1980 Yamaha GT 80 fluid basics

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May 6, 2007
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#1
Hi,new to here and to bikes.
Just bought a good running GT 80.Before I ride it anymore,I was hoping somebody could clarify some things.

Gas,what is the ratio 40:1? which oil?

The crankcase has a 500ml oil fill mark,what type goes in here?EDIT sorry,guess that is the tranny.gear oil??

Up higher sits a little tank,with a filler and small window,I assume that oil is suppose to be in there also? Its almost dry.What type goes in here?

The chain is awfully loose,pops off on rough trail.Adjustable or ned new one?

I am working to get a manual for it,anybody have any online links?
In the meantime any help to keep this thing from burning up are much appreciated :cool:
 
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#2
greensierra said:
Hi,new to here and to bikes.
Just bought a good running GT 80.Before I ride it anymore,I was hoping somebody could clarify some things. thats awesome was my first bike

Gas,what is the ratio 40:1? thats the oil to gas ratio , get a RATIO-RITE cup from your dealer so you can mix it correctly

which oil?
injected - tank on side of bike under side cover
pre-mix- oil/gas mixed in tank
make sure ya get the correct oil for whichever it has (pre-mix or injected, they are DIFFERENT)


The crankcase has a 500ml oil fill mark,what type goes in here? basically 1/2 a quart, get some good 2-stroke oil for the trans (bel-ray gear saver, yamalube trans oil etc.) the local bike shop will have what ya need

Up higher sits a little tank,with a filler and small window,I assume that oil is suppose to be in there also? Its almost dry.What type goes in here? thats your injector tank, you need two stroke INJECTOR OIL in that tank, DO NOT LET IT RUN DRY or you will destroy the motor

The chain is awfully loose,pops off on rough trail.Adjustable or ned new one? being that old it could prob. be replaced along with the sprockets

I am working to get a manual for it,anybody have any online links? your local dealer should be able to get ya one but ****y might help ya out to . the clymers will work for ya also.
In the meantime any help to keep this thing from burning up are much appreciated :cool:
 
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#3
Quick reply ,wow
All (yamaha) dealers/repair fac. that could answer my questions are closed today,Guess I'll drop in there to get the oils.. Thanks
I seached up and down for manuals,can only find a clymer that covers up the year 1976? and nothing to cover the newer models
 
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#5
greensierra said:
If I premix the gas into the tank is the oil injector still necessary?
as long as you use pre-mix oil you can get away with not using the tank but if ya go that route then take the line from the carb/injector pump OFF and make sure ya block it on the engine side. just dont forget to pre-mix.
 
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#7
i would run 32:1 on that little motor and dont use chain saw oil , get some good 2-stroke pre-mix oil and a ratio-rite cup.
 
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#8
Ok ,got fresh gas and good oil,smokes just a tad and runs good,not really revving out fully but thats ok for now,it pulls good down low and its for slow putting on the trail.
Is there oil in the engine? there is a large plug at the bottom by the skidplate,if that is a drain,where does new oil go in?
Sorry to sound like a Dummy,I dont have a manual yet..
I fly large 50cc RC aircraft,and those motoers 2 stroke and 4 stroke get all their lube from the mixed fuel.I am asumming that this little motor needs engine oil though??
 
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#9
Ok no engine oil..hahah
The plug is for the tranny which I drained and filled with 500ml,the guy at the bike shop says I can use castrol 4 stroke 10W-40 for that?? Now its time for the front forks,they leak badly and make a metallic bang when extended fully,like going over and object or raising the front wheel...hope its not a nasty job to do,or have someone do it.