What's the BIGGEST front sprocket option?

[robindean]

I've read, as well as posted, about this topic and it's been discussed to death - BUT - I would like to know:

What is the BIGGEST front sprocket possible for the XS400 DOHC?

My google search for "1982 xs400r front sprocket 18T" produced nothing. I shot for 18T just out of curiousity. I know that 17t exists.

 

[Lou Ranger]

A number of people have posted that there is not enough room to put more than a 17T on the front. I am researching the same thing - wanting to lower my cruising rpms. Since I have the DOHC 5-spd (not 6), I already have a 35T rear, so can't come down from 39 like others. Going 16T to 17T appears to be my only option. Let me know if you find a way to get an 18 in there.

 

[bentwrench]

Lou, you may want to look up local machine shops and see if one could be built...

 

[Lou Ranger]

I found a US site (Old Bike Barn) that lists JTF-571.17 as the part# for a 17T sprocket for a 1983-Yamaha-XS400-R-Seca.
While it doesn't look the same as the 16T pictured, I'm going to see if the local shop can order it from JTF direct.
If not, OBB might be worth a try.