PEP Rear shock, frame hits ground over jumps.

[lordmik]

Not sure exactly what I need to do with this. Here's what happens. Over any med to large jump, my frame hits the ground if I land on the rear first, but not all the time. I've got PEP shocks, not sure what they are to be honest with you. There's two springs, one red and one blue, and a big res on the back with 8 positions on the big red knob, and it's set on 8 already. Can I just crank the preload or do I need to get this thing revalved? I bought it from a guy on here who outweighs me by probably 40 pounds and haven't changed a thing. The fronts are perfect, the rear's the only problem. Any suggestions?? I can try to post a pic of the shock tomorrow if that'll help determine what it is. Thanks in advance.


Michael

05 trx450r

[JH Racing]

What is your ride height set at and when was the last time the shock was serviced. Adding preload is going to raise your ride height. You can adjust your crossover so it hits the main spring sooner that will stiffen up the shock and not chang the ride height. Also are you using the same linkage and swingarm that the shock came off of?

[lordmik]

The shocks were redone over the winter, just before I bought it supposedly. I bought the whole bike off a guy, haven't changed anything. Ride height is around 7.5 inches with me on the bike at the back, and just under eight in the front. It rides wonderfully, just hits sometimes.

[400exrider707]

Well then the shock is not correctly set up for the current setup on the bike. It could be it was set up for say 20" rear tires and you have 18" on it now or something (well not you, but the previous owner perhaps) Either way that shock needs to come off and be set up correctly for what is on it now and your weight.

[lordmik]

So in other words it needs to be revalved, right?

[TRX450RACER174]

Either revalved or maybe a different rate spring in it, was is setup up for MX or XC.

[JH Racing]

Being a PEP you can probally get away with 1 stiffer main spring but I would make sure the crossover is set right. Make sure you are running enough air pressure in the tires and alot of people over look this but check and see if your bearing carrier is rotated on top or bottom the way some swingarm and linkages are designed the carrier needs to be where the axle is on the bottom meaning the offset of the carrier is up.

[d3ktrix]

Originally posted by JH Racing
alot of people over look this but check and see if your bearing carrier is rotated on top or bottom the way some swingarm and linkages are designed the carrier needs to be where the axle is on the bottom meaning the offset of the carrier is up.

Maybe thats why my rear end has been lacking. Thanks for the info.
Right now my axle is on the top side, but I think the little bumps on the brake stay will hit the swinger if I try to turn it the other way though.

[lordmik]

Mine is setup for mx, it has the long travel houser linkage and the 1 3/4" longer than stock 05 swingarm. I'm not familiar with setting crossover and all that stuff. I had axis before on my yfz, and never had to mess with it. It was all set up from the get go. All I had to do with it was mess with the compression and rebound settings. :) So spring setup and stiffness and lenth, etc is all very new to me. The guy I bought the bike from weighed at least 230, and I'm 185. I have no idea if he had this problem or not, but I would assume so unless he didn't jump. I've only put one race on this bike since I got it (which I won, by the way) and it handles wonderfully. It's super smooth. I mean other than the bottoming on bigger jumps, it would be perfect. Thanks again for all the help guys. I sure need it. LoL

[JH Racing]

You have to grind the back bump off the caliper bracket

[d3ktrix]

Originally posted by JH Racing
You have to grind the back bump off the caliper bracket

Aight thanks, I'll switch that.
They weren't in the way when I was using a stock carrier, but with the Gibson carrier they hit.

[400exrider707]

Originally posted by JH Racing
Being a PEP you can probally get away with 1 stiffer main spring but I would make sure the crossover is set right. Make sure you are running enough air pressure in the tires and alot of people over look this but check and see if your bearing carrier is rotated on top or bottom the way some swingarm and linkages are designed the carrier needs to be where the axle is on the bottom meaning the offset of the carrier is up.

Correct me if I'm wrong, but even with a stiffer main, it still wont prevent the frame from hitting the ground before the shock bottoms out, which is setup incorrectly?

[lordmik]

I'm gonna do some measurements, and see what I can do with the linkage mounting points, there's some adjustability with the swingarm and where the linkage bolts up. Hopefully I can get this worked out. Thanks for all the replies guys.