Front Sprocket Swap Tutorial

[acecase09]

I agree with everyone who says that the RX3 needs lower gearing. Riding slow and technical in 1st, I constantly found that I was right at the speed where the torque wanted to drop off. To remedy this, I went with the simplest thing, which is a front sprocket swap. I changed to a SunStar 32313. Now, yes, SunStar did sponsor me when I raced supersport, but they make top quality stuff at very reasonable prices. I got mine from Amazon Prime for $17 USD. CSC wants $12.95+ shipping. So, it is about the same price. I do doubt that the quality of the CSC is equal to the SunStar. While holding the factory 14T and the new 13T, the 13T, while being physically smaller, was much heavier. I planed on using the Suzuki 1991 DR350 lock washer. The reason being that pretty much any motorcycle shop has or can get one. They are about $1 each. I picked one up from a local shop and did not notice that they gave me the wrong one until I got ready to change it Sunday afternoon. So I ended up using the other side of the factory one.
Speed and Rpm wise, there is a little shift. This is what I ended up with:
55mph = 7000rpm
60mph = 7200rpm
65mph = 7450rpm
As a note, I have seen on here where it has been stated the factory washer uses the hole in the factory sprocket as a lock point. This is not true, at least not for the 2019. The tab just folds up onto the side of the nut, as is industry standard.
Now on to the pics and the procedure.
First, it helps to get the rear off the ground, it is not absolutely necessary, but neither is light at night, but it sure helps. I am using a cheap Harbor Freight bike and atv lift.
Loosen and slide the rear tire as far forward as possible to create as much slack as you can.

You can see the sand and grit on my outside cover. I took an airline and cleaned everything loose off to create a good clean work environment. The two 8mm bolts secure the cover. Remove them and the cover.

[acecase09]

Next you need to flatten the locking tab. Use a small cold chisel to create a gap then switch to a center punch and flatten the tab to the sprocket. Remove the nut. It is a 32mm. Mine came right off with an impact. Remove the washer, you will have to pick and pry it off.

[acecase09]

Here you can see the two different sprockets and the locking washers. You can also see the wrong spline for the one in the bag.
Using just you fingers, rock the factory sprocket up and down until it slides off. There is more than enough slack in the chain to allow removal.
Clean the shaft if needed, lightly apply antiseize or grease and install the new sprocket. Tighten the nut and bend the unused side (or new tab) up to lock the nut. Tighten and align the chain. Secure the axle nut and reinstall the cover. That’s it! You are done, go ride.

[NzBrakelathes]

There are 3 style of locking tabs over the years, 1 bolt style 2 nut styles etc.

Did you get my video?

[calvarez]

I see you replaced the OEM shifter with the same one I did. Nicer position, and folds up if you crash.

[acecase09]

Originally Posted by calvarez

I see you replaced the OEM shifter with the same one I did. Nicer position, and folds up if you crash.

I have yet to find a brake lever that is the same way. I needed something a little longer and the folding tip is a huge bonus.

[calvarez]

I'm running the stock brake lever also. I didn't find another option. Haven't changed out the hand levers either, though I'd like to put shorties on soon.

[acecase09]

Originally Posted by calvarez

I'm running the stock brake lever also. I didn't find another option. Haven't changed out the hand levers either, though I'd like to put shorties on soon.

I put a set of 2" risers off of Amazon that I got for $19.99. makes all the difference in the world. I do spend a lot of time standing. They are quite comfortable for sitting as well

[NzBrakelathes]

China RX3 in 2020 gets a make over with a NT250 engine and bigger 17 and 19 inch wheels
https://mp.weixin.qq.com/s/7X5pEZhnanvHyRpWnAkhiA