What is different between 700 sx and the sxr?

[RUPP-NITRO]

What is different between a 700 sx and a sxr?
Is a sxr a better motor? Can a 97 sx 700 just bolt
into a 2000 700 sxr? Thanks

 

[Mysledblows]

Motor is basically the same. 97 had a crank bearing issue that was updated in 98. Everything interchanges otherwise and I believe the 97 case can be machined to accept the 98+ bearing.

 

[srxman72]

I don't think the 97 had the heated carbs either, so there's no fitting on the head.

 

[sleddineinar]

Mysledblows is correct, the 97 had a different bearing on the magneto side, which started to fail so Yamaha updated that in 98, some 97 had their cranks and cases updated. Srxman72 is also correct the 97 didn't have heated carbs. Another thing to remember is that 2001 and up the motors had updated electronics.

 

[RUPP-NITRO]

Is there any way of being able to know if a 97 sx has the
updated crank?

 

[sleddineinar]

Is there any way of being able to know if a 97 sx has the
updated crank?

I don't know the answer to that one. At least not without opening up the case and looking. Maybe someone else knows.

 

[RUPP-NITRO]

So, is there a real advantage to the updated crank?
Seems alot of people have had good luck with all the years
of the 700 sx's. Does anyone know for sure when the updated
crank was done and how to tell? thanks