starting problems

Joined
Sep 4, 2013
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30
Hi all
Ive recently rebuilt my gas bike. I believe it is a skyhawk GT5 motor that I put on a GX7 frame and wheels. I had to add some spacers onto the throttle cable to stop the outer sheath from moving. Its not perfect but it did mostly solve that part of the issue. The current problem is that I can only get this motor to stay running while at around 1/2 choke. With the CHOKE wide open (not engaged) the motor would not start at all. I tightened the idler screw clockwise and was able to get it to run fairly decently with around 1/2 choke. It is definitely not at full potential once moving and running at full throttle. Also before I tightened the idler screw when attempting to start as I would twist the throttle it would almost sound like the motor was bogging down.
does this mean the motor is running to rich? which way do I adjust the "C" pin on the carb needle up or down?

any and all help is appreciated!!!
 


Joined
Sep 4, 2013
Messages
30
I should note that this is a brand new carb, air filter, velocity stack for this project. The motor does run not at its optimal level. it is a Onyx GX7 frame, 29" tires with a 40 tooth sprocket.
 
Joined
Sep 4, 2013
Messages
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it is an NT carb. bought it from gas bike. the spacers I used to get correct tension in the throttle cable are end caps from the new brake lines I put on. The bike is now running but still feels like its not operating at 100%. I'm guessing it is topping out around 20-22 mph but I still need to maintain around 1/4- 1/3 choke for this to happen. does this mean the motor is running to lean or rich? Is this a common problem?
Thanks
EG
 

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crassius

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Jul 23, 2012
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not sure why cable spacers were needed - may relate to the problem

needing choke to run means WAY too lean - usually an air leak
 
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without the cable spacers I could not get the slack out of the throttle cable. (without them when I twisted the throttle nothing would happen.) can I buy a roll of gasket material from an autoparts store and cut a new head gasket myself or do I need to order this? I will also check the gaskets around the intake and exhaust and report back with what I find out.
 

crassius

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Jul 23, 2012
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check that throttle cable and carb slide are in correctly - rarely see cable that much too long

if intake is steel, then check that chrome plating didn;t get a blob at the end - file end at 45degree angle if it did to get rid of air leak there

a head gasket that isn't burned or cracked can be flipped over and reused
 
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Sep 4, 2013
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So after a couple days of tweaking with the carb settings and a fresh tank of gas at 32:1, I finally have this beast running fairly well. the C-clip on the slide position is in the middle position which after trial and error i have found to give the best air/fuel delivery. I still have to run with about 1/4 choke but on a test ride today I maintained 30 mph according to a GPS speedometer on my phone. not sure why the 1/4 choke is still needed but im not really complaining about topping out at 30.

on another note: on my last test ride today before heading to work the I snapped the master link on the drive (415) chain. not a terrible fix bit not to sure what caused this.
 

crassius

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Jul 23, 2012
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4,575
possibly clip was on backward - open end of clip must be at rear of chain motion around sprockets
 
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