12 Yr Old 2 Stroke 125cc Pissing Out Smoke

[Yimmy]

I bought a 12 yr old Yamaha tzr 2 stroke 125cc bike a while ago, it's a nice bike however it's burning oil like something else and pissing out smoke. I mean REALLY pissing out smoke. I've a good mechanic that fixes the little things that go wrong from time to time but there's a massive language barrier.

Is something like this fixable by buying a new engine part (is it the carb??) or is it unfixable and signals the end of the road?

It's a nice bike and I don't wanna see it go.

Thanks

[Tywais]

Most likely the piston ring and/or valves needs replacing. Not expensive to do, a couple of thousand baht I would guess. I'm not sure at what point the oil is injected with the petrol in two strokes, if at the carburetor then perhaps that needs rebuilt. I'm sure someone more knowledgeable on two strokes will be along.

[H2oDunc]

I'd put money on rings. Most Thai mechanics can do the job easily. Depnding on the state of the piston you might like to get a re-bore and oversize piston, which ever way you do it it wont cost more than a few thousand baht.

[Murf]

I think New piston rings as said above... But when you say

it's burning oil like something else

do you mean engine oil or 2 stroke oil?

If engine oil definetly the rings...

May get away with re-using the old piston too... carb shouldnt make it smoke.

If 2 stroke oil then you have a problem with the feeder, maybe the cable to the 2 stroke feed is sticking and its stuck open all the time??

Good Luck...

[monty]

It's been a while since my teen-age motorcycle days, but I was of the impression that 2 strokes only get their cylinder lubrication from the 2 stroke oil mixed in the fuel (or injected by the oil pump just after the carburettor and the engine oil doesn't come near the cylinder (but basically lubricates all the rest of the engine's moving parts).

So I doubt that the piston rings are causing the smoke, most probably the oil injection pump is bad, or badly adjusted. They are normally coupled to the throttle, so that at high power demands more oil gets injected. If it is stuck at maximum you'll get a terrible smoking engine, and your oil tank is empty in no time.

[VocalNeal]

I bought a 12 yr old Yamaha tzr 2 stroke 125cc bike a while ago, it's a nice bike however it's burning oil like something else and pissing out smoke. I mean REALLY pissing out smoke. I've a good mechanic that fixes the little things that go wrong from time to time but there's a massive language barrier.

Is something like this fixable by buying a new engine part (is it the carb??) or is it unfixable and signals the end of the road?

It's a nice bike and I don't wanna see it go.

Thanks

General comments: As I have an NSR not a TZR. Firstly it will smoke when first started and for about the first kilometer or so. It's got oil injection? Correct? Have you put any oil in the gas/petrol tank? The only oil it can burn is either in the petrol/gas or in the oil tank. If you haven't put oil in the gas then you need to get the oil injection system calibrated (involves adjusting the cable. The other cause could be that it's running too rich , proabably caused by the air filter being clogged. First drain all the gas/petrol out and refill with normal gas/petrol. Go for a long hard ride at least a mile or two at as high a speed as you can. Two strokes are like thoroughbred horses they need to be ridden hard. if that doesn't cure it.

Go to the nearest Yamaha main dealer which has a workshop and get the air filter replaced, the spark plug replaced, the oil pump adjusted and probably now the exhaust cleaned out. Oh and from now on only use Shell Advance VSX two-stroke oil. It's in the black can at the Shell station or 7-11.

Edited November 7, 2007 by VocalNeal

[mikethevigoman]

I think New piston rings as said above... But when you say

it's burning oil like something else

do you mean engine oil or 2 stroke oil?

If engine oil definetly the rings...

May get away with re-using the old piston too... carb shouldnt make it smoke.

If 2 stroke oil then you have a problem with the feeder, maybe the cable to the 2 stroke feed is sticking and its stuck open all the time??

Good Luck...

Idont think you will find 2 strokes have engine oil, its lubricated by the 2 stroke oil, gearbox has oil, but it wont be that,it will be injecting too much oil from its independant tank or needs a ring , hone or bore, thats all ,and give it he1l. cost should be about a round of drinks in thailand i would think !

[Thanh-BKK]

Hi.

There's a bunch of possibilities here.

First, does the bike have the YCLS system (Yamaha Computerized Lubrication System), it's a black round thing sitting beside the carb with oil hoses and electric wires going to it. This can be faulty.

Next - oil pump. It could be faulty or just wrong adjusted - DO NOT ADJUST THIS YOURSELF, if you set it too low, the engine may starve of oil and seize up.

Next - the oil itself. Many two-stroke drivers use cheap 15W40 four-stroke engine oil. While it essentially does the same job just fine (lubricate!), it is not designed to burn well and creates lots of smoke. Use only good quality two-stroke oil - my recommendation (after 20.000 kilometers on a Yamaha RXZ with it!) is Castrol GO 2T.

Next - engine condition. Worn out piston rings make for a lower compression ration, poor power development and poor combustion. This too may cause excess smoke as the oil needs a certain temperature to burn cleanly (hence the usual smoking when the engine is still cold). Same goes for old or wrong type spark plug.

Next - AIR FILTER. Very important! If dirty, engine gets not enough air to burn clean. Result - poor power and poor combustion and - smoke!

Next - oil sealant ring (what is it in english? Simmering in German, it seals a turning shaft against the environment) on crank shaft to clutch side of gearbox. If damaged/worn out, gearbox oil (usually just SAE 40) will be sucked into crank case and burned by engine, result - smoke. This generates a typical smell similar to when using four-stroke oil.

Next - Exhaust. If it is full of carbon, this too will cause excess smoke. There is a simple method of clearing the exhaust if it is a powerful bike like the RXZ or NSR - go on a long, straight road and really WHACK the bike for some kilometers, full speed/high RPM. This will cause the carbon in the exhaust to start burning off, at some stage you will feel the power decrease somewhat and when you look behind you will see you are trailing sparks and dense smoke - this is the exhaust burning clean. Keep racing, it will take 4-5 kilometers to "finish". You will notice that there is no more smoke and the engine develops more power, also the exhaust noise will be noticeably louder (part of the exhaust will be red-hot right after the drive). Important is NOT STOP THE ENGINE when stopping, let it run a minute to make sure all "fire" is out - if you just stop the engine and walk away, the carbon inside may continue burning and the bike may go up in flames! I have done this twice myself once in Germany with a 175cc Zuendapp and once here with the RXZ.

If all fails, have the bike checked by a mechanic. If you live close to Phra Khanong, there is a small shop where they know all about Yamaha two-stroke engines. can find pretty much all spare parts and do their work quick and cheap. They can speak english too.

Best regards.....

Thanh