Why didn't Yamaha copy Honda?

30 replies to this topic
  • bashn

Posted June 21, 2002 - 05:39 AM


It appears Yamaha has failed to seperate the tranny oil from the engine oil ala Honda. Too bad, because this helps prevent clutch and gear debris from circulating through thoose precious cams and bearings in the top end! With reduced oil capacity, this is even more important, as it takes less time to contaminate a smaller quantity of oil. This idea is certainly not new. It was used on British bike 50 years ago. Any thoughts on this?


  • SUnruh

Posted June 21, 2002 - 05:42 AM


while what you say sounds good, think of this:

how many street bikes (that make WAY more hp) have seperate oil chambers for the clutch and crank?

even my honda cbr600f2 had just one.

  • yzernie

Posted June 21, 2002 - 06:00 AM


Originally posted by bashn:
Any thoughts on this?

Quite honestly, I think Yamaha knows what they are doing. Enough said.


  • Kirtwell

Posted June 21, 2002 - 07:03 AM


I'm no expert in the subject but how I saw it was the clutch fibers from the clutch are so small(microns) that the engine can tolerate that type of debris circulating. Of course not for a prolonged time. The oil needs changing per their recommendations.
Besides this is a race engine....meaning it's not designed for long life. It's designed for a high routine maintenance and replacement of worn parts on a regular basis.
I think Yamaha factored in all of the issues,
and probably didn't see it neccessary to seperate the oils.

Just my .02

  • therapture

Posted June 21, 2002 - 07:03 AM


Originally posted by bashn:
It appears Yamaha has failed to seperate the tranny oil from the engine oil ala Honda. Too bad, because this helps prevent clutch and gear debris from circulating through thoose precious cams and bearings in the top end!

that's why it has an OIL FILTER...you know the thingy you have to change every so often because it gets full of "clutch and gearbox crud"


Yeah, as sunruh stated, MOST engines share the same tranny and engine oil, again, hence the filter. It will harm NOTHING as long as you change oil at specified intervals and change the filter. It is cheap to do.

  • bashn

Posted June 21, 2002 - 07:47 AM


The last thing I want is to start a Honda/Yamaha flame war. I'm really trying to understand why Honda was compelled to design their engine this way. There is a vast difference between a real oil filter and the screens used in dirt bikes, as well as the oil change intervals, and volumes. The obvious advantage to seperate engine/tranny oil is the ability to optimize the oil type used for each purpose. Maybe it's a wasted effort, but why would Honda's engineers go through such effort if there were no real-world benefits? With the trend of lower oil volumes, I think it's important to extend the life of the oil as much as possible.

My YZ250F is not showing any signs of wear due to lubrication or oil contamination after 2 years of racing. I also run Mobil 1 synthetic oil without clutch problems. I only wonder how long the oil would last if I wet-sumped the engine and used only 750ml of oil.


  • 98yz

Posted June 21, 2002 - 08:02 AM


Unfortunately engineering gets caught in the trap that corporate and sales says "We need something different". Whether different is good, bad or indifferent, the engineers are forced to just flat out make it different. Sometimes changes are just simply that. Then the rest of us overthink the thing, rather than just accepting it. In my line of electrical engineering work we would do that quite offten.

Could be a possibility.


Posted June 21, 2002 - 08:14 AM


one benfit is you can run 2 diff types of oil. & 2nd is it will stop the clutch particles floating around in the engine. Bikes have had just one oil cavity for years but i think that separating them is better if possible... if not just change your oil like you are supposed too

my crf has almost no metal shavings in the filter compared to my 426 though.

having said that my old 426 went 2 yrs without a top end job & was running fine.. i sold it to some guy "who will remain nameless" & he decided to go run some cross country with a lose oil drainbolt :)

  • therapture

Posted June 21, 2002 - 09:45 PM


Originally posted by LOOPOUT:

my crf has almost no metal shavings in the filter compared to my 426 though.

having said that my old 426 went 2 yrs without a top end job & was running fine.. i sold it to some guy "who will remain nameless" & he decided to go run some cross country with a lose oil drainbolt :)

HEY!!! Stop that! :D

'ya gotta admit, I was smart though, as soon as I heard something funny I pulled in the clutch and hit the kill button all at the same time while blasting across the sand whoops in 4th gear, and saved the cams and head, all it needed was a new piston, rings, and cylinder...as a bonus I got a crash course in 4-stroke top ends and ended up rebuilding both my 426 and my pals beater 400!!!

  • westladog

Posted June 21, 2002 - 11:23 AM


Originally posted by yzernie:

Quite honestly, I think Yamaha knows what they are doing. Enough said.


Although I ride the red bike, I have to agree with Ernie.

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  • LopeMX

Posted June 21, 2002 - 12:03 PM


Yamaha logged a lot of 4-Stroke miles before releasing their YZF-400. I'm not positive but, I gotta believe that they considered alot of different configuations and came up with their design for a reason.
I ride my YZF-426 hard and change the oil often.
Except for the first two oil changes, I don't have ANY problems with dirty or contaminated oil.
I like both designs in the Yamaha and Honda. But for me, I'll stay with Yamaha.
It's always been kinda understood at the track, that Honda's have the motor. But they also had Headshake for years! If your looking for the Ultimate motorcycle in design and performance then I wish you GOOD LUCK!

  • SUnruh

Posted June 21, 2002 - 12:40 PM


if you would like to see what a single oil cavity can do to a bike with 1000 race miles and another 1500 practice/play miles on it look here
granted, it's just a 250F and it only revs 2000 rpm more than a 426, but you'll understand. :)

  • Fireballsocal

Posted June 23, 2002 - 09:31 PM


Sunrah, looks damn good to me though I'm no expert. Are exaust ports normally that dirty? There wasn't a whole lot of crap but it would seem to impede the exaust flow. Everything else looks sweet! There is still a very pronounced crosshatch on the cylinder walls. Are you sure you didn't hone it before that picture? :)

As to Bashn, I think the guy that said honda was trying something different was right. You bought it hook line and sinker and so would I if I was shopping for a MX bike. The fact is that the wear just isn't that much of a problem. My 99 is still on the original top end and even though it has lost some compression, it still runs great. I trust it enough to take it out to BFE where I have to be able to ride back cause the truck can't get out that far.

  • sirthumpalot

Posted June 23, 2002 - 09:50 PM


I'm sure that both Honda and Yamaha have very good reasons for doing it the way that they do. I would love to hear from some engineers which worked on these bikes to hear some of the reasons that they went the way that they did. I'm not going to speculate. That said, bikes have been sharing oil between the motor and tranny for years and it obviously hasen't been a problem to this point so for me it's a non-issue between the two bikes. On the Honda you have to change 2 oils, on the Yamaha you have to change oil in 2 locations (motor and frame) so either way you're screwed. :D At least with the Yamaha I only have to buy one type of oil. :)

  • yankee

Posted June 23, 2002 - 01:15 PM


Things to think about when comparing bikes:

1. The crf450 has about 5 times less engine oil than the yzf. 2.5 times if you combine the crf's tranny and engine oil.

2. Engine and transmission oil are vastly different.

  • DethWshBkr

Posted June 23, 2002 - 05:23 PM


Agreed, they should have separate engine and clutch oil. ALL BIKES should. Even my
02 HONDA 954 has one oil. I've got 154 at the crank, 130 at the rear wheel, revving up to 11500 (red-line), and only one oil.
You'd think they would make all motorcycle oils separate. Then you could use synthetics, without ANY clutch problems.

Oh well, I've never had an engine blow, so I guess it's fine!

  • osheen

Posted June 23, 2002 - 06:02 PM


If an engine can live under severe conditions without separating the oil then why do it?

Example- I used to work at a Kawie dealer years ago. The local police department had a KZ1000 police bike with upwards of 70,000 miles on it and it still ran great. This bike spent 99.99% of it's life going extremely slow in town under 100 degree heat. The oil was changed every couple thousand miles or so. Sure it didn't have to spin 13,000 rpm, but it was most certainly abused.

There are some advantages to separate oils, but it isn't required to do so to make the engine last. I'd say that if you analyzed every YZ-F engine that has failed since 98 you would find that none were a direct result of combined oil.
You would find however that damaged was caused by- running out of oil, not changing the oil enough or at all, over-revving, manufacturing defect such as poor heat treatment or plating, freak mechanical failure and so on.

I think alot of guys are real paranoid about the whole deal. If you change your oil often even using generic motor oil, by the time you wear the engine out, the rest of the bike will be such a roach that you might as well throw the whole thing away anyway..............

  • Ga426owner

Posted June 24, 2002 - 04:11 AM


Guys, if you change your oil like you are suppose to. Then this separate oil issue is mute! The filter catches the particles. I see no advantage unless you are not going to change your oil as specified by the manufacturer.

  • Shawn_Mc

Posted June 24, 2002 - 07:11 AM


I think the point of separate oil chambers is totally lost on the crowd here.

The separate chambers allow two extremely different oils to be used in areas that in a perfect world, have very different requirements.

The "Engine" portions of the motor really want slicker oils, with friction modifiers. The trans and clutch do not want these things at all. Actually, if you could separate the clutch from the trans, you could get an even better senario. How many GP road racers run dry clutches? All of them. Not only do they have two separate chambers but the clutch is out of the mix also.

What ever you say, its a better idea to separate the engine oil from the trans if the bean counters will allow it. Yamaha didn't do it for cost reasons. Honda didnt do it to be different, they did it because they had a clean sheet of paper, and the bean counters had been put in they're places prior to design approval.
If you think the separate chambers are a gimmick, your mistaken.

  • osheen

Posted June 24, 2002 - 07:14 PM


The point is- is that it doesn't matter. All the engine and trans care about is that there is some clean liquid being tossed around in them. They don't mind sharing.
I agree that it would seem that separate oils would be better but in the real world if they last for years and years with one oil then what is wrong with it?

Prove to us that an engine with separate oils will last longer or perform better. Give us the results after you do your testing and have some facts to support your opinion.

Also, what makes you think that the bean counters had anything to do with it? Yamaha made new cases for the 450. They could have easily changed it to a wet sump had they wanted to. Cost didn't have anything to do with it.

I think alot of the reason Honda separated them is because us gear heads are more concerned about the oil we put in our bikes than we are about the food we eat. Honda is just giving the buyer what he thinks he needs.

Let's all head to Jack in the Box for a triple cheese burger and discuss it some more.......


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