WOT really chugging

W

woogie_man

New Member
Hey guys,


Well after getting the bike up an running,I have a slight problem. Throughout most of the rifle band I have great acceleration, and speed. But when I get to 100% it seem like someone is choking out the motor. It seems like it is starting to chug, and really lose power. Not sure what to do as I have moved the clip on the needle, and where I have it now it run great except for WOT ( clip is on the second space from the top )

I have been looking, and is this the for striking people talk about?

And if so that would mean that I have to adjust the key port smaller?
 
You didn't tell us what engine you have but if you're running a Chinese 2 stroke:

New engine? Less that a couple of hundred miles on it?
Don't worry about tuning for performance yet. They need to run for a while.
Your problem is common for a new engine. Be patient and ride the bike as much as you can. Things will improve. I'm not sure what you mean by "key port".

Tom
 
I have a Flying Horse 66cc with 135 miles now. Mine would lug a bit at WOT since new and will still do it a bit riding on level grade. Down hill I tend to coast, but going up hill she pulls pretty good. MY WOT on level grade is gradually getting better with every mile. My clip is also in second position from the top...which really has more affect on low and mid range, but I think that once you and I both get a few hundred miles on our engines....they should really smooth out.

As the rings seat in and the gears begin to mesh. The engine should only get smoother, quieter and more peppy as she breaks in.

I have ran Opti-2 100:1 since the very first start and the NGK BPR7HS spark plug is a happy looking chocolate milk color. What plug you using and how does it look? May want to experiment with using a different plugs. I have also had good luck with the E3.10 and E3.12 spark plugs, but have not tried them in my current Flying Horse engine yet.
 
Sounds to me like the classic china kit jetting.
Your main jet is too large and once you are WOT, it's too rich for best power. When you close it a bit, it feels better right? The needle is doing it's job but your main is too big.
Most of my engines have needed two-three sizes smaller on the main jet to run right from idle to WOT.
A easy way to confirm this is to turn off the fuel as you ride and see if it suddenly starts screaming right before it runs dry.
Sure sign of too big a main.
I'd wait until you are fully broken in, then adjust the main jet size downward.
 
Yeah I have been running opti 2 as well since the start.

Manic were you riding on my lap? Lol
What you describe is exactly what is happening. Now I would love to keep up with traffic in my area, around 35-40.

Was looking at other mod as well, and what would adjusting the muffler cap have?
 
He still will not hurt going a tad rich will breaking the motor in. I mean a lot of us have done it that way.

Bairdco ran some of his fastest motors, from what I read at 100 to 1 Opti right from break in.

Even when I ran rich I could see a power increase show up at break in.

Going with Manufactures recommindatios for the most part.

Then adjust carb for perfection if need be?
 
woogie_man said:
Yeah I have been running opti 2 as well since the start.

Manic were you riding on my lap? Lol
What you describe is exactly what is happening. Now I would love to keep up with traffic in my area, around 35-40.

Was looking at other mod as well, and what would adjusting the muffler cap have?
Click to expand...
If you're using Opti-2 at the recommended ratio of 100:1 then you will need to go much leaner (smaller jet size).

Look at it this way: Less oil in the mix means more of the mix is gasoline. That effects the air/fuel ratio. You have to adjust for that. Depending on your altitude above sea level you might need to go much smaller on the main jet BUT, again, don't agonize over performance until you get some miles on that engine.

Also, the needle only determines fuel flow to the engine at or below 3/4 throttle. Anything above 3/4 is the function of the main jet orifice size. The needle clip position has nothing to do with WOT.

Tom
 
Sounds good 2door.

Planning on running her until winter, then stripping some things down and working on them. So I have a few months of riding yet.

If I get some time, will open the carb and check the size of the jet. Well grab a pin gauge from work, and do some checking.
 
If it is hot where you are at, you may also want to wait to see how your engine runs in cooler outside temps. Cold air is more dense and thus your two stroke will want to run leaner and the extra fuel charge from a larger jet will be required to prevent it from going lean. Always safe to run a bit on the fat side in my opinion to compensate for changing temps and air conditions...especially on an air cooled 2 stroke.
A lean condition for any air cooled 2 stroke can be very detrimental. If you jet a 2 stroke to run perfect in 90 degree weather it is going to be way too lean in colder weather or if you jet it to run perfect in 50 degree weather it is going to be way rich when it gets to 90, but even more important to watch for then the outside temps would be dense air/humity vs thin air/dry . If you can keep your jetting on the slight fat side in all conditions..it may not run optimal for any, but at least you should be running "safe" in all outside temps and air conditions
Of course you can always have multiple jets you can change depending upon your climate at the time, but I always figure if I am just slightly rich in warmer/humid time of year....then come this fall she should be running about perfect. That's my take on it anyhow.
I also figure that since I am running 100;1... the bit of extra unbunt fuel may even help with a tad bit of extra cooling and lubrication.
Just a few more things to consider.
 
Well was able to ride her into work tonight. A trip of about 7 miles. With my little spedo hooked up, it looks like I had a top speed of 28 mph with an average of 20. So not to bad, though it honestly felt much faster :D

Will give it some time, and then close the jet down a little bit and see what happens then.


Will the jetting also help with a more consistant idle as well?
 
So do I need a larger jet or a smaller jet?

Just want to be 100% sure before anything is done.



Who would have thought that reading everything again you will get the answer! Smaller it is...Will use a pin set at work to check the size of my stock jet.
 
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