1986 125m valves, help needed

[hosscat]

I have another thread on here that has evolved and I thought I may get some more responces if I started a new thread directed more at me current problem.

First off I just bought a 1986 125M, I have rebuilt the carb, and several other small things. I think the valves are sticking sometimes. the last ime I rode it, it cranked up, idled fine, i drove it for several minutes (maybe 10) with no noticable smoke. Then one time when I shifted to neutral it idled up on it's own and started smoking like a train, and continued to smoke until I turned it off a few minutes later.

I think I have valve(s) sticking, I don't know if that could be the cause of the crazy idle or not, but I don't know why it can not smoke one minute and then smoke the next.

I need some feedback on whether my hypothesis is crazy or possible, also I would love it if somebody could help me determine what all I may need to take apart the top end of the motor and hopefully put it back together in a timely fashion and hopefully have everything I will need ordered before I take it apart, like special tools, gaskets seals, do you think I will need new valves, or springs, or seats (which would take machine work).

Thanks in advance.

[Daniel 250es]

I don't know if valves stick. But if it were me I would take it apart and then find out what I need. No way of knowing if valves,valve seals, springs,cylinder, rings and piston are good without them in your hands. Get a service manual and read it first and then you must take your time to get it right. Just my 2 cents. smoke on a 4 stroke would make me think rings or maybe just valve seals could cause that but either way the top end needs looked at

[fabiodriven]

I was watching your other thread. Your valves are not sticking. When valves "stick" it is in the open position. If your valves were stuck open, your engine would not run. You got some poor advice in that thread. I don't know what your problem is, but sticking valves is not it.

[hosscat]

could it be that my rings are not seating. I have seen vehicles that have set up for a while smoke until the rings seat themselves again.

If it is my rings can I just put new rings on it, or does it need to be bored out?

[Daniel 250es]

You can just put rings in it. But have the cylinder measured and honed if possible. I would check all of my top end though. I put a new piston and rings in a worn out cylinder and the piston broke and went into the bottom end. It was not worth the short cut. DO IT BY THE BOOK!!!!!!!

[fabiodriven]

I can appreciate your drive to fix this trike yourself, but it sounds to me like you may be getting in over your head. On the one hand you could take it apart, diagnose the problems, and potentially learn a lot. On the other hand you may not have the skill to take it apart and get it together and running again. There is only one way to learn. Either you've got it or you don't. It is impossible for us to diagnose your problems over the internet, especially where you're not all that experienced anyways. Good luck.

[RodKnockRacing]

there's a lot things that would make your engine smoke. excess carbon build up, worn out valves, seats, guides, and seals, worn piston rings, worn cam and rockers. Search in the world class help section on the site and look for the service manual and read it and if u feel confident in diagnosing your problem have at it and take your time.

[hosscat]

My gut was telling me it needed rings, but I was hoping it was something else, oh well looks like new rings it is. Thanks for all the advice, where can I order a rebuild kit, can I trust the ones on ebay?

[mrcribbs]

www.dratv.com

[hosscat]

they don't have rings for an 1986 125m. I've found some on ebay, and if I can't find them anywhere else I'll just get'em there.

[Vealmonkey]

First all, don't just tear the trike apart, do some detective work on it first. The cost is mainly your time. Get yourself a manual and read the trouble shooting section. How do you know the rings are trashed? it was smoking then it wasn't smoking, doesn't sound like rings to me. Have you done a compression test? If not, then don't even think of wasting money on a tear down yet! You got no clue what the problem is, yet you are ready to tear it apart?????? Have an herbal tea and mellow out. Do some yoga. LOL While you are drinking your herbal tea, read through your newly acquired shop manual. You could have some crappy old gas or who knows what, but if your valves are sticking the trike won't run. Do a tune up on your trike. Set the valve and ignition timing. change the oil and clean your filter screen. Adjust your clutch. Check your drive chain, lube it and make sure it's adjusted correctly. Lubricate your brake cables. Check your wheel bearings for excessive play or drag. But whatever you do, don't go tearing the engine apart needlessly. And if you do, you get what you deserve. Do you go to the Doctor and say, I have a headache, cut my skull open and check for tumors???????

[fabiodriven]

Well said Veal.

[hosscat]

I've run multiple tanks of gas since I've had it, I have already worked on the brakes, rebuilt the carb, changed oil and filter, sparkplug, adjusted clutch, adjusted drive chain, etc... everything you mentioned except set valve and ignition timing, which since it runs quite well I doubt are the reason as to why it is smoking (but I may be wrong) I already have a manual and have read it. I have never owned a 3 wheeler, nor have I ever worked on any small motor, but I doubt the teardown or assembly will be a problem (assuming this thing works on simple mechanics, and not voodoo, I don't understand voodoo). Maybe I'm over confident, but I'm about 95% sure that I'm about to go to the Dr. and say I have tumors cut my skull open.

So my current hurdle is finding somewhere to get the rings, or some reassurance about the ones on ebay.

Thanks in advance

[Vealmonkey]

Well, you did not explain that you had done all this in your thread. I commend you for your actions. Complete information helps people understand your situation better. Then you should know to run a compression check on your engine then. You might have something as simple as old and worn valve seals. Which means you wouldn't have to replace your rings, but that you still have to remove the head which means you still have to replace your head gasket and base gasket and all your top end seals. If you are going to all the trouble of doing that and you are still wanting to replace your rings, then you may as well have your head, meaning valves, guides and seals looked at as well. Rings are sort of only half the job. Once the top end is off, you may as well check your piston as well for excessive wear and possible replacement and re-boring of your cylinder. And you can check your connecting rod play as well. See how these things can get out of hand? LOL I mean you are talking 20+ year old machines here and you may be on your original bore and such.

[hosscat]

yeah I'm hoping to do a compression test this week, and I have been thinking about the valve seals. Here is my reasoning against the valve seals being the culprit.
I grew up on a farm and we used to have a truck that had bad valve seals, it smoked right as you cranked it up due to the oil seeping past the seals as it sat over night. Mine doesn't smoke upon start up, it seems to smoke more as it warms up, leading me to think that as the oil worms and thins out it gets past the rings more.

I plan on micing the jug and the piston once I get it broken down, but I am expecting them to be within specs, simply because it cranks quick, and runs great, I can't believe it's to worn out.

Riddle me this; if I were to replace the valve seals on this engine, does that require a machine shop? I'm a big advocate of DIY and would prefer as little "help" as possible.

[fabiodriven]

You can replace valve seals yourself. It's valve seats that require a machine shop. That's probably what you're thinking of.

[mrcribbs]

02 RING SET (STD)
13011-HB6-305 001 $33.16 $24.99

www.servicehonda.com

Sorry about earlier, I thought Beatrice Cycle had ring sets for your year...

I'm currently rebuilding the top end on my '84 125M and it smoked badly. I tested compression and had 175 PSI cold so I thought it was just a valve seal but once I got it apart I really didn't see anything obvious. Turned out the rings are worn badly - .027 and .031 ring gaps. Cylinder only has .0015 wear. The valve seal was intact but is very hard. (84's don't have an intake valve seal...)

[Vealmonkey]

Do you have a valve spring compressor? That will be your big limiting factor. You can get away with not having a valve spring compressor to get the valves out, but I don't really like how you have to do that, but you can do it. But a valve spring compressor is necessary to get them back together. You may want to de-carbon everything once you have it apart and maybe relap your valves before putting your top end back together. A cheap and easy way to check valve to valve seat sealing is just to pour some water in the underside of your head and see if the water leaks by your valve seals. A small can of valve lapping compound is pretty cheap and a wooden valve lapper with the rubber ends is cheap as well, so very little cash outlay there. With your valves out you will be able to check the wear on your valve guides as well. Valve guides are kind of a pain to do yourself, but it's possible. The thing is, without all the right tools, it's usually just cheaper to have a shop do it unless you really want to invest in the tools to do it right so you don't ruin your head.

[RodKnockRacing]

I bought a nice Tusk valve spring compressor from rocky mountain atv mc

[hosscat]

probably going to just do the rings and check the valves with the water idea for now. If that doesn't fix it then I'll just take it back apart and find a machine shop to work through the valves. I'm expecting the rings to be the major cause. Thanks, for all of the help. It will probably be a couple weeks before I have the time to break it open (our snapper season just started) but I will keep everyone posted.

Thanks,

[RodKnockRacing]

probably going to just do the rings and check the valves with the water idea for now. If that doesn't fix it then I'll just take it back apart and find a machine shop to work through the valves. I'm expecting the rings to be the major cause. Thanks, for all of the help. It will probably be a couple weeks before I have the time to break it open (our snapper season just started) but I will keep everyone posted.

Thanks,

What I have learned from working on my own stuff its best to check everything when you break down an engine. But for the rings pull them off the piston and put a ring in the cylinder and push down with the piston an measure the end gap with the proper feeler gauge before you go buying new rings. no reason to waste money if you don't have too. Just my 2 cents