Too much fuel, not enough air.

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maniac57

Old, Fat, and still faster than you
Oct 8, 2011
4,484
22
0
memphis Tn
Anytime you break stuff, it's always a good idea to clean the bottom end extremely good before bolting new (expensive) parts on it.
I rinse out all my new motors just in case....
might have something to do with my excellent luck with these motors.
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
When it comes time to install the new rings you'll need to be very careful and not break them. They aren't made of rubber and will only stretch so far to go over the piston. Go slow and carefully work them on in a circular motion into the ring grooves.

There are ring gap alignment pins in the piston ring grooves. The gaps of the rings must align with those pins or the rings can not be compressed enough to slide back into the cylinder bore. Lubricate everything, rings, piston and cylinder with whatever oil you use in your fuel mix before reassembly.

My concern is that if you had broken rings that there is damage to the cylinder walls. It would be rare that the rings would break when the engine is running and there not be damage to the cylinder. Inspect the cylinder walls for gouges. A damaged cylinder will not allow the new rings to seal and you'll be back to square one and will have wasted you money and time buying new piston rings.

Tom
Ditto.................................
 

Targan

New Member
Jun 22, 2013
56
0
0
Scottsdale
Rings have been installed! No luck with fixing my issue though :/ Plug still comes out oily and black-ish even on leanest settings possible for the carb. It ran choppy for a minute, then just fine for another minute, then it boggged and died. My bike idles just fine but as soon as it gets moving it jerks violently and won't idle anymore. Choke completely kills it and my idle screw has to be screwed almost all the way in.
 

2door

Moderator
Staff member
Sep 15, 2008
16,302
175
63
Littleton, Colorado
Rings have been installed! No luck with fixing my issue though :/ Plug still comes out oily and black-ish even on leanest settings possible for the carb. It ran choppy for a minute, then just fine for another minute, then it boggged and died. My bike idles just fine but as soon as it gets moving it jerks violently and won't idle anymore. Choke completely kills it and my idle screw has to be screwed almost all the way in.
Just curious here, but how slow are you trying to ride the bike with the clutch engaged?
From your description it almost sounds as if you're trying to idle along. That won't work. Anything below 8 to 10 mph and the clutch should be disengaged.
Or am I reading your last post wrong?

Tom
 

neum5464

New Member
Jun 13, 2013
25
0
0
Huntington Beach
Did you retighten the head bolts after break in? if engine is oily with low mixture it could be an engine leak causing both problems. only suggesting because you mentioned not messing with the engine. could be wrong but I think proper torque is around 12lbs for the head bolts?
 

Targan

New Member
Jun 22, 2013
56
0
0
Scottsdale
Just curious here, but how slow are you trying to ride the bike with the clutch engaged?
From your description it almost sounds as if you're trying to idle along. That won't work. Anything below 8 to 10 mph and the clutch should be disengaged.
Or am I reading your last post wrong?

Tom
I'm hauling ass down the road to keep it running lol. I engage the clutch around 12-15mph
 

Targan

New Member
Jun 22, 2013
56
0
0
Scottsdale
Did you retighten the head bolts after break in? if engine is oily with low mixture it could be an engine leak causing both problems. only suggesting because you mentioned not messing with the engine. could be wrong but I think proper torque is around 12lbs for the head bolts?
I don't have the proper tools to measure head torque, but they're on there super tight.
 

Targan

New Member
Jun 22, 2013
56
0
0
Scottsdale
Just wanted to update and say my engine is flooding really bad. What would cause this? It just makes me mad because my bike ran fine for 2 weeks after installing the NT carb, but all this crap happened
 

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
4,484
22
0
memphis Tn
Float needle dirty?
If gas comes out the air cleaner, clean the needle and seat and get a inline fuel filter to prevent trash from getting into it.
Every single kit I've built had paint chips and assorted trash in the tank, and even after cleaning, paint still chips off from around the gas cap opening for a long time.
A fuel filter is cheap insurance.
 

2door

Moderator
Staff member
Sep 15, 2008
16,302
175
63
Littleton, Colorado
Ditto:
If the bike ran good then the problem started the most common cause is trash in the float valve needle and seat.
Another possibility is that the float has a crack in it and it has filled with gasoline and sunk not allowing the needle valve to close which will also cause extreme flooding. Defective floats are also a common problem.

Tom
 

Targan

New Member
Jun 22, 2013
56
0
0
Scottsdale
Thanks for the info. The problem started after i installed the filter (along with the carb) so i doubt trash is the problem. When I dissasembled my carb last night I cleaned it thouroughly and the float was floating right. This whole thing is a nightmare. It's my main mode of transportation. I'm going to try bending the float tab thing to make the level of fuel lower in the float.
 

Targan

New Member
Jun 22, 2013
56
0
0
Scottsdale
Update: Before messing with the float i decided to buya new spark plug and read it. turns out my engine doesn't seem to be running rich. Spark plug is tan-ish with very little oil. But it is still very jerky and bogging. Idle screw is almost all the way in to keep it running. the choke completely kills the bike
 

Huffydavidson

STREETRACER/MANUFACTURER
Jan 29, 2012
1,076
4
38
st.louis,mo.
You do know BGF has NT carbs for like $12 on e-bay. And if your engine is not leaning to forward, you should'nt have screw with the float.
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
My carb appears to be in perfect condition. It's pretty much brand new too :/
If it is a fuel issue you're having then its a carb issue plain and simple, nothing else controls fuel supply or lack of to the engine, either you have adjustment issues or you have a bad part issue such as float, needle & seat not sealing properly.

I can really screw up the inside of a carb and it still look as though it is in excellent condition, looks can be deceiving so don't think that just because something looks good that it is, you have to understand what the problem is and how the carb can be the reason and why it will cause the problem if there is a malfunction or a defect.

If you can afford to spend $12 bucks go to BGF or LEB on ebay or even go Thatsdax site page 2 in his parts list is a new NT for $15.99, get a new carb, stick it on and see what happens, Huffy D mentioned this and I would say at this point that would be a good idea.

best wishes

Map
reddd
 

Targan

New Member
Jun 22, 2013
56
0
0
Scottsdale
WOW! It was the darn spark plug all along! I was using the wrong kind. I bought like 5 different ones when I got home and BAM I got it running like a bat out of ****! (also my bike seems WAY quieter than normal but FAST!) It wasn't the mixture, the carb, or electrical at all! My previous spark plug fouled when I used too much oil one time a month ago and I never replaced it. I thought cleaning it would work so I never blamed it. Then i bought the wrong spark plug as a replacement and again, ignored it. I was so mad I bought 5 spark plugs (lol) and tried them. dance1