Adventurizing my F800GS

Discussion in 'Parallel Universe' started by Camel ADV, Jul 8, 2010.

  1. tserts

    tserts Chaotic Neutral

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    Even though I don't have an F800, your mods seem interesting and invasive enough to be worth a read, thanx for all the info and the time you've put into this.

    Your blog is also worth visiting! :clap
    #41
  2. Camel ADV

    Camel ADV Long timer

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    Been in a holding pattern for a bit, waiting for parts to arrive. I was waiting on rims, they came in but the aluminum "seal bushings" that wheel seal ride on hadn't come in yet from the dealer. Was waiting on forks, they came in yesterday and I attempted get the guts swapped over to the original forks tubes last night but the seals I bought were wrong. eBay ad said "These oil seals fit ALL Marzocchi 45mm forks..." ....nope, they sure don't:deal So I went to the dealer today to get some over priced BMW seals...$43 each for the oil seals and another $43 each for the dust seals...if they had them in stock but "it's not an item that we normally stock". Same thing when I asked for wheel bearing and axles seals, "We don't stock those but can have them in 10 days if you like".:huh Maybe I expect too much but it seems like wheels bearing, and forks seals would be a stocked item.

    I decided to put the forks back together with the used seals. Normally I wouldn't do it but I really need to get out on the road/trail to get the suspension tuned and test out the other mods before we hit the road in Oct. I know I'll have to screw around with fork oil weights and different springs so there will be several opportunities to swap the new seals in when they arrive.

    The new (well not new but different model) Marzocchi Shiver 45s from an Aprillia Rxv, revalved by James at Super Plush Suspension:

    [​IMG]

    I got lazy and didn't take any pics of the fork assembling steps but there are lots in -W-'s thread as well as Gangplanks RXV fork swap thread. I opted not to limit the travel on the forks. The stock F8's were 9 1/4" and the RXVs are just under 12". The F8 fork tubes are longer the the RXVs so when the guts are swapped over without limiting the travel it ends up being about 10 1/2. I plan on replacing the rear shock and will try to up the travel in the rear as well. Hopefully the slightly unbalanced travel front to back won't be problematic.

    I did install the HyperPro progressive "TT Big Tank" springs. They say they are good for a 180-220lb rider with the extra weight of the TT tank and 20litres of fuel. I'm 235lb without gear so I think these springs should be OK even without the monster tank on the bike.

    I added 14mm preload and the sag (bike only) was 55mm. Bike plus me, sag= 65mm. 10.5" travel=266.7mm. 65mm is 24.3% of the travel. 1/3 is a good starting point so if I take out the 14mm preload the sag should be 79mm give or take a couple which would be 29.6%. This fork tuning stuff is new to me so it will be a learning experience!

    The zip tie shows the sag bike only:

    [​IMG]

    I did need to mount the tires and install the rims to check the sag numbers. the Rocky Mountain GS Challenge is this weekend and I wanted to check that out and there is a Motorrad Offroad training course that I'll be doing in a few weeks so I decided to mount up the rear Michelin Desert and the Pirelli MT21 front rather than the Anakees.

    Tomorrow I'll pull the 14mm preload out and add the fork oil so I can go for a ride to test the new bits and pieces out....finally!:freaky
    #42
  3. tserts

    tserts Chaotic Neutral

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    Just a quick note on the front fork oil, I saw at an earlier post that you have bought the recommended sae10w hyperpro oil, however for your height and weight I'd go a bit thicker, at sae15w. I have hyperpro on two bikes and I used 15w on both of them, contrary to what the dealer said. Mind you the oil only affects the "rebound", the upward extension of the suspension, so a thicker oil would give a smoother rebound after compression. You could swap them at a local dealer as they have the same cost.

    I'm 6,3 (193cm) and 90kg (you'll have to convert that :lol3) and the 15w has worked really well for me.
    #43
  4. Pcfly

    Pcfly Dude?! Seriously??

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    :lurk
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  5. Camel ADV

    Camel ADV Long timer

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    The oil was supplied with the spring so I can't just swap it. I'll try it with the 10wt and see how it is. I fully expect a lot of messing around to get things adjust properly but that was the whole point of converting to adjustable forks!
    #45
  6. Camel ADV

    Camel ADV Long timer

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    I got the bike back together on Friday and rode about 600km over the weekend. Of course the fork mod was the big change and I was expecting to see a huge improvement in handling but I didn't. Even with the the much heavier front springs and thicker oil the front end dive under braking was much worse than stock, quickly approaching the range of dangerous. Playing with the adjuster/bleed screws made no difference. Unfortunately the valving is way out. I hope swapping to 15wt or 20wt fork oil will help or solve the issue.

    The Woody's Wheels were excellent! The stockers were so tweaked that even running with Anakees, the vibration was so bad that my hands would go numb within a few minutes of riding. The 600km on the weekend were smooth and vibration free with the new (straight) rims. While standing and looking down at the front tire while in motion I noted it was dead straight, not a hint of a wobble. I know that's what I should expect to see but it's something I haven't experienced in well over 25,000km!

    Woody's did an excellent job! Awesome communication, I never once got the impression they were getting annoyed with my endless emails with questions and asking for their thoughts. Only a few days for the work to be completed and then the rims were in the way back! Big thumbs up :clap
    #46
  7. tserts

    tserts Chaotic Neutral

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    I think this would only soften your rebound. To my knowledge, the oil plays no role in compression.

    Brake dipping shouldn't occur to a new front HP set, there's something else that you overlooked. Are you sure the length is the recommended?
    #47
  8. itsatdm

    itsatdm Long timer

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    There used to be a Marzocchi service manuel on the net that should be of some help, but I no longer can find it.
    First of all I think you need to contact Superplush and get some answers on their set up.
    Generally, fork tuners will steer you away from variable rate springs. It is very difficult to get the right shim stack when they have to deal with a changing spring rate as well as making the proper stack to account for it.
    The 10 weight oil that came with the springs is meant to be used with the stock BMW fork to slow the passage of oil through whatever orifaces are used in the stock fork. Typically cartridge forks use a lighter oil, I think you are going in the wrong direction.
    Pulling out your spacer has no bearing on SAG. You are lowering the front ride height, but static sag really means how much the spring compresses with the bike alone. In your case, rider sag it is still 24%, indicating a very stiff spring. You are correct, 30% is about right for this type of bike.
    For your info, my dealer gave me the same weight limitations on the "lighter" Hyperpros, WTF.
    Oil weight, has a great factor on compression.
    Since it appears that the bike is over sprung, based on the Sag numbers, yet has a lot of fork dive, I am guessing the heavy oil is causing excessive bending of the shims. In short, you are blowing through the valving.
    For lighter bikes, Marzocchi recomments 7.5 weight oil, your tuner should have accounted for the weight difference in building the shim stack, so I would start there.
    I have never rebuilt a fork, but I have done a shock, similiar principle. To place on a heavier bike, I started with 10 weight oil. Made the ride harsh and compression and rebound adjustments had little effect. I ended up with 2.5 wt oil and all was well. What do you know, that was the recommended wt by the manufacture for the donor bike.
    #48
  9. Camel ADV

    Camel ADV Long timer

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    Thanks for the input. My comment on removing the spacing to increase SAG is correct because I was removing preload, I did pick up that 14mm in sag.

    I have been in contact with Superplush about it but haven't heard back yet. Thicker oil blowing past the shim stacks is an interesting idea, hadn't occurred to me. Bike suspension is new to me but I have experience with larger King coilover shocks and Fox AirShox. Increasing oil weight decreased shaft travel speed.

    I'll wait to see what Superplush has to say about it. They did mention they don't recommend or like working with progressive rates for the same reason you mentioned. We'll see shortly what they recommend to solve this problem.

    Cory
    #49
  10. itsatdm

    itsatdm Long timer

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  11. Camel ADV

    Camel ADV Long timer

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  12. Camel ADV

    Camel ADV Long timer

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    I decided to add a guard to protect the engine case in the event of another broken chain. I bought the TouraTech version. There are 3 holes that attach the original plastic cover as well as the TT aluminum guard. I managed to %$^ up the lower hole shortly after the buying the bike. There was a bunch of chain lube and dirt around the hole and I ended up packing the hole with gunk making it impossible to get the bolt back in.

    Due to the TT engine guard being mounted back under the foot pegs, the guard tube is in the way and I can't get the tap handle so I just used needle nose pliers.

    [​IMG]

    Needle nose pliers, not a good idea:shog
    [​IMG]

    2hours worth of dental pick work and I finally got it out:super
    [​IMG]

    [​IMG]

    I got the guard installed, hopefully I don't need it.
    [​IMG]

    I had some welding to finish on the pannier racks so I had to disconnect the battery. It seemed like a good time to swap the new battery in. I had planned on installing a DEKA (made by West Penn). I happened upon a thread that said Napa was now supplied by West Penn. I had called my local Napa and sure enough they sell re-stickered Dekas and the ETX14 was on sale for $117, perfect!

    Deka next to the temporary 9ah battery (plus the trailside repair shims)
    [​IMG]

    I installed a small voltmeter at the same time.
    [​IMG]
    #52
  13. DockingPilot

    DockingPilot Hooked Up and Hard Over

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    Those Shivers will knock your teeth out. Mine, even after re valving were just awful. Almost like having 2 2x4s for forks. In fact Ive never met a Zoke I liked.
    #53
  14. Camel ADV

    Camel ADV Long timer

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    Interesting. -W- and Gangplank are thrilled with their Shivers in the F8. Mine certainly aren't harsh, they are too soft. I'm confident that we'll get them dialled in and set-up properly. Time will tell I suppose!
    #54
  15. DockingPilot

    DockingPilot Hooked Up and Hard Over

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    Well Im referring to the oem Shivers that came on my TE610 Husky. Really, really harsh.
    #55
  16. bxr140

    bxr140 Flame Bait

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    Absolutely do not go that heavy. If you truly need oil that heavy, your valving is way off. Get the valving fixed first, that's why you did this in the first place.

    Not true. Everything plays a role in everything. Rebound valving is however...lets call it "less tight"...than compression valving, so changing the oil weight has more of an effect on overall compression than rebound.
    #56
  17. Camel ADV

    Camel ADV Long timer

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    I spoke with James today and he backed up what itsatdm posted about thicker oil over bending the shim stacks. Also, most bleeds (clickers) are designed for 5 to 7.5wt oil so the thick oil doesn't flow though them properly making the adjusters ineffective. James recommended trying a lighter oil and tweak the valving from there.

    I did a BWM Motorrad GS off road training course today, it was at a motorcross track. After the course was over I played around on a few of the sections and was pretty happy with the forks in that environment. I got a bit of air and pounded through some really rough stuff. The forks felt pretty good, never bottomed. Based on the zip-tie test I still had about 2" of travel left despite the beating it took. It is a dual sport so I guess it's all about finding the balance between on-road and off-road.

    [​IMG]

    Right at the end of the day I spit out the seals on the left fork. It seems that when I reassembled the forks (at 4am) I forgot the put the seal retainer snap ring...:shog

    [​IMG]

    [​IMG]

    Is there anyway to clean oil soaked brake pads or do I need to replace them? They are 75% so I'd hate to replace them if I don't need to.
    #57
  18. bxr140

    bxr140 Flame Bait

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    If you truly beat it and you still have over 20% of your travel available, its set up too stiff...or you have too much travel.
    #58
  19. Camel ADV

    Camel ADV Long timer

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    Yeah currently I have about 2" left but that's with an unloaded bike. Once my tank bag, panniers and dry bag go on as well as a bigger fuel tank I'm expecting it will be about right. We'll see if the lighter oil gets me to where I need to be. As far as "truly beating it" I'm a new(ish) rider so my beatings will likely get more intense as time goes on:nod
    #59
  20. itsatdm

    itsatdm Long timer

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    You may have less than that. Never thought to check when i installed my Bitubo's, but I have wondered since. Is there was something internal that would stop the fork before the last few inches are used up. Only way to check is pull the springs, put the cap on and see how far the fork will compress.
    Your picture is about the same as my Bitubo.
    #60