Area 51 Project: Ronnie & AJ's Winterized YX250 Dirt Bikes

 


Last winter (2017) Ronnie decided to try studded tires on his and AJ's identical Yamaha YZ250 dirt bikes. These guys race most weekends all summer long at Riverview Motocross near Bay Roberts, NL and wanted a way to enjoy their rides in the off season.

 

 

 

They picked up a bunch of 1/2" screw in studs, installed them following a standard pattern for installing studs and had the bikes ready for our annual cabin trip in February.

 

 

 

The studs worked extremely well providing great control on super slippery, glare ice conditions experienced during last year's trip, the only problem was the studs in the rear tires were prone to pulling out from the forces of acceleration.

 

 

Unfortunately for AJ, this played a big part in him loosing the big father and son drag race as many of his studs were missing.

 

 

The 2018 winterizing program began with swapping out the front summer tires for last year's studded set on both bikes as they worked well with very little trouble losing studs.

 

 

 

Ronnie is an old hand now swapping tires using tire spoons.

 

 

 

 

 

 

 

One down, one to go.

 

 

 

 

 

 

 

This years plan for the rear tires is a lot different than 2017.

 

 

 

This year Ronnie installed flat head Tapcon concrete screws in the tires using jam nuts to secure them in place!

 

 

Of course these will have a lot more resistance to pulling out than the old screw in studs.

 

 

The rear tires will have an extra liner installed to protect the heavy duty tube from puncture by the screw heads.

 

 

Although not winter specific, his next modification was the installation of a new ceramic coated pipe and an FMF Shorty silencer which will really wake up the 250.

 

 

 

 

Although the pipe wont be beautiful for long after the first mud race later this year it should stay pretty clean while winter riding.

 

 

 

 

Last year Ronnie picked up a couple LED cubes and mounted them on the handle bars of both bikes for winter night riding. They were easily removable for race season and featured a wiring harness and switch that I put together for him and a stand alone battery mounted under the seat. The 4 amp hour battery runs the light for hours so Ronnie simply charges it periodically with a battery tender.

 

 

This year Ronnie fabricated new mounts to hold the LED cubes much more sturdy than the old handle bar mount and keep it lower on the bike close to the fender.

 

 

 

 

The last item on the To Do list was re-jeting the carb in part for the new pipe and in part for the colder denser air temps experienced while winter riding.

 

 

On the YZ 250 you simply loosen the two clamps on the carb boots and twist it sideways to get access to the bottom drain bolt.

 

 

With the drain bolt removed you can unscrew the main jet with the proper size socket.

 

 

Finally the 178 main jet was replaced with a richer 180 and the carb reassembled. With this last step complete the boys are absolutely ready for the 20th annual winter trip to the Sooley cabin near Whitbourne!

Cheers, MIKE

 

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Copyright 2011 Michael Smith