I've been looking into sprocket options for the race bike... I know there are 415 sprocket set ups for the new gen bikes... I've got mixed information about the interchangeability of the new vs the pre fronts.. Are they interchangeable between the two... What if any options do I have here...

07 and back sprockets are held with a metal tab and two bolts. The 08-12 sprockets are held with a big nut. Also I don't think a 16 will go on an 07 and older model. I think but I'm not 100% sure of that. 08-12 can use ,14-15 and 16. 07 and back are limited to 14 and 15.

I'm going to look further into this when I spend some time in the shop tonight ... I believe the 415 setup for the new gen is running a 18 front but a 18 on a 415 chain is about equal to the size of the 15-16 on the stock 520.... I guess ill just have to dig a little deeper on this one

Oooops. Sorry I was speaking about 520 size chains. I missed the 415 part. I am interested in this also.

I run the 415 chain with a 18 tooth front sprocket set up for the 08 and up trans. I also swap in an older engine some times and use the same sprocket. So yes they are interchangeable. When using the new sprocket on the old engine I use a snapring to hold the sprocket on and safety wire the ends of the snap ring just to ensure that it wont pop off. I can grab a picture when I get home if you need.

That would be awesome I deffinitly could use some ideas.... Thanks Bruce

I use a circlip (snap ring) on my KLR for the last 5 years, never an issue, because I hated the plate/bolt hold down

Feed the safety wire through the holes before you put the snap ring on. Snap ring would probably work fine but a friend of mine got an unwanted helicopter ride to the hospital after his front sprocket fell off and locked up the beck tire at race pace !!!
http://www.ninjette.org/forums/picture.php?albumid=1389&pictureid=11038

Thanks Bruce I think the safety wire is a must for peace of mind... Do you happen to know the snap ring size right offhand

I didn't measure it. I have a bin of misc. snap rings here at the shop and found it in there.

Help me out with this. I am not worried about weight or mass. The 415 is better . But to get a higher rear wheel speed for a given Engine RPM . I would make the front sprocket bigger and the rear smaller. But my question is . Is it the number of teeth or diameter of the Sprocket that makes the difference? Is a 15 tooth 520 front sprocket the same as a 15 tooth 415 sprocket?

Diameter, but since the teeth are fixed units along the outside of the sprocket, we use those to compare ratios on sprockets.

Sprockets with smaller teeth and smaller chain links give you smaller ratio changes between different sprockets because you have a sprocket with smaller 'units' (chain links).




15T 520 will have a larger diameter than a 15T 415 because the length of each 520 chain link is larger than the length of each 415 chain link. circumference = (# of teeth)*(length of each chain link) = pi*diameter

That is what I was thinking thinking. So for my racing I should stick with 520.

Racerx^^^^
The advantage between the 415 and 520 is less weight on your rotating mass the 415 is around 3-4 lbs less weight ... Now on the 415 conversion kits out there it's usually around an 18t front and a 57t rear keeping the gear ratios about the same as your stock 520 setup.... But you will have less rotating mass by going to the 415

For top speed the mass will not hurt. Its really about fine tuning with the smaller teeth. I could find the perfect ratio for conditions and power. I run a 16/40 now. But I would also have to buy a pile of sprockets. I have to buy something anyhow. I will think it over. Thanks for the info

Don't forget the reduction in rolling resistance

Looks like I'm going to have to hunt up some circlips