Lost cam chain tensioner spring inside engine

[inroads]

So on my first oil change I removed the cam chain tensioner plug instead of drain plug..it came springing out along with the metal cylinder plunger..a comedy of errors then I inserted the spring in first and when I realized my mistake went to remove and only the plunger came out and no tensioner spring...
Yep big mistake...now what to do ??
I have been trying to fish it out with a magnet but no luck..
Next I am going to ask a Trail 125 engine specialist what he thinks about me replacing the spring and running it with that tensioner spring in there..with the hopes it will just lay dormant in some dark corner of the engine..
Really no good choices here...

Can anyone recommend a engine guy who knows these motors on the inside ?

TIA..

 

[dmonkey]

Don't leave the out of place spring in there same as you wouldn't leave a dropped bolt in there, that's likely to cause damage and get expensive. If you can't fish it out you can recover it by pulling the right side crankcase cover. Pulling that cover is a somewhat common service step for this motor as it's necessary for cleaning the oil spinner and oil screen that are every 8,000 miles in the maintenance schedule.
Here's a video that includes the process:

At that point you should be able to recover it without getting deeper into the engine or pulling the clutch assembly. It is time consuming, but it's not extremely overwhelming, you don't need to split the cases to get to that spring.

If you DIY it, just do your research and prepare ahead of time. Watch some YouTube videos, read the relevant sections of the Service Manual and Parts Diagrams which can be found in this thread:

Honda Trail 125 CT125 PDF Manual Downloads - Owners, Service, Parts Catalog

Owner's Manual: A booklet that is included with the purchase of a new Honda Trail 125. The Owner's Manual may be located inside the black toolbox located on the left side of the bike below the rear carrier rack. A hex key for opening the tool box can be found clipped to the top of the fuel tank...

hondatrail125.com

You would need to replace the right side crankcase cover gasket which will likely tear when taking the cover off, so order that for whichever model you have. It's a different part for the 2021-2022 JA55 model than the 2023 JA65 model according to the parts fiche.

If you aren't comfortable with DIY, you don't need a Honda Trail 125 engine specialist. A competent motorcycle mechanic should be able to work on it, and anyone who's worked on the Grom, Monkey, or Super Cub would have the extra familiarity with this motor's design.

 

[inroads]

Don't leave the out of place spring in there same as you wouldn't leave a dropped bolt in there, that's likely to cause damage and get expensive. If you can't fish it out you can recover it by pulling the right side crankcase cover. Pulling that cover is a somewhat common service step for this motor as it's necessary for cleaning the oil spinner and oil screen that are every 8,000 miles in the maintenance schedule.
Here's a video that includes the process:

At that point you should be able to recover it without getting deeper into the engine or pulling the clutch assembly. It is time consuming, but it's not extremely overwhelming, you don't need to split the cases to get to that spring.

If you DIY it, just do your research and prepare ahead of time. Watch some YouTube videos, read the relevant sections of the Service Manual and Parts Diagrams which can be found in this thread:

Honda Trail 125 CT125 PDF Manual Downloads - Owners, Service, Parts Catalog

Owner's Manual: A booklet that is included with the purchase of a new Honda Trail 125. The Owner's Manual may be located inside the black toolbox located on the left side of the bike below the rear carrier rack. A hex key for opening the tool box can be found clipped to the top of the fuel tank...

hondatrail125.com

You would need to replace the right side crankcase cover gasket which will likely tear when taking the cover off, so order that for whichever model you have. It's a different part for the 2021-2022 JA55 model than the 2023 JA65 model according to the parts fiche.

If you aren't comfortable with DIY, you don't need a Honda Trail 125 engine specialist. A competent motorcycle mechanic should be able to work on it, and anyone who's worked on the Grom, Monkey, or Super Cub would have the extra familiarity with this motor's design.

Fantastic..thank you for that info..I am going to tackle it on my own..just hope I can get to the cam chain tensioner area from the right side..

 

[m in sc]

you have to pull the LH (alternator side) engine cover, not the right. this is what it looks like w the alternator removed. you can see the tensioner push tube to the RH side.

fwiw, usually that gasket stays intact coming off.

with alternator rotor still on. this is more what you will see when the cover comes off.

I would think you should be able to fish the spring out w the rotor still on there. good luck.

 

[dmonkey]

@m in sc is right, I had the wrong side. Left side is even easier. If the gasket tears it will tear at the stator wire notch. Still, depending on where the spring went you will likely have room to fish it out without pulling anything deeper than the cover.

 

[inroads]

Got it.Thank you !!

 

[inroads]

Well got the rotor left side cover off and there is not enough room to get behind the gear to retrieve anything..so off comes the rotor...anyone have info or knowledge of pulling it ?...I need to source a puller now.

Looks to be a 27 mm female threaded puller that I need if anyone knows..
TIA

 

[dmonkey]

Do you see the spring? I would have expected you'd be able to see it and then fish it with a wire from there.
Section 2-26 in the service manual covers the necessary steps and the specialty tools, a rotor puller and flywheel holder. You don't have to buy the Honda ones, there are generic ones. I bought mine from Hard Racing here: https://store.hardracing.com/?target=search&mode=search&substring=puller&including=all
If you have a 2023 model then measure to make sure the 30mm puller will fit the flywheel nut just in case that changed on the updated engine.

 

[inroads]

There is little to no room behind the gear cannot see the spring...

Hard racing puller states they are for Grom and Monkey but don't list the Trail 125...I guess they are all the same ?
They are in North Carolina will try calling in the morning..

I have a vise grip chain holding tool so just need puller..

 

[Dr. Spark]

On my 2023 CT125 there is only one 12mm bolt on bottom of engine. They must have moved the cam chain tensioner plug.

 

[dmonkey]

They also changed it to an allen cap bolt, possibly to address the common mix up.

 

[Kev250R]

They also changed it to an allen cap bolt, possibly to address the common mix up.

That would make sense as it seems to be a common mistake.

I'll admit that I did it once 20+ years ago when I was working on a friends Honda Scooter (might have been an Elite? I'm not sure). Thankfully I was friendly with the local Honda dealer at the time and one of their Techs walked me through how to fix my mistake.

 

[dmonkey]

One of the reasons I bought this replacement drain plug bolt was so that I wouldn't confuse the drain plug bolt when doing oil changes, otherwise I'd likely have made that mistake by now.

SP TAKEGAWA : Drain Bolt with Magnet [02-09-0022]

A nice thing about magnetic drain plugs is that they often find their way to sticking to the bike once removed, rather than falling into the drain pan.

 

[m in sc]

the grom one i had worked on my trail. (its in the picture above actually)

 

[inroads]

Ok excellent...I wonder if the shift shaft support for the grom fits our trail 125 ?

It is discounted on Amazon for about $25
Ordered it..will let you know if it fits..

 

[m in sc]

it does, theres threads on it as well. (all my experience is on 1st gen trails though)

 

[m in sc]

me? id be fishing around in there with a curved dental pic. the rotor drum is magnetic so if it came out, it may be stuck to the back of the rotor. .02