badmotogoozer Posted October 31, 2005 Posted October 31, 2005 I'd like to know this as well... Just put my front end back together, included a fork oil change. No problem on the left leg - drain fluid (didn't measure it) and refilled with a measured out 400mls. Went back in no problem, put cap back on. But on the right leg, same drill, except when refilling it overfilled before I got it all in. Figured I didn't get it all out the first time. Drain again, this time pumped the heck out of it and left it sit longer. Nothing coming out at all for a long time, refill. Same thing. Wants to overflow. Got it all in, but I could see the top of the oil level, quite close to the cap... it was no where near this high in the other leg... It's all back together now... but I'm worried that the first good bump will hydraulically bottom out the fork... Rj
txrider Posted October 31, 2005 Posted October 31, 2005 Well it's a different fork but I had some of the same concerns on my 2004 when I did the fork service on it. Both forks pumped, hung upside down overnight, pumped some more until I was dead certain all the old oil was out. Then on refill I put in 430cc each leg. With fork compressed, lower spacer in, and spring out that amount of oil showed 77 mm freeboard ( fluid surface to top of fork) which is about 30-35cc less than the other usd Marzocchi forks I've done. in fact all forks usd or otherwise I've done the past few years showed 100-110mm freeboard which makes me wonder if that's too much oil even though MG recommended it. For you suspension specialists, wouldn't that account for too much compression damping for the forks? Assuming one uses MG recommended 10wt? The result on my bike is that it gives one jarring ride and I plan to make changes this winter to correct that.
Guest ratchethack Posted October 31, 2005 Posted October 31, 2005 Guys, I've just finished sorting this out. See the GuzziTech thread here: http://www.phpbbforfree.com/forums/guzzitech-about695.html The gist of it is that since it's very evidently impossible to get anywhere near all the oil out of the forks by simply taking them out and pumping out the cartridges, the only way to do it without overfilling is to do it by the air space (aka headspace, aka air gap, aka luftkammer). My Guzzi manual only specifies 400 ml per leg, and gives no spec for air space. The mfgr. of my new fork springs (Wilbers) specifies 100 ml from the top with springs removed and forks fully compressed. Per the thread at GuzziTech, it's easy to seriously overfill these forks. Nice graph provided by Dave there also, which demonstrates what can happen with a relatively small amount of overfill.
badmotogoozer Posted October 31, 2005 Posted October 31, 2005 Bloody hell!!! I just get a good chunk of my bike put back together... and now I have to go back and disassemble it farther than it was before! I've about had it with this thing. So... what do I need to disassemble the forks? Had a peek in there but have no idea how to actually take one apart Rj
Guest Nogbad Posted October 31, 2005 Posted October 31, 2005 Bloody hell!!! I just get a good chunk of my bike put back together... and now I have to go back and disassemble it farther than it was before! I've about had it with this thing. So... what do I need to disassemble the forks? Had a peek in there but have no idea how to actually take one apart Rj 65485[/snapback] You aren't the only one. In 1000 miles I am going to be faced with changing the fork oil too. I suppose I could just send it to the shop though....... temptation is a terrible thing.
Guest ratchethack Posted October 31, 2005 Posted October 31, 2005 Bloody hell!!! I just get a good chunk of my bike put back together... and now I have to go back and disassemble it farther than it was before! I've about had it with this thing. So... what do I need to disassemble the forks? Had a peek in there but have no idea how to actually take one apart Rj 65485[/snapback] Ryan, since you've already replaced the oil, no need to disassemble further than getting the springs out. Get a turkey baster and draw off the oil to 100 mm depth with the fork propped up to fully retracted position.
badmotogoozer Posted October 31, 2005 Posted October 31, 2005 Well that's a relief! I automatically assume worst case scenario with this thing. How do the springs come out? When I took the legs out and unscrewed the cap, the cap was still attached to all the guts. Put a wrench on the blue thingy (high tech lingo) but it only spun the lowers around. Figured I'd better stop before I wrecked something (a regular occurence). Thanks! Rj
Guest ratchethack Posted October 31, 2005 Posted October 31, 2005 Ryan, the fork caps are threaded onto the same rod as the blue anodized nuts that secure the spring collets. They're a jam fit against each other. The caps are broken loose by holding the blue anodized nuts and the caps, a wrench on each. If you've got the strength in your hands, you can hold the spring collets down so you can back the spring collet nuts off with the other hand. Or if y'er strong enough and *tough enough*, you can leave the nuts right where they are, retract the spring with one hand and slip the collets out with the other. In either case, springs and spacers then come right out. Per one of your previous posts, didn't you just go through this?? I recommend re-installation with the spring collet nuts in the same orientation they came out (yep it matters), 22 mm from the top of the rod. This is the distance mine came from the factory. Not sure if or why it might be important, but until I have better info, better be safe than sorry.
badmotogoozer Posted October 31, 2005 Posted October 31, 2005 I unthreaded the caps from the slider, slid slider down, drained oil, slid slider up, refilled and spun cap back on. At no point did I have any parts actually separated... Cap remained attached to blue thingy, which remained attached to whatever it attaches to. When I said "put cap back on" I really should have said "rethreaded cap into tube". It all worked quite well until it overflowed... This is my first new bike... before the Guzzi, the newest bike I owned was a 79 Honda 400... It has been quite a learning curve... Rj
helicopterjim R.I.P. Posted October 31, 2005 Posted October 31, 2005 Bloody hell!!! I just get a good chunk of my bike put back together... and now I have to go back and disassemble it farther than it was before! I've about had it with this thing. So... what do I need to disassemble the forks? Had a peek in there but have no idea how to actually take one apart Rj 65485[/snapback] Bring it out to Chilliwack and I'll get my friend Richie to do it. He is great at disassembling and assembling forks!!
Guest ratchethack Posted October 31, 2005 Posted October 31, 2005 I unthreaded the caps from the slider, slid slider down, drained oil, slid slider up, refilled and spun cap back on. At no point did I have any parts actually separated... Cap remained attached to blue thingy, which remained attached to whatever it attaches to. It has been quite a learning curve... In this case, you had no possibility of pumping out the cartridges. This would explain the gross overfill. Yeah, it's been a learning curve for me too, and I've had 12 bikes and rebuilt a pile of forks in the process. Kinda fun tho, innit?
badmotogoozer Posted October 31, 2005 Posted October 31, 2005 fun... at times... been a little too much "fun" this year and not nearly enough FUN! Gross negligence is my specialty officer! Thanks Ratchet!! Rj
Guest ratchethack Posted October 31, 2005 Posted October 31, 2005 Por nada. BTW - If you're at all inclined toward more fun than a barrel o' monkeys, this'd be your best possible opportunity to install that brand-new, properly matched set of springs - also an equally good time to dial in your laden and unladen sag by re-sizing those spacers...
badmotogoozer Posted October 31, 2005 Posted October 31, 2005 I have gone through the whole sag/spring/spacer thing on both my old Triumph and Ducati. Both were transformed by the process! I expected to do the same with the Guzzi, even bought the Yamaha F1 springs that were supposed to work but then someone posted that they actually don't... I've been watching the spring replacement theories progress, but it was extremely disheartening to not be able to figure out how the bloody legs come apart. It isn't like I've never done this stuff before... Once I've got it figured out how to disassemble/reassemble and what everything looks like, then I'll get playing on the sag/spring thing. Already bought one set of springs that will rust in the corner... Rj
soloNH Posted November 1, 2005 Posted November 1, 2005 OK guys, I've been following this thread very closely. Servicing my suspension is one of the items I have listed to do this off season. I now know that I have to replace my springs, front and rear. I weigh 230# and my MG has 17,000 plus miles and want to go through everything to improve handling and to make sure everything is up to snuff. Couple of questions for you all. 1. Are the Ohlins much more difficult to service than the others. My guess, yes. 2. Is it important to stick with Ohlins springs or are there other mfg. who make springs to fit ? 3. I have never serviced cartridge forks before so should I just send it all to an Ohlins service center or would someone else, like Traxxion be able to handle it?
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