GZ250 Cafe Conversion

[ruxpin76]

Well, I've finally done it.
I've probably bitten off a tough piece to chew, but I've been mulling over converting my beloved GZ into a cafe-styled "standard" instead of the cruiser that Suzuki intended. For a bit of background, I am a "reformed" mechanical engineer -- which means I switched majors to architecture when I got bored of calculus, but after completing most of my degree. As a consequence, I got a decent foundation of good design practice, structures, materials, and most importantly: machining and welding. I worked on the Formula SAE project at Pitt, giving me experience with fiberglass and more design, and I grew up racing kart-like vehicles, giving me more mechanical experience. That said, I plan to chronicle my conversion here in step-by-step detail, "simple" enough that the average knuckle-buster can follow along and attempt something similar. If it proves popular, I may produce some bolt-ons to make the job easier for the less mechanically inclined.

I'll catch up with the pics soon, but here's an outline of what I've done so far:

*PRIOR TO THIS PROJECT: did needle shim mod, added hi-flo filtro in place of stock, replaced gas tank.

in roughly chronological order:

*removed chrome covers from engine
*removed seat in normal fashion and removed latch from fender
*unbolted fuse block and relays from fender bracket
*removed tail and fender in one piece, disconnecting wires at their plugs and preserving parts
*removed battery wires from terminals and unstrapped battery, removing it.
*removed battery box
*unbolted airbox bootie and hoses from airbox
*removed airbox by sliding back into fender area (easy, and intact IF battery holder is removed!!!)
*clipped misc. ty-wraps holding wiring in original locations
*removed carb (disconnected throttle and choke cables and vacuum hoses) for jetting change
*removed gas tank for easier access

I have pics of most of this, step by step. The tools I've used so far: 10mm wrench, 10mm socket, 14mm (choke nut)
side-cutting pliers for ty-wrap removal, phillips screwdriver for clamp removal.

My digital cam is 14MP, so bear with me as I download and resize the pics to post. I'll be posting them here and on photobucket, so don't worry if you don't see 'em all here. Let me know if there's more that you want to see.

Tonight's to-do list: remove front fender, tape for trimming, trim, sand edges, reinstall.

[ruxpin76]

I've also removed the passenger seat from the fender assembly. It's nicely shaped to re-use as the main seat for the cafe project, perhaps. I have noted that there's a metal bracket underneath the fender that gives the rear end much needed additional support. I plan to replace it with a directly welded piece between the shock mounts or a bolt-in in the first fender-support holes. If that's clear as mud, just wait for the pics to see what I mean. :) IIRC, I had to add a 7mm allen key to the tool list to unbolt the seat...

[ruxpin76]

Further mods will include a main battery relocation to tail, uni-style air filter to replace airbox, and some rear fender improvisation to shield the air filter from rain spray.

[JWR]

Sounds like a fun project , keep us updated with pic's

[ruxpin76]

Did the fender mod to "sportbike" style today...posting pics tomorrow, God-willing...
And adding to the list of mods: longer rear shocks to gain some clearance and add chassis rake (reduce steering rake, though...) and possible front-end swap if I can find compatible triples that use the same bearing set...
More tomorrow...

[ruxpin76]

Sorry for the delay in pics... finally got 'em on the computer, but resizing will take a bit. Will post back here when I got 'em. Current stage: frame marked for tab/bracket removal. Additional mods for the list: new tubing for seat support.

[ruxpin76]

Bike Status:
http://i413.photobucket.com/albums/pp213/ruxpin76/motorcycle/current012011.jpg
Currently the bike is stripped, and I'm going to remove the forks and engine and rear swingarm assy so that I can trim the excess bracketry off and have the frame stripped and powdercoated again. While it's stripped, I'll drill and tap the holes for the rearset on the traingular rear pivot support and get my clip-ons, etc. worked out. I'm also converting to a MX-based carby with on-carb choke and single pull throttle cable. Will post back later. Cheers...

Fender Trim:
http://i413.photobucket.com/albums/pp213/ruxpin76/motorcycle/fendertrimtape.jpg
http://i413.photobucket.com/albums/pp213/ruxpin76/motorcycle/fendertrimmed.jpg
http://i413.photobucket.com/albums/pp213/ruxpin76/motorcycle/fenderinstalled.jpg

[ruxpin76]

Fender will be lowered .500"-.750" shortly...

[ruxpin76]

UPDATE:

Bike has been marked for extra bracket removal, and I've found that a Honda CB175 tank's inner circles fit the GZ's rubber tank pucks PERFECTLY. They are, however a bit high on the gas tank, so I'm moving the GZ's pucks to the topside of the chassis tube and reworking the rear tank mount. Pics to follow.

The rearset (passenger pegs) are being relocated about 6" forward and 1" down, on the "triangles".

I've decided to raise the cafe seat a couple inches ABOVE the stock seat location, and affix a sealed battery on the underside, in the area where the tubing triangles normally covered with the sidecovers are. It will barely be visible, and makes installation far better than trying to get the battery out to the tail. It also helps with weight distribution.

That's it for now. I still have a ton of pics, but they're all HUGE. That's what a 10MP cam does for you, I guess.

Drop me a line if you get too impatient for updates. :) Or need some GZ parts (Tank, airbox, air filters, rear fender assembly, rear fender, passenger or main seats, main footpeg assemblies...)

[emory70]

good to see a quality redo of the bike. i was interested in a cafe conversion for mine, but after riding a triumph thruxton, no thanks.

[ruxpin76]

UPDATE: 10/23/11

Well, this project was obviously on hold for a while... My wife bought me a Honda (*GASP*) CBR250 so we could ride 2-up at highway speeds (and I'm a sportbike guy anyhow, though I like cafes, standards, and liked the GZ as a cruiser). I've also been working at a machine shop (now unemployed...) and putting my own roof on. All that said, it's time to get back to the GZ. It will be my fall/winter project. The nice thing is that with the weather here in NC, testing in Dec/Jan/Feb is still sometimes an option.

So, here's the plan.

* New straight spine welded into the GZ's original frame.
* New "clean" lower rail from fork tube to the engine lower to get rid of the old footpeg slag...
* Monoshock conversion in the rear (tabs welded on the flat on the GZ's original swingarm going to the straight spine
* Angled carb bootie to clear monoshock, and canister filter.
* Dual exhaust fabricated from 2 stock exhausts
* Custom rearsets
* Wiring cleanup with new AGM battery in tail section
* New tank (Honda CB350 70's era) and new tail (custom fiberglass) and new seat (plywood and naugahyde...)

Will post pics as work develops. I think it should progress much more quickly now that I still have 2 rideable wheels, and less racing go kart paraphenalia cluttering the garage. Stay tuned! This thread's not dead yet....It just turned into a newt. It'll get better....

[Water Warrior 2]

A CBR 250 !! Sounds like your wife is a biker at heart. You are truly blessed.

The GZ project sounds like a lot of work. The results should be interesting with a monoshock and other major changes. Keep us posted.

[ruxpin76]

^^ Re: my wife, when she saw the CBR600's at $9000, and CBR750,1000's up around $12K, the $4K price tag for the CBR250 was more palatable. We paid cash and rolled it out the door for mid $4K... I've already broken it in, and am somewhere around 900 mi. for the 2 mos. I've had it. It handles UNBELIEVABLY well, and it's nice to be able to get outta' the way when needed. The GZ is nice for around town cruising, however, and lower speed backroads. I'll post smaller cellphone pics here as progress continues...

For those into cafes and sportbike custom work, check out FrameCrafters, as seen on Cafe Racer TV and Magazine...

[spicciani]

I am waiting on your solution to the rear sets .

[Wigginton49]

Any progress on this. I'm doing the same thing right now.

[ruxpin76]

OK OK finally some progress....Barely looks like a GZ now. HEre's a link to the FB pic:

https://sphotos.xx.fbcdn.net/hphotos-as ... 8990_n.jpg (https://sphotos.xx.fbcdn.net/hphotos-ash3/534907_910281062339_1618928990_n.jpg)

The plan is to add brackets for the shocks (they're just sitting there now), then add some rear facing tabs for a seperate tail section like the sportbikes do. If I find a cheap rear section for a sportbike, I may snag it and make my own fiberglass mold a la cafe... More pics soon.

RE: the CBR250, I'm up to 3000 mi. and haven't found it's limits (other than top speed on highway) yet.... Hopefully I never will as finding the limits usually means exceeding them. :)

Please keep me posted on other conversions going on, and I promise I'll have more regular updates now.
Cheers, ~Ted

[Water Warrior 2]

If those are the GZ stock shocks I have my doubts that they will work very well. The swing arm will have far too much leverage and compress them very easily. Of course you will find out for sure in a short time.

[PimpS]

Nice job ruxpin76! It's a pleasure to observe and read about art! ;)
Keep up the good work!

PimpS

[ruxpin76]

I plan on using different shocks and possibly a linkage setup to change ratio instead of the stock ones. They're just there to illustrate concept...

[Water Warrior 2]

You are thinking quite a bit ahead of me. Sounds interesting.

[ruxpin76]

The alternative is to move them back some to reduce the leverage and use shock for something heavy....like a Harley or something. :) Or maybe a Gold Wing... There will be 2 support bars coming up from the rear of the swingarm "triangle" and joining back into the chassis around the top of the shocks in the pic to triangulate that area and tie the chassis back together. Will post a mockup pics soon....

[ruxpin76]

Here's the frame, ground and ready for new rear members, and a piece of stock laid there to show rough idea...