2 stroke: oil injection pump vs pre-mix

[200XMichigan]

Just wondering why a lot of people are bypassing the oil injection pump to run pre-mix instead. When I worked at the Sea Doo shop I never saw one fail, even though I am sure they do, however rarely that is. Or did the Yamaha 2 stroke 3 wheelers have a problem with the oil injection pump? Just wondering. Seems so much easier to me to just make sure it works, then you can gas and go. I do live in an area where I can ride the 3 wheeler to the gas station. So for everyone who has to fill up a gas can its really not much more work to throw some oil in the gas can. Just wondering why is seems so common to take them off?

[rdlsz24]

Just peace of mind I guess. Sometimes you don't want to trust old parts to do their job. I was just talking to a guy here at work and he picked up a 96 Blaster over the weekend and the first thing he did was unhook oil injection so he could mix his own.

Rob

[3wheeledjunkie]

Just peace of mind, i wish I could do this on my little Honda Scooter, but no one makes a plug for the hole that oil pump leaves. Kinda hard to know it's happening until it's too late most of the time.

[200XMichigan]

Ever had one fail? Just wondering. However they make the pumps, they sure make them good. I've seen so many old ones with the pump working on them. I just like the convenience factor. Has anyone had one fail? Really just wondering because at the shop we never saw any and serviced some 700 Sea Doo's every summer, and snowmobiles in the winter.

[Dirtcrasher]

Well, you could MAKE a plug or have one made, it's not a hard thing to do......

I can take the OI or leave it. It seems to work very well, especially for people that maintain there trike/quad.

We have a Blaster here now, I suggested he buy the 18$ block off kit and get some premix. BUT, we added a DG pipe/K+N filter and took the lid off (or huge holes will be drilled into it.....) Jetting can be more work with oil injection. The factory generally sets it just below "plug fouling" point IMO.... You can adjust that so if anyone removes the OI because it was "too rich" it's an easy adjustment but you can't be a knucklehead and have to count either how many revolutions or how many times the pump moves in and out per minute at a certain RPM........ Do it for 30 seconds, multiply by 2 and your good.

I think OI is great for young kids that can make a mistake easier than there parents could (whether they are smart or not) but parents screw up too....... I get piece of mind by mixing my gas myself. Yamaha seems to be the leader when it comes to OI, and they do it well; The stuff seems to work forever. I think my old MX100 even had OI and I was happy to have it

When you mix it, you will certainly be leaner than the OEM had it set up to run. I can't blame them as they are making it nearly foolproof. If you run dirty filters/they fall off/ or don't run one at all; Then you may want to consider removing it. ANY of the ones I've seen can be removed with some ingenuity if there isn't a "block off kit". Make a plate for the pump cavity, once it's removed and seal up the inlet into the carb which is normally in the back portion of the carb, just after where the boot would clamp down on.

If anyone needs a plate made or a pice to thread or press into the carb, email me with what you have and we can come up with something....... You can't mess around with it though, it has to be done right or you'll have an air leak (lean condition) and a pump rotating or pumping without oil may fail too; Who knows......??

That Yamaha Blaster setup seems to work fantastic and you can lean the mix out a bit with s couple hours of patience. The biggest mistake people make is forgetting that the fuel in that carb bowl has no premix. And without draining the bowl, you are starving the topend and crank and main bearings of oil until the ne fuel (mixed) makes it's way through the system.

But, removing that mixing oil resevoir is nice and has to shave a bit of weight. It also leaves room for a toolbox in case your fenders are destroyed and no longer have one and or if MAIER even has a toolbox. Blaster people should be AOK because they left the main design AS-IS for a couple decades.....

EDIT - OT but, I still would love to see a Blaster motor in a trike. There so easy to work on, parts are plentiful and the upgrades such as with "Vito's", can give you lots of HP gains........ and for short $$$$$$$

[200XMichigan]

I guess I was just thinking if its maintained and the OI lines are checked a couple times a year they are great. I've heard of more people running the wrong mix or letting someone use it or just forgetting themselves and using regular gas.

So for stock the OI is fine, but if your building a performance motor you might wanna remove it?

On the Sea Doo's you could adjust the oil pump for less or more oil, but the Yamaha's didn't have this feature, is it the same on trike?

[Vealmonkey]

You can adjust the yamaha pumps, even the old ones, it's just more involved. But with the yt60 and the old yt125/175 it's just convenient and then you can run a custom throttle cable and not have to worry about your cable splitter binding up anymore. On the last yt60 I did, I cut the main pump shaft and removed all the guts and then I just cheated and jb welded the resulting cavity, a poor mans block off. LOL It's still working well with no leaks. You just have to be careful and not get any jb weld on the o-ring and you should be good. I put the pump piece on a piece of wax paper so the jb weld wouldn't stick. On some mods, you can get away with a low tech solution and on other mods I wouldn't cut corners. It just depends on what you are doing. I've only seen 2 oil pumps fail and it was more the stripping of the plastic gear than anything and both time it was on older yamahas, but I believe they were messed with by former owners and the former owner didn't have the gear meshing right and it made quite a mess. You really have to excercise your own judgment on alot of this stuff. And for me it works well since everytime I add fuel the premix is already in the gas and I don't have to worry about checking the premix tank. Plus alot of time premix tanks have been broken, or previous owners have pinched off oil lines or other really neat little tidbits of mechanical mayhem that people who should never touched a wrench or screwdriver had done.

[jeswinehart]

I have NO problem pre-mixing. Especially after 1/2 hour of riding on slushy lake ice that plugged up the little vent line on my Polaris trike that resulted in a seized galled up piston.
That top end cost 300 plus and on the hardest to work on trike ever built, the Polaris 250R/ES.
Yeah, worked really good, right up to the time it failed.
I remember carrying the oil reservoir tank to the trash can and said GOOD bye POS.
I now run it like my Tecate, pre mixed 100 to 1 Amsoil
That was 3 years ago

[beets442]

+1 on maintaining OI lines and pump.
Haven't had to many prob's with OI, its nice when they are adjustable.
I would premix(change ratio's) for conditons as far as humidity and heat, a 2 stroke can be temperamental when running in different parts of the US.
Need take into account the that the jets need be adjusted for oil induction thru the carb, it can help in those higher altitude changes... Beets

[Marc]

I just bought a yamaha tri moto 125 what would i mix hte oil and gas at?
I would like to remove the oil injection cause i dont want it to fail.
or how du i maintain the oil injector so it keeps running

[Thorpe]

Ditched the OI on my YT60... Lean it out a tish on the oil, use a little amsoil 2 stroke... Its like finding a whole extra throttle with the power gains...