Drive Sprocket won't give me a break

[Motley]

66cc/80cc 2T motor

I've dug all over the forum and it's definitely not coming off...
https://motoredbikes.com/media/29-pulling.39535/
https://motoredbikes.com/threads/ho...-sprocket-off-of-the-china-engine-kits.27442/

Followed everything plus what is on the internet plus what I already know.

I need to get it off as quickly as possible as there is a part I need to install: https://www.ebay.com/itm/MOTORIZED-GAS-BIKE-SPROCKET-SPACER-KEEPS-CHAIN-FROM-HITTING-TIRE-AND-OR-FENDER/182737075134?ssPageName=STRK:MEBIDX:IT&var=690054699664&_trksid=p2057872.m2749.l2649

The tool that comes with the kit can't keep up, It's shoot off of the gear and goes flying like a missile, literally every time I practically got it almost ready to come off it goes flying., It now looks like the threads could be wearing down...

So I'm going to kindly ask what is it that I can do at this point?

 

[crassius]

you need to clean the threads well and get at least 5 or more threads engaged to pull it - these are very fine threads, so easy to cross thread it

OTOH, it usually isn't needed to put a spacer there if you dished the rear sprocket out to clear a wide tire

 

[Spare_Parts]

A propane torch helps. Just don't over heat the area surrounding it.

 

[crassius]

forgot to mention that one should stick a short bolt into shaft so puller has something solid to push against

 

[Frankenstein]

Well if the threads are wearing away or just stripped on the tool only you can chop off the bad section and clean it up with something gentle and try again. I think it sinks about 5-7mm once seated in the gear, the best approach I found is to really really clean it well with wd40 and a q-tip or piece of fabric, spray the tool and the gear threads with wd40 and lightly thread it by hand backing off and forward enough times until it gets all the way it can go. The key is to get it seated well, jimmying it lightly with a wrench can help the threads work past imperfections and possible grit, it's really an art of handling it rather than a puzzle or rusted bolt, like learning to lockpick there's virtually no room for force, it all has to be felt out and you should know when you have it right.

If you heat it up keep a torch moving around the edges but not directly on the teeth, it will help the gear expand rather than both the gear and shaft, you have to keep it moving and don't overheat any part of it or it will break the temper and the steel will get soft and wear away quicker.

If the sprocket is stripped then all hope is lost, use a small pry bar to lift the edges, only small amounts at a time rotating it slightly between lifts. Wrapping a spare piece of chain around it may help prevent damage if you pry on it.

That spacer seems like a gimmick, the drive sprocket is tapered for the shaft, that's the main frictional force that keeps it from slipping, if the spacer is too thick the gear will not bed on the tapered shaft well enough to prevent it from slipping, then most of not all the force will be in the key (which also won't be fully engaged in the gear) which will sheer in no time. I honestly wouldn't even think to recommend it because of the design of these motors, tapered shafts just don't behave like straight keyed shafts.

 

[Motley]

:/ I'm trying my Arse off to save my rear fender. as well not to bend it, or cut it, or replace the rear wheel or tire. I dished the rear sprocket outward and this problem is still going on.

The chain is against the fender atleast less than one mm away from the tire. I might skip this method and just take a six dollar loss and have someone help me make a bracket to fit the motor more over to the left. It just wont be as centered on the bike... But the gap would be perfected....

 

[crassius]

using a hammer and sheet of rubber (or inner tube), one can gently tap with hammer on fender to make an indented area that will look just like on the peddle chain side without chipping the paint - not an easy fix, but some practice with an old fender will help (I use an old brake disk off my car as a curved anvil for this work)

 

[Motley]

I had considered doing that but the clearance of even the tire is too big. The fender is 2ish mm from the tire.. So that would cause more hazards

I really did not want to change out the tires and inter tubes what so ever.. but that would be sadly the easiest fix and it would defeat the main purpose of why I bought this bike versus another model I was looking at. I'm considering on just putting this bike away in storage and consider on working with it in a few years

 

[Motley]

 

[Frankenstein]

Well enjoy your gimmick then I guess, or extended storage option, whatever you pick..