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Title: 748 superbike front end on old M750 Post by: motolady on November 26, 2011, 06:08:25 PM I got my Monster in practically totalled condition. The previous owner had ridden it into a ditch and slammed and scraped onto the other side. Both sides of the tank were dented, the clip ons bent and scratched, front wheel bent, no master cylinder, etc, etc... I decided from the get-go that I wanted to overhaul the bike and trick it out instead of replace with [many times ugly] stock items.
First and biggest thing was converting the entire front end to a 748 front end. Major benefit here is that the old Monster shocks are not adjustable. Amongst other benefits like better shocks in general, thicker axel, looks awesome, etc. I am going for a retro modern look, ivory black and gold. So these 748 forks I got for cheap will look nice. I am doing as many of these mods myself as possible. However I do not have the tools or expertise for a lot of it. So my friend Jeff Yarrington in Maryland helped me out with the machining and such, after we devised what seemed like the best plan for doing the swap. Here's some major parts of the process in pictures. -- If I remember correctly, the old forks were 50mm on top and 54mm on bottom. This meant that we'd have to remove 3mm worth of material from the top triple and shim 1mm for the bottom. This was already a bad idea. Not as safe as it could or should be, etc. So I bought the whole front end. Triples, axle, wheel, and steering stem. I sent them to Jeff. The idea was that he was going to take the old monster stem and adapt it for the 748 triples. BEFORE front end swap: 1998 Ducati Monster 750 Dark (http://farm3.staticflickr.com/2027/5716665671_52856af3e7_z.jpg) AFTER front end swap (https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash4/314509_572284966330_214900900_32082209_1045479016_n.jpg) - words from Jeff: "The goal was to be able to bolt on a more modern 748 front end with better dampening. The stem on the 748 setup is a huge diameter, & the 750 stem is a more traditional size. This is where John Leatherman from Draft Cycle Works (website) was needed….a lot. He did his magic & made a thread in adapter for the bottom tree that the 750 stem pressed into. On the top, he made a beautiful spacer with an inverted step so the washer & bolt head would sit in flush. He likes neat & tidy and is very good at it." (http://media.tumblr.com/tumblr_lu3yu1s3kQ1qe98i5.jpg) The triples from the 748’s are also way better looking. Win. (http://media.tumblr.com/tumblr_lu3tw1axwX1qe98i5.jpg) jeff- "The part with X I need to remove, the remaining bit the thickness of my pinky will remain. This is what will make the ignition switch area on the 750 need a tweak, as the old 750 tree sits a billimeter from the ignition switch." (http://media.tumblr.com/tumblr_lu3w8hhXMP1qe98i5.jpg) jeff- "Here is the remaining bit that protrudes past where the original 750 tree went (750 tree sitting on 748 tree in the pic)" (http://media.tumblr.com/tumblr_lu3yf3FqFg1qe98i5.jpg) jeff- Adapter that has 750 Stem, pressed into it, & it threads into the lower tree, red loctite on threads. (http://media.tumblr.com/tumblr_lu3ygfTKvY1qe98i5.jpg) In place as it would be. (http://media.tumblr.com/tumblr_lu3yhiwbHl1qe98i5.jpg) jeff - "Screw the bolt in. Here you see where I removed the stabilizer mount as well, cut, rounded, polished a hair to look a bit nicer. Bam! Looks factory." (http://media.tumblr.com/tumblr_lu3yjtervV1qe98i5.jpg) You can see the entire process Jeff posted on his blog here: http://saintmotorbikes.blogspot.com/p/ducati-748-fork-adapted-to-750.html (http://saintmotorbikes.blogspot.com/p/ducati-748-fork-adapted-to-750.html) At this point I get them back and put it all together and encounter an issue, as many times happens. The steering stops are doing their job too well. http://media.tumblr.com/tumblr_lu3z1zzFLv1qe98i5.jpg (http://media.tumblr.com/tumblr_lu3z1zzFLv1qe98i5.jpg) (http://media.tumblr.com/tumblr_lu3z1zzFLv1qe98i5.jpg) Converting it to a dual disc system... (http://media.tumblr.com/tumblr_lu421sSAIY1qe98i5.jpg) And get 748 clip ons, as I suspected they would fit perfectly with the tank and not threaten to slap the tank. (http://media.tumblr.com/tumblr_lu423rmidN1qe98i5.jpg) Work dremmel magic on the steering stop.. (http://media.tumblr.com/tumblr_lu4271lThy1qe98i5.jpg) Very carefully. (http://media.tumblr.com/tumblr_lu427erCE81qe98i5.jpg) Some careful WHACKING with a rubber hammer... (http://media.tumblr.com/tumblr_lu428npIjJ1qe98i5.jpg) All gone with minor nicks to the frame. Since I'm getting the frame powder coated, this will be painted over after being sanded down and filled in. (http://media.tumblr.com/tumblr_lu42v9gwUp1qe98i5.jpg) As you can see, the bars do not contact the tank at all. I could honestly go without having a steering stop if I wanted to be ghetto about it. But because I believe in doing things the right way, we will be reattaching a single steering stop style nubbin in the middle of the frame, and also using this same bracket as a place to mount the headlight. A small bit of the bracket that holds the ignition needs to be carved away too, as the front bolt space on the triple contacts (blocks by about 1mm) the frame bracket. (http://media.tumblr.com/tumblr_lu42yl6FB51qe98i5.jpg) Looks frackin' pretty! (http://media.tumblr.com/tumblr_lu42zg3VX11qe98i5.jpg) I will be anodizing the triples and clip ons gold to match other bits of the bike as well as wrapping the forks above the lower triple, and maybe below it too. And FYI, there's more details and more pictures on my blog post... http://themotolady.com/post/12317023346/phase9monsterproject (http://themotolady.com/post/12317023346/phase9monsterproject) And more about the Monster Project in general on my blog.. http://themotolady.com/tagged/monster_project (http://themotolady.com/tagged/monster_project) Title: Re: 748 superbike front end on old M750 Post by: Heffe on December 12, 2011, 09:37:36 PM Looks great, can't wait to see it finnished...
Title: Re: 748 superbike front end on old M750 Post by: Raux on December 12, 2011, 10:32:10 PM Are the offsets the same?
Title: Re: 748 superbike front end on old M750 Post by: Spck31 on December 13, 2011, 07:17:08 AM really awesome project!! Killer look! [thumbsup]
Title: Re: 748 superbike front end on old M750 Post by: thought on December 13, 2011, 07:48:31 AM great first couple of posts :D
Title: Re: 748 superbike front end on old M750 Post by: motolady on December 14, 2011, 04:22:27 PM Title: Re: 748 superbike front end on old M750 Post by: motolady on December 14, 2011, 04:23:11 PM really awesome project!! Killer look! [thumbsup] great first couple of posts :D Thank you both! Looks great, can't wait to see it finnished... Me either, for reeeeeals. Title: Re: 748 superbike front end on old M750 Post by: junior varsity on January 05, 2012, 06:48:29 PM I don't think they are. No, they are 36mm on stock superbike triples. 25mm on first generation monsters, and 30mm on second generation ducatis. I would not have taken this approach, personally. I have done Superbike fork conversions on all 3 of my pre-01 Monsters. Title: Re: 748 superbike front end on old M750 Post by: motolady on January 07, 2012, 11:18:53 AM Oh? Would you like to share what approach you would have taken?
Title: Re: 748 superbike front end on old M750 Post by: junior varsity on January 07, 2012, 02:51:36 PM Have taken multiple times - I've posted about it a bunch. It involves some money, but the setup is great in the end. Here's a short list of the bits, and then three quick examples that are in my garage, I'll append pics later.
Hardware Supplies List: 1. Req: New Tapered Bearings / Seals, OEM Part 069191010 (x2)...much cheaper from source (like half off!), 2. Opt: Base Washer, OEM Part # 85210961A (x1) (or hassle w removing old from original stem & seal). 3. Opt: Replace dished special top washer if worn, mangled, ugly, whatever. 069137020 4. Opt: Replace stem ferrule if mangled by idiot using a screw driver instead of a spanner wrench. 079537120 5. Opt: Washer/Nylon-Washer (beneath cap-bolt, above top triple) if necessary: 85610401A 6. Opt: Cap-Bolt/Upper-Bracket Plug - if mangled, OEM: 87310161C, or get slick billet versions. Choose-From-List: (This is the plan-ahead part)
On Forks: Monster lower triples are 54mm diameter. Monster top triples are 50mm. Superbike-Showa forks are 53/53. Superbike-Ohlins is 53/56. Japanese forks are sometimes 50, sometimes 52, sometimes 48, you get the idea. Don't forget the steering damper: If you've got a damper, the fork damper clamp is at 54mm from the factory - that's what is included in every Ohlins SD-154 kit (for Monsters) * If you want to reuse original, you get to modify parts - Machine-shop time! shim lower & bore upper for SBK-Showa, bore lower & bore upper for SBK-Ohlins * I do not like modifying the original cast parts: They are weak to begin with, and the lower is the puny 2-bolt version (want to see something pitiful, look under the 848 and see the same bottom triple with stem staked at different offset position!). Here, your SBK lower is clearly superior to the monster lower, but the steering stems are all wrong, and stems are not intended to be removed and changed. For reusing OEM bits, I am not a fan of shims at all. There are billet aftermarket triple clamps out there that provide a very attractive solution: pre-made at correct sizes: no re-boring, no shims, no cast flimsy lowers. Usually they command a premium, and often aren't available for the first-generation monsters. I got mine from IMA Special Parts - the "MODEL 1" / "MOD1" line is for skinny-stem (early) ducati, like Monster/SS/851-888. They are available in OEM 50/54 sizing, 53/53 Showa-SBK sizing, and 53/56 Ohlins-SBK sizing, and custom sizing for japanese-fork retrofits. They also had billet damper brackets in the right size, so I could "one-stop shop". This was nice to find out, but on the first time I ordered IMA parts, my bonehead had already ordered the Ohlins fork clamp, which cost twice as much (and i was getting DEALER pricing on the Ohlins!). Needless to say, I've not made that mistake again. The MOD1 triples were under $500 shipped to my door, (MOD1-N and MOD1-S with bar risers and damper clamp on the clamps for second and third bikes - also for Showa-SBK forks, it was just over 600 i think) Tools:
My Three Examples: SBK Fork Conversion #1: Monster '99 "Cafe Monster" Red w/ White Corsa Stripe paint, 998 Showa Forks
SBK Fork Conversion #2: Monster 1998 - "Commuter" Blue/Silver Bevel-SS paint", 916 Showa Forks
SBK Fork Conversion #3: Monster '00 - "Trackster-Project" Black/Gold Darmah paint, 848 Showa Forks
In other fork-swap related stuff, I switched my 916-era SBK's forks out in favor of 1098-1198 type forks, with radial calipers and such. Requires the axle, spacers, and wheel+rotors (unless willing to do custom spacers and 998R-type 6-bolt, 15mm offset rotors) Title: Re: 748 superbike front end on old M750 Post by: Raux on January 07, 2012, 04:50:55 PM One of my biggest concerns with the way motolady did it is the offset. I wonder how the handling of the bike changes with that.
Title: Re: 748 superbike front end on old M750 Post by: junior varsity on January 07, 2012, 05:00:05 PM Going from OEM 25mm to SBK 36mm will be substantial. Its probably going to dive in crazy fast and not feel really stable on that Monster frame's geometry. I ditched the 36mm offset triples on my SBK, like many do, in favor of something closer to the 30mm range.
Some of that is mitigated since the forks are flush with the top triple, and the SBK forks are longer than the Monster forks. End result is not a lot of weight on a twitchy front end. Title: Re: 748 superbike front end on old M750 Post by: motolady on January 07, 2012, 05:13:00 PM Going from OEM 25mm to SBK 36mm will be substantial. Its probably going to dive in crazy fast and not feel really stable on that Monster frame's geometry. I ditched the 36mm offset triples on my SBK, like many do, in favor of something closer to the 30mm range. Some of that is mitigated since the forks are flush with the top triple, and the SBK forks are longer than the Monster forks. End result is not a lot of weight on a twitchy front end. I don't know, I've got a couple people at MotoCorsa (the shop I work at) that did it this way or something similar and they seem to really enjoy the ride with the different front end. I plan to rebuild the back shock so that it works better with the front end too. Title: Re: 748 superbike front end on old M750 Post by: Raux on January 07, 2012, 05:16:25 PM I would at least add a steering damper.
My first Monster (a 99 City) ended with a tank slapper. And it was stock. Title: Re: 748 superbike front end on old M750 Post by: motolady on January 07, 2012, 05:18:08 PM I would at least add a steering damper. My first Monster (a 99 City) ended with a tank slapper. And it was stock. I'd like to add a steering damper. It's not even possible for my bars to hit my tank at the angle of the 748 clip ons. [thumbsup] Title: Re: 748 superbike front end on old M750 Post by: junior varsity on January 07, 2012, 05:22:47 PM that's not what he means by tank-slapper.
you just have to get used to your setup, you may like the way it steers for your riding style. I would suggest a steering damper as well. Title: Re: 748 superbike front end on old M750 Post by: motolady on January 07, 2012, 05:24:10 PM that's not what he means by tank-slapper. you just have to get used to your setup, you may like the way it steers for your riding style. I would suggest a steering damper as well. hence the winky face... i know he means the actual action of the bars slappin and whackin back and forth in a loss of control. ;) i'm looking into the steering damper while I'm doing my frame chop and powdercoating. :) thanks for the feedback! Title: Re: 748 superbike front end on old M750 Post by: junior varsity on January 07, 2012, 05:37:04 PM no prob. as you may surmise, I dig modifying the bikes quite a bit.
Title: Re: 748 superbike front end on old M750 Post by: Raux on January 09, 2012, 02:44:58 AM ;)
a good tank slapper will tear apart your steering head, literally ripped the metal on mine, like a toilet paper roll being ripped open, from the steering stops being hit so hard. Title: Re: 748 superbike front end on old M750 Post by: corey on January 19, 2012, 08:47:19 PM okay okay.. so i know i'm no expert on this stuff, and by no means will claim to be one.
i've dropped 999 forks into my S2R with great results using stock triples with typical monster offset of 25mm... but what i'm thinking, and correct me if I'm wrong please, is that the 36mm offset will do exactly the OPPOSITE of making the bike more twitchy... technically the wheelbase has just been extended by what, 11mm because it's an older 750 with originally a 20mm offset? now doesn't a longer wheelbase typically mean MORE stability in straight-line tracking, and SLOWER turn-in? i do understand that now the weight ratio of what is over the front wheel is a bit lower, but with the obvious addition of clip-ons, that should negate that effect... (while also making this bike ridiculously far-stretched when it comes to riding position)... i'm not knocking her approach, i'm just genuinely curious on what the ACTUAL effects on geometry and mechanics are... thoughts? Title: Re: 748 superbike front end on old M750 Post by: corey on January 19, 2012, 08:54:39 PM I'd like to add a steering damper. It's not even possible for my bars to hit my tank at the angle of the 748 clip ons. [thumbsup] Also, and excuse the double post... I know it's not possible for your bars to hit your tank, which is no doubt a result of the extra offset from the 748 triples... but if that's the case, and considering you completely removed your steering stops from the stem tube of your frame... what this SHOULD mean is that if you WERE to enter a "lock-to-lock" "tank-slapper"... your forks would be bashing against your actual frame? I mean, with no steering stops, if you crank that sucker either way and keep going, eventually SOMETHING is going to make contact somewhere. what is it? is it safe? Title: Re: 748 superbike front end on old M750 Post by: junior varsity on January 20, 2012, 05:19:48 AM No no!
First your S2R and all Monsters 2002+ are 30mm offset from factory! Pre-2001 Monsters have the 25mm offset. The Ducati SBK's come with 36mm, but feature adjustable steering angle & many, if not most, Ducati racers are running aftermarket triples with a lower offset (or adjustable triples, like AMS, Attack Performance, or IMA Special Parts) Second, it is not the extension in wheel base here that is significant (adding to swingarm has a much more pronounced effect than anywhere else, hence why Ducati has been trying to move engine forward), the significant change is to trail #! I will ask Jason to post a better explanation, he's got a better understanding than I do. Title: Re: 748 superbike front end on old M750 Post by: stopintime on January 20, 2012, 07:55:29 AM Increase offset to decrease trail = better turn in, but less stablity.
From Motorcycle Consumer News (http://i329.photobucket.com/albums/l394/stopintime/001.jpg) Title: Re: 748 superbike front end on old M750 Post by: junior varsity on January 20, 2012, 08:05:42 AM Yes, and changes to rear ride height and fork-in-triples height will effect your geometry as well. (it alters several variables related to length of one side of the front end triangles, the wheel base, and the effective steering angle)
Title: Re: 748 superbike front end on old M750 Post by: junior varsity on January 20, 2012, 08:10:05 AM The converse of the above statement would be: "decrease offset for more stability (especially when leaned over, I'd say), but require more effort in your steering inputs."
Big offset: dives/darts into corners very quickly, but will feel twitchy or uneasy when you're in a sweeper. Small offset: push more to make it turn, but feels more stable, especially on driving out of the corner. Title: Re: 748 superbike front end on old M750 Post by: junior varsity on January 20, 2012, 08:44:52 AM I've seen a nifty spreadsheet that is Duc-specific for geometry stuff, I will have to see if I can find it or if it's "private goods". It had pull-down tabs and the various default OEM measurements - providing a glimpse into how any one change might affect others. Maybe the IMA folks here or in Torino will have a similar type document, or I could try to make one me self
Title: Re: 748 superbike front end on old M750 Post by: motolady on January 20, 2012, 05:28:09 PM Also, and excuse the double post... I know it's not possible for your bars to hit your tank, which is no doubt a result of the extra offset from the 748 triples... but if that's the case, and considering you completely removed your steering stops from the stem tube of your frame... what this SHOULD mean is that if you WERE to enter a "lock-to-lock" "tank-slapper"... your forks would be bashing against your actual frame? I mean, with no steering stops, if you crank that sucker either way and keep going, eventually SOMETHING is going to make contact somewhere. what is it? is it safe? To answer your question, I'm replacing the steering stops. I have someone working on frame chop/steering stops as we speak. I've seen a nifty spreadsheet that is Duc-specific for geometry stuff, I will have to see if I can find it or if it's "private goods". It had pull-down tabs and the various default OEM measurements - providing a glimpse into how any one change might affect others. Maybe the IMA folks here or in Torino will have a similar type document, or I could try to make one me self I would love to see this! Title: Re: 748 superbike front end on old M750 Post by: corey on January 21, 2012, 09:43:19 AM To answer your question, I'm replacing the steering stops. I have someone working on frame chop/steering stops as we speak. [thumbsup] we don't like to see anyone getting hurt around here. |