BackInBlack Posted June 6, 2004 Share Posted June 6, 2004 Hello XX Forum, This is kinda a long question but hopefully someone can help.... I recently bought a '97 Blackbird from a friend. He put Race Tech 1.0kg/mm springs in the forks (just springs no valving or emulators) and a Penske shock on the rear. He's 6'5" and weighs 230lbs and I'm 5'10", 170lbs. I already replaced the spring on the Penske, he had an 1100lb spring and I put a 1000lb spring on it. I called Penske and they said a 1000lb spring was recommended for my weight. The problem is that I've played around with the compression and rebound adjustments on the Penske and it still seems harsh over bumps. I currently have the remote compression adjuster set at 2 (out of 6) and the rebound dial is about 8 (out of 30) clicks. Is there anyone who's about my weight who also uses a Penske shock? If so, what are your settings? Also, according to Race Tech, I am inbetween an .95kg/mm and 1.0kg/mm springs for the front. As stated above, the bike has the 1.0kg/mm springs in it. Would switching to the .95kg/mm be that noticeable? I'm enjoying the bike and plan on using it mainly for touring so I'd like to have a cushier ride. I've already done a couple different 500+ mile days. The main comfort issue I'm having is with the suspension. It's great when the road is smooth but once the road gets a little bumpy (concrete block freeway with seems), feeling ALL the bumps can get old fast. I haven't owned a "sportbike" before so maybe I'm expecting too much? I'd appreciate whatever feedback or suggestions you have. Thanks, Ian Quote Link to comment Share on other sites More sharing options...
XXTi Posted June 6, 2004 Share Posted June 6, 2004 I have a Penske, but I'm closer to your friend's size than your's. I have the 1100# spring and run my rebound at 15 clicks from full damping and the compression on 1 or 2 if I'm just cruising down the highway. I firm it up a bit for the twisties. You can ask the tech folks at Penske for recommended adjustments for your size, weight, and bike. They were responsive when I contacted them by e-mail. I can't comment on the forks. I still haven't modified mine. :oops: Good luck and enjoy your 'Bird. Quote Link to comment Share on other sites More sharing options...
BackInBlack Posted June 6, 2004 Author Share Posted June 6, 2004 Hi, Thanks for the feedback. I might be guilty of trying to make a "couch" ride but I just don't have a frame of reference for what it should feel like. I've only owned 30+ year old UJM's and couple 80's BMW K-bikes up until now. Having a "real" suspension is something new to me :grin: I'm planning on contacting Penske again. I'm just trying to make sure I'm doing the adjustments correctly. I've also been trying to determine if sometimes what I think is a rear shock issue is actually caused by the front being a little too stiff instead? The initial hit on the front jolts or rocks the bike and makes the rear hit hard??? (Is that possible?) I'm leaning towards buying the .95 springs for the front but didn't want to spend the money if it's not going to make much difference. What is the stock rear shock like? It seems heavier guys don't like it because it's too soft. I'm a pretty mellow rider so I'm just wondering if it might work better for me in terms of sacrificing some performance for comfort? Ian Quote Link to comment Share on other sites More sharing options...
Northman Posted June 6, 2004 Share Posted June 6, 2004 My vote goes to re-valve the front forks. There is way too much rebound from the factory, and repetitive bumps make the suspension "pack up", and it rides like a brick. While you're in there, swap the springs to the .95's, and make sure your sag is set properly as well. Optimum sag should be 25-35mm with 30 the target. I don't think the 1.0's would seem very stiff after valving, though. You can also play with oil height to fine tune the springs. Dial out all of your compression in the rear, as well as rebound, and see how you like it. Just make sure that the lowest numbers on the adjusters mean the softest valving - usually the case, but I have no experience with Penske shocks. Quote Link to comment Share on other sites More sharing options...
Redbird Posted June 6, 2004 Share Posted June 6, 2004 Another culprit may be the stock damping, which many find harsh. All the spring/preload changes in the world won't change this. Quote Link to comment Share on other sites More sharing options...
RodeRash Posted June 6, 2004 Share Posted June 6, 2004 I agree about having the forks redone. The stock compression damping is way to stiff. Honda does that to make up for the soft springs that they provide. Adding stiffer springs without changing the damping will remove a lot of the excess fork dive during braking, but will only make the bike feel worse over sharp bumps (like concreate expansion joints) Another problem with stock forks, is excessive stiction. Most of the good fork rebuilders such as Stig Peterson, Dan Kyle, Lindemann, Max at Traxxion Dynamics will microfinish your fork tubes, and replace your fork seals and bushings with low drag units. Quote Link to comment Share on other sites More sharing options...
BackInBlack Posted June 6, 2004 Author Share Posted June 6, 2004 Hello, Thanks for the suggestions I do get some harsh hits through the front but not enough to be an issue. That's why I haven't messed with the front springs other than taking out some preload. Usually what I notice more are the hits through the seat which I assume are related to the rear suspension compression. It seems worse at highway speeds than on slower back roads. Dropping from the 1100lb to the 1000lb spring on Penske did help (when I first got the bike it'd buck me off the seat on big bumps). Now, even with the compression set to "1" (the softest) it can be a bit harsh. I think I'll call Penske and talk to them about how I might soften it a bit more. (Valving or going to a 950lb spring maybe?) So far I'm learning that suspension is a tricky thing and it's hard to find a balance on settings. What's good on one road is not on another.... Ian Quote Link to comment Share on other sites More sharing options...
Northman Posted June 6, 2004 Share Posted June 6, 2004 Have you checked out your rear sag? When you swapped out springs, is it possible there is too much preload? It shouldn't affect ride much, as long as you have somewhere close to desired. What about tire pressures, and tires? I recently rode on a set of 020's, set to 40psi, and found them to feel a lot harsher than my Avon's set to 36/38. You'd also be amazed how much the front suspension affects the overall bike, not just the feel through the clipons. Quote Link to comment Share on other sites More sharing options...
BackInBlack Posted June 6, 2004 Author Share Posted June 6, 2004 I thought about playing around with tire pressure but haven't yet. I have Michelin Pilot Sports on it and I set them both at 42psi per the sticker on the swing arm. You think I could lower those to 38psi and soften the ride? Quote Link to comment Share on other sites More sharing options...
Northman Posted June 7, 2004 Share Posted June 7, 2004 It's worth trying, and I prefer the tire pressures at those settings, too. At least with the Avon's, I do. YMMV, but they give a better feel, IMO. Quote Link to comment Share on other sites More sharing options...
BIG BOY Posted June 7, 2004 Share Posted June 7, 2004 I have the Penske, with the 1300 spring. I'm a little under double of your weight, so my comments mean dick to you. Sorry, i just had to post here. Quote Link to comment Share on other sites More sharing options...
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