CT 125/trail Suspension upgrades

[SneakyDingo]

Haha... I also remembered on my commute home that this is one of those things that really freaks me out when it happens as it's an unexpected loss of control sensation - that's why I was very particular about keeping it in spec on my bicycles. m in sc is right - it's probably fine. But it's also something that freaks me out and does not bring me joy when it happens, so I tend to replace them early.

I'd do the procedure first for bringing the bearings back into spec 100% of the time. There's almost no reason not to. It was a quick procedure, maybe set aside 30 to 45 minutes to do it so you can go slow and second guess yourself? It took me 10 minutes last night, but I had confidence in my abilities and knew what I was looking for.

 

[CTExplorer]

I have the same problem with the “clunk” even when the suspension isn’t bottomed out. Done it since the day I got it and the dealer of course, is useless. I’ll probably try changing the fork oil out in case it was underserved. Have you made any more progress in figuring it out?

After having this issue since day 1 and tightening the steering nut not being the solution I finally decided to pull the forks and change the oil with the specified 120cc/ml per fork. Clunk 100% gone. I guess they have some QC issue in the fork oil measuring division wherever these are made. The front end is much better dampened now as well especially in the rougher stuff with this corrected since fork oil level dials in the amount of air to compress and changes the dampening.

 

[dxdiag.exe]

After having this issue since day 1 and tightening the steering nut not being the solution I finally decided to pull the forks and change the oil with the specified 120cc/ml per fork. Clunk 100% gone. I guess they have some QC issue in the fork oil measuring division wherever these are made. The front end is much better dampened now as well especially in the rougher stuff with this corrected since fork oil level dials in the amount of air to compress and changes the dampening.

hi, did you put 10 or 15w fork oil?

 

[CTExplorer]

hi, did you put 10 or 15w fork oil?

I would up going back with 10w. I'm pretty light and didn't want it to be too stiff. Figured I could add a little more oil to reduce the airspace and make it a little firmer if needed as well but have not felt the need to yet.

 

[m in sc]

im at 200 lbs and used 15w

 

[Danman]

Anyone else notice serious clunking from the front end on bumps of all sizes? What exactly is the cause? I initially thought it was just bottoming (and yes bottoming does make a clunking noise) but then I will also hear it very small bumps .... think of the curb pulling out of a gas station.

I've installed the YSS kit, without typing my soap opera i've put about 350 miles on it so far and still get the clunking noise, but strangely seems to be just the left fork. Preload adjustment doesn't seem to matter, stiff or soft I still get the noise.

My 2023 has been doing it since new. I went ahead and changed the fork oil to Lucas 15wt and put in 4.1oz. I saw another thread where it was stated that the correct fork oil level should be 4.6oz. I added .5 oz to my forks and went for a ride. The clunking was very much diminished. I then decided to add another .5oz and viola no more clunk. Not sure if this overfill is a good idea but its working for me.

 

[Danman]

Hey there, just seeing if you ever figured out the clunking noise you were explaining? I'm thinking I have a similar issue that on random abrupt bumps it makes a clunking like bottoming out but at times that don't really seem severe enough that it should he bottoming out. Has done it since new.

Hi. I have a 2023 that has the same clunking prob. I changed to 15wt fork oil 4.1oz,s. I saw another thread where the correct oil level is suppose to be 4.6oz,s. I tried it and noticed a reduction in the clunking. So I figured maybe a bit more oil would do the trick and went to 5.1oz,s. No more clunk so far. Not sure if the 1oz overfill is going to cause me any fork problems but it great not having the clunking noise any more.

 

[dmonkey]

Check the fork oil level by measuring from the top of the tube down to the top of the oil. If you overfilled the forks that much they may hydrolock and blow the seals out. If there is still a clunk at the correct height then it is likely the steering bearings that are loose and need adjustment instead.

 

[Danman]

Check the fork oil level by measuring from the top of the tube down to the top of the oil. If you overfilled the forks that much they may hydrolock and blow the seals out. If there is still a clunk at the correct height then it is likely the steering bearings that are loose and need adjustment instead.

Thank you very much for the answer I did check the steering bearings already and did what the service manual recommended as far as tightening down the nut and then backing off and hand tightening there is no slop in the steering bearings at all I did put an extra ounce in each fork and took it out for a run and did not have any problems with the clunking anymore I do understand what you're saying about hydrolock and blowing out seals thank you for your time I will continue to monitor and see how this goes

 

[kekalot]

After having this issue since day 1 and tightening the steering nut not being the solution I finally decided to pull the forks and change the oil with the specified 120cc/ml per fork. Clunk 100% gone. I guess they have some QC issue in the fork oil measuring division wherever these are made. The front end is much better dampened now as well especially in the rougher stuff with this corrected since fork oil level dials in the amount of air to compress and changes the dampening.

Hi. new user here but these comments made me make an account.

I have been having the same issue since day 1 also and while I am still on warranty the dealership is trying to charge me about $180 to sort the problem. here we have speed bumps that are a little bit sharp (in a low triangle way) and if hit at anything over 15 km/h it clunks. I am currently in contact with Honda head office to try to get them to warranty the things (or at least look at what it is under warranty) as here in Thailand the dealerships do everything they can NOT to warranty thing because for them it's a "headache" to submit for warranty approval and so on.

Other than doing the above two things, is there anything else I should get them to check if Honda approves the warranty (or if I have to pay) ? Just asking cause they are being useless and I don't have the tools or knowledge to do it myself.

Also, if you have a surefire way to trigger the clunk that you know of, I'd like to know because on normal bumps it doesn't do it for me and pushing down hard on the front suspension with my 170 lbs doesn't do it either so they usually look at me like I'm dumb when I try to explain it

 

[dmonkey]

I haven't experienced the sound on my CT125, but one theory is that the fork springs fully compress to their solid height and when that happens the coils making contact with themselves produces a "clunk". I don't know if that's possible with the stock springs, and it's been reported in this thread that it happens even without the front suspension bottoming out, so that might not be the correct diagnosis. Sharing just in case:
https://www.facebook.com/groups/2081415881963022/posts/3364783996959531/
The videos may at least give you and idea to help reproduce the issue.

If you speak or write Thai, you may have an advantage over the westerners on this forum for running down this issue. The CT125 has been out in Thailand for longer and there are probably more of them there, and with more use, than in the USA. I'd recommend reaching out to multiple dealerships and third-party shops and asking if they have experience with this specific issue, you might find someone who has it figured out, and hopefully a solid solution as well.

 

[kekalot]

I haven't experienced the sound on my CT125, but one theory is that the fork springs fully compress to their solid height and when that happens the coils making contact with themselves produces a "clunk". I don't know if that's possible with the stock springs, and it's been reported in this thread that it happens even without the front suspension bottoming out, so that might not be the correct diagnosis. Sharing just in case:
https://www.facebook.com/groups/2081415881963022/posts/3364783996959531/
The videos may at least give you and idea to help reproduce the issue.

If you speak or write Thai, you may have an advantage over the westerners on this forum for running down this issue. The CT125 has been out in Thailand for longer and there are probably more of them there, and with more use, than in the USA. I'd recommend reaching out to multiple dealerships and third-party shops and asking if they have experience with this specific issue, you might find someone who has it figured out, and hopefully a solid solution as well.

This seems to be a different issue than what I and CTexplorer were having (I think), I can't make it clunk by doing that at all.. I tried the wall bump and pressing as hard as I could and I can't make it do the sound but if I run over some sharp bump (like a manhole cover that is off) it will do it.

With that being said, not very happy with the "resolution" that they had (no help from dealerships) and just told to ride it differently. haven't heard from Honda yet but I am sure they aren't happy with the wall of text I emailed them this morning. oh well!

 

[CTExplorer]

This seems to be a different issue than what I and CTexplorer were having (I think), I can't make it clunk by doing that at all.. I tried the wall bump and pressing as hard as I could and I can't make it do the sound but if I run over some sharp bump (like a manhole cover that is off) it will do it.

With that being said, not very happy with the "resolution" that they had (no help from dealerships) and just told to ride it differently. haven't heard from Honda yet but I am sure they aren't happy with the wall of text I emailed them this morning. oh well!

This seems to be a different issue than what I and CTexplorer were having (I think), I can't make it clunk by doing that at all.. I tried the wall bump and pressing as hard as I could and I can't make it do the sound but if I run over some sharp bump (like a manhole cover that is off) it will do it.

With that being said, not very happy with the "resolution" that they had (no help from dealerships) and just told to ride it differently. haven't heard from Honda yet but I am sure they aren't happy with the wall of text I emailed them this morning. oh well!

Sounds like the same noise I was having. I could not duplicate it outside of going over certain bumps, railroad tracks, etc. Squared off obstacles seemed to trigger it.

If you have the ability to get some fork oil of the same weight as the stock oil (maybe even from Honda) all you have to do is unscrew the top caps to add a little. I'd add an equal small measured amount to both forks and see if it makes a difference if working with the dealer isn't working out. You could always drain it back out with a syringe, etc if it doesn't work or know what the problem is and pursue a full fork oil change. It shouldn't hurt anything unless you overfill it. I'm sure mixing the oils isn't advocated but I doubt you ever get all the old product out if you do a regular fork oil change anyway.

 

[kevvyd]

This thread started as a "Suspension" thread and has most recently taken on a "Fork Klunks" kind of theme.
In the spirit of the Original post I am providing a link to a post I created detailing some of my experience with the YSS Fork Kit.

YSS fork spring upgrade kit. Y-FCM20-KIT-01-030

Hey all, I had installed the kit referenced in this posts' title and thought it was terrible! Honestly, I thought it was worse than stock. While the ability to pre-load the springs was desperately needed. The hydraulic damping was incredibly harsh at initial movement, but still blew though a...

hondatrail125.com

 

[DeadguyAle]

Back in the early 70's when I was racing motocross I learned that money spent on suspension improvements produced more wins than money spent on engine modifications. The magic package was to have both but money was limited for a kid racing motorcycles.
Rear suspension options were Koni's or Curnutt's, the gold standards for the day.
Front suspension best of the best was Maico, CZ, Husky, Bultaco being a close second. Japan was light years behind.
Zoom ahead to 2025 and once again I find myself shopping for suspension upgrades, this time it's not about winning races it's about comfort and better handling.
My assessment of the stock suspension on the trail is that it's the typical budget Japanese motorcycle product. Marginal at best but not so marginal as to be dangerous when used within its limitations.
Starting with the rear shocks simply because it's the easiest to deal with.
There are several options available, YSS, Racing Brothers, ebay special, to name a few and the gold standard Ohlins
Problem is the lack of good data, lots of anecdotal opinions but its not like we are dealing with a high end racing machine.
Back to another 70's racing learning experience, spend your money on proven products not hype and advertising promises. So Ohlins got my business, might have been swayed by the yellow springs also

Went on a 156 mile ride today, combination of twisting pavement and gravel.
Will follow up with my anecdotal opinion tomorrow.

 

[DeadguyAle]

Yesterday's 156 mile 5 plus hour ride was good opportunity to assess the Ohlin's.

Traveled new roads and roads that I have been on numerous times with the Trail and the KTM 450.
First set of suspension challenges were several sections of undulating pavement on the way to the ferry.
Difference in ride quality is quite dramatic, tendency to pogo from one bad section of road to the next is greatly diminished, harshness from the lack of rebound damping with the stock shocks has been replaced by a very smooth controlled flow in the back end of the bike.
There is no doubt you are moving over crappy pavement but it's in a much more controlled manner.
Made the ferry and crossing the Columbia.

Did close to 120 miles on small two lane roads with lots of 20 to 45 MPH corners, pavement quality was mixed but nothing severe. Once again the overall improvement is one of smooth and under control. No surprise butt slaps from the seat after hitting an undulation you failed to notice at 40 MPH and solid as can be when cornering.
Had maybe 20 miles of gravel travel in the mix, honestly I was not expecting to see much improvement due to the reduced speed and loose gravel just sucks even on the 450 with a Scotts dampener and exceptional suspension. However there was a notable improvement in tracking and reduced tendency to squirm around. Was not expecting that, but no denying it was there and very apparent.
One of the better gravel roads.

At the end of the day there were two other noticeable improvements. One was less fatigue, two was me "bum" was not feeling nearly as sore as I would have expected from 5 hours on the seat.

Downside is it's a lot of money for a set shocks to go on a budget motorcycle, I have to admit that I had a pile of unused Amazon prime bucks that made the purchase less painful.
The other downside is, as someone here mentioned on another thread that the improved back end really brings into focus the poor quality of the front suspension.
Next up I guess

 

[DeadguyAle]

I also considered going this route for the shock upgrade https://www.steadygarage.com/produc...ock-honda-trail-ct-125?variant=40824519262267
Not much in the line of real world usage reports that I could find, they do have both compression and rebound adjustments which makes them unique.
Price wise they are close to the Ohlins but without the reputation, so stayed with the Ohlins.

 

[m in sc]

hope you guys changed out the shitty rubber swingarm bushings to bronze or bearings.

 

[Second Chance]

Sound advice Mark. Kevin at MNNTHBX is on next week's call list for bronze bushings.

At 152 lbs. with gear the stock 2024 rear shocks need to be backed off a click, there's no sag in the center position. 11 mm spacers out of 18 mm aluminum stock are up front. The spacers along with a wee shade past 15 wt oil at a 145 mm fill have tamed the pogo. The bike feels very planted with a downhill time on my favorite gnarly mountain road that beats my Ohlins equipped Grom. Not exactly what I was expecting. My intentions for this bike were to slow down and get off the pavement. Stuff happens... Needless to say I am pleasantly surprised however I will continue on my original mission. ;-)

 

[DeadguyAle]

hope you guys changed out the shitty rubber swingarm bushings to bronze or bearings.

Be an interesting project, have made lots of bushings for other equipment but seems a little over the top for the low speeds the bike is capable of and used at, unless the stock bushings are worn out that is.
At this point you're headed down the road of diminishing returns. Those rubber swingarm bushings are part of a less than ridged swimgarm attached to the less than ridged frame by a noodle of a 10mm bolt.