Gauging Interest: 415 or 428 Chain/Sprocket Kit

[green_bread]

We are about 2 weeks out from my last talk with them when they told me it would be about 3 weeks for them to get the new sprockets from the manufacturer. I am going to be going to another race weekend on Aug 4th, so Im really hoping they can get me the new front by then! Ill keep you guys posted!

 

[Formula390]

So I wanted to wait until I was far enough along to announce, plus with the manufacturer green_bread has been working having multiple problems with fitment, I'm ready to let folks know I'm making solid progress on a 415 kit.



I have completed the CAD / modeling portion of the front and rear sprockets, and have as of this afternoon succeeded in the machining of the first side of the front sprocket. The key fit issue is the matching of the countershaft spline. It took 4 solid days of calculating, testing, 3D printing, test fitting, and repeating that process again and again and again until I finally had the spline identified! Then it was time to order stock, and tooling, and machine the softjaws and do the CAM / programming to actually manufacture the part! I am at the process now where I'm ready to do the "Flip Op" and start machining the backside of the part on a Flip Op jig which I also had to model, program, and machine. I should have the first parts finished tomorrow and get them mailed off for others to test fit on their bikes to confirm fitment on more than just the 1 test mule here. Then I'll start on the rear sprockets. I've got an initial 55T rear sprocket modeled and programmed. I'm waiting on quotes for stock and am working with two different shops to outsource the anodizing to and am waiting on quotes from them and turn around time. Once I have a solid price on the aluminum stock, and the anodization, I should be able to announce the pricing. I have a rough idea of what it's going to run, but I don't want to put the cart before the horse here.

I'm working really hard on getting this ready for y'all ASAP. I wanted to share todays victory tho and let folks know, I'm close, VERY close!

 

[isaac_]

Interested in something with a ~2.933 ratio


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[Formula390]

Interested in something with a ~2.933 ratio

Ratios for the current gearing folks are likely running, and the comparison to the ratios that will be available, can be viewed here:
https://docs.google.com/spreadsheets/d/1T42Kjs53Xbad4d_krrIw5OPAEve9NntuLEwNRPkrnOY

There won't be an exact match between the 520 and 415 ratios. The front sprocket needs to be 19T to clear the swingarm... This also then needs the rear sprockets to have a higher tooth count. So if you are currently running a 15F and 44R you'd be looking at the 19F and 55R. The spreadsheet has fairly complete listing of likely 520 gearing and shows the 415 ratios I'll have available. If there is a large demand for additional sprocket sizes I may be convinced to add more sizes. For now, I'm making a best effort at producing sprockets that I think the majority of racers will want/need. I could always make a one off if somebody REALLY needed a specific sprocket I don't already produce, but there would be additional costs and timeframe would be longer as I'd have to either send just that one sprocket out to be anodized, or wait until the next batch is sent in. For the initial run tho, I'm planning on making the 19F, and 6 sizes of rears in 49, 51, 53, 55, 57, and 59. The difference between each is so minor, is why I'm "skipping" and making every other tooth count. Plus I'm using historic sales data to reference against for what the most popular sprockets are that I've sold for the 520 chain.

 

[isaac_]

19/55 I think would work for me. 19/57 won’t work because I know stock gearing doesn’t work at my traxk


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[isaac_]

Ratios for the current gearing folks are likely running, and the comparison to the ratios that will be available, can be viewed here:
https://docs.google.com/spreadsheets/d/1T42Kjs53Xbad4d_krrIw5OPAEve9NntuLEwNRPkrnOY

There won't be an exact match between the 520 and 415 ratios. The front sprocket needs to be 19T to clear the swingarm... This also then needs the rear sprockets to have a higher tooth count. So if you are currently running a 15F and 44R you'd be looking at the 19F and 55R. The spreadsheet has fairly complete listing of likely 520 gearing and shows the 415 ratios I'll have available. If there is a large demand for additional sprocket sizes I may be convinced to add more sizes. For now, I'm making a best effort at producing sprockets that I think the majority of racers will want/need. I could always make a one off if somebody REALLY needed a specific sprocket I don't already produce, but there would be additional costs and timeframe would be longer as I'd have to either send just that one sprocket out to be anodized, or wait until the next batch is sent in. For the initial run tho, I'm planning on making the 19F, and 6 sizes of rears in 49, 51, 53, 55, 57, and 59. The difference between each is so minor, is why I'm "skipping" and making every other tooth count. Plus I'm using historic sales data to reference against for what the most popular sprockets are that I've sold for the 520 chain.

side note: ... uh... nice pix on your google plus account, haha.

 

[m3hl]

I'm still wondering about durability on these. Does anyone know how long these last? how many days roughly? Do you replace the chain more often than the sprockets?

 

[green_bread]

Ive run entire seasons with them on 250s/300s, but granted - those are Ptwin motors and a little less "torquey" on the chain than a single is gonna be. I see the guys on the 390R's in MotoAmerica running them with no issues (I talk to Shawn Ungvarsky and Dustin Apgar through FB Messenger a lot) and they are putting down quite a bit more power than what my bike is, so Im not too worried, personally.

 

[Formula390]

I've got front sprockets finished. Rears should be finished and be available next week.