Love You Long Time, but not happy time...

EKK001

New Member
Joined
May 5, 2008
Messages
13
OK Guys,

Have spent the past few weeks reading all the different posts on here trying to figure out what is wrong with my Grubee 66cc and have tried all the different remedies but still not much success so lets see if anyone here knows the answer... I will try and keep this to the point....
The main problem is that it seems to rev really high when I pull the clutch in (idling)...
So i did some research and discovered it may be a possible airleak. I did all the stuff the other threads said (put the 0-ring in the intake manifold along with gasket goo, made up some a new high temp gasket for intake/engine along with more gasket goo)
This was all very promising, so i fired her up and went round the block, all looked nice for about 2 mins then it started revving its head off again...
More research....
OK, perhaps i am running it too lean. Needle is on middle position, so i move it down one...
Reassemble.....
Round the block again, wow, seems to have made a big difference and seems fixed... I'm going for a ride.... all going beautifully till about half hour into it then it starts blowing its top again... i can pretty much sit on 25kph without even turning the throttle... had to kill it at every set of traffic lights....
Sounds like a cable issue right?
Well i pulled off the air filter and all is working to plan, cylinder thing going up and down nicely, no resistance or sticking....
Must be an air leak somewhere.....
Round the block again today, all nice till warm up then it starts revving again... i read if you choke it, it is supposed to die immediately...
Seeing as though i had the air filter off i figured i would use my thumb.. so i stuck it over the hole and fut fut futttt..... she dies pretty much straight away... so i fire it up again an try the same with the choke except now it revs really hard instead of killing it?
Have tried putting plumbers tape around the threads where the throttle cable screws in cause i figured air may be leaking through there....
I have lost a bit of top end performance with the needle settings but it did seem to make a difference to the idle....
I did notice my throttle cable adjuster near the handlebar had vibrated loose so i tightened that up.. there is about a 2-3mm gap underneath the piston in the carburettor when the throttle is closed, is this correct?
I need help please as it is slowly killing my love for my steed.....
Cheers, Paul :confused:

nb. In pic, it shows boost bottles and nitrous installed but i have since removed them....
 

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Joined
Mar 16, 2008
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688
NOS? How many times did work? What does your plug look like? What is your oil ratio? How old is the engine, and how long has it been doing this? Has it been rejetted for the chamber? I would loosen the adjuster at the top of the carb, and turn the idle screw out till the engine wont idle to make sure the slide (cylinder thing) is going all the way down. Clean the carb. Spray some wd40 or water around the intake, base of cylinder, while the engine is runnig to check for leaks.
 

GasKicker

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Joined
May 28, 2008
Messages
72
This might be a stupid question, but I've seen it done before (twice). Did you assemble your throttle piston/cable upside down? Or perhaps did you not align the slot on the throttle piston with the idle screw?
 

Skyliner70cc

Active Member
Joined
Nov 17, 2007
Messages
1,340
too lean idle mixture probably due to low back pressure or incorrect header length on that tuned exhaust. Get one of those fancy newer carbs that have a more advanced idle circuit.
 

EKK001

New Member
Joined
May 5, 2008
Messages
13
Well, i sprayed WD40 around intake, didnt notice anything really weird happen...
As for throttle cable/piston, yes all in the right way....
Dont think it would be cause of the exhaust cause it was working fine with it before, and it seems to work fine until it warms up i think....
Engine is only a few months old, about 700kms on it so far, running at 20:1...
It has been doing it for the past few weeks....
When I spray the WD40 on it, where should i actually spray it? JUst where i think there may be a leak?
Have turned idle screw pretty much all the way out, its not even protruding into the cylinder anymore...
Its really ****ting me.......
Cheers, Paul
 

EKK001

New Member
Joined
May 5, 2008
Messages
13
Update, took for a ride around the block...
THrottle cable/piston definitely around the right way...
Played with idle screw, got it to idle nicely for a little while...
Sprayed WD40 around potential intake leaks and nothing again, sprayed it down the intake and it revved...
Stuck my thumb over the intake hole and it died...
Then fired it up again, let it idle... full choke and it revved its head off again, like real hard....
Checked the plug, attached a pic for you, seems a bit gunked up..
Perhaps it is cause i am running rich now because of my needle adjustments last week?
Is it worth taking apart the whole carb and seeing if there is anything in there?
Thanks, Paul
 

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Pablo

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1,855
Looks nasty rich. Move back to notch#2.

Sounds like an intermittent hanging throttle cable or sticking slide. When the bike is idling normally does the idle speed change at all when you turn the bars all the way, both ways?

Can you take a picture of the top of your carb?
 

EKK001

New Member
Joined
May 5, 2008
Messages
13
Ok, will move back up a notch..... as for turning the bars, not that i have notived but then again i havent directly tried it....
Which part of the carb do you want a pic of? The top with the cable unscrewed?
 
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