Tom M Posted February 2, 2009 Share Posted February 2, 2009 My stock Bitubo is shot and from what I read in other threads here it's not rebuildable. I see HyperPro and Ohlins are popular replacements, but they seem awfully expensive to me. Traxxion Dynamics has a rebuildable damper that's interesting, but they don't have one with a ~80mm stroke like the Bitubo. Their next size up has a 100mm stroke which might be too long to fit inside the LeMans fairing. I emailed them to see how overall length of the 100mm unit compares to the Bitubo. Do any of you have any other suggestions for replacement units? It seems like there should be some sportbike riders out there who replace perfectly good factory dampers that would fit our bikes with Ohlins, GPR, etc, because that's what all the cool kids use. I don't need something off a MotoGP bike, one that works like the Bitubo did when it was new is fine with me. For future reference here's what I got for measurements on the Bitubo: overall length = 290mm stroke = 80mm body diameter = 22mm body length = 160mm Link to comment Share on other sites More sharing options...
Tom M Posted February 2, 2009 Author Share Posted February 2, 2009 I might have found what I'm looking for here: http://www.ronayers.com/catalogs/pu/parts....26&type=208 The standard model is 20mm longer than the Bitubo but I think I can live with that. Any other suggestions, or comments on Shindy dampers are welcome. Edit: I used part # D17-001 from above and it works fine on my LM. Link to comment Share on other sites More sharing options...
Guest ratchethack Posted February 2, 2009 Share Posted February 2, 2009 Tom, Ernst posted a few years back that he was able to have someone disassemble and refill his Bitubo. It didn't need seals. The "gritty" feel might just be air bubbles passing through the orifice from oil loss. Mine looks like it comes apart with snap rings. Just a thought. Link to comment Share on other sites More sharing options...
Tom M Posted February 3, 2009 Author Share Posted February 3, 2009 Tom, Ernst posted a few years back that he was able to have someone disassemble and refill his Bitubo. It didn't need seals. The "gritty" feel might just be air bubbles from oil loss passing through the orifice. Mine looks like it comes apart with snap rings. Just a thought. I guess I missed Ernst's post when I did my forum search. A decal on the Bitubo says it's gas charged so I think a home rebuild is out of my league. FWIW the Shindy can be rebuilt with a $15 kit, not sure what Traxxion gets for a Sprint damper rebuild. I got a bit of a scare last Fall when I suddenly felt like I was really wrestling with the bike just going slowly down the road. I thought I was going to drift into an oncoming car for a second there . I stopped and hopped off the bike expecting to find a flat front tire but nothing was wrong with either tire. I took a guess and backed all the way off on the damper and the bike returned to normal. I suspect something is floating around in there and sometimes clogging the damper orfices. FWIW the seals haven't leaked. Link to comment Share on other sites More sharing options...
jrt Posted February 3, 2009 Share Posted February 3, 2009 This is kind of a different league, but I have a Shindy damper on my Eldorado. Works just fine. It is smooth and even throughout the range. I have it set pretty light- I don't honestly recall what the heavy damping feels like, but I don't recall it as being real hard. For the price, I heartily endorse it. For a less expensive option that might need some engineering, you could look at the damper sold by Mike's XS, a website devoted mostly to the XS650. http://www.mikesxs.net/products-20.html Hmm, not all that less expensive. They were 50 bucks not too long ago. Oh, well. Go with the Shindy, it looks better. Link to comment Share on other sites More sharing options...
WitchCityBallabio Posted February 4, 2009 Share Posted February 4, 2009 FWIW, the HyperPro unit is spectacular.... Link to comment Share on other sites More sharing options...
Tom M Posted February 4, 2009 Author Share Posted February 4, 2009 FWIW, the HyperPro unit is spectacular.... Do you have the active model Doug? If not I'd like to know how it feels different from the stock Bitubo. Link to comment Share on other sites More sharing options...
raz Posted February 4, 2009 Share Posted February 4, 2009 Here is a thread about overhauling the Bitubo, with or without a rebuild kit: http://www.morini.com.au/phpBB2/viewtopic.php?t=3170 I plan to try it (myself, without caring about the nitrogen gas) on my spare one. It has at least half an inch of "slack" in the movement when you push it by hand and turn direction. The one currently mounted is better but has the same tendency. The failure mode you describe sounds pretty scary and such scenarios makes me hesitate overhauling it myself. But I think I'll give it a try and decide later if I dare mounting it. Oh, and this may be obvious to you or not, but don't be too worried about using the bike without the damper while you source a new one. Some people toss it away just on principle. I prefer keeping it, but I rode a lot last summer without it, including a track day. No problems. Link to comment Share on other sites More sharing options...
Tom M Posted February 5, 2009 Author Share Posted February 5, 2009 That's interesting Raz. Thanks. I already ordered a Shindy replacement, but I might take the Bitubo apart to see what's wrong and maybe try the rebuild. It seems strange that a rebuild would work without recharging the nitrogen though. By the way, another issue that mine has is the adjuster knob has a gritty feel to it when I turn it. I suspect it needs more than a fluid change, but I could be wrong... Link to comment Share on other sites More sharing options...
Skeeve Posted February 5, 2009 Share Posted February 5, 2009 It seems strange that a rebuild would work without recharging the nitrogen though. Why? Oleo struts had been used for a long time before they discovered nitrogen charging; they just fade more when hot; motorcycle steering being a process of slow movements, a plain oleo strut should work fine w/ no noticeable fading... And remember, "simple is best." Link to comment Share on other sites More sharing options...
badmotogoozer Posted February 5, 2009 Share Posted February 5, 2009 I bought the Hyperpro Reactive. Worth every penny - the bike is noticeably smoother than it was even when the Bitubo POS was new. Forget the cheap shite - may as well run without one completely. Link to comment Share on other sites More sharing options...
Greg Field Posted February 6, 2009 Share Posted February 6, 2009 That's interesting Raz. Thanks. I already ordered a Shindy replacement, but I might take the Bitubo apart to see what's wrong and maybe try the rebuild. It seems strange that a rebuild would work without recharging the nitrogen though. By the way, another issue that mine has is the adjuster knob has a gritty feel to it when I turn it. I suspect it needs more than a fluid change, but I could be wrong... Tom: There is a set of Aprilia seals available that fit that damper. Link to comment Share on other sites More sharing options...
Tom M Posted February 6, 2009 Author Share Posted February 6, 2009 Why? Oleo struts had been used for a long time before they discovered nitrogen charging; they just fade more when hot; motorcycle steering being a process of slow movements, a plain oleo strut should work fine w/ no noticeable fading... And remember, "simple is best." My thinking was since nitrogen charged shocks don't work well when the charge goes away, why would a steering damper be any different? You don't have to answer that, I'm just letting you know why I thought a rebuild might be a problem without the gas charge. I'm sure the reactive HyperPro works great, but I expect the simple Shindy will work fine for me once the snow & ice goes away here. I've never had a head shake problem with this bike so I consider any steering damper more of an insurance policy than a necessity. Link to comment Share on other sites More sharing options...
Tom M Posted February 6, 2009 Author Share Posted February 6, 2009 Tom: There is a set of Aprilia seals available that fit that damper. Thanks Greg. I'll keep that in mind if I rebuild the Bitubo. Link to comment Share on other sites More sharing options...
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