Rear sprocket/chain

5

50nas

New Member
I bought the OORacing tuning kit for the ACE 50 https://www.ooracing.com/store/tuning-kit-big-bore-50cc-to-70cc-suitable-for-ace-50cc-bikes.html (22mm carb, ign.box, rear sprocket etc). Now I´ve changed the rear sprocket to the smaller one from OOR, 40T 428 pitch, to get more top speed/lower rev.

The sprocket is much smaller than the original, and now the chain feels to slack. I´ve moved the wheel maximum to the rear, but still too slack. Do I really need to shorten the chain? How can one do that?

black-sprocket-124561234612.600.jpg
 
Have a look on you tube, lots of good tutorials on how to shorten a motorbike chain.


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Easier than me describing it on here. Just watched one called" how to shorten your chain" by rat trap productions. Shows all you need to know


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Wow, what a difference! I bought the full tuning kit from OOR (50 to 70cc), but waited with putting the sprocket on till now. Before it almost wanted to rise when pulling away, but I had to change gears quick and never got over 30mph/45kmh on 4:th gear (and with crazy high rpm). Now with new rear sprocket it pulls away steady but still with power, and 40mph/65kmh is no problem. I´m still to test it out on open road, but it feals like 50mph/75kmh is possible. 8)

Luckily I found this thread (post #14): http://advrider.com/index.php?threads/bike-in-a-box-a-winters-project-a-skyteam-ace.902645/

The original sprocket has the print on the outside, so it would seem logical to put on the tuning sprocket the same way, but then the circlip doesn´t go deep enough to lock the sprocket to the hub.

And now the chain is perfect length, thank´s for the help!
 
Ace 125 Sprocket / chain

Replaced the front sprocket standard 15T with a 16T. A noticeable improvement in the lower gears that makes the bike more useable in Sydney traffic. (1st gear now gets past a slow walk) Did a "Nasho Run" this arvo and mildly surprised in the very small lose of power. The extra legs in each gear definitely outweighs the loss of any punch.

Picked the sprocket up from Assassin Dirt Bikes in Sydney for $10.

No need to mod chain as it is only a slight increase in overall size and was able to be taken up with the chain adjustment.

Here's a link to a table of Sprocket gear ratios https://drive.google.com/file/d/0B4qht3FwsV_Jb0huNEdUNVpQaEk/view?usp=sharing
 

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And here is a calculator :)

Type Skyteam in the filter

And then pick from the first drop down. A while since I used this, I think the tyre size needs tweaking if I remember rightly.

Measure circumference of tyre by marking a point on tyre and ground then wheeling bike until mark on tyre is in same position, then mark ground, then measure distance along the ground.

Then mess with the tyre size so that the circumference further down the page comes out to that number.

Then you have potential speeds for each gear and can recalculate by changing the sprocket sizes :)

http://woodsware.aciwebs.com/gears/

And this may be of interest too...

https://docs.google.com/spreadsheets/d/1USvziYIyzfyxfZA1YYpQf9eP4djb0GLWbvWcmME88Gk/edit#gid=218053251
 
Ace 125 sprockets / chain

Thanks 2b, I knew I had seen this a week or two ago, but couldn't find it again.
 
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