iSHOCK - Popular 10.5 inch Aftermarket Shock

APPLIED ENGINEERING Fork Springs

Fork Bushings

Applied Heavy Duty Shock Spring

The Honda CRF50 rear suspension and shock spring is rated for up to 88 lbs. It does work well for kids in this range if not ridden exceptionally hard. If they’re not bottoming out severely the shocks are probably fine for them.

To do a good suspension upgrade is VERY expensive requiring a new fork, shock and swing arm! This would cost around $1500 and not what this particular project is about. This project bike is meant for a kid weighing less than 88 lbs. Although it has been modified to handle some motocross riding no adult rides it and it is not raced. So here’s what we’ve tried so far, trying not to spend big bucks.

REAR SHOCK:

We have tried a stiffer rear shock spring($30) and a 10.5” shock (eBAY $10) and they proved to be too stiff. The shock would hardly compress, so we ended up going back to the stock spring. I looked for other aftermarket shocks but they all have eye to eye lengths of 10.5”. The stock shock is 9.5”. So all the aftermarket shocks raise the stock swing arm a lot. They are really meant for extended swing arms and typically combined with a new front fork. What I really need is some round shims between the spring and spring stop so I can add a little preload to the shock. I haven’t seen anything like this but I may try to fabricate something myself.

FRONT FORK:

I’ve got a set of APPLIED ENGINEERING fork springs ($40) and some new DELRIN fork bushings yet to be installed and tested. The main concern I have with adding stiffer fork springs is that the stock CRF50 forks are JUST SPRINGS, there’s no OIL DAMPING like on a big bike. Therefore the ride can be stiff AND bouncy with no damping to slow the springs down. The bushings will be replaced, they are much better than the stock units which have a lot of “slop” in them. Because this bike is meant for a little kid and we didn’t want to spend a fortune on it (although what we’ve done so far wasn’t cheap) we didn’t want to get into frames, swing arms or forks.

TECH TIP: If you are going to do any serious work on the suspension I highly recommend the official SERVICE MANUAL. It will make your life a lot easier.

TECH TIP: Shoot some video of the bike landing a good size jump. If you can play it back frame by frame on your computer you can see the suspension travel and tell if it is bottoming out at all.

Another option for the front forks is an extended fork leg kit like the Red Baron’s or SANO below. They add an inch in length and are made of stronger material than stock. The SANO kit comes with a disc brake, brake lever and a hub adapter. They both come with the needed longer brake cable. This is a good modification especially if you go with a stiffer rear shock/spring.

RED BARON Extended Fork Leg Kit

ALTERNATIVE:

SANO Extended Fork Leg Kit

TEXT AND IMAGES COPYRIGHT PROJECT CRF50 2008