The passing of a legend


I had just read that John Underwood (xsjohn) was killed in a tragic car accident several days ago during a heavy rain storm. He was in a head-on collision with an SUV.

For those who don’t know of XSJohn, he designed and made adjustable needles for the BS34 Carburetors found on 1980+ xs650s.  If you have worked with these carbs, you’ll find them very limited in adjustment/jetting compared to the BS38s. His expertise in these carbs have brought them up to be great performers, especially with exhaust and air filter modifications.

His ad on eBay claims major increase in performance, smoothness, torque and starting. Lowers head and cylinder temperatures 20 degrees and vastly improves performance and cruising smoothness. Better balanced cylinder temperatures with custom turned needles for each cylinder. Mileage 49-53.

Personally, I’m not sure of all these claims, but I do believe in them. After an exhaust mod on my 1980 xs650SG, I could not get the jetting right. So I ordered a set of his needles. Before he sent them to me he emailed me asking for details on my setup. Satisfaction was his goal over profit. He gave me great advice and with his needles I got my bike running great. This was about a month ago.

John was very passionate about the XS650 and will be missed by many.

Mike (aka grepper)


  1. Bodhi says:

    Wow, I had read alot of his comments on the other xs page, bought two sets of his needles ( the claims are all true) , and spoke with him over the phone about some xs issues. He certainly steered me in the
    right direction and his dedication to this motorcycle was second to none.

    He will be missed……………………

  2. REEB! says:

    Rip xsjohn!

  3. BLACKWIDOW says:

    Damn I had the pleasure of talking with xsjohn and he was a very knowledgable person and very helpful, Sorry to heaf of his passing. 🙁

  4. Gearbanger says:

    My condolences go out to John’s family.
    I was in the process of setting up my carbs with John’s needles with his expertise & advice when I heard this tragic news. Bike now runs great & will forever have a connection to John as the exhaust note from my bike echos throughout the countryside.

  5. hpnchpp says:

    Rip john. talked with him on the phone in the past as well knew his stuff u will missed

  6. RRule says:

    This news saddens me greatly. First off because i never actually got the chance to experience his knowledge. Second because im just about to use his kit and now im unsure what im going to do for jetting. My regards go out to the family, i have heard nothing but good about him.

  7. Shawn Dennis says:

    R.I.P. Mr. Underwood you will be greatly missed, and the xs comunity will never be the same with out you……………….

  8. BigJimmyW13 says:

    Thanks for your help, John. RIP

  9. Tebo says:

    My condolences to the family. I didn’t know him ’til I read about him here. When a Brother goes down, it affects us all. Prayers.

  10. Rusty Nutz says:

    This is some suck news. I know I can’t/won’t do a thing without expert help. My condolences to the family.

  11. petie says:

    I also have a set of needles I purchased from John and they work very well I will forever be grateful. He was a great man with a vast amount of knowledge RIP xsjohn.