Hi all, i just put a offset intake on my bike yesterday. my carb was leaking so i replaced it with a spare nt carb i had. however now when i hit anything higher than 20 mph, my engine makes a spluttering noise and wont go faster. its almost like the spark plug is not ingniting at that speed, it sounds like when you "tap" the kill switch. Any ideas?
Engine spluttering when I hit 20mph...
- Thread starter dimentio
- Start date
I also have a similar problem I have a new sd stinger and when I hit around 20 mph it will bog down does anyone know what could be the problem?
To the OP, is the jet and needle clip the same in the replacement carb as the original? Also check your float level.
Bigdaddy, which carb are you using and how many miles are on your engine?
Bigdaddy, which carb are you using and how many miles are on your engine?
Well, apparently you changed the intake (to offset) AND changed your whole carb as well? Even if they are both the same or similar carbs they may not run the same on your motor due to float adjustment, jet size, needle setting etc. So you may need to tune the new carb a bit to make it run like the old one (unless this carb has previously been tuned to your motor). You could swap over the float and jet from the old carb and set the needle the same, that should give you a damn close starting point. With a different float and jet in the new carb chances are it will run... different...
PS is the air filter the same on the new carb as the old?
Check your spark plug if you've been running it for a while.
Did you stretch any wires when you installed the new intake manifold and carburetor. Check to see your wiring connections are good and check to make sure your spark plug wire is solidly connected to the CDI and also to the spark plug.
How long was that NT carburetor sitting. Did you clean it before installing it. How is your fuel filter?
How is the engine vibration. Possible that your fuel is foaming due to the longer intake manifold. It is possible that the vibration of the engine is causing a foaming which might cause a lean condition. Check your engine mounts to make sure they are secure.
Disconnect your kill switch from the circuit to see if any improvement.
Good Luck,
Chris
AKA: BigBlue
Did you stretch any wires when you installed the new intake manifold and carburetor. Check to see your wiring connections are good and check to make sure your spark plug wire is solidly connected to the CDI and also to the spark plug.
How long was that NT carburetor sitting. Did you clean it before installing it. How is your fuel filter?
How is the engine vibration. Possible that your fuel is foaming due to the longer intake manifold. It is possible that the vibration of the engine is causing a foaming which might cause a lean condition. Check your engine mounts to make sure they are secure.
Disconnect your kill switch from the circuit to see if any improvement.
Good Luck,
Chris
AKA: BigBlue
Well, my bike will hardly idle now when i come to a stop. i tried multiple carb slide positions and the weird part is that if i put the choke on all the way up, i can still pull the throttle 3 or 4 times and it will rev before it dies.... does that mean the fuel is foamed in the longer intake?
If you close the choke and the engine will still run you have an air (vacuum) leak. Start looking. The most common place is the carburetor where it attaches to the intake manifold and the gasket at the manifold to cylinder.
There are other possibilities such as a crank shaft seal or a case gasket but start with the simple and most common places first.
Tom
There are other possibilities such as a crank shaft seal or a case gasket but start with the simple and most common places first.
Tom
Try the original carb on the new intake (even though its leaky or whatever) if the motor runs well then swap over the jet and float from the old carb to the new carb. Again, just because they are the same model carb doesn't mean the float is set the same, or the jet is exactly the same size, these things are all thrown together and stuff varies... And again, has the air filter changed? The flow of a different air filter (or clogged air filter) can certainly effect how a motor runs...
had this a couple times with those long intakes - fuel was foaming in the carb and just leaving air bubbles to run on
I've done 2 fixes that worked
1) add a piece of rubber hose in the middle, then tie-wrap the carb to the frame to support its weight - that way it can't shake
2) turn the intake upside down, cut it off so it right angles toward the drive chain, mount the carb, bend the clutch arm down a bit (and maybe rotate it a bit on its shaft) to clear the bottom of the carb - this way intake is as short as stock
both worked
I've done 2 fixes that worked
1) add a piece of rubber hose in the middle, then tie-wrap the carb to the frame to support its weight - that way it can't shake
2) turn the intake upside down, cut it off so it right angles toward the drive chain, mount the carb, bend the clutch arm down a bit (and maybe rotate it a bit on its shaft) to clear the bottom of the carb - this way intake is as short as stock
both worked
Yeah, that happened when I was running too rich recently. Mine was just bogging down and losing power though. It wasn't sputtering (4-stroking).
I remedied it by moving the e-clip up one notch, but I think the OP has already tried that.
Like 2Door mentioned, you may want to check for a vacuum leak. There are many posts on this topic. Some people recommend having the bike idling then spraying potential leak areas with (WD-40?), and if the idle changes you've found the leak.
I remedied it by moving the e-clip up one notch, but I think the OP has already tried that.
Like 2Door mentioned, you may want to check for a vacuum leak. There are many posts on this topic. Some people recommend having the bike idling then spraying potential leak areas with (WD-40?), and if the idle changes you've found the leak.
Here's a link to a NT tuning basics that has pictures of the NT carburetor broken down and parts labeled. It might help:
http://www.motoredbikes.com/showthread.php?24867-NT-Carb-Tuning-Basics
Chris
AKA: BigBlue