Carby Carb problem

I

Irish John

Guest
I've just built a 70cc 2-stroke and have taken it for a test run. All is OK except the engine dies off if I open the throttle to full on a hill. How can I eliminate this so full throttle is restored?
 


kimhas

New Member
Joined
Mar 24, 2008
Messages
4
Hallo, I also build i bike with a zbox 80cc motor. I have the same problem. It goes good in lower speed and when its flat but when i give full trottle its no response. spesialy when its uphill
 

RdKryton

Active Member
Joined
Nov 6, 2007
Messages
949
I'll try to help. sounds like the carb is set wrong.
Here's a link with a similar question.

http://www.motoredbikes.com/showthread.php?t=8209

Also check for proper plug gap. It's very important. There is a sparkplug wire upgrade that helps too. You will need to search for that link. I have to run for now.
Good luck

Jim
 
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I

Irish John

Guest
Solved Carb problem

I solved the carb problem by moving the clip in the carb needle to the lowest groove on the needle - i.e. the one nearest the pointy end. It was being starved of fuel on the higher setting. I've done it on 2 engines now and the problem is solved.
 
F

fetor56

Guest
I solved the carb problem by moving the clip in the carb needle to the lowest groove on the needle - i.e. the one nearest the pointy end. It was being starved of fuel on the higher setting. I've done it on 2 engines now and the problem is solved.
Yep man i figured u would have already tried that...my message was more meant for kimhas but the general message of giving it time and distance still applies.
 
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I

Irish John

Guest
Carb

I think it was Fetor (Thanks so much for that) who told me about the carb needle settings and it confirms what a really knowledgeable motorbike mechanic also told me. This problem would not have ironed itself out over time. It needed done straight away. I find the majority of my motors are improved on that highest carb setting. It's all academic because soon I'll become a 4-stroker and can kiss good ridance to the HT. If the 4-strokes go Ok I can build and sell them - something I would never do with the HT because people would be forever coming back irate and angry. The motorbike mechanic mentioned above won't have a bar of these motors after doing a few rebuilds.
Despite there being 3 different sizes of HT motor they all have the same ports and exhaust which just about tells you everything.
Does anyone know what speed the chinese 4-stroke that comes with the Grubee gearbox cruises comfortably at? Is it similar in power output spec to the Honda GXH50?
 

kimhas

New Member
Joined
Mar 24, 2008
Messages
4
Thanks for anwers. I have now take a trip with the bike. I im the run in periode so i take it easy. It goes better with the choke half on. So i also think its get to much air/ to little fuel. I will do the o-ring triks and adjust the needle and see if its helps. its around 0 celcius , mayby it is easyer to get it run smooth when its hotter outside.
The oil/fuel is now 16/1. I think it will run better after run in when I can use less oil.. right?
 
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