Building a 4-stroke bicycle

[Sidewinder Jerry]

That's a GREAT idea Jerry. I was surprised to see more damage on the backside than the front. But here's a bigger mystery..........Let's assume the diameter of the 20T pulley is one inch. We know it's a little larger, but it's OK for illustration purposes. The circumfrance equals Pi x D with Pi being 3.14 What this means is (assuming only one set screw) each time the pulley goes around it makes an impression on the belt and the distance between contact points is going to be 3.14 inches. That is definitely not the case here as the picture shows. Take the belt off and see how many set screws are in the pulley. If there are two directly across from each other the distance between contact points will be 1.55 inches. Unless there is something in between the teeth of the large pulley I believe this to be a used belt that has been damaged previously. Your thoughts.......................................

I believe the OP said a cover case screw caused the damage to the back of the belt.

 

[Sidewinder Jerry]

get that set screw flush or it's gonna ruin the belt in short order

Yeah I know the damage on the OD of the belt was caused by something else, but that set screw will soon start chipping away at the belt teeth on the ID and your belt will be trashed in a short time

Get a new belt anyway it's already compromised

The majority of the time with these set screws they contact a flat part of the shaft. If put under enough stress the set screw can still move slightly on that flat part.

They also tend to leave a mark on the shaft when tightened down. If there's no mark, you can remove the set screw and use a marker in the hole to mark a spot on the flat part of the shaft. That's the spot where to use a drill bit to make a dimple. This can flush the top of the set screw and makes it impossible for it to move any on the shaft.

 

[GodMan]

Everyone while testing my setup more yesterday. I noticed the engine will die after running at idle for a little while.

I had the choke off, and the engine ran fine for 10 minutes or so. I believe this is a fuel issue.

It seems that the fuel line and the fuel filter get a small flow of gas.

I had the fuel petcoc open as well.

 

[michael whiteman]

All us 4 stroke guys are running the same fuel line and filter and seeing yours is brand new, I doubt if fuel delivery is your problem. The first thing to do after it is warmed up and idleing would be to adjust the idle mixture. Have you done this?

If you think the fuel is not flowing enough take the cap off and blow in the tank to pressurize it. Take a deep breath, hold the pressure and see if this helps.

 

[Wrench]

Everyone while testing my setup more yesterday. I noticed the engine will die after running at idle for a little while.

I had the choke off, and the engine ran fine for 10 minutes or so. I believe this is a fuel issue.

It seems that the fuel line and the fuel filter get a small flow of gas.

I had the fuel petcoc open as well.

Don't run the engine at idle for 10 minutes, it'll overheat

 

[GodMan]

@michael whiteman I have not. I massaged the fuel line to get the fuel filter to feel with a good supply of gas, and it did not happen again.

@Wrench Good to know. I added a small, but strong fan on my bike to keep a strong airflow over the engine for idling at a stop. I'm not sure how well that would work thoughts.

 

[Risk Man]

@michael whiteman I have not. I massaged the fuel line to get the fuel filter to feel with a good supply of gas, and it did not happen again.

@Wrench Good to know. I added a small, but strong fan on my bike to keep a strong airflow over the engine for idling at a stop. I'm not sure how well that would work thoughts.

View attachment 211724

I use high velocity (40cfm) compact computer fans for cooling all of my bikes. I think it makes a difference especially when you are stopped and idling.

 

[Will'smotobikes19]

Don't run the engine at idle for 10 minutes, it'll overheat

Hmm maybe for a whizzer but the huasheng has a fan on the flywheel and a blower shroud. Don't think it would overheat in 10 mins. These engines were originally pump engines being stationary while running for a long time.

 

[GodMan]

Guys. What is the difference between a 79cc 4 stroke and the 53cc one I have now.

For example I see a 79cc one. I think it's referred to as the "predator engine", and even some claiming 100c 4 stroke engines.

Obviously more torque right? Are they faster?

 

[Wyvern]

Guys. What is the difference between a 79cc 4 stroke and the 53cc one I have now.

For example I see a 79cc one. I think it's referred to as the "predator engine", and even some claiming 100c 4 stroke engines.

Obviously more torque right? Are they faster?

More cc's more grunt (usually), maybe get the gearing slightly taller, but most these engines are governed under 3800rpm unless you remove it and do the work to it so it doesn't blow up.

Worth mentioning the shaft is going to be totally different than the little Zehoa type engines, they take go-kart style clutches and converters.

Predator is a brand name from harbor freight, they have a reputation for selling quality Honda clone engines.

I have a 224 Predator, totally different monster.