Front Sprocket / Renthal? Sunstar? JT?

8 replies to this topic
  • crfrookie

Posted January 10, 2007 - 08:07 PM


I am replacing my 13 tooth front sprocket to a 14 and I was wondering if a Sunstar or JT sprocket would fit. Reason for the question is the original 13 tooth one has a cut out / groove on the side facing the motor. When I looked at the Sunstar and JT sprockets they did not have the groove but the Renthal did. Is this groove nessessary? Will the Sunstar or JT ones work or should I buy the Renthal? I know that you get what you pay for, but since I am not gonna use the larger sprockets for a long time I thought that I would save some coin. Thanks for your help.

06 yz450f

  • grayracer513

Posted January 10, 2007 - 08:36 PM


The groove is necessary to clear the output shaft seal dust cover. If you use a sprocket without that feature, or reverse the stock style so the groove is facing out, it will bind on the dust cover.

  • DSMotorsport

Posted January 11, 2007 - 07:57 AM


Thanks for the tip. Im in the middle of rebuilding my 06 YZF450, including new 13/50 sprockets (got 24 hours out of the stockers with a new chain).

I bought Primary Drive sprockets from Rocky Mountain MC, the Primary Drive front sprocket does not have a groove like the stock front sprocket. Will check to see about the binding issue before installing now, I woudn't have even given a second thought untill seeing this thread.

The primary drive were cheap though, $7 for the front, $34 for the rear aluminum.

  • grayracer513

Posted January 11, 2007 - 09:22 AM


The way I found this out is one of those little moments that you kind of hope no one ever finds out about. When installing one of these one day, I looked at the grooved side and thought to myself how much cooler that looked than the plain side. Since the teeth are not offset either way, I stuck it on inside out so it would look cool. And it did. It didn't turn worth a damn, but it looked good. :lol: :confused:

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  • crfrookie

Posted January 11, 2007 - 04:34 PM


Thanks for the information. It makes me wonder why the other companies would advertise sprockets that would fit the 06 yz450f and not have the groove. Are all the yz450s like this as well?

  • buzzgrizz

Posted January 11, 2007 - 04:50 PM


Don't get a jt front because my dad had one on his ktm and a tooth broke off. He road around the house with the one tooth broken the every tooth broke off all at the same time.

  • grayracer513

Posted January 11, 2007 - 07:35 PM


Are all the yz450s like this as well?

The '06 could be different in that regard. I haven't had the front sprocket off of one yet. If the dust cover doesn't overhang the collar, the groove is unnecessary.

  • Kyle Prior

Posted January 11, 2007 - 08:13 PM


My 426 doesnt have a groove... Im sure its differant than a 450 though. I like my Tag front sprocket btw.

  • DSMotorsport

Posted January 12, 2007 - 07:37 PM


I installed the non gooved Primary Drive sprocket today. The non groove PM on the doesn't have anything interfering or binding. The dust shield has a bolted on plate that is behind a ledge on the output shaft that the sprocket sits up against.

Anyway..there is no issue at all, PM sprockets without the groove will fit fine.

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