no guts to pull from stop

nodar · #1 08-02-2009, 05:17 PM

I have a "80cc" engine kit from tsunami bikes that I have installed. It's working pretty well and am pleased with it for the most part. My only dissapointment is the lack of power when starting from a stop. I may have expectations that are too high, but I thought that it would get going more like a dirtbike. ie. no need to pedal to take off once the motor is running. With the bike idling, if I give it gas and let off the clutch and don't pedal with it to break the inertia of starting the motor stalls. I thought mabey it would have a little more pull but should I assume all the chinese kit engines are more or less the same in that situation. It rides great once I pedal with it and get some speed.

Is this just how these small motors work?

thanks.
Pete

Pablo · #2 08-02-2009, 05:39 PM

With a stock set-up you will need to pedal to start unless you have an extra large rear bolt on gear.

Retmachinist · #3 08-02-2009, 05:50 PM

It's not the engine that is keeping you from starting from a dead stop, it is the clutch set up on these engines and the gearing. If you go to a large enough rear sprocket, depending on your weight you will be able to take off. The down side is you will be sacrificing top end speed.

John

chrisme · #4 08-02-2009, 06:41 PM

Just having one gear on the bike is like always having your car in 3rd gear. You can't really start from a stop, and you can't really go that fast. That is why sick bike parts made the shifter kit, so you can shift gears on your bike just like you would in a car. You can start from a stop, and cruise along at a nice speed with low RPMs.

Cabinfever1977 · #5 08-02-2009, 11:46 PM

actually its like always having your car in first or second gear. my bike takes off from a start like a rocket with no peddaling and could drag a person or 2 behind it. and i can cruise around 30mph. i weigh 120lbs and i have a 48cc with 44t sprocket and everything is stock.

matt167 · #6 08-03-2009, 12:28 AM

I have to pedal up to 5 MPH b4 it will go on it's own..

nodar · #7 08-04-2009, 08:30 PM

I built up a bike with the same engine for my cousin and it will take off from a couple easy pedal strokes and accelerates a lot quicker than mine. They are the same engine with the same set up on the carborator. When I think back on it I've been having less than stellar preformance since I took ot on a ride in the rain and mud. The barrel the needle is attached to got stuck open, so I cleaned it up to allow the throttle to work again, although the throttle is stiff to turn and the cables are gritty the carborator did seem to work fine. (slide easy) I thought. I'll clean it up again just in case but I don't know what else could cause the lack of get up and go at the start.

cheers

chrisme · #8 08-04-2009, 08:39 PM

Does yours have more in the top end than his? Because there was someone on here a while ago saying there wasn't much quality control in the ignition. As in, some of the engines had slightly advanced ignition, and some had slightly retarded ignition. That could be part of it. These engines are really 'luck of the draw'. Some are good, some aren't as good.

nodar · #9 08-04-2009, 08:58 PM

It goes a little bit faster but not that much. You used the word ignition and it got me thinking. His bike fires up after two pedal strokes no problem and I think my engine doesn't ignite right away. I am finding I have to help it along with pedaling until it catches a lot more than I used to. The engine is only about a month old but I use the **** out of it off road.

cheers

**2door** · #10 08-04-2009, 11:08 PM

Quote:

Originally Posted by chrisme

Does yours have more in the top end than his? Because there was someone on here a while ago saying there wasn't much quality control in the ignition. As in, some of the engines had slightly advanced ignition, and some had slightly retarded ignition. That could be part of it. These engines are really 'luck of the draw'. Some are good, some aren't as good.

Chrisme,
You are correct. I've checked the ignition timing on 4 engines and had different readings on all of them. The best running of the four had a timing that was over 3 degress advanced from the next one down and it runs great. Power and easy starting. The keyway in the crankshaft that indexes the magneto rotor (magnet) appears to be cut,
in-the-ballpark, from the factory and not the same for every engine. It's probably why some run better than others. A few guys have played with off-set keys to advance the timing with good results. I'm playing with a way to rotate (advance) the magneto coil. No results to report yet but I'll keep working on a movable mount.
Tom