I picked up a fairly original U.S. model 76 ty250. It still has the autolube hooked up. I know alot of people disconnect them and premix fuel. what are the pros and cons of doing this. I know about saving weight and piece of mind in not worrying about the pump failing. But has anyone ever really seen one fail? Do you think the lubrication is better if pre mixed.

If you continue to use the current system then you are committed to using the two part cable, one piece to the carb and the other to the pump. Using pre mix at about 40:1 you can dispense with that and use a Domino throttle. Look at all the parts that could fail. Pump, broken cable to the pump, failure to keep the oil in the tank, failure of supply line to the pump, failure of line to carb on your model from the pump.

The choice is yours but most people convert back to premix.

Tony

If you continue to use the current system then you are committed to using the two part cable, one piece to the carb and the other to the pump. Using pre mix at about 40:1 you can dispense with that and use a Domino throttle. Look at all the parts that could fail. Pump, broken cable to the pump, failure to keep the oil in the tank, failure of supply line to the pump, failure of line to carb on your model from the pump.

The choice is yours but most people convert back to premix.

Tony

I picked up a fairly original U.S. model 76 ty250. It still has the autolube hooked up. I know alot of people disconnect them and premix fuel. what are the pros and cons of doing this. I know about saving weight and piece of mind in not worrying about the pump failing. But has anyone ever really seen one fail? Do you think the lubrication is better if pre mixed.

I agree with what Tony said and yes I know of two Yamaha single cylinder two-stroke motors that siezed because the oil pump stopping pumping

Ok I guess I'm gonna do the swap. Q: when I unbolt the pump from the case does the pump shaft just slide out or do I need to take the cover off to get at it?

Edited December 17, 201114 yr by fergie

You need to take the clutch cover off, and fit a little cover to seal off the hole where the pump was

You need to take the clutch cover off, and fit a little cover to seal off the hole where the pump was

The clutch cover? I thought that was on the other side. I realize I have to fit a cover over the pump hole after removal. My quesstion is does the shaft come out with the pump or do I need to romove the case which the pump bolts to to remove the shaft?

The clutch cover? I thought that was on the other side. I realize I have to fit a cover over the pump hole after removal. My quesstion is does the shaft come out with the pump or do I need to romove the case which the pump bolts to to remove the shaft?

The oil pump resides underneath the oil pump cover and is attached to the Right hand side engine outer cover (I call that the clutch cover). You have to take the clutch cover off to get the shaft out because the gear on the inner end of the shaft will not fit out the hole the pump drive shaft goes through.

The oil pump resides underneath the oil pump cover and is attached to the Right hand side engine outer cover (I call that the clutch cover). You have to take the clutch cover off to get the shaft out because the gear on the inner end of the shaft will not fit out the hole the pump drive shaft goes through.

Thanks feetupfun that makes everything clear. Cheers, fergie

A previous owner did a neat job on mine simply by cutting the shaft! As your main objective (apart from the reliability) is to get a light throttle action there is no harm in leaving the shaft present.

If you remove the pump fully you need to block the hole using a coin and epoxy otherwise the oil pump cover will fill with oil

I picked up a fairly original U.S. model 76 ty250. It still has the autolube hooked up. I know alot of people disconnect them and premix fuel. what are the pros and cons of doing this. I know about saving weight and piece of mind in not worrying about the pump failing. But has anyone ever really seen one fail? Do you think the lubrication is better if pre mixed.

Another advantage to pre mix, which Tony mentioned, is that you can set the ratio, as opposed to whatever the the pump was set at. Which was probably nearer to 25:1 in that era.

I want to take the bike for a ride before I do the pump removal. So i decided to pull the pump cover off to make sure the cable is actuating the pump. To my suprise the cable was just lying there not hooked up at all. I dont know if it came off all by itself or the po unhooked it intentionally. I hooked the cable back up and the bike seems to run good I'm not sure if the tank has mixed gas or straight gas in it. The lines from the tank to the pump to the carb seemed to be all connected. I bought the bike from a shop(on consignment)and the shop owner is not sure either. I guess having the pump hooked up as well as premix wont hurt anything other than maybe fouling the plug. Anyway, Im going riding tomorrow and I dont know whether to fill it up with mixed gas or straight gas. Any thoughts?

Edited December 18, 201114 yr by fergie

I want to take the bike for a ride before I do the pump removal. So i decided to pull the pump cover off to make sure the cable is actuating the pump. To my suprise the cable was just lying there not hooked up at all. I dont know if it came off all by itself or the po unhooked it intentionally. I hooked the cable back up and the bike seems to run good I'm not sure if the tank has mixed gas or straight gas in it. The lines from the tank to the pump to the carb seemed to be all connected. I bought the bike from a shop(on consignment) Im going riding tomorrow and I dont know whether to fill it up with mixed gas or straight gas. Any thoughts?

Because you don't know what is in the fuel tank, and the oil pump may have lost prime over time, or have been disconnected from the cable because of a problem with it, it is safest to mix up a batch of new premix fuel before you go riding and get rid of what was in the tank when you got it.

If you want to reinstate the injection system, it should be primed by hand to get all the air out of the system. There is a bleed screw on the pump and once that has just oil coming out operating the pump by hand, then put the screw back, remove the line at the point it goes into the motor and keep pumping by hand until all the air has come out. You should also check the pump settings are right. There is a line on the cable pulley that should line up with a pin on the pump plunger when the throttle is closed. There are lots of things can go wrong with an injection system so there will always be a risk of lunching the motor.

Because you don't know what is in the fuel tank, and the oil pump may have lost prime over time, or have been disconnected from the cable because of a problem with it, it is safest to mix up a batch of new premix fuel before you go riding and get rid of what was in the tank when you got it.

If you want to reinstate the injection system, it should be primed by hand to get all the air out of the system. There is a bleed screw on the pump and once that has just oil coming out operating the pump by hand, then put the screw back, remove the line at the point it goes into the motor and keep pumping by hand until all the air has come out. You should also check the pump settings are right. There is a line on the cable pulley that should line up with a pin on the pump plunger when the throttle is closed. There are lots of things can go wrong with an injection system so there will always be a risk of lunching the motor.

Is it ok to just disconnect the cable and mix up a fresh batch of 40:1 and put it in the tank?