Loss of power

sboricic123 · Jun 27, 2013

I have a China 66cc engine with about 300-500 km's on it. I have noticed that I've lost power...especially going up hill. It doesn't pick up speed like it used to on flat road either. I used to do up to 40+ kmph. I wouldn't do that for long periods though. Now I can't seem to get over 32 kmph. I've adjusted the throttle, cleaned the air filter, cleaned the spark plug, checked for any fuel leaks in the line and tightened head gaskets bolts.

I'm lost now and not sure what might be causing it.

dodge dude94 · Jun 27, 2013

What oil mix are you using? It's also possible that your muffler is clogged.

sboricic123 · Jun 27, 2013

Break in 20:1, right now 40:1. The still see exhaust smoke coming out the muffler but could it still be plugged?

dodge dude94 · Jun 27, 2013

40:1 outa to be fine. But the thing that gets me is that you still have smoke. I use 40:1 and don't have smoke so that leads be to think that your carb may be running a tad on the rich side. That will cut power down.

Groove · Jun 27, 2013

Might want to do a plug chop. Make sure the plug isn't all gunked up which would indicate it's running too rich. You can experiment with the air/fuel mixture by moving the e-clip up or down. Moving it away from the smaller, tapered end should lean the air/fuel mixture a bit. I'm probably telling you what you already know, but maybe this will help someone.

biknut · Jun 27, 2013

Check for oil leakage which would indicate a intake leak, especially check the crank seals.

If your bike was running good till you got off the break in pre mix, you're probably running too rich now. Less oil equals more gas.

crassius · Jun 27, 2013

check gasket & seal leakage by looking for oil - check muffler for a clog

as the engine is now about finished with getting a good seat of the rings, you may need to change your mixture a bit

sboricic123 · Jun 27, 2013

I'll have to go through the above in the morning. What would you recommend I clean the muffler with? Any good cleansers or brake fluid?

biknut · Jun 27, 2013

sboricic123 said:
I'll have to go through the above in the morning. What would you recommend I clean the muffler with? Any good cleansers or brake fluid?

As low mileage as your bike is I'd wait before doing that, but don't rule it out.

dodge dude94 · Jun 27, 2013

Knowing the track record of these engines and their components he could have a bum muffler. Not entirely out of the question.

crassius · Jun 27, 2013

oh, don't forget the obvious like something rubbing on the wheels, or wheel bearings tight : )

KCvale · Jun 27, 2013

It's loud and just for testing but pull the tailpipe and go up the street and back.
Get your power back?
If so you know where the problem is.
Sorry, no advice on how to clean oil out of the cat in the tailpipe.

sboricic123 · Jun 28, 2013

Well I took off the muffler and it looked to be clogged up. I let it soak in vinegar, baking soda, dish soap and water overnite. Then used engine cleaner to loosen up some more gunk and rinsed it with water. After that I air hosed it out. Now I just have to assemble it again and try it out. But that won't be until morning. I'll post the results once completed.

sboricic123 · Jun 29, 2013

Well I put the muffler back on after cleaning it. When I used the air hose, air was going through it quite fine. Put fresh gas/oil in it. Removed cylinder head and cleaned gasket. Cleaned spark plug again. Changed fuel filters and hoses. But it still didn't improve any.
It wants to bog down a bit when I give it gas.

sboricic123 · Jun 29, 2013

I switched carbs and that didn't solve the issue. I must have an air leak somewhere that I can't figure out.

Toadmund · Jun 29, 2013

sboricic123 said:
It wants to bog down a bit when I give it gas.

So you increase the amount of gas supplied, and it chokes on it.
What happens when you put more food into your mouth than you can swallow and your nose is stuffed up?
You can't breathe.

When I had cylinder/piston damage due to destroyed bearing, I had to give it gas to keep it going.

So maybe your choke is on, or your jet hole is too big?

sboricic123 · Jul 1, 2013

I wasn't familiar the way these carbs or 2 strokes work. Now, after Googling, I realized what some were saying about the e-clip adjusting on the jet needle. I'm going to try that next.

maniac57 · Jul 1, 2013

Most of my ht's have liked the needle clip in the second groove from the top of the needle.

sboricic123 · Jul 2, 2013

Well I tried all different settings and it didn't solve the problem. I did another compression test, 120 psi, but I noticed it losing air. Within a minute, approximately, it was back down to 0. I also noticed some smoke and pinging/grinding sound coming from right side of the engine.

biknut · Jul 2, 2013

sboricic123 said:
Well I tried all different settings and it didn't solve the problem. I did another compression test, 120 psi, but I noticed it losing air. Within a minute, approximately, it was back down to 0. I also noticed some smoke and pinging/grinding sound coming from right side of the engine.

That's all normal.

Loss of power

Member

New Member

Member

New Member

New Member

Well-Known Member

Well-Known Member

Member

Well-Known Member

New Member

Well-Known Member

Well-Known Member

Member

Member

Member

New Member

Member

Old, Fat, and still faster than you

Member

Well-Known Member