Yamaha QT

I just got a Yamaha QT with a build date of 5/84. It has been sitting for many years. I got it to run but I want to change the oil before using it. The engine says 300cm3 on it. That equals about a third of a quart. Is there a way to check the oil level or should I just put a third of a quart in and leave it? Also what type and weight oil is recommended? I also will new a new air filter element for it. Do they still make them? Where can I get one? I am looking forward to having fun with it. Any info would be greatly appreciated. Thank You

Re: Yamaha QT

Any info on the driveshaft oil would also help, Thanks

Re: Yamaha QT

That is the transmission... Just put the 300cc in it and leave it.

You can use any car motor oil (or ATF) for both the tranny and shaft drive unit.

Changing the tranny oil in these is not like changing the motor oil in a car.

Its more like changing the oil in the trans of your car... you don't have to do it very often... and its not very critical.

The oil in there never comes into contact with the crankshaft or main bearings or rod and rod bearings or the piston.

There is no 'motor oil' in a two stroke quite like a 4 stroke..

There is however.. oil in the 'under seat' tank.. which supplies the auto-lube oil injection to the motor.

Use 2 stroke oil in there.

Keep an eye on that oil level because it gets burned and consumed by the motor (slowly).

Re: Yamaha QT

Thanks Fred. Are the trans and driveshaft seperate or does one plug drain them both at the same time? I usually run 20W50 in everything. Do you think that will be too thick? Also where can I find an air filter element for it? Does Yamaha still sell them? Is there anyone online that might have them?

Re: Yamaha QT

Go to a Yamaha motorcycle dealer for Yamaha parts.

Online ?

I guess you can try




I don't know if the shaft and tranny are the same on it.

20w/50 will prob work fine.

Re: Yamaha QTno?

mike hartel /

what? any car oil will work and atf?NO thats not rite i tryed and it slips you have to have motercycle engin oil it has detergents in it for the clutch so it works properly.you can get it at yamaha and honda dealer 10w30 is what the yamaha dealer told me Mike hartel.

Oil.. here we go again

mike hartel wrote:


> what? any car oil will work and atf?NO thats not rite i tryed

> and it slips you have to have motercycle engin oil it has

> detergents in it for the clutch so it works properly.you can

> get it at yamaha and honda dealer 10w30 is what the yamaha

> dealer told me Mike hartel.

Nah... thats a bunch of nonsense Mike Hartel.

You tried what oil in what bike ???

First of all you would NEVER need MOTORCYCLE ENGINE OIL is the transmission of a 2 stroke .. OK ?

Why ?

because it doesn't go in IN THE ENGINE !!

It only goes in the transmission.

Motorcycle engine oil is designed for 4 stroke engines... the oil circulates around the cam shafts and crank and rods and pistons.

the oil in a QT50 tranny only touches tranny parts and the automatic clutch.

And the deterrgents in engine oil have nothing to do with any slippage in any clutch.

10w30 is the correct weight as specified by the manual... but they will use virtually any oil with no slippage... they really like ATF the best.

By the way... dealers are notorious for not having a clue what they are talking about... an experienced knowledgable person is the best source... so is the manual.

But experienced and knowledgable people know tricks tha manual doesn't allow for.

if you are going to argue... you tell me specifically what oil you put in what bike... and did it actually slip?.... or did the dealer just TELL you it would slip?

I mostly run ATF in two stroke trannies... but have run 5w30, 10w30, 10w40, 20w50 in them at various times... with a lot more HP than any QT50.. and they don't slip... I have even talked to people who used 90w gear oil in them... the first thing I asked when I heard that was... "Doesn't it slip ?"

The guy said... "NO... it works great!"

so... if your clutch slipped... its shot anyway.

Re: Oil.. here we go again

Ron Brown /


if you got $5.00 a quart, you would recommend MC oil too.


Re: Oil.. here we go again

egggggggggg zactly

And thats what sooo many people don't realize.

Re: Yamaha QT

Does the driveshaft take oil too or is it packed with grease?

Re: Yamaha QT

I really don't know... I have seen them.. but never worked on one.

Look for filler plugs and drain screws maybe ??

Re: Yamaha QT

Got your answers. Had some of the same problems. First, it takes good ol' 10W-30. Drain it really good, put 1/3 quart in until gets good and hot, then drain and refill. If still looking yuck-O, then repeat. Lot of contaminates will build up in there. Since sitting so long, would take the tank off, really easy on the QT50, 4 bolts and a brace. Clean out the tank the best you can and put a filter on the gas line along with a new petcock. Believe it or not, Yam dealers still have parts for this ped. Air filter will run you about 5 bucks. The battery you can get at JC Whitney, on the web also. Get new plug. You can also get new brake shoes at the dealer, at resonable prices. When the pads sit that long, they loose their binding to the metal plates and will disintegrate very quickly. Lube ALL cables and drain carb. bowl. Fact, take it off, you can do so with the carb. still mounted on this model. Just loosen the clamp from the carb. to the intake port and move it vertical. From there clean out both jets and slide choke. Might also want to pop the rear differential housing off and get some good grease on the gear. I use Mercruiser grease, good stuff. One last thing, see if you got smoke coming out of the exhaust, that means that your autolube pump is working. If not, you'll have to premix. It's rare the autopump will quit but the line may just clog up or air lock, remove line and drain. This ped will still crank up with no battery and the lights will all work once ped is running, even at full speed. It will not blow bulbs or fuses.

Peak speed should be around 25 to 28 MPH. This is also a two speed transmission.

Re: Yamaha QT

Thanks for the help guys. Scott, are you sure that new brakes are available at the dealer? The one near me said they were discontinued.

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