Member Contributer joneill Posted January 13, 2013 Member Contributer Share Posted January 13, 2013 This might be a stupid question but….. I have this Penske 8987 shock with the rebound adjustment on the bottom of the shock. You can see the adjust screw on the left. Below that is a locking nut and threaded eye for the bottom mount. To adjust height with the shock installed, can I back off the locking nut and put a wench on the bottom of the shock (flats below where the rebound adjuster is located) and rotate the bottom of the shock leaving the bottom of the shock bolted in place or do I need to unbolt bottom of the shock and thread the bottom mount in or out and then rebolt the shock n place? This is a used shock and it look like some has put a wench to the bottom of the shock before. Link to comment Share on other sites More sharing options...
Member Contributer vfrAustin Posted January 13, 2013 Member Contributer Share Posted January 13, 2013 My bad Link to comment Share on other sites More sharing options...
Veefer800Canuck Posted January 13, 2013 Share Posted January 13, 2013 Shouldn't the preload adjuster be on the other end? It sure looks like a ride height adjuster to me???Though I have an ohlins and not a Penske, so......I'm saying you gotta remove the shock, loosen the jam nut, and rotate the shock eye to lengthen the shock. Lefty loosey. The spring and body would not move, just the lower eye. Then retighten the jam nut.From the small pic on my iPhone, that's what it looks like. Went to the PC, and yeah, that's what it looks like. The preload adjuster would be on the shock body, at it's widest point, not where the rod is. Link to comment Share on other sites More sharing options...
Tamworth Posted January 13, 2013 Share Posted January 13, 2013 Veefer is correct, this is NOT a preload, this is the shock length adjustment. You should unmount the bottom of the shock to alter this, you don't want to be rotating the rebound valve body. Link to comment Share on other sites More sharing options...
Veefer800Canuck Posted January 13, 2013 Share Posted January 13, 2013 You might not have to remove the shock entirely, if you put the bike on the centerstand and remove the lower shock linkage, you could probably undo the jam nut and rotate the lower eye, lengthening the shock, without undoing the top mount, so the shock stays in the bike. A bit of finangling, but less disassembly. Link to comment Share on other sites More sharing options...
steve27bha Posted January 13, 2013 Share Posted January 13, 2013 I had a Penske 8981 on my 750FR and transferred it to the 800FiY. Pic below shows the bottom end adjusters. The red collar is the rebound adjuster, and to the left of that are two 1" AF nuts to adjust the shock length. You can do the adjustment in situ by slackening the locknut (on left side) then turning the right nut and the whole bottom mount for the spring and the shaft. It will be stiff to do because you are fighting against the friction caused by the spring preload on the bottom perch (unless you have a torrington bearing to allow easier movement between the spring and the upper perch as I had). So do this on the centre stand, and if necessary back off the preload temporarily. However, on a 5th gen. I'd remove the triangle plates, unlock the adjuster, rotate the lower eye, relock the adjuster and replace the triangles. That would be easier and involve less swearing. The thread is 1/20" pitch IIRC. Do what you can to get the rose joints in their central position before locking up the second nut. PS - the previous owner of the shock chewed up the nut with a vice grip or similar, not me! HTH Link to comment Share on other sites More sharing options...
zRoYz Posted January 14, 2013 Share Posted January 14, 2013 My penske is same as posted by steve27bha which the ride height adjuster nut spins free of the rebound adjustment body so no problem adjusting when installed on bike. The other pic looks like the ride height adjustment doesn't spin free of the rebound adjustment body so to adjust you would be spinning the complete rebound adjustment body after you loosen the locking nut. That is a pain because you always want to spin the body for good access to the rebound screw but there is no problem spinning the complete rebound adjustment body the internals of shock on shaft will just spin freely with it. BUT it is highly recommended before adjusting that way when installed unload the rear wheel on center stand & back off preload completely before making adjustment to unload shock completely. Just remember were your preload adjustment ring was before you back it off so you can return to same position. You can get away with just unloading rear wheel if your lazy because the penske has the roller bearing type washers either end of spring which allows for rotation easier. Link to comment Share on other sites More sharing options...
Member Contributer joneill Posted January 14, 2013 Author Member Contributer Share Posted January 14, 2013 Veefer is correct, this is NOT a preload, this is the shock length adjustment. You should unmount the bottom of the shock to alter this, you don't want to be rotating the rebound valve body. Right, the pre-load is on the top and the rebound is an adjustment screw, just visible on the left. The issues is can I turn the lower half of the shock body instead of removint the lower shock mount and threading the lower mount in or out. It would seem that loosing the lock nut and leaving the lower mount fixed would let me adjust the ride hight by roating the lower half of the shock body. Not sure if this is bad for the shock. Link to comment Share on other sites More sharing options...
steve27bha Posted January 16, 2013 Share Posted January 16, 2013 If you are worried about rotating the whole thing, just do as I suggest in my third paragraph and take the triangles off. It will be easier and just as quick because of the restricted access with them in position. You need a centrestand of course, or similar. Good luck finding a pair of 1" AF spanners / wrenches. I had to modify a plumber's tool by filing the jaws to size unless I was prepared to pay a fortune. Link to comment Share on other sites More sharing options...
Member Contributer JamieDaugherty Posted January 17, 2013 Member Contributer Share Posted January 17, 2013 You can rotate the shock as you suggest - that is no problem at all. It won't hurt anything doing that. Enjoy! Link to comment Share on other sites More sharing options...
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