Tbr7 520 chain upgrade.

[Larky]

Guys, I’m struggling to find the part numbers for a chain and sprocket set I’d like to order. My bike originally came with the 420 chain and matching sprockets, but I’m tired of the chain stretching. I’d like to upgrade to the 520 set, and maybe the stretch will occur less often. If anyone has the part numbers for a 42 tooth rear and a 17 tooth front sprocket set for a 520 chain I’d appreciate it. And speak up if you think I’m making a mistake with this change.
Thanks

[drstansbury@yahoo.]

I think Megadan has written about the 520 chain and sprocket swap for his hawk. Maybe search under his posts or look in the resource and information posts stuck at the top.

[Magician16]

Research it' there's no way the 17 tooth 520 will fit.

[Larky]

Thanks for the reply’s. I’ll research it as suggested. It was my understanding that newer years of the tbr7 came with a 520 chain. So I assumed it would fit. Perhaps I’ll need to make sprocket changes to accommodate the larger chain.
If anyone has more information, let’s hear it.
Thanks again

[Magician16]

This is from Megadan.

For a 520 chain, which is something I personally believe is better for hard use (also the stock chain on a CRF230);
Front Sprocket: JTF328. Available in 12, 13, or 14 teeth counts. 13 is about as big as you will
want to go
Rear Sprocket: JTR279. Available from 30 to 42 teeth counts.
Chain links: Depending on the sprocket combinations it will be anywhere from 100 links to 112 links. I suggest buying at least a 115 link chain, and removing links as needed to get the desired length you need. I bought 120 links just to be safe.

A couple of gearing matches to the 428 chain combinations when using the 520 upgrade sprockets include;
Stock 15f/50r = 12f/40r
The popular 17f/45r = 13f/35r
My personal preference for mainly road use is a 17f/43r = 13f/33r

If you are unsure of what gearing combination is best for you, or what to go with, then you can use this site thanks to JerryHawk to help calculate your gearing changes. https://www.gearingcommander.com/
Simply type 2016 into the filter box at the top right, select filter, and then select "Haosen Hawk 250". Then simply type in your sprockets into the fields to compare.

[Larky]

Thank you magician16. I was digging through different threads and decided to check back on this one and you had beat me to it!
I appreciate your help.
I need to actually clean the dirt off the sprockets and read what tooth count they are. I simply looked back at my Amazon purchases and assumed I knew what I have on it. But I’ll check to make sure.

Just so I have this straight. Mega Dan is saying that the stock chain (428) with 17f & 45r would be the equivalent of 13f & 35r with a 520 chain?

Because I believe I run a 17f & 42r, I would need to order a 13f & 32r?

[buzz]

Listen to Dan