Cylinder Works Big Bore Kit and Hot Cams - Dirt Rider Magazine |

I've been living on the Honda 150R lately. What's not to love about this bike? It makes power everywhere, has great suspension, and can handle with the best of them. Let's face it, the 85s haven't been updated since I was born.The 150R is the closest thing to a modern MX'er you are going to find for a kid. The 150R is built to be a pure motocrosser, but I like to ride it in the woods just as much as the MX track. You don't have to hammer the clutch to keep it screaming and the 4-stroke power really hooks up. It always looks and feels like I am going slower on the 150R than an 85, but the stop watch doesn't lie.

As I have gotten better on the 150R I have been searching for a little more bottom end power. My home track has slowly turned into a full blown Supercross track that Reed could be proud of. As fast as the 150R is bone stock it could use a horse power or two more right off of idle. This would help you clear the big jumps that have a short run up to them. In the woods, a little more torque would smooth things out also.This is where Cylinder Works and Hot Cams come in. Cylinder Works makes a big bore kit that ups the ccs to 159. I have tried some of the bigger bore kits all the way up to 170cc, but they can take away that quick revving motocross feel and turn it into a slow revving vet bike real quick. I'm only twelve, so I am still standing up and ricocheting off of everything!

Hot Cams makes two different cams for the 150R. They make a stage one that is for bottom end power and a stage two that is geared toward top end. Installation is not as hard as people make it out to be. Even with the stock Honda manual in hand, you can get the job done. The hardest part is setting the valve shims. Hot Cams makes a shim kit with all of the different sized shims, so make sure you order that with the cam. The only special tool you will need is a set of metric calipers. This is what you will be measuring the shims with when you install the cam. You can order a set of metric calipers from that will get the job done. You might as well order them now and learn how to work on 4-strokes.With the bore kit and cam installed, I was amazed how much more bottom end the bike had. From the crack of the throttle, it pulled hard and still had good top end. I had to scream the stock 150R's guts out to clear the big jumps before, but they seem effortless now. Riding in the woods and trails? So much easier! I didn't have to constantly worry about stalling the bike or over revving it.One last trick for the 150R, is to back the accelerator pump screw out a couple of turns counter clock wise. This helps get rid of that off idle hiccup when you snap the throttle. The accelerator pump is located under that black plastic cover on the right side of the carb. Just loosen the allen bolt and pop the cover off. You will see the Philips adjustment screw sitting right there. Just loosen it up and the bog will magically go away. As far as jetting, we ended up with a 42 pilot and a 140 main with 92 octane gas. This will get you close. For more info, go to and you at the races - CarsonHot Cams Stage 1 Camshaft $219.95

Hot Cams Shim Kit $89.95

Cylinder Works Big Bore Kit $549.95

Harbor Freight Metric Calipers $12.99 - $49.99