Whooshing noise at high rpm's and possible overheat?

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#1
Hi, I'm on my second tank of breaking in my Zeda Stage 2 engine, the bike has been running okay so far. Recently I noticed at higher rpm's the bike starts to make a whooshing noise that I haven't heard before, and whenever I come down off the throttle after running at higher rpm's for 10-15 seconds, the bike runs really choppy until its back lower. Also the last ride I took the bike started like misfiring? It was almost like turning itself on and off again then I pulled the clutch in and it died. I let it cool down for 5 mins and it started right up. Is my bike overheating? Is the noise from too advanced ignition timing? The bike isn't really running how it should at high rpm, and I know it's still breaking in, but this doesn't seem normal.
 



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#3
The chain could be hitting the frame, it's fairly tight, maybe a half inch of freeplay. Would that be the noise? I'm running 24:1 synthetic, first tank I ran 20:1 non synthetic.
 


crassius

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#5
you should probably try to find where the noise is coming from - clutch slipping or chain rubbing is common
 


crassius

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#7
could just be that it doesn't have enough power at idle to pull a rubbing chain

first fix alll things like that that are wrong and then see what you have
 

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#8
Does it idle slow or fast? Maybe an air leak? You can check by spraying WD40 where you mount the intake manifold to the engine, or where the carburetor is on the intake manifold. If you spray WD-40 and the idle changes you have an air leak. You can buy red Hi-temp silicone gasket wich is in a tube, and apply it when the engine is cold, spread it, and wait a day. Be generous with it. I needed to do it too.

If it idles slow, screw the little screw in with the spring on in a bit
 

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#9
It was like stalling out at 20-25mph, the chain rubbing isn't that bad. I definitely don't have a vacuum leak because it idles fine, and when I pull in the clutch the revs drop fast.
 




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#13
Replaced the CDI with a new one I had around and it ran alot better at higher speeds. I fixed the chain rubbing completely. The bike runs good for a solid 15-20 mins then I let it cool down for 5 minutes before continuing. But normally at the end of my rides (30 mins total maybe) the bike starts misfiring, shaking back and forth and when I pull the clutch in the bike stalls. It starts right up again if I let the bike cool down. Also I noticed after coming off the throttle after being at high rpms, the engine runs kind of rough. Not really sure whats causing all of this...
 

Frankenstein

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#14
Replaced the CDI with a new one I had around and it ran alot better at higher speeds. I fixed the chain rubbing completely. The bike runs good for a solid 15-20 mins then I let it cool down for 5 minutes before continuing. But normally at the end of my rides (30 mins total maybe) the bike starts misfiring, shaking back and forth and when I pull the clutch in the bike stalls. It starts right up again if I let the bike cool down. Also I noticed after coming off the throttle after being at high rpms, the engine runs kind of rough. Not really sure whats causing all of this...
Wasn't there a cdi heating up issue that could be causing this type of problem? They warm up and get funky, unless this has been happening before the cdi swap.
 


crassius

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#16
that heat problem was mags internally arcing due to loose rivets or loose ground

there was an air leak earlier in this thread, so may be just motor overheating
 

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#17
that heat problem was mags internally arcing due to loose rivets or loose ground

there was an air leak earlier in this thread, so may be just motor overheating
I don't think I have an air leak, it idles fine when I start it and the spark plug is a nice tan color. What is this internal arcing, and how can I fix it?
 

gary55

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#18
The chain thing is total bullsh*t. The vibration thing is highly possible, but generally that causes a oscillating speed up slow down speed up slow down cycle without the engine dying and no change in throttle position. I'm leaning towards CDI just on account of the misfiring.
 

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#19
I've had this problem before and found out it was the spark plug. once the spark plug gets over a certain temp it stops firing. i recommend you go replace the cheap Chinese spark plug with some ngk plugs
 



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