motorized bicycle 44 to 36 tooth sprocket swap

[Norman]

Wheel off the bike and mounted in the vice so its easier to work on. The 36 tooth new sprocket is laying on the bench, ready to go on after truing up the center hole which was 1/8" off center

I cheat when I can to make it go easier using an air rachet to get the bolts off. Yes the rachet isn't on the bolt I'm taking the pictures and doing the work Rufus is taking the day off again something about union rules and Sunday.

All parts are off I'm holding the fiber washer that goes inside the spokes it is the only one that gets cut. I'm reusing all mounting hardware

 

[Norman]

Making sure the sprocket fits with a little slop and not tight on the hub. Use the dremel if its a little tight on the center hole.

I'm putting the inside fiber washer in place. I cleaned off the hub and spoke area and checked for loose or broken spokes none were so I'm good to go.

This is the outer fiber washer resting in place. Be sure to have one fiber washer inside of the spokes and one fiber washer on the outside of the spokes.

 

[Norman]

The sprocket goes on next eyeball through the bolt holes so all bolts will go through with out hitting the spokes rotate the sprocket until you get it right. In this picture is not quite there yet.

How to get the nuts on working around the spokes. I put on all three backing plates and one bolt in each center hole of the backing plates and tighten lightly then all the rest of the bolts washers and nuts get put on but not tight yet.

Here is what it looks like with all hardware in place. Make sure the backing plates are all even and not over lapping on each other.

 

[Norman]

I put some blue dry marker ink on the 3 bolts and the screwdriver is Pointing at these 3 bolts they are in the center of the 3 backing plates I tighten these first while watching the backing plates so they won't over lap each other. Then I start tightening the rest of the bolts, I also check the trueness of the sprocket as I go up and down and side to side wobble. I try to get all up and down slop out and side to side to around no more than 0.015 play.

Look close, you will see a wire pointer I'm using as a guide to true up the sprocket As I spin the wheel I don't want the gap between the wire and the teeth to change. The sprocket is marked with blue dry marker ink and the pointer wire is next to it. I have the wheel mounted in the vice by its axle and griping the axle on the axles nut so I don't damage the threads on the axle.

You can see the pointer wire against the blue funnel in the back ground. The pointer wire is mounted on a strap of flat strap and clamped to a shelf in the back ground and not hanging in the air by magic. Look close and you will see the bolts are sucked up quite abit in this picture.

 

[Norman]

I have the dial indicator mounted on the iron strap and the dials stylis on the sprocket checking for side to side wobble once the up and down wobble is gone which I used the wire and eyeball method to true. I should have taken a picture of the strap from the side so you could see it better as to how it was done. The dial is on 0.000 here

The max side to side wobble is kept at 0.015 in this picture. Most of the wobble is adjusted out by tightening the high spot bolts

The difference in 44 and 36 tooth sprockets. Rufus likes to play with the drill incase you are wondering why the sprocket has so many holes

 

[Bikeguy Joe]

How did you measure to find that the hole was off center?

 

[Norman]

This picture shows how it all looks after all bolts are tight and the sprocket is trued up the chain is shortened and back on the bike. All I now need to do is put the guard back on and test ride.
I got it up to 38 mph and chickened out. But the engine speed in the 20 mph range is very nice and smooth just about 1/8 throttle and I motor along. It really lowered the cursing rpms. I can still let the clutch out almost from a stand still and motor away.
I did not go into great detail on this but you all should get an idea on how to mount the rear sprockets and true it up. I used the 3/8" drive air ratchet set at 80 psi tighten up all bolts until it stalled then I used my 1/4" drive hand ratchet to tighten up the bolts when truing the sprocket along with the 10 mm end wrench. This compressed the fiber washer tightly against the spokes and sprocket so nothing will wiggle loose I hope. Thats it.
Rufus now wants me to rub his fur backwards and then start taking the engine apart for the wrist pin replacement. He said he will let me play with the new 36 tooth sprocket for a few days before I tear into the engine. Man what a nice kitty.

 

[Norman]

measuring in an X pattern from the end off the teeth to the edge of the hole. I then bolted a good sprocket to the 36 tooth sprocket and compared them and then scribed the 36 tooth where I would need to remove material which I used a dremel tool to remove the excess material. I then mounted the sprocket on a machined shaft in the lathe to see if and when it was true I then checked that there is a small amount of slop or space between the inside edge of the sprocket hole and the bikes hub so I could center it up while getting the bolts tightened up that is where I used the wire to align the sprocket on the bikes hub to get the up and down play out of the sprocket this is more important than the side to side play because the up and down play will make the chain be tight then slack.
Norman

 

[paul]

i accidently removed some posts on this when moving to classic area. my apologies

 

[Norman]

Crusier

Which ones? Replies to what I did or some of the posts I did.? For me no big deal I can replace the pictures but I'll have to lie about the text as I 've forgotten it.
You doing good so don't sweat it. One question though? Does the new light work more like a torch instead of a candle?! I got to kid you to keep you in line you could use the new light to signal planes from the tower With the proper colored filters. I can't remember what they all mean so if I see a light flashed at me I kick in left rudder or right and roll into the light and take off the safety's on the guns and rockets and go to combat power. wide open.
Then all **** will break loose when my wings tear off .
Don't work to hard.
What about a Texas get together Bob has been talking about it he likes to grill and I like to eat and we all like to play with bikes, motorcycles, airplanes,cameras,hot cars, trucks, anything what moves and some that stand still
Norman

 

[paul]

no it was a couple responses. i put move instead of copy to the post i wanted in the classic area. it was only like 4 posts i lost. one was mine and one andy's not sure if any others. my bad

the light is unbelievably bright. i am going to have to make sure it is adjusted right so i do not blind oncoming traffic. you did a good job vader. i have come to the light side

 

[NickDK]

I just bought a 80 cc 2-stroke and on the instructions it says to cut BOTH rubber/fiber washers and to put BOTH on the inside of the wheel, over the hub. This way the sprocket is tight against the spokes (metal to metal). Is this right? I see you put one of those fiber washers between the spokes and the sprocket...The way I have it with both washers over the hub on the inside is working great -- over 30 miles so far and the chain has never slipped off and the sprocket is very true.

 

[MrLarkins]

what's the increase in top end speed?

 

[Saddletramp1200]

Nick, that don't sound right at all! The rubber keeps the sprocket tight against the spokes. Metal to metal is not good! Those spokes are not that strong! Maybe Andyinchville will be kind enough to help with this one. He is one of our sprocket experts.

 

[TwoWalks]

I just bought a 80 cc 2-stroke and on the instructions it says to cut BOTH rubber/fiber washers and to put BOTH on the inside of the wheel, over the hub. This way the sprocket is tight against the spokes (metal to metal). Is this right? I see you put one of those fiber washers between the spokes and the sprocket...The way I have it with both washers over the hub on the inside is working great -- over 30 miles so far and the chain has never slipped off and the sprocket is very true.

When reading install instructions I have seen both, cut and do not cut 2nd rubber washers. I decided the do not cut sounded correct. What I have not been able to understand is the wording "Tighten Bolts", how tight is that? 12 ft lbs - 30 ft lbs or ???? - think I am getting anal in my old age.

 

[Norman]

there isn't really a proper torque for them what I go by using a 1/4 drive ratchet when it hard to tighten I stop I also use an electric screw driver to do most of the work and the ratchet for the truing.
The spokes should be sandwiched, fiber discs on both inside the wheel against the spokes and a fiber disc on the out side against the spokes. it will keep the spokes happy. if you do it different it may work for a while but you will be sorry as it will eat the spokes in the long run. There is a bad miss print on some instructions and some very bad translations on some what we tell you here is to make your ride a success and not a failure at least I ain't going to lie to ya.
Norman

 

[TwoWalks]

there isn't really a proper torque for them what I go by using a 1/4 drive ratchet when it hard to tighten I stop I also use an electric screw driver to do most of the work and the ratchet for the truing.
The spokes should be sandwiched, fiber discs on both inside the wheel against the spokes and a fiber disc on the out side against the spokes. it will keep the spokes happy. if you do it different it may work for a while but you will be sorry as it will eat the spokes in the long run. There is a bad miss print on some instructions and some very bad translations on some what we tell you here is to make your ride a success and not a failure at least I ain't going to lie to ya.
Norman

Norman, thanks for this information as well as a lot of other good information you have placed on this site. The bolt torque really helps

 

[Andyinchville1]

HI All,

Concerning the use of the rubber spacers on the 9 hole mounts , I have to agree with Norman....Best to use the rubber spacers to sandwich the spokes.....rather than steel on steel as suggested.

In theory, one may be able to get away with steel on steel for awhile IF there is no movement between the two pieces (in this case the steel of the 9 hole mount or sprocket and the spokes themselves)....which could result in a cutting action between the 2 pieces and result in damaged parts / possible accidents.

The hub obviously has the spokes passing through them which is steel on steel or steel on aluminum depending on hub material, BUT since there is no real relative motion between the parts that is why they last....

Lastly, since the rubber "conforms" to engulf the spokes, they allow for more surface area to transmit the engine torque to the spokes rather than just the "tops and backs" where the metal touches the actual spokes should the rubber parts be omitted.

That's my take on the rubber or no rubber situation.

Hope this helps.

Andrew

 

[psprat496]

Where did you get the small sprocket?

 

[Norman]

got it off of ebay from a guy in Az.
I think its off a front sprocket from a bmx bike.