Captain 80s Posted October 12, 2022 Share Posted October 12, 2022 9 minutes ago, twistednoble said: Can anyone speak to the blackbird shock's damping when it's installed a VFR? I've got my eye on one currently. I've got 34k miles on all stock components. I had to fix a leaking fork seal last weekend and now with new bushings and 10w oil the front end is drastically improved from where it was. The front end eats up undulations and expander gaps. This had the side effect of making the 34k mile worn shock feel like junk. The front end will float over the bump and then then the rear wheel will go over the same bump and feel like someone kicked me square in the buttocks through the seat. I wouldn't expect it to be any better than a VFR shock, even with half the miles. Why would it? It's pretty much the exact same shock, that wasn't that impressive when new. Better than something from the 80s? Of course, but that isn't saying much. The only thing you'll gain is maybe 5mm in length for some additional ride height. An actual improvement doesn't have to break the bank (but it can I know). Perhaps look at YSS. I have them on 5 bikes now and they are a great shock and value, which I need when I am upgrading so many bikes. Quote Link to comment Share on other sites More sharing options...
twistednoble Posted October 12, 2022 Share Posted October 12, 2022 15 minutes ago, Captain 80s said: I wouldn't expect it to be any better than a VFR shock, even with half the miles. Why would it? It's pretty much the exact same shock, that wasn't that impressive when new. Better than something from the 80s? Of course, but that isn't saying much. The only thing you'll gain is maybe 5mm in length for some additional ride height. An actual improvement doesn't have to break the bank (but it can I know). Perhaps look at YSS. I have them on 5 bikes now and they are a great shock and value, which I need when I am upgrading so many bikes. Thanks for the reply. I'm pulling for a super budget option at the moment which is why the ebay special BB shock is in the running. If I had the money I'd ship the stock shock off to Jamie and have him fix it up for me. Unfortunately the VFR is pulling commuting duty so extended downtime while the shock is getting worked on for a week or two isn't in the cards. It looks like the YSS is in about the same price bracket too. Maybe I'll get a BB shock and set it in the vice and see what the stack looks like. At least then I can swap back and forth between the two and still be able to ride to work on Monday. If it's really underwhelming it'll still give me time to refresh the stock shock. Hopefully if it's cleaned up and given an oil change it'll match the front fork's drastic improvement. Quote Link to comment Share on other sites More sharing options...
Captain 80s Posted October 12, 2022 Share Posted October 12, 2022 Not a bad plan. At least you'll know and it won't be expensive to experiment a bit. And like I said, a little ride height might liven the bike up a bit too. Quote Link to comment Share on other sites More sharing options...
Member Contributer Terry Posted October 12, 2022 Member Contributer Share Posted October 12, 2022 While I am all for experimentation with suspension, I don't believe it is possible for us mere mortals to open a shock and change oil or shims. Showa shocks like the Blackbird or VFR have a nitrogen charge above a floating piston at the blind end of the shock body. To open the shock you will need to fight against that gas pressure to get the circlip out, followed by an "exciting" pressure release. How Showa build these shocks in the first place is a mystery to me, but as there are no shortage of sealed gas shocks in the world it must be simple with the right machinery. To do the job right, you need to breach the blind end of the body and release the pressure in a more controlled manner, then fit a valve there so you can re-pressurise after rebuilding the shock. YMMV and all that. Quote Link to comment Share on other sites More sharing options...
Captain 80s Posted October 12, 2022 Share Posted October 12, 2022 7 minutes ago, Terry said: While I am all for experimentation with suspension, I don't believe it is possible for us mere mortals to open a shock and change oil or shims. Showa shocks like the Blackbird or VFR have a nitrogen charge above a floating piston at the blind end of the shock body. To open the shock you will need to fight against that gas pressure to get the circlip out, followed by an "exciting" pressure release. How Showa build these shocks in the first place is a mystery to me, but as there are no shortage of sealed gas shocks in the world it must be simple with the right machinery. To do the job right, you need to breach the blind end of the body and release the pressure in a more controlled manner, then fit a valve there so you can re-pressurise after rebuilding the shock. YMMV and all that. The CBR shocks I've had DMr modify for my old VFs have a new "port" installed at the top just for that reason. 1 Quote Link to comment Share on other sites More sharing options...
twistednoble Posted October 13, 2022 Share Posted October 13, 2022 5 hours ago, Terry said: While I am all for experimentation with suspension, I don't believe it is possible for us mere mortals to open a shock and change oil or shims. Showa shocks like the Blackbird or VFR have a nitrogen charge above a floating piston at the blind end of the shock body. To open the shock you will need to fight against that gas pressure to get the circlip out, followed by an "exciting" pressure release. How Showa build these shocks in the first place is a mystery to me, but as there are no shortage of sealed gas shocks in the world it must be simple with the right machinery. To do the job right, you need to breach the blind end of the body and release the pressure in a more controlled manner, then fit a valve there so you can re-pressurise after rebuilding the shock. YMMV and all that. Thank you for pointing that out. I stumbled across Jamie talking about how he de-gasses and re-gasses montoubes on the superhawk forum. Might be interesting but I think I could do it; I have the know-how to try it, and I'm just dumb enough to consider doing it. I'll do some thinking. A F4(i) shock would probably be easier to rebuild but would leave me needing a spring if the VFR spring isn't usable for it (which I don't believe it is). Does anyone have a chart for spring rates per rider weight? I'm hesitant to trust racetech's calculator coming from my experience in the dirt world (they spec overly stiff springs like I'm gonna be doing supercross on a DRZ or DR). Quote Link to comment Share on other sites More sharing options...
Member Contributer ducnut Posted October 13, 2022 Member Contributer Share Posted October 13, 2022 Race Tech sell the Schrader valve to recharge an OEM shock. Most common spring rates I’ve seen are over 1000#. My Penske has a 1300# spring and is perfect for my fluctuating 200-220 pounds. You’re going to need to alter the valving, if you’re planning to change the spring. Not sure anyone will be giving up shim stack info for a specific spring. If it were me, I’d buy a YSS and be done with it. However, the shock will highlight how bad the frontend is and you’ll be needing to rework that, as well. 1 Quote Link to comment Share on other sites More sharing options...
twistednoble Posted October 13, 2022 Share Posted October 13, 2022 17 minutes ago, ducnut said: Race Tech sell the Schrader valve to recharge an OEM shock. Most common spring rates I’ve seen are over 1000#. My Penske has a 1300# spring and is perfect for my fluctuating 200-220 pounds. You’re going to need to alter the valving, if you’re planning to change the spring. Not sure anyone will be giving up shim stack info for a specific spring. If it were me, I’d buy a YSS and be done with it. However, the shock will highlight how bad the frontend is and you’ll be needing to rework that, as well. Interesting, RT spec'd a 1300 lb spring for me too and I'm heavier than you. You are correct, shim stacks are highly coveted and no suspension tuner would ever reveal their secret sauce. Thankfully from what I've read the OE showa uses a straight stack. Shouldn't be too difficult to make a pyramid stack that provides some level of improvement. The best you know is only the best you've ridden. So long as I don't taste the $600 sauce I don't know what I'll be missing. 1 Quote Link to comment Share on other sites More sharing options...
Member Contributer bmart Posted October 13, 2022 Member Contributer Share Posted October 13, 2022 I've never heard of YSS. What are they similar to and can they be purchsed set up properly for the rider's weight before they're shipped? Quote Link to comment Share on other sites More sharing options...
Captain 80s Posted October 13, 2022 Share Posted October 13, 2022 42 minutes ago, bmart said: I've never heard of YSS. What are they similar to and can they be purchsed set up properly for the rider's weight before they're shipped? The most available models have rebound damping adjustment, spring preload and separate ride height adjustment (+/-5mm). If you buy from the UK YSS Research and Development Center, Firefox Racing, they will fit the shock with a spring rate of your choice for an additional charge. I think it's like 40 bucks or so. I find their spring choice a little on the firm side (which I prefer), I am about 180 lbs without gear. I have never felt the need to change it when ordering after my first one (VF1000F). Hawk GT 1995 VFR750F ST1100 I think I'm on my 5th or 6th. I am very pleased with them. 3 Quote Link to comment Share on other sites More sharing options...
twistednoble Posted October 13, 2022 Share Posted October 13, 2022 New avenue to report. The cbr900rr(893) shock appears like it will function. It has a remote reservoir and is adjustable for compression and rebound. Its also 318mm in length so almost spot on for the VFR. Quote Link to comment Share on other sites More sharing options...
CornPoweredV4 Posted October 14, 2022 Share Posted October 14, 2022 I haven't upgraded my VFR suspension yet, but for the record I put a new YSS shock on the back of my 07 SV650 two years ago and I've been loving it. I researched for weeks and found they were the best value for getting a brand new shock that's great for aggressive street riding, has a good range of adjustability, and is fully serviceable at the end of its life. For me, it beat out the prospect of going with some old, used shock from a different bike or trying to hunt down a Penske or Ohlins that would probably be overkill for what I'm doing anyway. I never even adjusted the shock after mounting it on my bike, it felt pretty good as is. They are made in Thailand so the English on their website is not the best, but the payment and delivery process was very professional and quick. Just throwin my two cents out there since I saw it being mentioned. 1 Quote Link to comment Share on other sites More sharing options...
LEGEND Posted October 15, 2022 Share Posted October 15, 2022 My vfr is still riding on its stock suspension, good to know about a new shock option. 1 Quote Link to comment Share on other sites More sharing options...
twistednoble Posted October 30, 2022 Share Posted October 30, 2022 Picked up a 893 shock and fitted it. Required some wiggling to get it in but it fit like it was meant to be. This particular specimen came off a CBR1100XX and has a 1000# Eibach spring on it, and has been into some point going off the schrader valve on the reservoir. Got a deal on it for for the low cost of $80 including the CBRXX linkage and mount. No parts compatibility there beyond the upper shackle unfortunately, so I'll see if I can't resell the excess parts to someone who can get some use out of it. The reservoir hose isn't the longest but you can run it to the LH side and tie it to the subframe. I've got it cable-tied in place for now, a proper mounting solution will be figured out soon. First impressions, it definitely jacks up the rear. I'm up on my feet now compared to how easily flat footed I was previously. I incorrectly set the preload and gave it far too much and now I have to figure out how I twist the adjuster without removing the shock. I was using a pipe wrench and a C-clamp to get it adjusted on the bench. Damping is much improved compared to the monoshock excepting a little harshness from the excess preload. Now the expansion grooves and undulations in the road are whispered through the pegs instead of no feedback until it hits the bottom of the stroke and boots me in the ass like it used to. 1 Quote Link to comment Share on other sites More sharing options...
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