Fixing super soft forks on a 1975 honda MR175

[j_freak]

The front forks on my MR have about 6'' of travel. If I sit on the bike, near the front, they'll sink about an inch and a half. If I put the brake on and lean forward, they'll sink to a total of about 3 1/2 inches. If I shove the front end downward, I can bottom them out.

Since they are obviously too wimpy for me, I believe the best (cheapest) course of action is to take off several coils, then put spacers in. My question is, how many coils should I take off? I weigh 145, and basically just putt around the farm (cause the bike isn't dependable enough to go anywhere) :( I do jump off a few small hills occasionally.

 

[dirt bike dave]

You will need to remove the springs and measure the gap between each coil and count the total # of gaps between coils. That will show you how much the spring can compress before it coil binds. Make sure you allow for pre-load when determining how much to cut off. If you have plenty of coils to work with and are not at risk for coil bind when the suspension is fully compressed, I would start by cutting off 10% of the coils.

While you have the springs out, measure the fork oil level by compressing the fork, and see far low the oil is from the top of the fork tube. Raising oil level will dramatically improve the fork's stiffness as you get close to bottoming out.

Thicker fork oil will not really help much on compresssion, but will slow the fork's rebound down. With the stiffer sprnigs, you might want more rebound damping.

On my old '84 KDX, removing about 10% of the spring (3 coils) and raising the oil level from 6" to 4" made a huge improvement. Your bike probably has very small fork tubes, so I would start by raising the fork oil 1" from where it is now (springs out, fork compressed).