Replace piston/ rings without pulling motor

[The Terminator]

Is it possible to replace the piston and rings without pulling the motor on a '82 model 200? I am probably going to do this in the next few weeks. I am wanting to stop short of tearing the entire motor off of the frame if I can do this. I know that I cannot get the jug off because the studs are too long to do this with the motor mounted in the frame, but can't I raise the jug and take the piston loose?

The former owner had just had a set of new valves put in it, I think that this may have blown rings out on it, I don't really know. I know that I can let it sit for a week and it will still crank on the first pull of the rope. Now, if I could just get time and replace the piston and rings, I am sure that it would be mechanically a very solid machine.

I am surprised at how much differently it drives and handles than my 200x. Thanks - Ted

[250r]

I dont know about the 200 but my 250r i can replace the rings/piston w/o taking the motor out.

Randy

[Yamaha200EL]

I pulled the head and cylinder off of my 200 today with a little problem but got it in about 30 minutes. Pull the head off first you might have some problems with the timing chain tightners getting in the way but you can work around them and finally get it off. Then you can remove the cylinder. To replace the piston in the cylinder while it is attached to the rod you can use a larger hose clamp to hold the piston rings in place - once you get the piston in just remove your hose clamp works great!!!

Later:D

[The Terminator]

Thanks Yamaha, but did you do this with a Honda 200 or with a Yamaha 200? - Ted

[Yamaha200EL]

I did it with a Yamaha YTM 200 but I've found that Yamaha and Honda are pretty close to the same - Maybe not though.

[Fuzzy]

I dont think you will have the room. The only thing you can do with out pulling the motor is change cams. Which i have done and it was a pretty tight fit. And i wished i didnt do it that way. Because when i did i didnt notice dirt on the under side of the frame and when i hit it with the valve cover it knocked stuff loose into the top of the motor. I would highly recommend pulling the motor to do a piston change. And believe it or not pulling the motor dosnt take that long at all. I can have mine out in about 30 minutes with out air tools. With air tool i bet you could have it out in 15-20 minutes. If you are going to spend the $100.00 on the piston and rings. And another $20.00 on a top end gasket set. I would take the time to do it right. If you drop one tool/bolt/rock down the engine you are going to have to pull it anyways to get it out.

Just wondering why you want to replace the rings in the first place?. You said it starts on one pull. And you didnt say anything about it smoking. So i was just curious why you think it need rings?. I would hate to see you go through the money and time if that is not your problem. Could you fill us in a bit more on what it is doing.

[The Terminator]

Fuzzy,

The trike smokes a good bit. I don't know why else it would smoke so much. It does not have much power on a steep concrete driveway, it will sputter a couple of times on the way to the top. I was told that the prior owner had some new valves put in it. I figured that this might have blown the seal on the rings. There is oil leaking out of the top, where the cover for the valves and the rocker arms is at. It is leaking over the top of the muffler. Now if this is getting into the exhaust somehow, that may be the cause of the smoke. I don't really know just yet. It does however, crank just fine, and runs OK. BTW, how do the gases blowing by the rings translate into a smoky exhaust? - Ted

[Fuzzy]

Well it sounds to me like when they did the head work they didnt tighten the head down properly. Or reused the old head gasket. Or didnt work on the valves at all. The head gasket shouldnt be leaking all ready.

Ok here is a little smoking 101

Is the smoke blue or black

Blue=oil
Black=fuel

If it just smokes at statup and goes away after a few minutes.

Valve seal=oil dripping into the cyl after engine is turned off.

If it smokes all the time.

Rings=Oil scaper rings not cleaning the oil off the cyl walls and burning the oil with the fuel.

Another good sign of piston failure is a lot of blowby coming out of your crankcase breather. Due to the rings not being able to hold the compression and leaking past them down into the crank case.

Ok now that that is out of the way. I didnt know what your motor experience was. So i just wanted to make sure we covered all the bases.

The good news is your head gasket leaking HE HE :D . Between the head and cyl there is guide pins. On at least one of the guide pins there is a rubber o-ring. The guide pins are used to move oil up to the head. Being how the head gasket is leaking. I am guessing that the o-ring is probable bad also. And letting oil leak out of it and in to the cyl and on to the outside of the engine. Due to the compression of the piston blowing it out of the head gasket. Explaning the lack of power(headgasket not sealing) And The oil burning(leaking oil past the o-ring on the way up to the head)

So the good news is you probable only need a $20.00 top end gasket set from dennis kirk. The bad news is you are still going to have to pull the motor. And its up to you if you want to spend the money on the piston and rings. It wouldnt be a bad idea at all to do them while the engine is out. But it you are going to take the cylinder to be honed and checked for out of round. It is just going to add to your exspence. Or you might just want to take a afternoon and pull the motor and replace the top-end gaskets and see how much it helps. If would be worth the $20.00 for another top-end set if it still smokes and you want to spend the extra $$$$.

[The Terminator]

Fuzzy,
I am 99% sure that you have diagnosed the problem. Next week I am going to pull the motor and gamble with a new gasket set. I believe that a gasket system failure is evident. The smoke is definately blue. I have a good set of tools, air ratchet included. I am realizing that I don't have to strip the motor before I take it out of the frame, right? I am thinking that I only have to disconnedt the exhaust, spark plug, chain,throttle, and fuel line. My point is that Clymer recommends that you just about strip the engine before removing it. If I am correct, won't the engine come out with the carb, pull start, and gear shifter in place? - Ted

[Fuzzy]

Yea they kind of make it sound tougher then it is. The only thing you have to remove is. Your chain,exhaust front pide,And carb.

There are two 8mm bolts holding the intake to the engine just remove them and leave your carb and intake and cables and everything hanging there.

Remove the two nuts on the front exhaust studs and remove the front pipe. If you cant get the pipes apart. take the two bolts out of the back pipe and remove the whole exhaust.

Then just disconnect the two electrical connecters. And pull the 9 bolts holding the motor in and yank it out.

No disasemble of the motor is required. And you can leave your shifter on there.

Then try to do as much to the motor as you can while it is out. Like setting up your timing and valves. Let us know when you get that far if you need help. And when you drop it in it will be all ready to go. I just put my motor in yesturday and it started on the first pull. It is a lot easier setting the valves and changing oil and every thing with the motor out. So after you bolt it in you can just crank it over and ride.

Have fun. And let us know if you need any more help on it.