Speedo Drive For 18" Front Wheel

O

Odradek

XS650 Member
Messages
7
Reaction score
7
Points
3
Location
England
Hello,
Not a 100% XS650 question, but I'm putting spoked wheels on a Yamaha XV920R, and apparently XS650 wheels are the easiest way to do this.
So, I have new front and rear hubs and am going to get wheels built.
Am switching to an 18" front instead of the 19", hence the question.

To keep the speedometer accurate, I'm guessing I have to change the speedo drive.
Looking around, it seems like the RD400 came with an 18" wheel, and has the same axle diameter, 17mm, as the XS650.
Does anyone know it this is a straight swap ?

Thanks for any info.
 
00b0495e76fc685bbeb0000b8f098189.gif
 
5twins said:
I don't think the change is in the speedo drive down on the wheel but rather up in the speedo itself. I think you may need a different speedo, one from a bike that had an 18" front wheel stock.
Click to expand...
I think you are wrong on this one. But I seem to remember that different brands (Honda/ Kawasaki/ Suzuki/ Yamaha) in some cases have different ratios in speedos and tachos.
As to the original question, the RD 350 and XS650 tacho drives seem similar, from my memory, so are likely to be interchangeable. Note that I never actually tried this...
Now, I believe there are still people who repair mechanical tachometers and speedometers. They may be able to calibrate the speedo to show correctly with a smaller front wheel. The odometer will not show 100% correctly, however.
What about using an aftermarket electronic speedo/ tacho setup? They can easily be calibrated spot on....
 
OK, Also using Partzilla the gear drive unit is also the same part number for the RD and the XS which means the drive ratio is the same.
This would mean the difference is in the speedo to allow for the different wheel diameter.
In reality it shouldn't affect the reading that much as the difference in circumference is only about 5%
So at 100 mph it will be off 5 mph. Hardly worth worrying about
 
Thanks for all the replies and the info.
As I've had to use a modified XS650 axle to fir the XS650 hub onto my bike, I can't use my original speedo drive, so I think I'll try an RD400 drive and see how that works out once the bike is back on the road.

An electronic speedo is also an option further down the line, but I think I'll try to get the original working first.
 
Wagner73 said:
Very nice bike!!

It doesn't appear that Tarozzi makes a brace for the XS650 anymore, unless I just missed it somehow.
Click to expand...
looks like the XZ550 brace also fits the XS650?

Front Fork Stabilizer Brace For Yamaha XZ550D 1983 XZ550 1982 XS650 1980-1983​


https://www.fastfromthepast.com/25-0018
just based off some random ebayers fitz description....
 
gggGary said:
looks like the XZ550 brace also fits the XS650?

Front Fork Stabilizer Brace For Yamaha XZ550D 1983 XZ550 1982 XS650 1980-1983​


https://www.fastfromthepast.com/25-0018
just based off some random ebayers fitz description....
Click to expand...
Could be, worth a contact. In the details (which there really aren't any 🤔), it only says "Fork Brace Yamaha XZ550 1982"
 

Similar threads

K
Twin disc conversion
Replies
18
Views
2K
Wingedwheel
Wingedwheel
O
XS650 Wheels On A Yamaha XV920R ?
Replies
9
Views
2K
Grewth
G
W
Unknown front wheel - anyone can identify it ?
Replies
12
Views
1K
650Skull
650Skull
AlanW
B model front wheel installation help
2
Replies
23
Views
3K
650Skull
650Skull
L
Mystery front wheel
Replies
13
Views
2K
Its been a long time
Its been a long time
Back
Top