Sprockets

[dmonkey]

They're there, just international shipping.

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I bought my rear sprocket from this site which also carries the 13T front, ships from Italy:

JT Sprockets Front Sprocket JTF273.13

 

[AZ7000']

I have one I'd sell, probably couldn't ship it until after the new year. With the abs and computer issues I decided against it...

Guessing it was $20 or so shipped to me

 

[Tim]

Hummmm ?? Front stock sprocket is a 14?
I think I'd like to try out 14/45
See how it goes....

 

[Tim]

Hummmm ?? Front stock sprocket is a 14?
I think I'd like to try out 14/45
See how it goes....

.....
What gearing would I wind up with ?

 

[dmonkey]

On https://www.gearingcommander.com/ you can select Honda -> CT -> 125 Hunter C. '20-'21 to load the bike gearing and then key in custom changes like front and rear sprocket differences to see the outcome in ratio, mph, rpm, etc.

 

[r80rt]

.....
What gearing would I wind up with ?

3.21

 

[Tim]

3.21

Trying to get the gearing commander to work on this phone....
But 3.21 should haul my 270# around fairly well..
Probably only go 50 mph...
But I could climb a vertical wall... slowly.

 

[Tim]

3.21

Thank you.

 

[Tim]

Trying to get the gearing commander to work on this phone....
But 3.21 should haul my 270# around fairly well..
Probably only go 50 mph...
But I could climb a vertical wall... slowly.

According to gear commander.. 14/45 will give me about 53 mph......13/45 would be something like 49mph..
Either one.. would work for me I thinks.
Im planning on sticking to the back roads and gravel . 40mph on a gravel road is way fast enough.

 

[r80rt]

I'm a dirt road , log trai lrider in the hills of Arkansas, 15/45 sprockets for a ratio of 3.00 carries my 185 lbs anywhere I want to go. The old CT90's and 110's came with 15/45 sprockets and went anywhere, it 'still a good combo especially with the extra power we have now. Gear it for what you are doing and have a blast. I don't care about speed, it will still go way faster than a sane person will ride on gravel. I have another bike for pavement, horses for courses.

 

[m in sc]

gearing commander doesn't take into account hp or wind resistance. just fyi. so estimated top speed is probably NOT what you are actually going to get, but close.

the ct90s have no bearing on gearing on the new ones, I don't understand the constant comparison.

also bear in mind the speedometer will be incorrect unless you have an opmid unit , or a speedo healer, and its calibrated every sprocket ratio change.

 

[SneakyDingo]

and its calibrated every sprocket ratio change.

I watched the calibration video recently. It doesn't look that bad, enter configuration menu and adjust 1.4 and 1.5 to the correct number of teeth depending on which sprocket you're messing with.

 

[m in sc]

no, its not hard at all.

 

[CT125 RIDER]

I'm a bit confused . I've read through this thread and it's unclear which chain size 420 or 428 is the OEM chain for the CT 125 Trail, US version? And if OEM is 420, and you want to change say....rear sprocket to JTR 269.42, which I believe is 428. Don't you need to change the front and chain to 428?

 

[dmonkey]

420 is the OEM chain size, 428 is stronger and a more commonly available x-ring and o-ring type chain so it's an upgrade. The rollers have a larger diameter on the 428 chain so you should replace both sprockets to match the chain size if you upgrade to it.

---
Correction: OEM chain and sprockets are all 428. Honda listed it incorrectly on their website for the Trail 125 specifications.
You should still replace all as a matching set since they are wear items (and not very expensive)

 

[CT125 RIDER]

420 is the OEM chain size, 428 is stronger and a more commonly available x-ring and o-ring type chain so it's an upgrade. The rollers have a larger diameter on the 428 chain so you should replace both sprockets to match the chain size if you upgrade to it.

Ok Thank You for clarification. So these guys that are throwing 13T front sprockets on their brand new bikes are purchasing a 420 sprocket and keeping orignal rear sprocket and chain? whats the general census on upgrading to 428 drive sprockets and chain, does it rob HP because chain is heavier, or negligible? Does everyone pretty much eventually go 428?

 

[m in sc]

428 is stock pitch on the trail. you -can- use 420 sprockets. but will need to swap them out all complete. 420 and 428 are both very readily available, make no doubt. groms run 420 sprockets and chains stock, and ive seen 3x stock HP run thu those sizes with zero issues. also, grom and monkey sprockets will bolt right up to the trail motor, and there is tenfold more aftermarket choices for the groms than the trail. you aren't going to break either on the trail, sorry, not going to happen due to 'overpowering' it. however, a 420 will have slightly less parasitic drag and an o-ring chain IMHO is a flat waste of time on these things, BUT, if i were to go o-ring, id swap down to 420 since they are narrower.

as a side note... rebel 250 rear sprockets will fit the trail if you wish to go to 520. I converted by grom to a 520 to run the lt250 motor. But then again thats a 40hp 2 stroke so.. the possibilities are out there.

 

[dmonkey]

You're right, my mistake. The OEM chain is DID428HDS3-108RB
IMO any chain is an upgrade over the stock one, you'll find plenty of complaints about how much it "stretches" even with how easy it is to maintain a chain on this bike.

 

[AZ7000']

You're right, my mistake. The OEM chain is DID428HDS3-108RB
IMO any chain is an upgrade over the stock one, you'll find plenty of complaints about how much it "stretches" even with how easy it is to maintain a chain on this bike.

No complaints here, but I ride it, put the key in and go. I don’t even have a magnetic drain plug!!!! Gaassspppp!

 

[CT125 RIDER]

428 is stock pitch on the trail. you -can- use 420 sprockets. but will need to swap them out all complete. 420 and 428 are both very readily available, make no doubt. groms run 420 sprockets and chains stock, and ive seen 3x stock HP run thu those sizes with zero issues. also, grom and monkey sprockets will bolt right up to the trail motor, and there is tenfold more aftermarket choices for the groms than the trail. you aren't going to break either on the trail, sorry, not going to happen due to 'overpowering' it. however, a 420 will have slightly less parasitic drag and an o-ring chain IMHO is a flat waste of time on these things, BUT, if i were to go o-ring, id swap down to 420 since they are narrower.

as a side note... rebel 250 rear sprockets will fit the trail if you wish to go to 520. I converted by grom to a 520 to run the lt250 motor. But then again thats a 40hp 2 stroke so.. the possibilities are out there.

Thanks for your response... I reached out to JT Sprockets a few dys ago and this was the guys response:
If you look is up as CT125, the fiche shows a 428 chain.

If you look up Trail 125, the Honda flier says 420 chain.

This is why we have not listed anything so far.

We are supposed to base recommendations on the micro fiche which is why I say 428.

I am not sure how best to go on this other than asking the local dealer.