Topic: Front sprocket changed on my 400F

[gregk]

I was just going over my parts bike and noticed an aftermarked rear sproket.  It's a solid steel sprocket rather than the stock piece.  It has 38 teeth like the OEM. 
This got me curious about the front sprocket, so counted teeth and found 18 rather than the stock 17. 
What is the purpose of this change?  I assume that PO was trying to get higher top end from bike?

Greg

[ttr400]

That's what he was probably trying to do, but all it will do is lower the rpm slightly. it won't manage to pull a higher top speed. I have found the best combo for the street is the stock 38 rear with a 16 front.

Kevin

[gregk]

Kevin

Thanks for the confirmation.


Greg

[JZEROE]

Hey there.

I know this topic has been down for a while, but I just got a 400f, and it definitely wants a little goosing on the bottom end. But I'm hesitant.

I had a 550f, and I dropped a tooth on the front sprocket. Definitely helped me take off from the light, but it also killed my highway driving: at 75MPH, it was around 7500RPM, which was a little nerve wracking on a 35-year old 550.

I know the 400F has a higher redline, but what do you guys cruise at on the highway (I live in CA... freeways are unavoidable)? And what RPMS will a 16-tooth front sprocket bring you to at around 75?

Thanks!
J