Keeping my arse end on the ground

**breakaway** · 16th January 2008, 20:39

Hello,

I feel like there are some issues with the rear suspension on my CBR400RR.

I don't know if this is normal but, when I go over a bump (more so when I actually go over it and land back down), I can feel the engine loading up because the road is pressing the driven rear wheel upwards into the bike.

I probably did a really shitty job of explaining that.

A month or so ago, I was riding to my mate's house (geared up of course, dress for the bin etc), and was turning left at a roundabout, wasn't really pushing hard or anything, I gave her some gas as I was about halfway through the 90° turn, and suddenly found myself on my ass in the middle of the road.

The rear had spun up, and I had just kept on the throttle (it happened way too fast for me to do anything else). Ended up with a broken indicator and smashed screen.

Investigation of the 'crash site' showed that there was an uneven surface at that roundabout where I went down. I'm guessing one of the little bumps sent my rear flying and it spun up and came down spinning and caused the lowside.

I don't know if this is rider error, but it wouldn't hurt to get my suspension looked at, especially since this bike has been messed with to no end (Supposedly an RGV250 front end, yamaha brake mcyl, etc). Is my rear spring too hard or too soft? People riding behind me have told me on multiple occassions that my rear has been lifting up a bit too much.

The previous owner did tell me that the spring was set up for someone weighing 85KG. I'm about ~10KG lighter, so I didn't really think it would make a difference.

TIA

**Katman** · 16th January 2008, 21:12

Originally Posted by breakaway

I don't know if this is rider error

Are you serious?

**Robert Taylor** · 16th January 2008, 21:33

[QUOTE=breakaway;1383693]Hello,

I feel like there are some issues with the rear suspension on my CBR400RR.

I don't know if this is normal but, when I go over a bump (more so when I actually go over it and land back down), I can feel the engine loading up because the road is pressing the driven rear wheel upwards into the bike.

I probably did a really shitty job of explaining that.

A month or so ago, I was riding to my mate's house (geared up of course, dress for the bin etc), and was turning left at a roundabout, wasn't really pushing hard or anything, I gave her some gas as I was about halfway through the 90° turn, and suddenly found myself on my ass in the middle of the road.

You didnt say how old the bike is and how many clicks it has on the odometer. Irrespective, the internal damping is very crude meaning that square edge bump absorption is a pipe dream. Measuring sag correlation will also give some idea if the spring rate is correct or otherwise for you. I dont have time to explain that fully at present. Dependent on age the shock could be chernobyled....