DC CDI  By  gy6girl (Read 2,915 times)

It seems like all the easy bases have been covered.

Your oil leakage may be the key. Try this, disconnect your plug wire, remove your oil dipstick and turn the motor over a couple of revolutions. If you shoot oil out across the floor, (not just a mist) it is possible you have a broken ring. We have had this happen before, symtoms, WOT issues and oil all over the engine.

Just a thought.

Jim/Owner
Rapid Repair

I am a heck of a mechanic, Carbs, Motor, Trannies, CVTs etc.. and for the life of me I am trying to picture how a blown ring in a scooter would spill oil all over the motor and NOT create a cloud of smoke at any speed. Now if it was a Valve leaking it would smoke only on initial starts till it warmed up. But a blown ring you would not let people behind you see the road.
Alleyoop

Don't even have to put my thinking cap on to tell you what you did wrong that caused them to run worse. First the #40 Pilot jet is to big second the Main jet was also to big. If you read one of my previous posts I said LEAVE the pilot jet and if you slap on a free flow filter you go up 2 sizes on the main jet. If you also put on a free flow exhaust you again add another 2 sizes to your main pretty simple stuff. You may get away with a #38 Pilot jet but you will have to adjust the Fuel Ratio and Lean it out.

People think well I will just slap in really big jets for more speed that is not the way it works.
Simple example when you eat something you take a fork or spoon and put some food on it and shove it in your mouth you chew and swallow. Now Fill your mouth with twice that amount of food and you have trouble chewing and only swallowing part of it at a time you cannot swallow the whole amount.

Can't be the altitude or gas the other scoots live in the same place and they run good.
Alleyoop

Well you read but did not listen, did I not say that if its a 24mm carb it comes with a #35 and that is fine!! and that to go 108-110. You have to realize two sizes up allows quite of bit more fuel to pass through. I have a bored out 157QMJ which is now 182cc motor and I have a #38 Pilot jet. The guy that works on them every day as you say should know better. If your pilot jet is 107 you can go to 110 if it is a 105 go with the 108, if its a 103 go with a 105. Pilot jet go with a #35.
Alleyoop

Is it possible the exhaust is clogged?

It's no big deal. You didn't really offend me. I was playing mostly.

I will give what you say a try. And you might be right. The person before me might have changed the jets, but I don't think so. That's what I have been doing with it so far. Fixing everything the guy before me did to it. You should see how he put the high performance air filter on.

But first, look how I put mine on...


That's how I did it. That's how I put a high performance component onto an engine.
How he did it, was to cut the end off of the stock plastic air filter box and use that piece as the extension, with hose clamps and some silicone. It's really ugly. So if a person puts something like that on there, do you really think they would have changed the jets? I don't think so, and the jets are corroded. They are not shiny.

But I do know that a 115 is too much. That's something learned.
I also know that the jet that is in there is smaller.
So I would say try a 110 or something like that. What ever they have.
We'll see how much those microns of differences can do.

OK it seems that this motor to say the least is a real needle in the haystack and IMO some of the best suggestions by all have come out here so not only do we want this scooter to run right it has become a mission in doing so. When we do figure it out then not only will it be a thread to remember for future problems like this I'm going to personally salute the suggestion that fixes it.

I've read this very closely and I can relate to what Jim said on a couple of things myself as far as pressurizing the crankcase due to a ring problem, one was on a old time favorite that Jim, Alley and myself remember and that's the old 235 straight six Chevy of the 50's and 60's. Two things come to mind from that old solid lifter engine, (1) a ring journal can break or crack and she'll blow oil even out of the oil cap cover (2) if all the rings line up for any reason with the break in the ring all lined up she'll do the same thing, as the piston rises on the compression stroke it'll blow back to the crankcase yet not smoke.

Ya forgot, that one Alley. I had to think back myself and I had that happen to me on a old Clinton engine once, remember the look alike Clintons of yester year that copied the B&S ones. My dad had some choice words for that lawn mower that I can't say here!

Also I'll throw out some food fro thought? Colorado? High elevation? Should we not hold the jets down to a stock size and try to get her extra air say with a unifilter? Yes she has other scooters that are doing fine but this one for whatever reason is being a problem child kind of like the old saying in the family, the black sheep.

Let's put our heads together and if one thing that common sense says it doesn't work scratch it and we go back to the drawing board. It's a conquest now so get your pencils out!

JR