Vintage Dirt Bike Q & A

some say to pull it some say to leave it.

if i do keep it on and running what oil should i use for the injection system?

Thanks

Yamalube 2S is a good oil to use with the injection system. when shopping for oil look on the container if it is suitable to use with oil injection or autolube is another name for it.

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(2) 1968 DT1 1970 RT1M,1970 DT1C 1971 RT1B Enduro 1974 MT250 1974 DT250A (2) 1975 DT400B 1974 DT100,1978 DT175
1975 CR250M1 1979 CR250R 1979 Kawasaki KZ400H1 Jesus is Lord!!

Thanks Dave,

Some people say to tear off or block off oil injector??? Whats your opinion/

PS: the bike im buying has sat for 12 years. Should i clean out the original oil from the injection system?

i run it when i can pretty much.it is a lot more convenient to run the oil injection and if maintained they are very reliable.

i have a 1968 DT1 that someone removed the autolube in the past and i put one back on plus and i repaired the one on my 1975 DT400B and i have a 1978 DT175 that was not running when i got it and i started the engine on premix and made sure the oil pump worked before i started using the autolube on that one.the only bikes i have that runs premix is all 3 of my Hondas.

keep the cable to the pump adjusted properly and they rarely give any trouble.might not hurt to replace the oil pump drive seal to be sure,when that seal goes bad it leaks 2 stroke oil into the transmission.that seal is still available from Yamaha.

it would be a good idea to get rid of the old oil if it sat that long or if the bike was properly stored,chances are the oil is ok.i would go ahead and drain it and fill it with the oil you plan to use then bleed the pump and you are good to go.i would initially start it on premix to make sure the oil pump is working.

if starting to test the oil pump or just running it on premix i would run the oil/gas mix ratio at 32:1.

if you want to remove the oil pump and run premix on a 1974 to 76 DT250,360 or 400 you need to make a block off plate to the clutch cover and bolt it on to the cavity where the oil pump was and block off the line to the cylinder if on a 1974 model or to the carb on the 1975-76 models.

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(2) 1968 DT1 1970 RT1M,1970 DT1C 1971 RT1B Enduro 1974 MT250 1974 DT250A (2) 1975 DT400B 1974 DT100,1978 DT175
1975 CR250M1 1979 CR250R 1979 Kawasaki KZ400H1 Jesus is Lord!!

Whoa. You seem to know your stuff about this injection business. Thank you.

I guess I will drain the old oil, hopefully its easy to drain, and buy a service manual. I have no idea how to maintain a throttle line for injection, or even replace the seal between the clutch/injector.

Forget removing the oil injector.

one other thing i may mention,the oil has to be designed for use with oil injection.the oil for only premix is too thick in viscosity and it will not pump.oil like the Yamalube 2S.in the directions for the oil it will say it is good for premix and oil injection on the label.

on a 1968 to 73 250 the clutch cover and oil pump drive gear and shaft will need to be removed to replace the seal.

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(2) 1968 DT1 1970 RT1M,1970 DT1C 1971 RT1B Enduro 1974 MT250 1974 DT250A (2) 1975 DT400B 1974 DT100,1978 DT175
1975 CR250M1 1979 CR250R 1979 Kawasaki KZ400H1 Jesus is Lord!!