Is a jerky ride at slow speeds normal?

G

goofyfoot2001

New Member
Just finished a build and have about 20 miles on the bike. The motor is very jerky at slow speeds, is this normal? When the bike is in its good range (20-25mph) everything seems fine.

Oh and sometimes when I'm coasting I get an audible flat ping sound and a second of hesitation like it caught on something. any ideas?
 
It would help if we knew what engine/drive you have. If, it is a Chinese in-frame two stroke here's some advice.

How slow is "slow speeds"? Just like any vehicle with a manual transmission, if you try to go too slow the engine will buck. If you want to ride under about 8 to 10 MPH then you should disengage the clutch (squeeze the handlebar lever) and pedal. 10 MPH seems to be about the normal minimum speed for a chain drive 2 stroke.

Check your chain tension and alignment. Too loose and the chain can try to 'wrap' around the engine drive sprocket. This noise could also be a result of your low speed with the clutch engaged. You'll want 1/2 to 3/4" of slack in the chain. No more, no less.

Tom
 
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With my two stroke I'm in the same boat, I have about 75 miles on it. At the beginning of my friends build who built it before me and I rode it and I call it piston clank going at slower speeds or persay engine braking the engine makes this noise and you can feel it almost buck. I find this to be normal because it happened to my friend as well as me until I got it broken in more. And as time goes on the ride gets smoother and smoother my friend, who has a good month on my bike I am surprised when I get on it how smooth it is, even at slower speeds. It gets a lot better!!!
 
Everything about the Chinese 2 strokes gets better with miles. They seem to mature with age, like fine wine :)

Tom
 
Before a motor is broke in they can be a bit jerky, specially at low speeds. If they are still jerky at low speeds after broken in then you might look into tuning the carb a bit. Mine used to jerk badly, after tuning the carb she runs really smooth at the slowest speeds, I can pop the clutch going a couple mph and the motor starts right up and the bike rides smooth even at slow speeds. Right now my carb is tuned a bit rich due to a change in the air filter, I haven't had time to tune the carb to match the air filter yet. I noticed when tuned a bit rich its extra smooth at slow speeds, but the top end is a little lacking...
 
I replaced my carburetor and had the same problem as you with the new carburetor. No matter how I adjusted the carburetor, the bike would be jerky when I let off the throttle, especially at low speeds. It helped to set the needle a bit leaner but that just made it less jerky, not eliminating the problem altogether. The needle on my new carb had only four notches, but the old needle had five. I put the old needle in the new carb and it ran much better. So for what it's worth, try finding a needle that has five notches and see if that works better. The setting I used is dead middle on the needle
 
Some of this jerkiness is due to the clutch shaft sprockets being made with a lot of eccentricity in their teeth and there's really no way to get rid of it except to order a few and weed out the ones with the worst out of concentricity.
 
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