XS Front End Swap for CB350

Hey guys, thought I’d share some info on the front end swap I did over the winter on my ’72 CB350. I decided to go this route for a number of reasons, but it started out as just wanting to beef up my fork tube diameter from spaghetti noodle thin 33mm to a sturdy 35mm. In doing research I also found that road racers look for triple trees with four bolt pinch mounts on the bottom yoke as apposed to the CB’s two, giving more clamping surface area and a more secure attachment. This left me with a few options but I decided to try out a Yamaha XS front end because of the added benefit of aluminum shouldered rims and a simple dual disk conversion. Took a lot of time researching and sourcing parts but here’s the quick version:

The assembled front end consisting of XS650 trees, wheels, and forks.  Brake calipers and dual lines are from a XS750 and the brake rotors are from a XS1100.  I used a super helpful Yamaha Part Finder website to figure out which parts are interchangeable between the different years and models.

Tapered bearing kit for CB350 from All Balls Racing works perfect with the XS stem, no modifications needed.  I also bought a bearing kit for a XS650 thinking I would need to combine pieces of both but since I didn’t need it if anyone is looking to upgrade their XS bearings I’ll part with them for cheap.

Lower bearing in place and new upper bearing race installed.  The kit replaces both stock ball bearing races.

Final product:

Brake master cylinder and stainless lines I picked up from MikesXS.com

All in all I’m happy to have a rock solid front end.  Being such a light bike dual disks are probably overkill… but it looks bad-ass and I’ll be able to stop using one finger.  Can’t wait to get it on the road and test it out.  I’m doing a shit-ton of other modifications to pretty much every aspect of this bike so I’ll share them as they get completed if you guys like.

9 responses to “XS Front End Swap for CB350”

  1. ed says:

    the clip-ons look sick.
    no ape-hangers?

  2. Adam says:

    you’ll be doing endos with that setup! haha. Looks legit Bob

  3. dan says:

    Very nice, can’t wait for the finished product, should be epic.

  4. chris says:


  5. david says:

    I have a cb 350 in Australia and loved your conversion, can you give me more details of the parts required eg year of parts
    cheers David

  6. ed says:

    Hey Dave,
    I’d love to give you more info but the person who did this conversion isn’t around Philly anymore. My guess is all parts are from the late 70’s.

  7. david says:

    cheers, great site will come here often

  8. bob. says:

    Hey, havent checked back in a while. Dave what kind of info do you need? XS650 front ends came in two sizes, 34 or 35mm depending on year, later years were 35mm and there a ton of aftermarket stuff out there for these front ends. Dual disks came from a 76-81 XS750 and extra rotor from a 78-81 XS1100. Bearing were from all balls CB350 kit with a couple large washers to take up any slack. Plenty of brake line kits and master cylinders out there to fit the bill. Hope that helps.

    I am outside philly now but only in KOP, conveniently close to RT.23, I’ll try to meet up with you guys mid ride sometime this summer. Wont be on the 350 though, got bigger fish frying…

  9. Michael Gibson says:

    Hello everyone. I just picked up a 78 TT500 and was wondering if this front end would work for my bike?

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