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Yamiryder

07 yz450f piston life time

47 posts in this topic

Hey guys, I'm considering buying an 07 yz450f that the owner "claims" has 20 hours on it. I'm not new to bikes, and if i go look at it, i'll be able to tell if it really only has 20 hours. Anyway, i'm curious as to what your maintenance intervals are. I do all sorts of riding, but if i get the bike i'm going to do an AWRCS race that is 3 hours long. The regular maintenance i would do is clean the air filter every 2 or 3 rides and change the oil every 4-6 hours and change the oil filter every other oil change. If i do this, how long should i expect a piston to last and how often should i be expected to shim valves? sorry about the long post, thanks!:cheers:

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I bought my 07 450F last January. Had about 50 hours on it. I had the valves adjusted and timing chain replaced. Have no plans to do anything else besides oil changes and and filter cleanings for a while.

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It's going to blow up
Really? Why hasn't mine, with 150 hours on it? Why didn't my son's with over 200? Or my '03 with over 400?

Why does your opinion in this post differ from your last post on the subject?:

Lol I know a few people with well into 150 hours on a yz450 piston and the bikes only go to the tracks and they run perfect, change your oil, you'll be ok. Or possibly you could get James Stewart to steal you one :cheers:

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Really? Why hasn't mine, with 150 hours on it? Why didn't my son's with over 200? Or my '03 with over 400?

Why does your opinion in this post differ from your last post on the subject?:

Easy because it was a joke, derrrrr

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I'm not stupid. i know it's not going to blow up. I'm just curious as to how often guys with 06-09 yz450's check valves and replace the piston....if it blows up with 20 hrs on it, we have a problem

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The regular maintenance i would do is clean the air filter every 2 or 3 rides and change the oil every 4-6 hours and change the oil filter every other oil change. If i do this, how long should i expect a piston to last and how often should i be expected to shim valves? sorry about the long post, thanks!:cheers:

I clean my airfilter every ride. The airfilter gets dirty pretty fast.

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i clean my air filter every other ride, i am probably too nice to it too. i could drag it out longer. i would check valves right now. if they are fine then dont check them for another 75 hours. you could definitely get away with more then 4-6 hours for each oil change. i know a guy who changes his oil twice a year on his 06 250 sx-f. (im not recomending this) and his bike has ran fine with a new top end every 150 hrs and valve checks every 50. i usually go about 12 hrs for every oil change and change filter every other oil change. if you do what you say you are gonna do except the air filter. maybe you should do it every 2-3 rides. then i think your piston should last you well over 130 hours more then what it has on it right now.

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Certain non-synthetic oil can get up to 5hrs of use or with some high grade full synthetic oil you could get 8hrs. Keep in mind these bikes share the oil with the motor components and transmission.

Edited by KJK_JR

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thats for dirt bike fanatics. do you put oil in every 5 hours on a street bike? no. synthetic will get more but it probably goes about 8 for regular oil. 10 for semi synthetic and 13 for full synthetic...thats for normal people not racers or total enthusiasts. and btw oil doesnt go bad when its black read this article http://www.motor-oil-engineers.com/oilcolor.htm

this scientific study is contrary to what most people think which is when it looks dirty it is dirty

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thats for dirt bike fanatics. do you put oil in every 5 hours on a street bike? no. synthetic will get more but it probably goes about 8 for regular oil. 10 for semi synthetic and 13 for full synthetic...thats for normal people not racers or total enthusiasts. and btw oil doesnt go bad when its black read this article http://www.motor-oil-engineers.com/oilcolor.htm

this scientific study is contrary to what most people think which is when it looks dirty it is dirty

Street bikes aren't exactly dirt bikes.....I never said anything about black/dirty oil being bad. Anyways oil has a certain level of viscosity that is lost with use. Since these yzf's share their oil with the engine and transmission, viscosity levels diminish quicker than those of a crf or ktm that have separate engine oil and transmission oil. If you dont believe me send out your 15hr used oil (from your yz250f) to get tested and see what the results say.

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Synthetic vs. petroleum base has little or nothing to do with whether the oil can be run for any length of time in a YZF. High grade true synthetics (as opposed to Group III oils like the original Castrol SynTec) are actually far more temperature tolerant and resist oxidization better, but the oil rarely lasts long enough for that to become the issue with engines that share oil with a transmission.

Multi-grade ENGINE oils blended for automotive applications are almost never blended with viscosity index improvers (the additives that enable the 10 weight base oil of a 10W-40 to behave like a 40 weight when it's heated to 200 degrees) that are capable of surviving any length of time when used as a gear lube. Rotella T Syn, as an example, is an excellent commercial graded truck engine oil. Starting out at 5W-40, when used in a YZ450, it will shear down into no more than a 5W-25 in two hours time, whereas Golden Spectro 4, a synthetic/petro blend, will last 3 times that long at least.

The killer is virtually always viscosity retention in the face of shear loads imposed by the transmission, and oils not blended to withstand that can't be expected to hold up nearly as long as you suggest. Send out a sample of your own once and examine the results. Look at the measured vs. grade viscosity at 200 degrees.

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Street bikes aren't exactly dirt bikes.....I never said anything about black/dirty oil being bad. Anyways oil has a certain level of viscosity that is lost with use. Since these yzf's share their oil with the engine and transmission, viscosity levels diminish quicker than those of a crf or ktm that have separate engine oil and transmission oil. If you dont believe me send out your 15hr used oil (from your yz250f) to get tested and see what the results say.

whats the point? i have an 02 and it runs like a top. and i actually get longer piston life then my buddies. this bike has been run like i told you for 9 years with a new top end every 150 hours and air filter every 2-3 rides and oil every 13 hours, checking valves every fifty, and greasing everything up once a year and is still a very good running bike but you are definitely correct about getting less life then a crf or ktm. my dads ktm gets about 20 hours. (not riding hours, actual engine hours)

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Synthetic vs. petroleum base has little or nothing to do with whether the oil can be run for any length of time in a YZF. High grade true synthetics (as opposed to Group III oils like the original Castrol SynTec) are actually far more temperature tolerant and resist oxidization better, but the oil rarely lasts long enough for that to become the issue with engines that share oil with a transmission.

Multi-grade ENGINE oils blended for automotive applications are almost never blended with viscosity index improvers (the additives that enable the 10 weight base oil of a 10W-40 to behave like a 40 weight when it's heated to 200 degrees) that are capable of surviving any length of time when used as a gear lube. Rotella T Syn, as an example, is an excellent commercial graded truck engine oil. Starting out at 5W-40, when used in a YZ450, it will shear down into no more than a 5W-25 in two hours time, whereas Golden Spectro 4, a synthetic/petro blend, will last 3 times that long at least.

The killer is virtually always viscosity retention in the face of shear loads imposed by the transmission, and oils not blended to withstand that can't be expected to hold up nearly as long as you suggest. Send out a sample of your own once and examine the results. Look at the measured vs. grade viscosity at 200 degrees.

im sorry i have no idea what youre talking about. could you put it in a little simpler words...not being a smart ass, i swear im being honest

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Synthetic vs. petroleum base has little or nothing to do with whether the oil can be run for any length of time in a YZF. High grade true synthetics (as opposed to Group III oils like the original Castrol SynTec) are actually far more temperature tolerant and resist oxidization better, but the oil rarely lasts long enough for that to become the issue with engines that share oil with a transmission.

Multi-grade ENGINE oils blended for automotive applications are almost never blended with viscosity index improvers (the additives that enable the 10 weight base oil of a 10W-40 to behave like a 40 weight when it's heated to 200 degrees) that are capable of surviving any length of time when used as a gear lube. Rotella T Syn, as an example, is an excellent commercial graded truck engine oil. Starting out at 5W-40, when used in a YZ450, it will shear down into no more than a 5W-25 in two hours time, whereas Golden Spectro 4, a synthetic/petro blend, will last 3 times that long at least.

The killer is virtually always viscosity retention in the face of shear loads imposed by the transmission, and oils not blended to withstand that can't be expected to hold up nearly as long as you suggest. Send out a sample of your own once and examine the results. Look at the measured vs. grade viscosity at 200 degrees.

Okay so your saying the amount of "viscosity index improvers" in an oil determines how long it will last in a yzf?

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Okay so your saying the amount of "viscosity index improvers" in an oil determines how long it will last in a yzf?
No. VII's are long chain polymers that prevent oil from thinning as it heats. It is the physical toughness of the VII's that matters.

First, oil heats up, oil thins out. Originally, you were stuck with that. You had a choice of running an oil that was heavy enough to protect a hot engine when it was hot, and hoping it didn't get so thick when it got cold overnight that it refused to flow, or an oil thin enough to circulate right away on a cold start and hope it didn't turn into water on the freeway.

To cure that problem, multi-grade oils were created. Taking a 10 weight base oil, VII's are added so that it no longer thins out as much as it used to when it gets hot. The Viscosity Index of the oil is a measure of how much the viscosity changes as it heats, and the higher the number, the less change there is. If the oil is now heated to 200 degrees, and is still as thick as an unmodified SAE 40 weight, then the oil is labeled as a 10w-40.

So what is the problem with lubing gears? VII's are big things on a molecular level. They are large, long, complicated molecules that tend to curl up when cold and uncurl when hot to become bulkier, thus thickening the oil. They are so large, in fact, that when the oil is pressed between two loaded gears, they tend not to fit in that reduced space very well, and they get physically torn apart. Since their effectiveness in preventing the thinning of hot oil depends on them being big and long, they no longer do anything once shredded by the gearbox, and you're back to the 10 weight you started with in no time.

To solve this new problem so that multi-grade gear oils could be made, tougher polymers were created that would resist the shearing the trans dishes out. Like many things that are better, these tougher VII's cost more, so oil blenders who are building an oil that's going to be sold as an engine oil are not going to be disposed to pay up for the extra protection that that they don't need so that one in every 100,000 customers can run cheap oil in his Yamaha. Blenders of top quality motorcycle oils started catching onto to this issue about 8 years ago, and more and more are adding the tougher, gear oil grade VII's to their oils.

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so the oil is better now is what you are saying?
No. Some of the correctly blended motorcycle specific oils are better.

You were the one waving the "scientific study" around a bit ago, right?

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yes i was the one. please dont bag on it, i am not in the mood right now. and oh yeah well i use the motorcycle oils. i dont know why anyone would use car oil or anything like that in their bikes

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