05 YZ450 oil in engine only quantity question

I've got an '05 YZ450.. that was formerly a factory Yamaha race bike! For real it has a factory Yamaha race frame with NO vin numbers or markings, and NO oil inside the frame. Yes, there are no oil lines coming out of the bottom front rectangle downtube of the steel frame, and there is no dipstick that screws in.. on the left side just behind the steering neck.


The engine hole for oil tube connection has been plugged with silicone.



So, the engine oil quantity I have is what is stored in the engine only, and I have no way to properly 'check' the level.


I just drained the oil (I had changed it once before, and I seem to remember it was something like 750ml I had measured drained out previously but I may be off).

Drained all the oil into a regular full size paint-cup (if you're an automotive painter).. it filled the cup to the brim and overflowed just slightly on the ground. I think that paint cup completely full is over 850ml?


So my question is what quantity of oil should I re-fill my engine(only) with!?


Whatever number I come up with being correct first, I am going to add 100ml to because I'm now installing a SFB racing clutch cover I obtained which allows the engine to hold 100ml more oil..


My bike is supermoto on 17" sportbike tires and becoming street legal now, what is a good service life of this low quantity of oil in the engine only? Change oil every 750-1,000 miles? And change oil filter every 3rd oil change AT LEAST? I'm sure I'll stay on the safe side of things.

See if it has a sight glass on the left side of the crankcase below the output shaft.  It would be where the neutral switch would usually be.  What's been done is called a "wet sump kit" conversion.  The return pump is removed, a special oil pump plate installed, and the bike becomes a wet sump instead of dry.  It also looses 40%+ of it oil capacity, so it's not a great idea for a play bike.  You really do have to change the oil every ride to keep it in good shape because there's so little of it.

What is your definition of a 'ride'?

8hrs of play on the bike?


See, this WILL be a street legal bike, for street duty and VERY LITTLE dirt/trail use if any.

I know its not ideal..

but I'm just installing a Boyesen Supercooler now, I just installed new bigger aftermarket radiators, I'll be running Engine Ice coolant, and I have a Trail Tech Vapor computer to monitor engine temperature. I don't think that engine temp will be a problem (I'll install a small 12v radiator fan if I see it necessary with stop-go traffic). I run Yamalube 10-50 semi-syn.


I figure at most I would change oil every 500 miles?

My oil, which I changed once then went on a few rides with, just drained pretty clean.. I'd almost re-use it a bit longer.


When I get to my shop tomorrow I'll see if I can find a sight-glass in that location.. but if not, what is a realistic oil quantity to expect needing in the wet-sump engine!?


At least at 500.  I would suggest starting there, and sending off a sample of the used oil to Blackstone Labs for analysis.  That will give you much more solid info to operate on.  Pay particular attention to the actual measured viscosity of the oil vs. its rated grade.

Oil change with filter is 1.16 qts as listed by dealer

That's about 1097.77 ml of oil

-40% = about 658.66 ml of oil remaining (for my wet-sump setup, but not sure how much +/- that should be)


JEEZ, I feel so strongly about the 750ml number I drained before... 

What I just drained out this time (filling and overflowing that paint cup) seems to be closer to 950ml!!

Crap, I can't recall, maybe I overfilled slightly to be on the safe side last time..

And also i didn't change oil filter last time, but did this time.


Either way, I have 100ml greater oil capacity now, I couldn't see myself filling any LESS than 760ml honestly.. probably closer to 800 or 850 ml !?!?!?!?!?


I do NOT have a sight glass, there is just a black plastic plug where that neutral switch would go underneath the output shaft.

Is there an aftermarket place I can buy the sight-glass? Is that even the correct level for sight glass to be installed? Is my bike leaning more forward now anyway, with 17" supermoto wheels front and rear instead of stock dirt bike?

so many questions


I wouldn't be opposed to converting back to a stock oiling situation later

Alright, contact Dubach Racing Development and find out if they still offer the site glass they used to sell.  40% was a number that applied to the steel YZ450.  That bike had an oil capacity of 1.1L with a filter change, or 1.0L without.  1.6 liters is the capacity of a 426.

Alright, contact Dubach Racing Development and find out if they still offer the site glass they used to sell.  40% was a number that applied to the steel YZ450.  That bike had an oil capacity of 1.1L with a filter change, or 1.0L without.  1.6 liters is the capacity of a 426.



yeah that's what the dealer just told me, for '05 steelie, 1.16 quarts for oil/filter change.


I imagine that sight glass will get me in the close range, EVEN if my bike is leaned slightly different than a stock 450 on dirt bike rims..

Found old thread


it was 34 oz of oil I drained the first time


so that comes in at about 1,000ml


I'm thinking now I should add 100-200 more ml than the 800ml I just filled..

I'd like to see you run as much oil as possible, but I don't know how much that is.  An excess has nowhere to go but up, and when it gets high enough for the crank to dip in it even occasionally, it can cause oil burning, a lot of deposits, oil out the vent, fouled plugs, etc.


The biggest number I remember seeing posted for oil capacity on a wet sump conversion is 650-700cc

What does the special plate look like? What is the purpose of the plate?

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