Four stroking on low rpm, no four stroke on high.

Shwepsas1

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Hey,

I’m new in this forum and have a little problem on my 80/66cc engine. When I’m going on 1/2 or 3/4 of throttle my engine four strokes a lot, but when I’m full throttle there is no four stroking. I’ve read the forum and found that four stroking at low rpm is bad and no four stroke on full throttle is also bad. I think my bike runs a bit too rich (looking at the plug). But now I’m messed up and don’t know what is good or bad.
P.s. I installed two head gaskets, because with 1 piston was hitting the head.
P.p.s engine has torque in low rpms and flat outs about at 37/38 mph with standard sprocket.
So do I need to make it leaner with the jet C clip? But if I make it leaner won’t it be worse on full throttle with lean surge ?
 

Cisco

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But now I’m messed up and don’t know what is good or bad.
No worries. The engine will burble at low RPM and will clear its throat when you open it up. It is running too rich, and you may have to raise the clip on the needle up a notch to lean it up a bit (for the first 1/2 - 3/4 throttle). The recommended 16:1 break-in mix is a bit rich too. After you've run through several heat cycles, a couple of tanks of fuel, and have tightened everything up (check the head torque 144 in/lbs) then switch to a leaner mix (32:1?). Switch to a preferred spark plug (NGK) if you are still running the stock plug. How does it run now? Then try raising the needle clip up and check again. Look at the plug. Does it seem too oily or black? Only then consider reducing the jet size. Remember, incremental steps. Changing several things at once results in 'Corrective Cause Unknown' questions.
 

DAMIEN1307

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Hey,

I’m new in this forum and have a little problem on my 80/66cc engine. When I’m going on 1/2 or 3/4 of throttle my engine four strokes a lot, but when I’m full throttle there is no four stroking. I’ve read the forum and found that four stroking at low rpm is bad and no four stroke on full throttle is also bad. I think my bike runs a bit too rich (looking at the plug). But now I’m messed up and don’t know what is good or bad.
P.s. I installed two head gaskets, because with 1 piston was hitting the head.
P.p.s engine has torque in low rpms and flat outs about at 37/38 mph with standard sprocket.
So do I need to make it leaner with the jet C clip? But if I make it leaner won’t it be worse on full throttle with lean surge ?
Sveiki atvykę į forumus Shwepsas1...DAMIEN
 

Shwepsas1

New Member
Local time
3:36 PM
Joined
May 15, 2022
Messages
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Thanks for the help. I haven’t clarified that the engine has 200 miles on the clock with hitting piston in the head, no issues with running, cleaned all the internals no gouges or something on the cylinder walls. Why I put two gaskets, because of the engine overheating, so now it’s not overheating but also four strokes a lot. Thanks for the answer Cisco I will try to move the clip on the needle.
 
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