AJS Stormer Y4 250

Vintage AJS 250 Y4 StormerAJS produced a 247cc motocross bike, the Stormer Y4, from 1968 to 1974. The Y4, also called the Stormer 250, was an innovative dirt bike because it was the first to use leading axle forks and raised shocks. In addition to these innovative features for the time, the AJS Stormer Y4 had a four-speed transmission and right-side shifter, a 32mm Amal MK1 “932” carburetor, and Flywheel Magneto ignition. The engine had a bore and stroke of 68x68mm, and between 6,000 and 8,000 rpms, it put out a modest 25 horsepower.

When they were introduced to the motocross market, the AJS Stormer Y5 had an orange or yellow gel-coated gas tank, which helped the bike stand out. This 229-pound Y4 also came standard with Dunlop Sports tires, a Reynolds chain, and Girling shocks. The 1968 and 1969 British 250cc Championships were won by Malcom Davis aboard a Stormer Y4.

Japanese-made Yamaha and Suzuki both introduced similar bikes to American riders around this time, however at a much more affordable price. AJS decided to give them a run for their money, though, and within a few short years, they were offering the Y4 at a very competitive price.

Published: September 4, 2012 1:42 am Categorized in:

AJS Stormer Y4 250 & Parts

View all AJS Stormer items on eBay »

4 Comments

  • Poul Marker Jakobsen says:

    Hi
    Can Some tell me or list a photo of the pipe system on a Stormer? Have One in Denmark and NO One can tell how it looks. Or maybe one crash pipe to see after.
    Good Day

  • Jerri says:

    @Paul, did you ever sell the 250 AJS?! Im looking for one.

  • Gary says:

    I just got a 1971 AJS 250 Stormer and discovered that the magneto and points have been left with water and are beyond repair. Is there an electronic system available that I can replace the old setup with?

  • Paul Catelli says:

    I have an AJS 250 like the one in the photo and I’d like to sell it. I’m in Califorina and would like to know what the value is. 1 being low and 5 being restored.

Leave a Reply

Please do not submit "for sale" or "wanted" style comments. If you have something for sale or something that you need to buy, please visit our free listings page. Listing style comments will not be posted!

We value your privacy, your email address will not be published or shared.

This site uses Akismet to reduce spam. Learn how your comment data is processed.