front end problems

[rider1D]

The front end on my 75/5 is bouncing very bad and front end dive is excessive. I put new 10 wt. oil in the forks, replaced the springs with the thick progressive ones, and installed new rear shocks. Also replaced the entire fork assembly. The springs have enough of a preload so they had to be compressed when screwing in the top caps.

I'm thinking of adding another 10cc fork oil just to see what will happen.

If that doesn't work, maybe replace the main stem, bearings and triple clamps with an entire extra unit I have. Outside of that, the Haynes manual said look out for a possible cracked frame. The bike currently feels dangerous to ride.

Can anyone please help?

[20774]

Bouncing could be a badly balanced tire? As for the dive, is it possible that the damper holes in the bottom of the fork assembly are way too big? How much fork oil did you put in? 10wt should be more than enough...typically for most riders 7.5wt is fine. Then again, one manufacturers weights might be different than other.

[lmo1131]

My /5 used to bounce quite a bit when I had the Windjammer on it, but it never felt dangerous to ride. The bounce quit when I ditched the faring.

If it feels dangerous, then park the bike. Pull the tank and have a look around, it wouldn't be the first BMW to break a frame. These old /5 frames are made of pasta, or something akin to it, but they're sufficiently engineered to get the job done, and you shouldn't be feeling like it's going to come apart on you.

If you have a spare front end, by all means plug it in. You will know immediately if there is a difference, and it would take a lot less time than a rebuild. If you get the same results (severe bounce) then you know it isn't the front forks. I think I would suspect a cracked stanchion.

Regardless. Park the scooter until you have thoroughly checked everything out.