oil injection

I have a 79 honda express II with the 50cc oil injection engine. I think the oil system is too much trouble, can I simply premix 2-cycle gasoline and forget about the oil injection?

Re: oil injection

sure can

Re: oil injection

just be careful about how you disable the oil pump .. tie up all the loose ends .. make sure the pump's parts are not running without lubrication. Search the forum for tips on disconnecting the pump.

Re: oil injection

Don Pflueger /

you will need to plug up the oil fitting where it is mounted to the engine. if you do not do this, it will suck air, run too lean, and sieze.

Re: oil injection

Jonas Quimby /

The proper method to bypass the oil injector is to completly remove the line to the oil tank. Then take the line that runs to the engine (still full of oil) and connect it to the intake of the pump, making a loop. Now you just need to seal off the connection on the motor really well so no air gets sucked in.

If you really want to go all out, you might be able to unbolt the pump and remove it's drive shaft. Then bolt it down tight to seal the crankcase again.

Why on earth is it too much trouble? I really like it on mine.

Re: oil injection

Don Pflueger /

oil injectors are very unreliable and fail quite easily. and youb wont know it has failed until its too late and your piston and cylinder are scored.

on an oil injected engine, the pump is controlled by engine rpm. when riding up a hill, your rpm is very low. yet your throttle is wide open. this means you are running very lean with very little lubrication.

but, going downhill your engine rpm is high. this causes excess oil to be pumped into the cylinder. and your throttle is usually closed. this excess oil will foul a plug and causes engine temperature to climb dramatically because it is now burning more oil than fuel. this will cause a seizure as well.

oil injection is convenient, but not worth the risks, or the money it costs for a new top end.

Re: oil injection

Jonas Quimby /

Dont wish to make this a huge debate, but...

The Express's oil injector tends to be pretty reliable from what I've heard, I've only heard of one failing first hand. Even then the person was rather unclear as to exactly how it happened. Though I will say they tend to leak oil into the engine when it's not running due to gravity. Get a nice blue cloud on first start if it's been awhile.

Having it pump large ammounts of oil going down hill is a Good thing in my books, the high RPM of the engine could potentially cause a lockup if it didnt get enough oil otherwise.

Sure most mopeds dont have oil injection and are fine, but I wouldnt be surprised if this shortens their life.

And low RPM, low oil condition? I dont Think this would be too bad... there's still the same ammount of oil passing through the engine. I'm willing to bet the slight watering down of the oil here will cause less damage then high RPM idling on a non injection bike.

So, take which ever side you wish. They both have their points. All I know is my Express shall be keeping it's injector.

Re: oil injection

Don Pflueger /

"And low RPM, low oil condition? I dont Think this would be too bad… there’s still the same ammount of oil passing through the engine. I’m willing to bet the slight watering down of the oil here will cause less damage then high RPM idling on a non injection bike.

"

well, the problem with that is not so much the fact that the oil rate is matched to the rpm. but, the problem is that you are usually at wot. this dumps excess fuel/air into the cylinder. the excess fuel/air then washes away the very little amount of oil that is being pumped.

think about mixing paints for an example. mixan equal amount of red and white, then mix in a small amount of blue, maybe 2/3 of the amount of red or white. then what predominatecolor will you see? i know this is a bad example, but its the best i could think of.

the olarger amounts will dominate over the lesser amounts. same with fuel/air/oil.

it usually takes longer to go up a hill then it does to go down. andduring that time frame you are running extremely lean.

and excess oil in a 2 stroke makes the engine run hotter. put a temp guage on one and test it.

if your gonna keep the injection, you should at least mix some oil in your gas.

Re: oil injection

Steamboat Aka J. R. Stevens /

I have owned a Mercury Mariner and a Suzuki outboard engine with oil injection. Every marine mechanic I asked recommended removing the injection system and using premix. Jim.

Re: oil injection

Don Pflueger /

out on a lake is one place you do not want an oil pump to fail and sieze an engine. lol

especially here on lake erie. gets rough real fast.

Re: oil injection

Jonas Quimby /

Just wanted to mention one last thing.

It seems honda decided a low oil condition at full throttle and low RPMs could exist, so in 1981 they started using a new style oil injector. This one is connected to the throttle cable as well, and will up the ammount of oil if you gun it.

This means running at high speed and no throttle, or low speed and full throttle will still get enough oil to the engine. Rather smart, I think.

Re: oil injection

Don Pflueger /

yea as long as that mikuni pump doesnt fail.

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