Can't get 4G T belt on, have cam loosened

[chrisnbush]

I am cross posting this from motoredbikes.com, if anyone has a tip or two, I would appreciate it. I don't THINK I have a version of the Grubee 4G clutch where I can take the clutch bell off, I need to check when I get home

Thanks !

*************************************************

I have the cam loose, so the 100 tooth wheel is as close as it can be to the small toothed drive wheel.

I have the 4G grubee 78mm style clutch, the one that fits on the Hua Shuangs that come with the clutch shoes (has a freewheel, not the one way bearing).

It needs probably another 5mm, I am trying to work it around the big wheel (have it on the little wheel) like putting a tire on a rim. But it is just TOO tight, and again i have the cam set on the big wheel to make the smallest distance.

Probably could get it on by prying the big wheel around with a big screwdriver, but am concerned I might damage the threads in the belt. Anyone have any experience with this ? Pretty sure I have the right belt, it is the 570 mm one.

By the way, I love my grubee ! I have 3400 mi on the clutch plus mount (this much on the belt before it broke). At 700 miles I blew up my first Hua Sheng (my own fault, I was racing a bicyclist with a pipe I have strapped to my exhause for heat in the winter - routes the exhaust thru my jumpsuit to keep me warm - and also was running a real low gear for winter travel - i seized up the motor). I got a Super Titan from DAX and I really like it. It gives it more power than i used to have with my 80cc modified HT. So I have 2700 on this new motor. I use something called TufOil in the oil - it is teflon particles - to make the oil slick. Hoping to get 5K out of the motor, we will see. By the way, I am got 2700 miles on the freewheel before replacing it, thought that was pretty good. I kept it lubed by dripping tri-flow into the circular crack between the inside and outside of the freewheel...

Anyway, I'm not going anywhere until I get this belt replaced. Grr......

 

[The_Aleman]

Can't you just unbolt the gearbox from the engine, pull the rear side towards you, then slip the belt on and bolt the gearbox back on? That's how I do it on my 5:1 4G.

 

[chrisnbush]

Yeah thats how I am doing it. These grubee 4g clutches are all different, they have more than a few different varieties. The housing on mine is all one piece, so other than loosen the cam and rotating the large wheel towards the small one, there is no other way to make the distance smaller, to EASILY get on the replacement belt.

What I ended up doing was grinding off a bit of the lip on one side of the big wheel (the edge on one side that keeps the belt in the track) just a touch, about 1/3rd way around the wheel. This gave enough play to feed the belt on, torquing the big wheel around by prying with a screwdriver. One thing though, after grinding I needed to take off the burrs created on the inner side of the lip with a file, to prevent the belt from catching on it. Since the grinding actually flattened the lip a little, the belt rubs just a touch going around - if anyone wants to try this they need to use caution as the track the belt runs on isn't much wider than the belt.

Anyway it is working now and I am back on the road ! Had a wonderful ride up to town with my wife to get some cofee this fine Sunday.

Thanks for the post ! Ride well