SECApocalypse

Re: So it starts... XJ750 Seca

Had a very enlightening day. As in, I pulled off nearly 50 lbs of metal, plastic, and foam. Also picked up a bit that might add some fun to the project:



Its already looking much better with just the rear peg structure and electrical **** from behind the side covers removed. Not sure about the air box. For now I'm keeping it stock.

Condition of the bike is kinda hairy. Yeah, it runs, but really needs some (not so) tender loving care. Airbox is full of oil, found one of the bolts that clamps the leg in the tripple clamp was only finger tight, fork had 0 air pressure, wiring harness had a big melted / rusted plug pin at one of the large junctures, mud and oil is in every cranny. Looks like a fairly complete strip down / rebuild is justified for more than the cosmetic purpose of doing modifications, so I'm feeling less bad about pulling apart a "working bike".

On the other hand, most of the bolts are super-clean. No wrecked heads, no frozen threads. Its one of the easiest bikes to work on that I've ever owned.

Here's how it sits:

Re: So it starts... XJ750 Seca

Got the stock footpegs and right rearset support off. Looks like the bolts that held the footpegs on are also engine mount bots, and are to damn long to tighten down. Will have to find some new, shorter bolts (in high strength steel). Hopefully I can get them with allen heads, so much easier to deal with.

Pulled off the rear brake and shift lever. My plan is to use the rearset support bolts to mount my new foot pegs, shorten up the brake lever a bit (not much- I have huge feat) and grab a shift lever that can go directly on the shift peg (was link activated). This will result in 1-up-4-down shifting, but I can't see why that would be a problem (unless I burn it in as a habit, and then I'll be stuck riding race bikes- what a problem to have).

Have ALL the electronics (harness, modules, etc) freed up and can actually hook them all up in thier new positions. Didn't need to do any splicing, but there was a lot of pulling plugs apart, freeing up a branch, snaking it through a new route, etc. Main grounding wire is typical - was bolted to back of engine, total PITA to get off, but once I did it was easy to re mount it under the tank, bolted to the coil mounts. If anything, I'll end up with a lot of un-used slack in the wire harness, since I'm pushing the whole system up and forwards.

Re: So it starts... XJ750 Seca

Was out in the garage bashing up a template for the battery box build, and got to playing with some parts I had laying about. Goosey gave me an old, rusty, off color seca tank... cafe racers used to build thier rear cowls from tanks... I have a sport bike saddle and tail light....

Here's what I ended up with:


Is a bit longer than actual because the seat and "cowl" can snug together much better once I cut holes in the metal for the seats mounting tabs. Dark line indicates where the top of the frame would run, so that rear metal might get trimmer up a lot. I'd be cutting the whole bottom out of the tank by just removing the entire seam, which will make it look much less "tank like". I dofigure to use the whole thing, and leave the (open) bung, though! Both bits of metal would get fresh black paint and a layer of color-shift (rattle can). Logo would get fresh gold & black brush work (model paint). Seat stays black vinyl, is in great shape.

3q rear view shows why the seat and rear aren't fitting flush; they will be like hand and glove when the tabs slot into the metal.


I absolutely LOVE the way the sportbike tail light fits in the rear of the tank / cowling. The little bit under the brake signal is the bikes stock plate light unit. Will also get some restoration.


The only question is, does this fairing make my ass look fat?

Re: So it starts... XJ750 Seca

94yzf75fighter said:

I like the idea can't wait to see it CHOP THAT FUCKIN TANK UP

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Don't have the tools for that just yet. I'm joining community workshop called Hack Factory that has all the tools though. $55 a month, 24 hour access. Beats a gym membership 6 wasy to Sunday, then rapes its ass and sells the porno. However, you can't use all the tools right off the bat. Wood shop, electronics, and basic metal tools are open access, but the welding equipment (plasma cutter, tig wilder, mig welders, torch) require you to take a 2 x 4 hour class first. Already bought my class ticket for December 6.

Did I mention they also have an old school bridgeport mill, lathe, and shaper? Full electronics shop with 3d printer? CNC 5 axis router for wood and plastic? CNC Laser cutter / engraver for wood, plastic, and light metal?

In the mean time, I'm setting up all the work I plan to do. Muffler is already off, next up is to pull the pipes. That gets me better access to clean the engine and pull off those nasty highway pegs. Also lets me repair the dents in the bottoms of the pipes (from jamming it over the lip into my truck bed) and wrap them before re-mounting. Have a pattern for my battery box laid out so I can fab it at my class. Will be bringing the tank to class so I can hit it with the plasma cutter (its so empty there's RUST, so no fire risk).

I went to an open house last week, and there were two other bikes being stored in the space, and was told there's maybe a half dozen guys there who do bike mods. Before I take the bike over there, I plan to build a combination work stand / tool chest / dolly for it. Basically a big chest on wheels, say 2 foot tall by 6 foot long by 2 foot wide, so I can store the bike on top and parts / personal tools underneath. I don;t think theft is an issue I need to worry about, but the place is a bit of a mess, and I don;t want to cause myself / others headaches by having things scatrered about in shared storage areas.

OH, and to keep the pictures rolling, here's something I whiped up because I like the band & song.

I think it will go on the tank side as a "logo", so when people ask what kind of bike it is, I can say its a "Yamaha Stript". I'm leaning away from the color shift, and instead thinking flat primer grey for the frame, and bed liner for the tank and seat fairing. Apocalypse cliche, I know, but I'm a rivet head from WAY back, and its meant to be an 80's bike....

sebwiers - Yamaha XJ750RH - project "Secapocalypse"

Tossing my hat in the ring because hey, I bought a bike from another CF member on and immediately started hacking it. Wife says it's taking ll my time, spreadsheet shows its taking ll my money, might as well make it official.

http://en.wikipedia.org/wiki/Apocalypse said:

An apocalypse (Ancient Greek: ἀποκάλυψις apocálypsis, from ἀπό and καλύπτω meaning 'un-covering'), translated literally from Greek refers to a revelation of something hidden, although this sense did not enter English until the 14th century. .... Today, it is commonly used in reference to any prophetic revelation or so-called End Time scenario, or to the end of the world in general.

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The word applies in both senses here, for various reasons.

Start date proof photo - sorry, none taken. I suppose I could start now, but would rather start in "as purchased" form. Bike was putrchased from Goosey on Nov 10. If there's any doubts, the mods can dig into my personal messages to see the transaction being set up.

Here's what the stock bike looked like. With the exception of a 4-1 aftermarket pipe and some front LED turn indicators, that's what it looked like as bought. Problem was, the tank it came with was on Goosey's project bike, and the alternate Seca tank he had was very rusty. Still, it was (appearance wise) pretty much in this condition when I went to pick it up.


Here's the bike's condition on Nov 10, after a few hours work at Gooseys mounting up the Virago tank he'd pulled off his project bike. I did all that work myself, after November 1, so I'm taking credit, good or bad.



Did I say spreadsheet? The purchase price is fluffed and will remain so unless Goosey is OK w/ me sharing that.

Re: sebwiers - Yamaha XJ750RH - project "Secapocalypse"

A taste of the basic shape of the bodywork to come:

Re: sebwiers - "Secapocalypse" discussion

So, I plan on building a Hassock front end for this thing. Gonna throw out some basic parts specs so people can pint out if I'll be killing myself / building a tank.

Basic materials / construction : 11ga (~3mm) steel, tig welded or bronze welded / brazed (as seen in the heavy metal forum here - looks awesome, new to me though). Setup should be highly adjustable (rake, trail, ride height, travel) though may require replacing some bolt-in parts to do so. Setup also designed to be potentially swapped over to another bike (again, replacing some bolt on parts).

Ball joints - automotive units made for Nascar racing. Ball holder slots into 2" tube with a threaded retainer, ball tension is adjustable, etc. Seems plenty strong. Not really aware of other options, I suppose they might be a bit bulky. Bottom unit goes spindle up to position ball as low as possible, top unit could go either way - does it matter?

Control arms - basic A arms. Ball joit at tip, spherical rod ends on arms (parallel for adjustment). 3/4" rod ends seem the largest common size, no reason I can see not to use em even if overkill (I've seen Nascar units for sale with em). Will thread into 1" x 3/16" round DOM tubing, which in turn get welded into 1.25" 11ga square tubing used to build the arm (easier to work with).

Shock - picked up a couple gxr units, will be testing them to determine spring rate and mounting appropriately. Aiming for 6-8" travel (adjustable), adjustable. May try a rocker link setup, since I have the parts (came with shock) and it would let me mount the shock lower (though not sure I want it down by the headers).

Fork - Probably the scariest part to be designing, since if it fails.... splat. But also shouldn't be overly heavy, or handling / ride quality suffers. Would love to build in cad and do stress analysis, but kinda doubt I can teach myself in the time given (even if I did manage to pirate the software).
Considered a lot of shapes and materials, decided girder structure of steel was best combo of cheap, light, strong, stiff, and easy. Same 1.25 11ga square, two legs spreading out from axle to be at least 3" apart (front to back) at ball joint joining. Metal rectangle tube over this at bottom holds aluminum block machined for axle, brake caliper bolts. A thinner third "leg" will go out to the side from there to widen each fork leg (torsion resistance). Triangulated bracing (flat bar stock) spaning between the three creating tetrahedral forms in addition to triangulation between front and back leg. May cut the bracing from flat sheet / wider bar stock to allow nicer shapes / avoid stress risers. Braces 1" x .125", spaced 3" or so appart.
Will probably work on building a wood mock-up first, just to be sure I have my construction details hammered out. Once its built, put it in a jig for some stress testing, measure fork flex to see if its within the range I'm expecting (less than .05" for 1000lbs braking force).

How much does a pair of fork legs with tipples normally weigh? My target fork weight is under 20lbs (which seems kinda heavy, but also safely do-able). On a tele fork this probably corresponds to the weight of the lower legs. Rest of the system (shock, control arms, steering link) will likely be another 20 lbs, but can arguably be considered sprung weight (as much so as a swingarm is).

Re: sebwiers - Yamaha XJ750RH - project "Secapocalypse"

Project planning, progress updated as of Dec 4

Phase 1 - Body Work

* new tank - done
* seat mount - TODO
* rear cowling (made from old, rusted tank) - TODO
* detab - DONE
* subframe chop - done
* subframe additions - TODO
* move pegs & controls rear by ~4" - TODO

Phase 1.1 (overlaps all others) - Electrical

* relocate electric system, battery and harness - done
* battery holder - TODO
* Replace rear brake with LED unit from gs600, mounted in custom cowling - TODO
* LED headlights with integrated turn indicators - TODO

Phase 1.2 (overlaps all others) - Maintenance

* Everything required @ 25K miles, minus fork & front brake work (valve adjust, fluid changes, driveline inspect, frame inspect

Phase 2 - Front End (custom designed Hossack system)

* Design fork / linkage geometry (pref 3d w/ FEA) - TODO
* Build fork - TODO
* build control arms - TODO
* modify frame for control arm links - TODO
* bar holder & control linkages - TODO
* mount brakes on fork with solid lines (master cylinder is cable actuated, will ride on fork) - TODO
* Safety test the shit outta that mofo - TODO

Phase 3 - Paint & Deco

* tank & cowling in chrome
* frame in flat grey w/ reflec coating
* clear & reflec coating on fork
* 3d printed logo plates for tank
* laser engraved lexan clutch cover
* restore original logos (gold metalic plastic) on read cowl (old tank) and rear plate light

Re: sebwiers - Yamaha XJ750RH - project "Secapocalypse"

Used the newly aquired grinder to de-tab the frame and prep it for welding. Chopped off the tail end of the subframe. I'm loving my cheap Harbor Frieght grinder so far; light, powerful enough to do the job without being so strong it has a mind of its own. Under $25, amazing. I love cutting metal and making sparks fly!

Pictures also nicely show the effect of my electrical component / harness relocation and fender removal. No battery holder yet, but it will be resting on the frame rails above the carbs, totally covered by the tank. Bars are on upside down right now because they are too narrow to fit over the triple clamp (or instrument pod). Figure I can chop it in the middle and widen it a bit. On the other hand, it probably won't be an issue once I replace the fork. Actually kinda wish I hadn't bought the bars, as I expect I'll end up doing custom bars anyhow, but maybe I'll alter them and use em. Original thinking was to have clubman's to play up the fact that it's cafe inspired, although its really NOT gonna be a cafe bike in any traditional sense. For one thing, it will have a trunk...

Re: sebwiers - "Secapocalypse" discussion

dezmo said:

the best part of this years build is all the non tele fork builds. theres a few of em.

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Well crap, there goes my only really competative advantage. :bawling: Seriously though, who esle is doing one for the buildoff? There's the sweet 2 stroke job is make that thing forkless doing, but I thought that was for an outside contest. Are there others?

I haven't joined Hack Factory yet because I need to meet up with the treasurer to sign papers and get keys. They have open house every Weds night, that's when people are "supposed" to join, so I'll do it next week. My welding class is next weekend, already paid for, so after that I'll be free to use most of the metal shop equipment (still need instruction on mill / lathe).

I'll be doing all my work over there once I join. Getting to cold to work in the garage, its a much nicer space, and I'm dumping a few hundred (partly on a rolling work table to make storage easy, plus membership and classes) to be able to work there, so dammit, I'm gonna spend time there! Seriously, I plan to go over before work and so on (its not to far from the office) - for me, its a gym membership. Just working the mental / skill muscles instead of (or actually, as well as) the body.

We had nice weather this weekend so yesterday I washed the bike up pretty good. Used half a bottle of citrus degreaser and killed two scrub sponges and a brush. Had to lay er down on a pile of empty cardboard boxes to get the mud-oil sludge off bottom of engine and frame. Hope that's just from a clumsy oil change, though I'm pretty sure the valve cover gasket leaks. Did some shopping to pick up grinding wheels and other consumables / special tools Hack Factory won't have. Spent the morning de-tabbing the frame, doing weld prep (wire brushing paint) on spots where I plan to attach new tabs for seat / bodywork.

Yeah, I could build the fork without a model, but there's some measurements I want to be sure I can get right. Being able to adjust dims with bolt on parts is nice, but I don't want them so far off that it looks odd. There's a very specific geometry I'm shooting for that I don't really know the math for. I can buy a computer program that will do it (not a 3d prog, rahter one specifically for linkage forks that calculates link dims given desired behavior & anchor points, etc) or I can build a model, take a picture, and work it out using diagrams / geometry.

I'll probably to do the model just to have something to look at- I'm sure the final product would be more refined if I work out a model first. I've got most of the details sorted in my head, but things always go differently when you build them for real. (Unless you are Nikola Tesla - dude had solidworks in his skull.)

I'm considering setting up a kickstarter to fund the project, with the higher level funding reward being a "production prototype" derived from the design I end up with, modified to suit the sponsors bike. Having a model to show off would help a LOT with that. Lower level rewards would be copies of 3d prints I end up making, and the lowest the traditional t-shirt with the logos I'm using and some cool exploded diagrams from the seca maintenance book. This shit is getting EXPENSIVE! I figure if I can bring in $1000 or so, I'd be funded, and I can afford to do a fork for $500, easy. So really, I'd just need two top level sponsors; lower levels would be gravy. Not sure of the legal aspects though; I suspect if I build a fork and somebody blames their crash on it, I'd at least have some big lawyer bills defending myself.