Couple of questions about oil injection, and plugs

[scottfla]

Hi, Some of you may have seen my threads on scootdawg, where I bought a Vento-ish scooter.

After riding it a bit around my neighborhood, I have tomorrow off so I'm going to do some cleaning and inspection and maintenance.

But, being a newbie to working on a scooter, much less a two stroke, I was hoping to get some guidance. I did try to search these forums by reading threads and using the search function, but couldn't find exactly what I was looking for.

First off, I'm pretty wure my engine oil resovoir has been disconnected from the engine. I noticed it was empty and poured a little two stroke opil in it, which promptly leaked out. Tomorrow when I pull off the plastics, beisdes an unconnected hose, what should I look for to make sure it is disconnected?

What can I look for to make sure the PO used premixed oil/gas? That it runs seems to me it has oil but like I said, I want to make sure

Next question, what's the best spark plug to get?

I'm planning on pulling all the plastic off, checking all bolts and wire connections and cleaning the carbs. I have someone coming over to help who has done this quite a bit so he'll be there to oversee everything.

But, while he's here, what else should I check?

Thanks for any and all advice!

[90GTVert]

I know you've been a member here before posting, but welcome anyway. ;D

You should see a nipple on the carburetor that would most likely be capped if they've been pre-mixing. That's where your oil injection line would have hooked up. If they knew what they were doing they probably would have removed the drive gear or the whole oil pump from the engine too. Most likely if it's still running they had oil mixed with the gas. I know when I tried running 80:1 with a synthetic it didn't take long to seize up. lol

You'll probably want an NGK BR8HS or BR8HIX. The HS is the standard NGK and the HIX is the iridium version of the same plug. I like iridiums, but they are pricey.

Might be a good idea to make sure the oil pump isn't being driven by the crankshaft as I mentioned before. Maybe check out your CVT and make sure the belt is in good shape at least. Check the variator and rollers for wear if you feel like it. See if it looks like your belt is riding all the way up in the vari so you know if you've got more potential there. You could check/replace the fuel lines and filter as well. Check the air filter and clean that if needed. Maybe change the final drive transmission oil.

Good luck with it.

[Reign]

I got a spark plug that I'm never going to use again. It's for the stock cylinder and only has about 150 miles on it max. It's iridium. I'd give it to you as long as you pay shipping. Save yourself about $10 ;D

[scottfla]

Weird, the oil injection doesn't go to the carb, but directly to the engine? Does this make sense?

[shiftless]

The injection should go from the tank to the pump (behind flywheel) then to the carb

[scottfla]

Hmmm, ok, the tank goes to a smaller tank with the 'oil sensor' screwed in. The line then goes to the front of the engine area, but the carb is near the back middle of the engine.

Is this just a really bad routing or am I more blind than I thought?

[Fox]

These pics should help explain the tube routing. The throttle cable has a "Y" in it so one side goes to the carburetor and the other side to the oil pump. The farther the throttle is opened the more oil it puts out. To switch to premix, you plug off the oil injection port on the carb and remove the oil pump drive gear from the oil pump. You have to remove the oil pump from the engine and then remove a circlip to get the drive gear off.There's a little rod that slides off the pump shaft too. Then you re-install the pump back on the engine. You'll probably have to bend the pump output nipple a little to get the pump off the engine without removing the flywheel/stator. I use a flat screwdriver to break the 2 pump mounting screws loose then a Phillips to turn them so I don't chew up the heads. Then tighten with a flat too.

The easiest way to make a plug for the injector port is to cut a 1 inch piece of the oil injector tube and screw a small screw in one end and put the other end on the injector port with the same little clamp that was on there to begin with.

See pics:

[scottfla]

Ahhh, thanks so much, that must be the line we saw.

Are the injection systems really problematic? I'd rather just leave it alone if they are somewhat dependable.

[Fox]

Well, I suppose they are okay but why take a chance? The injection is for convenience. Most people don't want to hassle with pre-mixing but if the pump should fail the engine will fail within a few miles after that so using pre-mix gives you an oil source that won't fail.

BTW, there's some great Tech stuff on the club home page here:

49ccscoot.com/

[scottfla]

Believe it or not, I have read or at least skimmed over about everything there. Did I miss anything specifically about the oil injections?

[Fox]

There's some really good close-ups of the oil pump in the Minarelli engine disassembly:

49ccscoot.com/disass.html

You can leave the pump off the engine if you want to. I prefer to re-install it because that area is exposed to incoming air from the fan and I don't want any pebbles or other debris rattling around in there with a crankshaft seal.

[90GTVert]

Sorry for my initial poor description of the oil line routing. I had someone waiting on me and was trying to get you some info in a hurry. Thanks to everyone else for straightening it out.

[scottfla]

Don't apologize, I appreciate everyone taking the time to give me some good info.

[scottfla]

Hey, what's the pro/con of blocking off the lines but not removing the drive gear or the oil pump on the scooter?

[Fox]

I'm no expert but I think running the pump dry will most likely result in the pump getting hot and seizing up which will result in metal shavings and stuff like that. In other words: A metal mess... Yukk!

Why bother with that?