NT on new Grubbee 80 has intermittant bog/ skip.

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30Ratt

New Member
Mar 8, 2011
35
0
0
Lewes, DE
Have a new build w. a Grubbee 80 & NT carb. It bogs/ skips intermittantly.
This is what I.ve done so far:
Tightened the intake (used a shorter one).
Tightened the exhaust.
Sealed around the carb mount.
Looseened & tightenend chain.
Leaded mounts (vibration).
NT carb. idle (dinked with & still won't idle)
NT carb needle adj.: changed clip level (this helped a bit)
First tank of fuel & I have about 5.4 oz. of oil/gal
[The NT is still better than the CNS]
It bogs/ skips intermittantly
 
3

30Ratt

New Member
Mar 8, 2011
35
0
0
Lewes, DE
OK....
Opened gap in plug & it helped some.
Rebuilt (inspected inside) carb and it helped some more.
Put larger breather on carb. no change.
Would a larger Jet help? (keeping in mind it is a Grubbee 66cc w. a new stock NT carb)
I heard mention they were all jetted for 49cc.
 
rohmell

rohmell

Active Member
Jun 2, 2010
1,531
6
38
New York
Does it bog/skip at all throttle positions?
The main jet only comes into play at around 3/4 to full throttle.
 
3

30Ratt

New Member
Mar 8, 2011
35
0
0
Lewes, DE
It skips at many throttle positions quite intermittantly like this: (DaaaaaDDDaaaaaaaaaaaDaaaaDaaaaaaaaaaaaaaaaaaaaaaaDD).
Sorry tried to create an audio, but it wasn't crisp enough.
I put on a chrome exhaust from an old R-- engine. that is much quieter than the 'Black Cat' that comes with the kit. Maybe too much back pressure??
 
3

30Ratt

New Member
Mar 8, 2011
35
0
0
Lewes, DE
Could be. Maybe I'll order a new one today. Connections are fine. Never did like the cap to sparkplug connections on these things.
 
3

30Ratt

New Member
Mar 8, 2011
35
0
0
Lewes, DE
Maybe I'll try replacing the spark plug wire w. a car spark plug wire. They sell these separately from the CDI anyway. Are they hard to replace?
 
3

30Ratt

New Member
Mar 8, 2011
35
0
0
Lewes, DE
Put in a new plug wire (easy)w. no change.
Tried a different CDI w. no change.
Getting to the bottom of the first tank. What mix do you for break in?
 
3

30Ratt

New Member
Mar 8, 2011
35
0
0
Lewes, DE
Finally found the problem.. A GIANT AIR SUCK HOLE (no, not Congress).
I remembered the shade tree mechanic's trick (back when you could work on your own car) of spraying starting fluid around the 'suspect' area. I had resealed the head/intake gasket and the intake/carb pipe. Still getting reaction, so must be the carb/bowl gasket. Ran out of time. Check it out over the weekend.
 
3

30Ratt

New Member
Mar 8, 2011
35
0
0
Lewes, DE
Plug wires a no go. Just got new cdi. Will try that tomorrow. Done the starting fluid thing on the NT. Fixed a couple of air leaks. Just found out the primer button is supposed to suck air. Upgraded plugs gapped at .32 I put a 36 :confused: toother on the back & that really reduced vibration(maybe she was revving too high).
 
rustycase

rustycase

Gutter Rider
May 26, 2011
2,746
5
0
Left coast
I got the same symptoms, 30...
and u made a valiant effort at typing the sound! lol

I am presently richening mine to get it to the point where I drown out everything, then I'm gonna start leaning it out, little by little til I get optimal running.

It started out four-stroking, so I leaned it out. went from #71 to #74. it fell on it's face! NO power. NOTHING there!
Now I'm taking it back fat, a step at a time.
AND, I now got my needle high as it will go, on the #5 groove.
I'll deal with the mid-range mix AFTER I get WOT resolved.

(((I suspect the needle diameter/and taper could use some attention AND would really like to hear from someone who has filed a different angle on the slide)))

Anyone know of a cheapie method of recording audio for u/l'ding ? :)

Best
rc
 
C

Crazy Grandma

New Member
Jun 8, 2011
27
0
0
mission viejo, ca
rohmell said:
Does it bog/skip at all throttle positions?
The main jet only comes into play at around 3/4 to full throttle.
Click to expand...
I have a question mine does that and I'm running a NGK B6hs and only half the electrode is black the other tan. Read a thread on here going to a B7hs tonight but its been running good in the cool morning and up hill from work and warm bad home. how do you adjust the clip also on the needle jet. I hope I didn't mess up a piston
 
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