new to me 1984 ATC 125M

[Goatwrangler]

Hello all,

I'm new to 3 wheelers. A friend of mine who is on this forum finally talked me into getting one. Thanks Tyler...

I'm from Whitestown, Indiana and dont know jack when it comes to these trikes so I'm hoping to learn all I can.

The problem with my 84 is that it has spark (blue) but wont even try to hiccup when using starting fluid on it.
I dont have a manual on it so I'm not sure how to check the timing or anything like that. Does anyone have any ideas for me to start with ?

Thanks,

Jason

[GunsShooting]

Try a new spark plug. I have had plugs make a nice spark outside the engine, but fail to spark at all when installed in the engine.

Russ

[Goatwrangler]

Thx Russ,

I was thinking that but seemed to have good spark so I didnt think about a new one.
Ill replace it and report back.

Jason

[tripledog]

Just a tip, but carb cleaner is less likely to damage the piston rings and other internal engine components than starting fluid. Good luck, and welcome to the forum! :p

[bigman00]

some times the plug will not fire under compression. ever thought it looks good out of the cylinder. good luck with the 125 nice trike that was my first. look forward to seeing some pics

[Goatwrangler]

Thanks everyone and I was unaware carb cleaner could be a substitute for ether.

Jason

[kb0nly]

I buy a little spray bottle from the local hardware store, cleaning isle, get a little one for like a buck or less, fill with fresh gas. Better than ether or carb cleaner, etc. They are meant to run off gas, give it gas, thats my philosophy... You can set the bottle to stream to pump into the plug hole or set it to mist and spray into the back of the carb while your cranking.

176454

So you have spark, nice blue spark by the sounds of it, but she won't fire... Since its a 125M, you got a battery in it and the electric start working? If so put your thumb over the plug hole and hit the start button and crank her over a bit. Does it have enough compression to pop your thumb off when your trying to keep it on the plug hole? You can use the recoil to do this also, but a lot easier to use the electric start when you got one hand occupied down on the plug hole.. LOL

If its got good spark and she won't start with some fresh gas squirted in, and she has good compression, then i would check timing.

Service and owners manual for that model are on my manuals website. Link below in my signature.

[Ghostv2]

Buy a new plug, clean the carb, see if itll run. If not, try pop starting it. Works for me usually with my 200s. I have a a semi rusty tank and it tends to make it run crappy if it sits for a little but pushing it up a hill and throwing it in gear usually seems to do the trick even when starting fluid and all that other stuff will not.

Thats the lazy way because i never want to take the carb off my 200s.

[Goatwrangler]

The electric starter does work. I can keep my thumb over the spark plug hole while cranking. I dont have a compression gauge to check it out though.

[GunsShooting]

WD-40 also works as starting fluid and it's much less volatile than other things.

Russ

[kb0nly]

If you can keep your thumb over the plug hole while cranking you got bigger issues. I would check to make sure the valves are moving. Pull the valve adjustment caps off and crank it over and see if the valves are moving. You might have a stuck exhaust valve, been there done that on a 125M. If your lucky you can get it freed up. The last one i worked on i sprayed PB Blaster around the valve guide and tapped on the rocker with a small block of wood and a rubber mallet a few times until it got free. But it could also be a broken valve spring on either the intake or exhaust but that doesn't seem to common.

If you crank it for a bit and pull the spark plug out is it wet? If the plug gets wet than at least the intake valve is opening, but it could even be stuck open.

Sounds like you need to diagnose the valves and if that takes you nowhere then its time to pull the motor and take the top end off it. You shouldn't be able to hold your thumb on the plug hole while cranking, the compression should pop it right off if the motor is healthy. You could try bump starting it as well, in case its a stuck ring that needs to free up.

When you crank it over is there any odd noises? Such as piston hitting a valve, etc.

[Goatwrangler]

Thx KB. I havent had much time to mess with it today. I did manage to throw a new spark plug in it and it backfires every now and then but thats it.

[kb0nly]

Hmm backfiring could mean a few things. I would still check the valves and timing, and pull the air cleaner tube off the carb, make sure the air cleaner isn't a rats nest starving it of intake air as well.

[Goatwrangler]

Will do. Air cleaner is off currently. I wasnt able to download a manual through your link. Probably something on my end but I'm not sure where to access the valves.

[kb0nly]

The link should take you to my website www.atcmanuals.info then click on the Manuals tab below the banner image. That page should show you a list of manuals to choose from. If thats not working let me know what your viewing it on, phone, computer, tablet, etc. So i can troubleshoot it in case there is a formatting issue.

Here is the direct link to the service manual.

http://kb0nly.info/ATC/index.php?dir=ATC125M%2F&download=Honda+ATC125M+84-85+Service+Manual.pdf

The valves are accessed via the caps up on the head, looks like a big bolt head, those caps come off and you can see the rocker arm.

[Goatwrangler]

Thx Kb, the download worked that time.

[Goatwrangler]

If you can keep your thumb over the plug hole while cranking you got bigger issues. I would check to make sure the valves are moving. Pull the valve adjustment caps off and crank it over and see if the valves are moving. You might have a stuck exhaust valve, been there done that on a 125M. If your lucky you can get it freed up. The last one i worked on i sprayed PB Blaster around the valve guide and tapped on the rocker with a small block of wood and a rubber mallet a few times until it got free. But it could also be a broken valve spring on either the intake or exhaust but that doesn't seem to common.

If you crank it for a bit and pull the spark plug out is it wet? If the plug gets wet than at least the intake valve is opening, but it could even be stuck open.

Sounds like you need to diagnose the valves and if that takes you nowhere then its time to pull the motor and take the top end off it. You shouldn't be able to hold your thumb on the plug hole while cranking, the compression should pop it right off if the motor is healthy. You could try bump starting it as well, in case its a stuck ring that needs to free up.

When you crank it over is there any odd noises? Such as piston hitting a valve, etc.

Pulled the valve adjustment caps off. There was oil in the exhaust valve adjustment cap. Is that normal? Both valves move freely when i crank the engine over.

[kb0nly]

Your welcome, and yes its normal on the oil, it pools being the bottom side, there should be oil there, if not you got worst problems... LOL

Ok on the valves, good to hear everything is moving. I would check the adjustment, aka valve lash on them as well, procedure is in the manual all you need is a feeler gauge. Its possible they are too loose or too tight causing issues as well, so its worth checking.

Need to find out why there is little or no compression.

[Goatwrangler]

im getting a compression tester tomorrow and I'll report back with numbers. i'll try to get the valves adjusted tonight.

[kb0nly]

Did it sit a long time before you got a hold of it??

I'm expecting the compression test to be pretty low considering it won't pop off your finger.

[Goatwrangler]

yes, it sat quite awhile. Number of years are unknown to me. The guy had it in storage and said he never had time to mess with it. I traded him a snowblower that I got from work so I have no money into this trike other than what it cost me in diesel fuel to go pick it up.

[kb0nly]

Ok, well if it sat that long, got any PB Blaster or similar penetrating oil? I would pull the plug, spray a good amount into the cylinder and turn it over slowly with the recoil while spraying some in. Get the cylinder and rings lubed up, i have had some that had really crappy compression from sitting a long time, rusty cylinder walls that then messed up the rings when someone cranked it over. If you get lucky you might get it to come up on the compression, but it will still need a top end rebuild once it starts burning oil and smoking like a diesel... LOL

[Goatwrangler]

I sprayed some PB blaster in the spark plug hole this morning before I left for work. When I get home ill spray in some more and crank the engine a few times then do the compression test. Hope everyone has a good day.

[auto5man]

Glad to see you working on the same machine as me Goat! I'm also a total newb working on these things so we can both benefit and learn from each other's posts. I look forward to the point where I'm trying to crank....I'm deep inside the motor of mine at the moment, lol. You will need the service manual many times,,,too many to have to run to the computer with greasy hands on the keyboard. I printed off the whole thing and had it bound....much more convenient access to the information.

[Goatwrangler]

I already printed it off Auto. I just waited so I could use my work's paper and ink.

[kb0nly]

Good to hear you got a hard copy of the manual.... LOL

I printed off a copy of the 200ES manual and had that bound into a nice spiral bound copy by a local office supplies place. I think it cost like $8, but it was so worth it to keep from greasing the keyboard!

I have a computer at my workbench with a cover over the keyboard like you see at businesses, to keep the keyboard clean. The only problem is still having to pull that off and clean the cover, what a pain.

Looking forward to what you get for results on a compression test!

[Goatwrangler]

bad news on the compression test: pulling the manual start, I got just under 30 PSI. Engaging the electric start I barely got 10PSI. I think its time to rebuild this little engine. I have NOT checked the valve clearance yet though.

Let the fun begin. This will be my first engine (small engine) that I've ever redone.

Any good suggestions on pistons ?

[kb0nly]

Shindy is the brand name i have used a few times now, they make a good kit. Your going to need a gasket kit also. However, its more then that. Your probably going to have to give it a valve job, and most likely if the compression is that low it will need to be bored and honed on the cylinder. If you have a local machine shop that can do it then your set. Otherwise there is a few guys on here that do it, and also G&H Discount ATV offers a service of sending your cylinder in.

[Goatwrangler]

Alright, so I decided to try and adjust the valves. Boy, what a pain in the butt. I got sick of it and ended up pulling the engine from the trike and put it up on the workbench. Both valves were < .07mm clearance so I'm hoping that the valves were hanging open some when I originally did my compression test. I got the valves adjusted to right around .07mm on an obviously cold engine since it won't start and run. I'm going to hang the engine back on the 125m here in the next few days to see if the valve adjustment was my issue with the compression. If not, Ill yank the engine back out and tear the head off and go from there to see what will need replaced. Hopefully, I'll get it all done here soon but only time can tell.

The last guy(s) that have had this machine were some real hacks. Looks like some type of liquid gasket material ran down the intake to the intake valve. There were multiple items loose that were just hang tight.

Auto, I feel like Im getting closer to you now LOL with the engine sitting on the workbench.

[auto5man]

Yep you are rapidly catching up Goat....much more comfortable working at it on the bench too, than squatting around on the ground. I know what you mean by hacks. So far everyone one of these I've looked at has been hacked so far from stock it's painful to see. I keep following craigslist ads and hoping that I find that bone stock un tampered with machine that just needs a carb clean and spark plug b/c it's been sittin up for years (for non-running as is cheap, of course), but I haven't found it yet. Today I went and looked at a 125 from CL, talked to the guy on the phone who tells me "yeah it's got all the parts...nothing's missin, yeah the ignition is there....there's a key but its broke off in there etc etc". I get there....no battery, no starter solenoid, no battery box or battery wiring, wiring harness is spaghetti in spots, broken plastic front and back, no brakes, no chain housing, ignition not there and some crazy switch hacked in, etc. On the bright side it did start easily with pull cord and ran fairly smooth. The more I showed him what was missin the more he went down on price. I backed out wanting to hold out for something nicer (already have two project trikes) but still need a sub trans and other parts for my current 125 project trike....sigh. I guess I'm hooked for sure.

[Goatwrangler]

Gotta love it. Yep it's all there... Everything is there from when that person got it but not all the right covers and whatnot. Same thing happened with mine but I traded him something I had money in anyways so oh well

[Goatwrangler]

Found out today I might be trading an old revolver I have for an 85 honda atc 200s that needs some work

[GunsShooting]

Oooh, I like guns even better than ATCs.

Russ

[Goatwrangler]

It's an 1894 columbian firearms mfg in New York 5 shot revolver. They aren't worth much and use .32 black powder rds. It's in pretty good shape.

On another note, I had a few minutes to do a compression test after adjusting the valves and now I'm sitting at about 100psi. I don't have much time tonight but I plan on getting the engine back in and seeing if I can get this beast fired up and running.

[GunsShooting]

Sounds good, best of luck in both things.

Russ

[Goatwrangler]

Threw the engine back in tonight...double check connections and she starts first pull!!! I need to adjust the carb but she runs!!! Can you tell I'm a happy fella ?

[kb0nly]

I would do another compression test on the bench and save some work! Then if the valve adjustment helped hang it back on the frame. You can run the electric starter easily with a jumper starter or just take the battery you were using and a set of jumper cables, negative to the motor somewhere and positive to the starter. Just touch the other end to the batteries positive terminal and she will crank over.

[GunsShooting]

Threw the engine back in tonight...double check connections and she starts first pull!!! I need to adjust the carb but she runs!!! Can you tell I'm a happy fella ?

Good job, congrats!

Russ

[Goatwrangler]

Thx fellas

[Trike_crazy]

I like how you thanked me for getting you into all of this lol. I didn't tell you to trade for it but it's good you got it running. Now you can come out to the house and ride with me!

[Goatwrangler]

Lol yea I know man but you always would talk to me about them and my father in law got an 83 atc 110 so I figured what the hell