Largest Rear Sprocket XS400

Oleschool

Oleschool

XS400 Enthusiast
Messages
48
Reaction score
8
Points
8
Location
NWT Canada
I'm building a scrambler from my stock 79 XS400 and would like to increase the rear sprocket size.Whats out there and who has experience with larger than stock rear sprockets?I am not concerned about top speed and would like to make the bike a little more fun down low.

I'm looking for information from others who have swapped sprockets and how well it has worked.
 
The gearing commander site looks like it would be nice to find out results but it don't list the sohc xs400 in it's database :( Only the xs650 and dohc xs400.
 
Thanks for the links.

I'm sure I saw a 40 tooth rear for my bike which I'd like to try.

Anybody ever done this?
 
For every tooth you go up on the rear sprocket it will raise the rpm's by 250. If you have the 79 F xs400 your should have come with 16/37 sprockets and 18" rear wheel. At 55 mph the bike should run about 4500 rpm's or so. So with a 40 tooth you would be around 5250. Have you driven the bike mych yet? Whith a 6 speed trans the bike has low 1-3 gears already.
 
No I haven't driven the bike at all.I knew it ran and immediately started cutting it up.It has a 16" rear wheel with 34 tooth sprocket now.(I think 34 anyway)
 
Sounds like you have an 80 or newer bike. Take some pics of what you have. 34 is very small and high geared. A bike with a 120/90-16" rear tire will have higer rpm's than a bike with a 110/90-18 tire with the same sprockets. The 16" with stock size 16/37 sprockets, the bike would run around 5000 rpm at 55mph. If you have never ridden the bike you may find it is all you need.
 
xschris you were right.I counted last night and it does have a 37 tooth rear sprocket. I may just wait and see. I thought I'd put it out there just in case anyone else has tried this before.Once its on the road 90% of the use will be short blasts around town and to work and back.It may stretch its legs down the highway once in a while.

My VIN is 3W5000218
 
With that vin you have a 1980 xs400sg canadian model. Pics will still also help:wink2:
 
Lots. Exhausts, ignition/wiring, front brake system is a different design, carbs are a different design, rear wheel size and the seat is a different style/setup. There are other little things also. Like I said before WE NEED PICS!!
 
Ok thanks for letting me know I have a 1980.This is twice that I've bought a bike that had the year misrepresented.My last one was bought as a 77 KZ650 and it was actually a 76.I'll snap a few pics later today.


BTW,what does TCI stand for?
 
A lot of people think the year stamped on the neck tag is the model year. It is the date it's manufactured. Like most cars/bikes they come out with the new models a few months before that year. 79 for 80 etc. My 80 was made 10/79 but it's an 80 model. My 79 was made 6/78.
 
XS400_zpsthvjdbel.jpg


Here's the bike.Originally black,it was painted a few years ago.I've ordered a flat seat for it and will be repainting it black with some type of Yamaha graphics.The exhaust is from a CRF250 and sounds better than the aftermarket tips that were there before.Still need to install some dual sport tires and paint the wheels as well,but I've got lots of time before the snow is gone.

xschris said:
Lots. Exhausts, ignition/wiring, front brake system is a different design, carbs are a different design, rear wheel size and the seat is a different style/setup. There are other little things also. Like I said before WE NEED PICS!!
Click to expand...
 
Its going to be a cool ride for blasting around town.I'm trying to do this as a low buck project and use stuff I have laying around.
 

Similar threads

stillwater
rear sprocket swap question
Replies
2
Views
391
CaptChrome
CaptChrome
G
1980 XS400 Chain Rubbing
Replies
7
Views
301
CaptChrome
CaptChrome
D
Starter motor installation
Replies
2
Views
608
Drew
D
G
Did i just ruin this swing arm? 1980 Yamaha XS400
Replies
0
Views
164
Guitarguy1996
G
S
What Chain Do You Use?
Replies
4
Views
921
SupsChad
S
Back
Top