CBR F4i 520 12 tooth sprockets

[mythical bird]

If anyone is still looking for a 520 pitch 12 tooth custom sprocket from sprocket specialsits, please contact me at adamgoel@ku.edu.

As many of you are aware there is a minumum order of 6 sprockets, I'm looking to combine an order because I only need two. I called sprocket specialists today and if memory serves me they quoted $35 a piece.

[MythicalTurkey]

I noticed that the quote works out to a smidge under $3 a tooth. So I was wondering if it is actually a better value to buy a sprocket with more teeth, or does the cost per tooth ratio stay about the same?

[Daves]

Why not go 11 tooth with the 520?

[Cement Legs]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by MythicalTurkey:
I noticed that the quote works out to a smidge under $3 a tooth. So I was wondering if it is actually a better value to buy a sprocket with more teeth, or does the cost per tooth ratio stay about the same? <HR></BLOCKQUOTE>

well your not buying dentures...lol I guess the best deal is the sprocket that gives the ratio that you are looking for.... is it not???

[mythical bird]

Honestly, I like the 11 tooth ratio better. But, I'm afraid of reliability issues.

Now that you mention it I would like to have one at least for testing purposes.

Have you guys had good luck with the 11 tooth?

[mythical bird]

I forgot to mention in my last post, I recently discovered my e-mail account was disabled becasue it was too full when I made the posting about the 12 tooth F4i sprockets a few days ago.

If you tried to e-mail me and it didn't work, please try again (Yes, I'm kind of desperate http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Daves]

We have had no reliability problems with 11 tooth sprockets in the 525 series. We even have a 10 tooth, but it probably has a factor of safety close to 0.7

An 11-tooth 520 should not lose much strength compared to a 525.

This year we are using a 14-tooth 428.

[mythical bird]

I just submitted my order for six 12 tooth sprockets this morning, then sprocket specialists called me back and said they had some lying around, and they would sell me two. I don't know how many more of these they have, but any body wants one, I'd call quick.

[mythical bird]

After talking to Dave, I'm really tempted to get an 11 tooth sprocket for testing purposes. I'm sure there would be a min order of six if we got them from sprocket specialists, but if any of you guys wanted one I'd be willing to go in on an order.

-adamgoel@ku.edu

[rjwoods77]

Hey Dave at L.U.,

We are using 428 chain too. I was planning on making getting a 12 tooth made by Sprocket Specialists. Doing a 48 tooth rear sprocket for starters but I will end up in the area of 36 to 48. I am using a cvt so I have to tune it in to what combo i need based on the cvts setup. Lemme know if you want a 12 tooth. What type of final drive chain are you going to use? I have always been faithfull to DID but i heard through the grapevine that there is some manufacturer that makes 7500 lbs 428 chain that is non-o-ring?

[Daves]

Adam,

You may not need to order (6) 11 tooth 520 sprockets. If you buy (1) 17 tooth 520 sprocket, you may be able to have a local gear/spline/sprocket shop (donate their services &) cut new teeth.

Rob,

Thanks for the offer, but we've already made our 14T 428 countershaft sprocket and ordered our 65T rear sprocket. Your cvt sounds very interesting since it is using chain drive. Is it a chain from the engine to the transmission and a belt from the transmission to the differential? Are you using a Briggs & Stratton engine? We tried to order the RK (Japan) chain from S.S., but they are on backorder for up to 6 months. Instead, we ordered a D.I.D. heavy duty chain that should withstand about 5500 lb. A 428 7500 lb chain sounds awesome, but our car will not have enough power to require such a strong chain. If you could recall who makes it, I'd be interested in reading about it.

[rjwoods77]

Dave,

I read about it in some atv or motorcross magazine. I have been looking for it all over the place but i cant find it. The combination goes engine, cvt, one stage of chain. The cvt just serves as a transmission. You need to hook up a chain,belt,gear drive to it to get the power to the wheels. I sourced a super efficient cvt from a race class out there. It has a rollerized secondary and primary. Rollerized primaries are hard to come by. Both pulleys with belt together weigh 9lbs and it is super compact. 3:1 low gear and a 1:1 high gear. Thing should work pretty good. I'll keep looking for that chain. Seeya.

[Bubba]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Rob Woods

We are using 428 chain too. I was planning on making getting a 12 tooth made by Sprocket Specialists. Doing a 48 tooth rear sprocket for starters but I will end up in the area of 36 to 48. I am using a cvt so I have to tune it in to what combo i need based on the cvts setup. Lemme know if you want a 12 tooth. What type of final drive chain are you going to use? I have always been faithfull to DID but i heard through the grapevine that there is some manufacturer that makes 7500 lbs 428 chain that is non-o-ring? <HR></BLOCKQUOTE>

We are using a 15T 428 front sprocket. There is hardly any material between the spline for the F4i and the inner roller surface of the sprocket. I'd bet that a 12T 428 for an F4i is not even possible to make based on the geometry.

[Daves]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>I'd bet that a 12T 428 for an F4i is not even possible to make based on the geometry. <HR></BLOCKQUOTE>

He is probably using the 12T 428 sprocket on a Briggs & Stratton engine that has more clearance due to a smaller internal spline. A 12T 428 may be possible for an F4i sprocket (since a 10T 520 sprocket is possible), but the resulting geometry would be very weak. 14T 428 is the smallest we are willing to try this year.

[rjwoods77]

The sprocket isnt going on the motor. It goes on a countershaft so I am not restricted to anything really.