Storm 428H to 520 chain upgrade

Thumper · 04-22-2022, 10:33 PM

The JTF328 front sprocket (I got one with 12 teeth) is a perfect match and the OEM front sprocket retainer fit exactly (used the same OEM 2x 10mm bolts with a drop of blue locktite). The JTR279 rear sprocket (35 teeth) fit perfectly (same bolt pattern), and I used a fat finishing nail clamped in a vice grip to get the snap ring on. Not too bad

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But the recessed ring on the rear sprocket was incompatible with the original bolts

, so I found thick washers and cut them to fit:

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Then the bolts fit just fine

I added a drop of blue locktite just before bolting the sprocket on:

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I had to take about 12 links off the 120 link RK M520H chain.
Here is a side by side pic with the 520 on the left, original 428 on the right. Much heftier link thickness and a slightly longer pitch. I destroyed that old chain with clay/mud. Never again. I am staying away from mud!

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Views: 221
Size: 188.8 KB

I am going about 7% lower final drive ratio so it will be slower but 1st and 2nd gears will be better off road. I can't wait to try this out

04-22-2022, 10:33 PM	#1
Thumper Join Date: Feb 2021 Location: Kansas City Posts: 2,421	Storm 428H to 520 chain upgrade The JTF328 front sprocket (I got one with 12 teeth) is a perfect match and the OEM front sprocket retainer fit exactly (used the same OEM 2x 10mm bolts with a drop of blue locktite). The JTR279 rear sprocket (35 teeth) fit perfectly (same bolt pattern), and I used a fat finishing nail clamped in a vice grip to get the snap ring on. Not too bad But the recessed ring on the rear sprocket was incompatible with the original bolts, so I found thick washers and cut them to fit: Then the bolts fit just fine I added a drop of blue locktite just before bolting the sprocket on: I had to take about 12 links off the 120 link RK M520H chain. Here is a side by side pic with the 520 on the left, original 428 on the right. Much heftier link thickness and a slightly longer pitch. I destroyed that old chain with clay/mud. Never again. I am staying away from mud! I am going about 7% lower final drive ratio so it will be slower but 1st and 2nd gears will be better off road. I can't wait to try this out
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