Being a lightweight I took the caps off the forks to pull some oil out, to soften them a bit as I am using no where near the full travel, even stoppies downhill. No lock nut under the cap for the valve rod, just a tapered shroud / spacer ? So just dropped the bike down 25mm and put it all back together, nice improvement but now keeping me awake at night as to the innards of these things, if we have to pull the things apart to change oil I will be really pissed. Peace and Love Navelgazer
Standard on any fork made int he last 15 years. In fact you are supposed to measure the level of what you poured in.
I'm a lightweight too and these forks are STIFF! Even with my fiance onboard I'm blown away by how stiff. Please keep us updated with what you do to make them work for you. Otherwise I'm gonna send them out to a suspension expert sometime this summer.
I have had showa , marzocs and kayaba usd apart in the past and always use the old method of attending to springs and oil weight and level to get where I want to be for my weight usually with good results. After having the fork caps off, I can't see how to undo them to remove them in order to suck some oil out and there is no clearance down beside the spacer and spring to slide a fine tube down, let alone measure the level. So when time permits I will dig deeper. Not that they are bad but for me it's the only area on the bike that, like a dog with a bone, won't let go till I find an improvement. PS, there's a blog somewhere I read about Mysterious Sachs Forks for the BMW1000RR. Aussie Superbikes retain the oem forks so they all just stick ohlins cartridges in. Not in my budget. I will keep you posted.
After consideration of all the info I have on these forks, which is not a lot, 7.5 oil std but which brand, Racetech say 0.7 kg std spring and for my 154 lb mass a 0.75 kg spring which must be longer by about 70mm, so the stock spring I will leave in for the moment rather than change everything all together. I am going to replace the oil with Maxima 5 wt fluid and set the level at 130mm as this is what the racetech bokes have come up with. From what I can see from the BM s1000r forum sachs use softish springs, high oil level and a bit heavier oil to get where they are at. Hope to do it this W/E, will give you a result when done.
Curious to see how that works out for you. I'm running about 122lbs at the moment and I'm getting no sag at all out of my suspension, front or rear. We were going to take the forks apart to see what was in there but, like you, we ran into the same obstacle. Eric is going to have to make a holder of some sort in order to get them apart. No biggie, we can do it, it just takes time that we don't have at the moment. Looking forward to getting this thing softened up with some proper springs. A nice side benefit will be getting a little closer to the ground once I get proper sag out of it. The bike is a tad tall for my 5'1" frame.
My experience with the racetech published spring rates is that they are hit and miss. The best way to judge the spring rate and oil level is to gauge the travel for the kind of riding you do. I use a zip tie on the inner fork tube to show the actual travel on rough surfaces, then adjust to get maximum travel with oil level changes. If that doesn't do it, then a spring change may be in order. I'm 165 lbs and I'm using full travel, stock, when riding off road, and the suspension is on the firm side stock, the way I like it. Diving when braking hard is minimal and the rebound seems to control the front well in the rough. So the damping is close, the springs are close and the oil level is close for my weight - not bad. The racetech rate that navelgazer references seems like it might be too high for a 154 lb rider, based on my bike's setup. I haven't looked at the fork innards at all, but I'm guessing they're an open cartridge design. I wonder if they can be disassembled with an impact wrench, like I use on KYB's and Showas without any special tools.
On an adventure bike isn't the 'weight' dependent on how much of an adventure is being planned (luggage/gear)?
I would think so. You set up the suspension based on tank size, luggage, etc., whatever the weight and expected terrain is for the individual. I'm mostly a day-tripper so the bike's suspension is pretty good "as is" for what I do. I was pleasantly surprised by the bike's dirt road manners, I was able to stay mid-pack in a group of experienced dirt riders on much lighter dual-sports, although I was likely working harder to keep pace, especially in the turns.
Stock TR650 suspension seems like a good middle of the road ballance. On a bike with such varied uses and possible two up riding it really should be multi adjustable but that drives the price up.
I rode mine 2 up last week. I'm about 220lb 100kg and wife is about half that. I have never felt the need to change the suspension from the stock setting as that seems to be fine to me one up riding on various road types. With wife on the back only on sealed roads the bike hardly felt any different in the way the suspension behaved or the bike handled, the only thing I did notice was the brakes noticing the added weight and stopping force and distances changed. Wife felt quite comfortable on the back (although it was only a 20 min ride). Her only complaint was the force of the wind on the pillion when we were doing 100kph, but like me, she's used to riding bikes with plenty of wind protection so anyone who is used to riding naked bikes with no screens probably wouldn't make this observation.
Hi WoodsChick, changed the fork oil and a huge improvement. Now for me the front and back are much closer in their action now with the front rolling the bigger bumps nicely instead of bouncing them. Happy to leave it alone now. My obs are the factory oil is quite thick, almost like engine oil so I went with Maxima 7 wt, factory oil level is 130 mm and there is a lot of preload on the spring. It's hard to measure how much but I think you could shorten the spacer by 20 mm maybe more and still have some preload. This would give you a bit of sag but for your weight sounds like a lighter spring, FYI and good luck.
I HAD pictures but managed to delete them..... The stock spring are a bit soft for me at 80kg (180lbs) for the road and about right for dirt roads. There IS a locknut under the spring spacer/preloader. Because the spacer rests on the underneath of the cap it has pretty much no effect on the preload. It also is a complete pain to work on the forks. The spacer only puts about 10mm preload on the springs. You can shorten the spacer but I wouldn't shorten it by more than 5 or 6mm or you will effectively have no spring seat contact on full topout spring compression ( about 10mm of movement in it). You could put another additional topout spring above the standard one and shorten ( change) the preload spacer. That would make the forks more compliant but it won't help getting more travel much ( it will a bit but only because you start from furthur down in the travel). This requires pulling both forks apart completely but it isn't that hard a job relatively. I would change the preload setup at the same time to make the forks easier to work on. I put a washer under the locknut and shortened the spacer the required amount so it bears on the washer. Forks are now WAY easier to change around now. Also worth noting that one fork is compression and one rebound. If you lighten the viscosity in the compression damping leg, it will help the forks move in compression stroke but leave the rebound uneffected. Compression leg is the right leg if I remember correctly ( flow holes in the TOP of the chamber). Try 2 wt oil and if two divey try 5wt. Another alternative: The spacer is relatively long. If you can't find a spring about the right size you could shorten the spacer and put another short spring of the removed length on top of the std spring. This will give you a lower spring rate. I would make it about the same wire diameter as the std to start with and then go softer ( smaller wire diameter, closer coils or longer spring) if needed. If it is too light the extra spring will just coil bind and the std rate will take over, If it is about the same wire diameter and coil spacing you OR HEAVIER, will have a softer fork springing throughout the travel. Ain't Hooke's law wonderful
Thanks Greg for the mind blow and what you have said fits with what I observed but did not pick up on the compression and rebound being separate, did not pull them apart , just changed the oil. I am 70kg and the sag on stock springs is OK so will stick with them, but you have given me fiddle time on the oil, mmmmmmmmmmmmmmmmmmmmmm, I get to play again this W/E and yes they are a pain to work on as is and thanks again for the upload.
I have not seen this on any past bike I owned. Should I ride 100 miles to dealer right away? shock seems a bit stiffer 1300 miles on it. The black marks has to be seals or oil right? It is tough to get clean. And right side only.....Any ideas/suggestion?
If not at least call them and tell them. Maybe sent them that pic. Feel the chrome for any sharpness (any nicks) that might have cut the seal. If not it might only be dirt and still can be removed by cleaning the seal. You don't need a "SealMate" just something made of plastic a thin. (Like an old 35mm camera film) sorry if I dated myself there. How to fix leaking fork seals with SealMate Watch this one...she's way cuter Seal Doctor
Based on the observations of navelgazer and Greg (thanks for sharing this), I started a first attempt to soften the fork. I weigh 110kg and I am often driving on bumpy roads. My impression was that the rear of the works quite ok but the front works too stiff and bouncy instead of rolling over bumps. Hard(est) breaking on grippy street with the front break uses 160mm of travel of the front. This just for orientation of why i did what I did. I removed only the right forkleg from the bike. When compressing it by hand I had the impression it is damping. I did not observe rebound damping, when the spring fork comes out again. Then I opened the upper cap and I drained the oil by holding the forkleg upside down and moved the damper 30-50? times so drain as much oil as possible. The oilvolume that came out was approx. 480ml. The weight of the oil was exactly 391g. Sorry for the metric units. I refilled the same Volume/weight of Oil with Castrol 5w forkoil. The result is a definitely smoother riding on bumpy road and as also Navelgazer observed, front and rear fit much better together in their work compared with standard. It is not a bumper eliminating soft front as on a f650gs twin (i rode it in comparison), but you still have the crispy feedback and stability when riding hard. I like it. Maybe I try more thinner oil next time to see where the limits are. Greg, are you sure that compression and rebound are separated in the left and right forkleg? Here some numbers I measured: Oilweight (drained)of right forkleg: 391g Oilvolume (drained) of right forkleg: approx 480ml Outer diameter of spring: D=41mm wire thickness: d=5mm winding distance, winding to winding: (not middle to middle) 13.2mm (but as the spring was still a bit compressed because I did not disassamble the forkleg this value is not much worth)visible lenght of the plastic spacer under the cap: 81mm + the lenght under the cap) plastik spacer is conical: D_top: 35.4mm; D_bottom: 34.2mm good luck, guys
The more I ride mine (2000 miles now) the more the forks are fine with me but the shock is what I would like to address. Seems harshish on choppy gravel braking bumps, rocks, and roots etc. Wish the compression was adjustable on the shock. The rebound makes some difference but not fixing my issues. Good overall suspension but would like to make it work better off road.
Hi Peterjumpt, Greg is right compression damping right and rebound left. The oil level should be 130mm with spring out and fully compressed as this is what I measured. Depending on the load you can go a little bit either way on that but this really is the level they were designed to work at, not for me to reinvent the wheel. Lighter oil in both legs made a big difference to my ride. And yes the rear is quite good until it needs to move fast, high speed comp needs a tickle.
