Gas in the oil

I have a '78 NC-50. I am getting ready to ride it and figured I would exchange all the fluids before I consider it done. I pulled the oil injector tube to drain the oil tank and found that the oil tank was full of gas. It drained completely in a minute but continued to just trickle. I would assume that this is the result of the pin hold between the two parts of the tank. Now to my question. Will the Kreem stuff plug up a small pin hole for good?

Re: Gas in the oil

Kreem is a soft, flexible fuel-proof coating, impervious to water and air with good adhesion .. this is why it can cover rust and not allow that rust to grow or flake off.

Although it can and often does plug small pinholes, it's not meant to plug holes..

that said, unless you can get at the hole(s) and then use something like an epoxy, one or more Kreem coatings may be the only practical solution... this assumes the holes are tiny. It may not plug larger holes.

Since it's vital to keep oil and gas separate, thorough testing and examination after the attempted repair might be wise..


oil does run very slow through the pump.. maybe an ounce per 25 miles of riding.. that translates to around one milliter (one cc) of oil per mile.

Re: Gas in the oil

First of all,I don't understand the question.What is an NC-50?Is it a 2-stroke or a 4-stroke?From your description,it sounds like the oil tank and gas tank are all part of the same tank?

Re: Gas in the oil

jerry -

The NC-50 is an oil injected two-stroke, but I have no idea where the oil tank is located.

Re: Gas in the oil

Then it would seem like the best thing to do would be to get rid of the oil injection,and use premix.

Re: Gas in the oil

Today, many hundreds of millions of vehicles from cars to airplanes totally depend on an oil pump and reservoir .. once in a while one fails and an engine is destroyed.. But if my mechanic suggested changing my car's engine to a 2-stoke and premixing.. well.. i'd think he was nuts.

An owner who performs routine maintenance and is watchful for problems, as was done in this case, can be confident the system is working... (A whole lot of people woulda just fired it up, jumped on the bike and rode it to destruction).

Maybe it's not for everyone, but I see no reason to abandon the injector system... in fact it would be nice to have it for change.. premixing is a chore i could live without.

Re: Gas in the oil


The NC-50 is a Honda Express. The oil tank and gas tank is located inside the rear rack. They are in the same body.

Mike, I'd recommend that you take the tank out of the rack and fill up one side with gas. See if it leaks on to the other side. If not, then somebody probably made the mistake of putting gas in the oil tank. That's not good news, because it's possible that the Express was run without lubrication for a while and might have soft-siezed before if it actually turns over.

If the tank indeed leaks, I'd forget about Kreem. Just get a new tank. It'd be easier. In the meantime, you could disable the oil injector and premix oil and gas in the tank until you get a new tank. Then when you get a new tank, enable the oil injector and hook it up. Just a suggestion.

I owned a NA-50, which is a Honda Express II. These scooters are fantastic! I miss my old one. It ran beautifully.


Re: Gas in the oil

Jonas Quimby /

I'd go this way myself. It sounds like it sat empty for awhile and the devider wall rusted through.

To run straight premix, unbolt the oil injector and disconnect it's drive shaft. Then bolt the injector back down.

Now put a tight sealing rubber plug over the intake's oil connector, loop the existing hose from the oil injector's output to it's input and cap off the oil tank output connection. This last one's important too since obviously the gas would otherwise drain onto your exaust.

After that you just need to mix the right ratio of oil to gas and you're set.

Myself I like the oil injector though, so I'd probably get a new gas/oil tank off ebay, clean and kreem it for durability and go with that.

Re: Gas in the oil

Thank you all for your comments.

Been working on this for a year and was able to get a short run on it.

It inspired me to move forward.

I'll post a shot of it when it's done and running.

Unfortunately it's inspired me to feel confident enough to rebuild my childhood 1962 10 HP Johnson outboard.

I am a glutin for punishment I guess.

Thanks all,


Re: Gas in the oil

I defended the injection system on my Tomos for quite a while,because it was convenient,and SEEMED to be working,but after hearing how unreliable they were over and over again,I finally decided to take a closer look at it.I was absolutely horrified at what I found.Connections that just fell apart in my hands,severely kinked and crushed oil lines,and air in the lines.I immediately removed the system,and considered myself lucky that I did not destroy my engine.Maybe not all oil injection systems are like this,but it seems like if you are having serious problems with one,and are not sure you can repair it properly,it's best to just not use it.To me,the slight inconvenience of premixing sure beats having to constantly worry about whether your injection system is working or not.Cars have either an oil pressure gauge,or at least an idiot light to warn you if you loose oil pressure,mopeds don't.Oil pumps on 4-stroke engines also seem to be a lot more reliable than oil injection systems on 2-strokes.In my case,the pump seemed fine,it was the lines and connections that were the problem,although I have heard of several oil pump failures on Tomos mopeds.Jerry.

Re: Gas in the oil

well.. you did finally get down there and look. and you saw stuff that needed maintanance ..

This is what i was saying.. You gotta keep an eye on things.

Your choice was to disable it rather than repair it, and that's ok.

Although a car's engine may not be destroyed when an oil pump fails, at least you'll be stuck somewhere on the side of the road. But if it happens at freeway speeds, warning-light or not, you can bet some bearings took a beating before you pull over and stopped.

And dummy-lights are about as unreliable as.. as.. an oil pump :)

The scary thing about injector systems in no warning of possible engine damage.. Not to be argumentative, but suppose a rusty brake cable snaps during a panic stop? Engine damage would be the least of my worries..

These old machines require TLC. Without it i would suggest premixing.

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