstarter all-together. It's a tad bit wasteful for a bike this small to have both as an option imo. You can start the bike without a battery, for instance. Just need to kick twice.

You can remove the kickstarter and just put a cap over the end of the shaft that sticks out if you want to. I think it's a nice feature. I sometimes use mine because it's quieter than the electric start. I wouldn't recommend running the bike without a battery as it could overwork the charging system and burn something up, but it's also needed for the ABS which is required on new motorcycles sold in some countries the CT125 is available in (Japan). In the USA the ABS is also likely to result in a lower cost to insure, as people found with the non-ABS Grom and Monkey models compared to the ABS ones.

 

[FizzBuzz3000]

Oh, I don't run it with out the battery! That would be an insane thing to do! Also, I'm curious; How would the ABS be affected in a battery-less scenario? It doesn't require that much power to work the brakes, does it?

I wonder if a large enough capacitor could work, I've heard of people doing that with older bikes to save on maintenance/reliability/weight.

 

[dmonkey]

I haven't toubleshot that, but the ABS has a minimum operating voltage and I suspect the voltage dips below that at times without a battery, causing it to fault. It may have even more sensitive checks than that since it's a safety system and should alert you if conditions aren't met for it to function reliably. If low voltage is the issue, capacitors are low energy storage density so if a supercap replacement setup does not have enough energy storage it could also dip below the required voltage as well. Some folks who are into automotive hypermiling (or just niche interest folks experimenting with stuff for the sake of it, hobbyists gonna hobby) "solve" for that by running a hybrid setup of supercapacitors and a lithium battery.

IMO the simpler "solution" to that, for a motorcycle, is to just run an appropriately spec'd lithium battery. My experience with lithium batteries in motorcycles has been very positive in terms of maintenance, reliability, and weight. I have just over 3 years on the one that is in my CT125, have never needed to charge it with a charger since the self-discharge rate is slower than a conventional battery while parked, and it was a weight savings of ~2.5 lbs from the stock battery.

 

[m in sc]

Oh, I don't run it with out the battery! That would be an insane thing to do! Also, I'm curious; How would the ABS be affected in a battery-less scenario? It doesn't require that much power to work the brakes, does it?

I wonder if a large enough capacitor could work, I've heard of people doing that with older bikes to save on maintenance/reliability/weight.

I have done this on a few occasions on older bikes. (couple of kawi triples, an RZ, etc) It has its downsides (no lights w key on but not running, etc) , but on the trail -might- be ok. its worth a shot but not sure how the efi and abs would react. Nothing harmful im sure.. On one of my RDs, i run a cdi with a charging system very similar to the trail, that includes led headlight and tail-light. the only downside on that is at idle, the headlight can flicker a bit. the trail has a stronger charging sytem than the one i have on that bike, so might be ok.. but 7 years not an issue so far on that one. Might be wort a shot to try and see.

 

[pa2220mjd]

My older trail bikes, 2 ct70's, a 90, and a 110; will not run without a battery.. not sure about my 125

Matt

 

[dmonkey]

Unless they've been rewired the CT70 and CT110 should be able to run without a battery, the CT90 would not. The CT90's ignition is wired off the battery, CT70 and CT110 off the alternator. If there's a 4-P pigtail connection for the battery you would need to jump the black wire to black wire to close that circuit. I would NOT recommend doing this as the battery acts as a voltage regulator and without it the light bulbs do burn out. This applies to the 6v bikes, not sure about the late model 12v ones.

@Cursivealpha , were you able to track down the sound? The kick starter doesn't get in the way of my boot so I haven't encountered that kick starter sound by accident, but it sounds like the likely culprit.