Please help!!! I need help SO bad!

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captemo

captemo

New Member
Jul 25, 2011
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Florida
Please help! I am new to this forum ad motorized bikes in general. I have a Grubee SkyHawk GT5 66cc 2-stroke engine. With the regular carb not the CNS specialty one.

Anyways when the clutch is pulled in it idles at a very high rpm. However when I let the clutch out it drops down to a normal average rpm. It works fine until about mid-throttle. Then the engine boggs out. If I drop the throttle back it works fine. It didn't use to do it. My dad has been the one that has been modifying the carb with the idle adjustment screws.

I have tried to read up on it but can't find anything in particular on this problem. I think I may have to turn it to less fuel, more air. If that's correct or incorrect please let me know. Also should I be running a more lean gas mixture? Please help. Thanks in advance! If you need more info let me know. I will try to get back to you as fast as I can.
 
Pilotgeek

Pilotgeek

New Member
Apr 6, 2011
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Green Bay, WI
Does your carb say NT on the side? It sounds like you might be running too rich. I know mine will idle high if it's rich. If you back off the idle screw a bit, you can probably get a lower idle that way. Do a plug chop (search the forums on how to) and you can get a good idea of which direction you need to go in tuning your carb.
 
moronic_kaos

moronic_kaos

New Member
Apr 6, 2010
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Connecticut
Too much air or fuel

Causes: Air leak or improper mixture setting.

Solution #1: Try adjusting the air/fuel to make it richer/leaner.

Solution #2: Clamp the carb in a slightly different position on the intake. Wrap it in gasket paper temporarily if possible. Just make sure it's absolutely 100% sealed to that intake. Common problem out of the box.

Solution #3: Replace gasket. Usually where the intake meets the cylinder or the cylinder base gasket. Look for cracks or a tear.
 
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biknut

biknut

Well-Known Member
Sep 28, 2010
6,631
409
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Dallas
Could be an intake leak. That will make it idle fast. Is there any oil leaking out around where the manifold connects to the head?

If you're running the NT carb try the needle in the leanest position. both of my bikes like that position best.

Get a NGK BP6HS spark plug. Toss the stock plug in the trash.

And welcome to the forum!
 
captemo

captemo

New Member
Jul 25, 2011
9
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Florida
Thanks everyone but I found out that it was actually a CNS carb and not the NT. I will try the ideas though. I will also try to get back to anyone as soon as I can to further update this. I thought the CNS was the special one not the NT. Got a little confused.
 
captemo

captemo

New Member
Jul 25, 2011
9
0
0
Florida
I have also heard that the CNS stock carb's jet may be starving the engine for fuel. It may be a result of being too small. If you have any information on this please help. My dad and I have been researching for anything that may help. That's why I turned to this forum.
 
K

kevinkrg6

New Member
Jun 3, 2011
170
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ohio
The main problem that causes bogging with these CNS carbs is a bad intake seal. They're just not sealed well, it's a plastic gasket ring. Seal the intake (coming from the carb, going to the engine) with black silicone gasket sealer, and seal it up good.

Otherwise, the engine is getting way too much air.
 
captemo

captemo

New Member
Jul 25, 2011
9
0
0
Florida
@kevinkrg6
Do you have a CNS and did this happen to you and work for you? Ours appears to not be sucking air and seems perfectly sealed. If this has happened to you and worked for you we will give it a try. We don't want to seal the gasket and not be able to open it back up. You don't want to go forward and then not be able to turn back if it turns out wrong.

Is the sucking of excess air undetectable? Also gasket sealer will get hot. So with engine heat how long would we expect the sealer to last?
 
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captemo

captemo

New Member
Jul 25, 2011
9
0
0
Florida
@biknut
Thank you so much! The post you led me to seems like the exact one. It is very helpful and sounds exactly like ours. How is yours running?

So far you have been very helpful so thank you! As well as everyone else you have helped me too! :)

Also didn't do anything about this earlier but thank you for welcoming me to the forum.

_______________________________________
pino. Drivin' away like a gangsta!
 
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biknut

biknut

Well-Known Member
Sep 28, 2010
6,631
409
83
Dallas
captemo said:
@biknut
Thank you so much! The post you led me to seems like the exact one. It is very helpful and sounds exactly like ours. How is yours running?

So far you have been very helpful so thank you! As well as everyone else you have helped me too! :)

Also didn't do anything about this earlier but thank you for welcoming me to the forum.

_______________________________________
pino. Drivin' away like a gangsta!
Click to expand...
You're very welcome. That's what this forum is about, and I've been on the receiving end of a lot of help here too.

That bike belonged to a Customer. It runs pretty good now, but I had to give it back to the owner before getting it perfect. It ran a lot better than it did out of the box, that's for sure.
 
captemo

captemo

New Member
Jul 25, 2011
9
0
0
Florida
Okay, we have done everything except for drilling out the jet. We will do that next but before we move on to doing that the question we have is this; which jet is the main jet that we need to drill out?

We know that there are two but would like to find out which one is which. We will try to figure it out on our own but if you could get to us quickly that would be great. Thanks!

___________________________
usflg Drivin' away like a gangsta!
 
captemo

captemo

New Member
Jul 25, 2011
9
0
0
Florida
Woot! Just edited stuff to have an avatar as well as a signature! This message is just a test of those changes.
 
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