03 Xr650r

[rick nelson]

I BOUGHT THE BIKE NEW WITH THE HONDA FACTORY HOP-UP KIT TISTALLED (NEW PIPE INSERT/ NOT 2" DRILLED, CARB JETING DRILLED AND AIR BOX RESTRICTORS AND INTAKE MANIFOLD REMOVED. ADDED HOLES IN SIDE COVER AS PER DEALERS MODS FOR THERE BAJA BIKE. ADDED THE UNI FILTER.
BIKE RUNS WELL BUT WHAT NEXT?? CAM STAGE 1 OR 2, PORT WORK AND / OR A BETTER EXHAUST SYSTEM.
I HAVE NOT SEEN MANY PUBLISHED MODS YET.
THANKS FOR ANT INFO, LINKS ECT.

 

[BigBore]

The next step is motor work. You can get a Power Up motor kit from Honda, but its quite expensive. I believe it comes with an 11:1 piston, cam, stronger cam chain, gasket kit, and different jetting. You could probably by those parts seperate for cheaper than what Honda wants for the whole kit.

A lot of guys are slapping on an Edelbrock Qwiksilver pumper carb. Supposed to provide a lot better low end snap, and easier starting. Not really that much in the way of overall increased power.

Don't waste your money on exhaust systems on the stock motor. Its tough to beat the HRC insert.

BTW......you might wanna kill that CAPSLOCK. ;)

 

[mike perry]

Rob Barnum at Edlebrock has fooled around with these engines. Also Freddy at XR's only ran one out of his shop, and may have some pieces for it. Rob can be reached at Edlebrock or through the Thumper Talk web site.

We have a spring kit for the head, but valves are a problem. Honda decided to go with a 6.5mm stem, which is an oddball size- they are about the only company that has used this size over the years. Right now there are no good blanks available in that stem size.

We've actually made some oversize valves from 7.0mm blanks for a couple of racers, where we turned the keeper groove detail down to the factory 6.5mm dimension, and the customer bored and honed the guide to accept the oversize stem dimension. That was the cheapest way to go. An all out racer might go to a 5.5mm conversion...