05 RMZ 450 buring oil

Mophuka · Oct 8, 2006

like the title says, I have a 05 RMZ that is burning oil. what can cause this? any help would be great.. haven't had a chance to look into the engine yet. bike still has compression but haven't checked it to see how much..

biglou · Oct 8, 2006

Rings, valve guides. That's all I've got...

Rich Rohrich · Oct 8, 2006

After about 15-20 race hours these engines will start burning oil from ring wear. Sounds like it's time for a top end.

Roma · Oct 9, 2006

burning oil on 06 too

I have to say my 06 does this too. It makes me feel uncomfortable to see it go down so quick. 2 rides and you are 1/4 of a quart down almost. That is just not right. I thought this was fixed in 06? Anyone else having this problem?

Rich Rohrich · Oct 9, 2006

Most four-stroke engines are designed with a piston that carries two compression rings and an oil ring package (two thin rings seperated by a spacer) . The second compression ring on these pistons really serves more as an oil scraper than a compression ring. This second ring scrapes oil off the cylinder wall which helps prevent it from slipping by the top compression ring and burning in the combustion chamber. It's a common trend for ultra high speed engines to use only a single compression ring and the oil ring package in an effort to reduce friction losses and to allow the piston to be as short and light as possible to permit the high speeds these engines can safely run at. The RMZ engine is designed with this current engineering thinking and only uses a single compression ring. When the engine is cold it is difficult for the single compression ring to stop all the oil. This situation is at it's worst when the engine is new, but it will always do it to some degree even when the engine is broken in. Single compression ring four-strokes always tend to use more oil then their dual ring competitors. Using a little bit of oil in exchange for performance is a good trade off in the long run for most of us.

Once the single compression ring starts to wear they start to leak like a sieve, and the only fix is to replace the rings and maybe the piston.

All the blather on the internet about special break-in procedures fixing this, is just wishfull thinking. The OEMs can change the ring face coating and help it last a bit longer, and some may work better than others but as long as there is only one compression ring you are going to use some oil.

Mophuka · Oct 9, 2006

thanks for the info guys. was hoping that the engine wasn't going to blow soon. going to do a compression check to see how bad things might be then I will check the valves while I have the tank off. then do a top end rebuild. does anyone know if there are any aftermarket companies that sell different pistons for the bike that might correct this problem?

Roma · Oct 10, 2006

Nicely explained. No other problems w/ RMZ that I can find.

Rich Rohrich · Oct 10, 2006

Roma said:
Nicely explained. No other problems w/ RMZ that I can find.

There are definitely other issues but they seem to crop up mostly with the really fast guys who race them every weekend, or guys who ignore the maintenance schedule.

Here's a thread that goes into some of the cam, cam chain tension and valve spring issues.
http://www.dirtrider.net/forums3/showthread.php?t=126625&highlight=rmz450

Mophuka said:
does anyone know if there are any aftermarket companies that sell different pistons for the bike that might correct this problem?

I haven't seen any aftermarket pistons with two-compression rings, which is the only "fix", if you can call it that. Most aftermarket companies try to avoid de-engineering an engine for reliability over power. It can be tough to sell components designed for a race bike that are biased towards reliability and lower rpm running rather than power.

Mophuka · Oct 10, 2006

I have looked at a few aftermarket companies but couldn't find anything. so I picked up a new set of rings and gaskets for $50.00. not too bad.

Rich Rohrich · Oct 10, 2006

It's a really easy engine to work on so you'll find maintaining it to be pretty straight forward. In the hands of the average weekend racers they seem to be holding up pretty well. Cam chain tension is the one area that you really need to keep a close eye on though.

Mophuka · Oct 10, 2006

thanks for the helpful hints.

06450F · Oct 10, 2006

Can anyone give some insight into valve lash? If the valves clearance became extremely tight or loose could this cause the motorcycle to smoke? If not any clue to some other common symptoms when the valve lash is out? Hard starting, loss of power, etc???
Any insight would be greatly appreciated.
-Peace out my brotha's-

biglou · Oct 11, 2006

06450F said:
Can anyone give some insight into valve lash? If the valves clearance became extremely tight or loose could this cause the motorcycle to smoke?

Nope. Not by itself, unless there were other things going on.

06450F said:
Hard starting, loss of power?

Yes. Worn rings could cause this also.

ps2112 · Oct 16, 2006

Somewhat on this same topic. My '06 takes 1650 cc's to get the oil to come out of the check hole after oil and filter change. If this is indeed overfilling will it harm anything? It does go through aboout 100 cc's every 2 hours or riding.

Mophuka · Oct 16, 2006

well I redid the topend. put a new set of rings in and checked the cylender for wear then checked the valves. buttened it all back together but still smokes when I start it up. after it warms up it doesn't smoke anymore. what can cause this. before it would smoke all the time, now it only smokes when it is cold. could this be a worn valve guide? doesn't seem to be hurting preformance, but don't want some major problem arising because of this. I will have to keep an eye on the oil level. also adjusted the cam chain adjuster while I was working on it.

CRF_450GUY514 · Oct 16, 2006

Rich Rohrich said:
Most four-stroke engines are designed with a piston that carries two compression rings and an oil ring package (two thin rings seperated by a spacer) . The second compression ring on these pistons really serves more as an oil scraper than a compression ring. This second ring scrapes oil off the cylinder wall which helps prevent it from slipping by the top compression ring and burning in the combustion chamber. It's a common trend for ultra high speed engines to use only a single compression ring and the oil ring package in an effort to reduce friction losses and to allow the piston to be as short and light as possible to permit the high speeds these engines can safely run at. The RMZ engine is designed with this current engineering thinking and only uses a single compression ring. When the engine is cold it is difficult for the single compression ring to stop all the oil. This situation is at it's worst when the engine is new, but it will always do it to some degree even when the engine is broken in. Single compression ring four-strokes always tend to use more oil then their dual ring competitors. Using a little bit of oil in exchange for performance is a good trade off in the long run for most of us.

Once the single compression ring starts to wear they start to leak like a sieve, and the only fix is to replace the rings and maybe the piston.

All the blather on the internet about special break-in procedures fixing this, is just wishfull thinking. The OEMs can change the ring face coating and help it last a bit longer, and some may work better than others but as long as there is only one compression ring you are going to use some oil.

I have a 2003 CRF450 and it has countless hours on it I am using a JE 12:5.1 piston and it doesn’t burn any oil at all, I here what your saying about the single compression ring but the crf450's are the same. I think this oil burning you are getting could also be from a improper brake in, if you just baby it OR use synthetic oils at brake in then the rings wont seat in very good. Also probably the most important thing for brake in is that you have the cylinder honed before you put your new piston in, the shaper cross hatch pattern will help the rings seat in better. Allot of people think that its just the ring tension keeping the gasses from blowing buy the face of the ring’s well that’s RONG, the gases are trying to escape and actually push the ring agents the cylinder with tremendous force. This is why you don’t want to baby the bike at brake in because the rings won’t be pushing up agents the new cross hatch pattern as hard and will not wear in fast enough before the cross hatch pattern dulls.

06450F · Oct 17, 2006

As Mophuka stated. He got the top end all rebuilt but his bike does still smoke at start up and warm up. Now granted the machine performs great.....but still my question and im sure Mophuka (pernounced...Mo ****a.....as in Mutha Pucker,ehehe) is that his machine has been rebuilt up top.....shouldn't this have solved the smoking?

I (we) understand a little bit of smoking while cold is normal. All of my street bikes do it, and so does my KX450F. But it only smokes a tad and only when rev'd a decent amount while very cold. His RMZ450 is still smoking enough while cold to leave that little lingering wonder in the back of his (and my) mind.

Rich Rohrich · Oct 17, 2006

Mophuka said:
well I redid the topend. put a new set of rings in and checked the cylender for wear then checked the valves. buttened it all back together but still smokes when I start it up.

Did you hone the cylinder when you had it part?

CRF_450GUY514 · Oct 18, 2006

06450F said:
As Mophuka stated. He got the top end all rebuilt but his bike does still smoke at start up and warm up. Now granted the machine performs great.....but still my question and im sure Mophuka (pernounced...Mo ****a.....as in Mutha Pucker,ehehe) is that his machine has been rebuilt up top.....shouldn't this have solved the smoking?

I (we) understand a little bit of smoking while cold is normal. All of my street bikes do it, and so does my KX450F. But it only smokes a tad and only when rev'd a decent amount while very cold. His RMZ450 is still smoking enough while cold to leave that little lingering wonder in the back of his (and my) mind.

Please re read my last post, just cuz he put a new top end in it isn’t going to guarantee anything, if he didn’t take the rite steps. The cylinder MUST be honed; this is something that can’t be over looked especially with a signal compression ring piston. Also synthetic oils at brake in are a big NO NO.

Mophuka · Oct 19, 2006

didn't have the cylinder rehoned. looked in the cylinder for wear marks but neglected to have it rehoned. guess that could explain the smoking problem. this is the first time I have done this to a 4 stroke bike and I still have some stuff to learn. Used regular oil. staying away from the synthetic stuff for a now.

could not having the cylinder rehoned cause any damage in the future. I planned on going through and rechecking the valves in the next 15 hours. being that I will have the engine apart I could easily redo the rings and have it rehoned. or should I get this done ASAP.....

thanks for the help...

Rich Rohrich · Oct 19, 2006

Mophuka said:
didn't have the cylinder rehoned. looked in the cylinder for wear marks but neglected to have it rehoned. guess that could explain the smoking problem. this is the first time I have done this to a 4 stroke bike and I still have some stuff to learn. Used regular oil. staying away from the synthetic stuff for a now.

could not having the cylinder rehoned cause any damage in the future. I planned on going through and rechecking the valves in the next 15 hours. being that I will have the engine apart I could easily redo the rings and have it rehoned. or should I get this done ASAP.....

thanks for the help...

Honing the cylinder will clean old burnt oil from the cylinder walls and change the surface texture to something more appropriate to seat the new rings. Suzuki plating is very hard so it generally takes a multi-shoe diamond hone to get an effective surface finish.

Don't worry about using synthetic oil in your engines. The myths people have spread about seal problems from synthetics are largely unfounded once the cold hard light of logic is shined on them. The same goes for that "hard break-in" and dry break-in nonsense. Anyone who has ever spent anytime looking at rings under high power magnification, and examined a cylinder before and after with a Surface Profilometer can tell you that the factory suggestion for break is a good one.

If you get the cylinder properly honed, and a final plateau finish is applied to the bore, the break-in for the rings is almost immediate, so it's a non-issue. That's reason enough to get the cylinder honed properly. ;) You get back to riding sooner.

You won't hurt anything leaving the engine as is till it's time for a new set of rings. You might get a bit more leakage past the rings than you would in a perfect set up, but it's a 450 so the power difference will go largely unnoticed unless you are really sensitive or really fast.

Put good oil in it, and go have fun riding it. :cool:

CRF_450GUY514 · Oct 20, 2006

Don’t get me wrong I to use synthetic oils after brake in and I strongly recommend them. The first season of riding my crf I used standard pro Honda 10w40 and at the end of that season when I took my top end apart I noticed almost all of the black coating had wore off. After I put my new stock piston back in I switched to AmzOil motorcycle spec 10w40 oil after brake in and continued using it for a full season. At the end of that season I took my top end apart like I do every season and noticed NONE of the black coating had wore off. I still have both pistons today to show people the difference synthetic oils make; both of them were used every weekend for a full Canadian season of ridding and have about the same amount of time on them.

As for brake in I don’t believe that a wide open brake in is the way to go, I personally found a medium brake in is the way to go. I have baby’d my bikes before at brake in and noticed Blow by on the piston at the end of the season yet when I do a medium brake in I don’t get any blow by at all. I’m just telling you guys and girls my experiences, I’m in no way an expert, but I have bin rebuilding my own engines for 10 years now. I have found no diff in wet vs dry assembly of the top end. I change my oil every ride most of the time.

Mophuka · Oct 20, 2006

thanks guys for the helpful info. like I said I have alot to learn about this 4 stroke business, but getting this helpful info from people with experience with them is priceless. thanks again...

05 RMZ 450 buring oil

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