Top tree question

[Jay5]

Hey guys just a quick question.

Picked up a Xs650 in pieces frame, fork, etc.
Building a bobber, the forks I believe aren’t the stock ones.

I’ve been reading and researching stock XS650 are 34mm & 35mm.

I measured the tubes I have and they are 38mm. Unless some XS650 have had the bigger tube or is it from a different Yamaha ?
Plus the top tree has the built in house riser/clamp

I’ve added a picture of the top tree

 

[RC4MAN]

You are correct

 

[fredintoon]

Hey guys just a quick question.

Picked up a Xs650 in pieces frame, fork, etc.
Building a bobber, the forks I believe aren’t the stock ones.

I’ve been reading and researching stock XS650 are 34mm & 35mm.

I measured the tubes I have and they are 38mm. Unless some XS650 have had the bigger tube or is it from a different Yamaha ?
Plus the top tree has the built in house riser/clamp

I’ve added a picture of the top tree

Hi Jay5 and welcome,
'tree is XS750/850/1100 Standard. If memory serves, the 38mm fork tubes say XS1100. Any style of post '73 XS650 front wheel fits no problem.
Pics of the rest too, please?

 

[Jay5]

Hi Jay5 and welcome,
'tree is XS750/850/1100 Standard. If memory serves, the 38mm fork tubes say XS1100. Any style of post '73 XS650 front wheel fits no problem.
Pics of the rest too, please?

Awesome ! As for neck bearings would they be the same ? Or would I have to get a xs750/850/1100 bearing.

 

[Jay5]

 

[fredintoon]

Awesome ! As for neck bearings would they be the same ? Or would I have to get a xs750/850/1100 bearing.

Hi Jay5,
I never tried a fork swap so I dunno. It's more likely it'd need an XS650 steering stem swapped into the 38mm lower 'tree.
Either someone will post in about that or The Tech and search buttons will tell you for sure.
Whatever bearings are needed, best you upgrade from the XS650's stock crowded ball-races
to the appropriate tapered rollers

 

[RC4MAN]

There were some companies that offered ball to tapered bearing conversions for various Jap bikes.
However while you might find the appropriate stem fit cone for the fork you have acquired the cups may not fit in the Yam headstock.
You can download the Timken catalog in pdf format and peruse all the various cup/cone combinations to get part numbers for what will directly fit or items that could be made to fit with some modifications to either the stem or the addition of cup adapters to the headstock.
If the stem is removable it will be easy to have a shop turn it to accept the new cones.
If not it can still be done, just a little more work.
The XS stem is welded to the lower tree so when I had it fitted to Timkens in the Trackmaster frame they turned the stem and tree as a unit to fit.
You will want to leave a step at the bottom or allow use of a washer to space up the lower cone to have space for a seal.