Suzuki GR650 Scrambler/Tracker - The Strangler!

Joe Suzuki

Been Around the Block
And now for something completely different! Been a lurker for some time on all sorts of sites, but I think this is the place to document what I am about to undertake. I've read through many of your projects and I love the community and ingenuity on display here. I've got grand plans (and a not so grand budget) so this will be an exercise in planning and patience, with a lot of stuff laying around my garage likely to end up in the build. The plan: take a stock 1983 Suzuki GR650X Tempter and make it into something cool and noteworthy, while being completely reliable and rideable on a daily basis (when weather permits). My other bike is a 2005 BMW F650GS, so I lean toward the dual sport/ off road end of the riding scale. My commute can take me on some fun off road back alleys to avoid some traffic in the Portland area, so it does really need to perform in those circumstances. I have many, many styling influences which I have been collecting over on my Pinterest page, titled "Everything is Better With Knobbies!".

http://www.pinterest.com/joefr8tus/everything-is-better-with-knobbies/

I'm a mechanical engineer by trade and have done many car projects, but this will be my first full-on moto build. I've been riding for over twenty years, so I figured it was time to try something in the two wheeled realm for my next project. I used to design military vehicles and helicopter equipment, so I tend to skew towards that design aesthetic. So I'll be after a rugged looking military themed build, with lots of black and dark green hues (not a big fan of chrome unless under the right circumstances). But I also plan to add fuel injection to the bike. Whaaaaat? You heard me, fuel injection! I love the simplicity of carbs as much as the next guy, but I love challenges and the reliability associated with EFI, and have done other engine swaps before that take a similar tact. Think of this bike as a retro mod/pro-touring scrambler build, and you start to get where I'm coming from.

So the donor: a 30 year old GR650 that I got for $200 and a rifle. It only has 11,500 miles on it and is a really clean, well running example. Its got the usual Zuki/GR650 issues such as a weak electrical/starting system and a not tall enough sprocket setup. Its had a PO tank seal job that worked, but looks awful inside the tank. I've already begun the mods by installing some aluminum dirt bars and fresh rubber grips. I deleted the front turn signals and replaced with some LED's, though they aren't in the permanent location as the headlight mount will change eventually. Other than the EFI, my plans include a wheel swap to a larger rim in the rear (from 16" to 17" KLR) and possibly a smaller one in the front (maybe 19" down to 18" or 17") to get bigger, knobbier tires in place and balance the look of the bike some. I plan to lose weight where I can, so swapping for a Ducati Monster rear shock is in order, as well as a LiIon battery of some sort, though probably a 12 cell (I don't think 8 will cut it with the EFI). I actually like the pseudo-Triumph shape of the tank, but the angle of the tank will have to be addressed. Along with a the tank mods, a complete sub-frame redo to remove the chopper-esque hind quarters is in order, though I'm thinking of making the sub-frame a removable bolt on affair (instead of weld on) since this is a mono-shock bike. A new seat, a new headlight (HID), and new gauges will complete the look. Electrically, a new stator and reg/rect is in order to remedy one of the Achilles heels of this model. I'll also do the regular maintenance items along the way, like seals/bearings,etc. I also want to have the possibility of some storage since I will commute on it, so some form of removable soft or hard luggage may be attempted, again aided by the mono-shock setup. I'll add a skid plate and some new side panels to go with the new rear sub frame. Due to the fuel injection and extensive nature of the changes to the bike, I'll probably end up doing a full re-wire along the way too. Finally, I'll try my hand at a custom exhaust, complete with O2 sensor for the Microsquirt controlled injection system. So stay tuned for hopefully frequent updates. Even if I don't have consistent progress, I'll use this space for my brain dumps when things come to me or I'm stumped on something. So thanks for checking it out. Looking forward to hearing from everyone as I go.
 

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So this hit my desk today. All this technology can be had on Ebay for $40! Its a throttle body from a 2010 Kawasaki Ninja EX650, with injectors! Looks barely used! I think its a pretty good candidate for my EFI swap. Time to take it home and take some measurements. I'm sure I'll have to come up with some sort of adapter as the carb/throttle body center to center distance is likely different, and the bore diameters are probably different too. But these are simple mechanical things to overcome. I'm going to try to use a Ninja throttle and grip assembly as well, but it may be too short. We'll have to see.
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Signed up! Welcome Joe. Gotta love a Tempter build, there aren't many of us on here. Give Big Rich a haloo if you need any parts, he's the go-to guy for GR50-specific parts and advice.

Stoked to see how this EFI works out!
 
Cookie said:
Signed up! Welcome Joe. Gotta love a Tempter build, there aren't many of us on here. Give Big Rich a haloo if you need any parts, he's the go-to guy for GR50-specific parts and advice.

Stoked to see how this EFI works out!

Thanks! I've read through many of Big Rich's posts in prep for this, I know he's a wealth of info on our obscure obsession. I'm sure I'll be using many of the tricks and tips you guys have sussed out on these bikes along the way. By the way Cookie, ever find a way to mount an oil cooler to yours? I'd be interested in that as well.
 
Pm big rich he wrote the service manual for the dealerships on the gr
 
It may be a min before BigRich gets back to ya though. I think he's in Japan working w Suzuki on a Tempter resto for their museum.
 
Joe Suzuki said:
By the way Cookie, ever find a way to mount an oil cooler to yours? I'd be interested in that as well.

Not yet, sir. The project has been stalled as of late, what with baby stuff, house breakage, kids' hockey...other various excuses.
I wasn't able to find an easily accessible port (best to put a cooler on the return side, as opposed to the pressure side) to run in from, I think it's going to wait either until I have to do a tear down of the engine or I can get my hands on a spare to rebuild for future use. Main goal for now is to get it running again
 
VonYinzer said:
It may be a min before BigRich gets back to ya though. I think he's in Japan working w Suzuki on a Tempter resto for their museum.
Nice! And hilarious!

I found the factory service manual here:
http://www.vanluik.eu/GR%20650%20tempter%20Service%20manual%20(eng)%201983-1984.pdf

I also found the service manual for the Ninja from whence the throttle body came, and the fuel system portion of the manual from the Honda TRX 700 that my fuel pump is going to come from. Isn't Google wonderful! Anyway, since I didn't have any real physical progress, at least I can show you some virtual progress. Here's some of my concept art. My scanner is down, so I used the camera phone. I found the only real side view photo of a GR650 that I could (super low res, and mag wheels, which mine doesn't have) with a white background, deleted key things in areas I wanted to change, then filled in the blanks with ideas.

Side+View+White+Background.JPG

I printed out a bunch of these, then I sketch away. This is the best one so far:

GR650+Concept+1+Side+View.jpg


Of course this is just one concept and there are many subtle things that I can and probably will change, but its a start.
 
Cookie said:
Not yet, sir. The project has been stalled as of late, what with baby stuff, house breakage, kids' hockey...other various excuses.
I wasn't able to find an easily accessible port (best to put a cooler on the return side, as opposed to the pressure side) to run in from, I think it's going to wait either until I have to do a tear down of the engine or I can get my hands on a spare to rebuild for future use. Main goal for now is to get it running again
Ok, well something to look at down the road. I'm not sure how necessary it will be. With a head temp sensor installed as part of my EFI project, I may be able to display that temp on the dash and determine if it'll be needed when sitting in summer traffic.
 
I really dig your concept art sir. nicely done! And that right there is the main reason I could never be an engineer. My drawing abilities are limited to stick figures and puffy Simpsons-type clouds.

I think that scrambler idea needs high pipe(s) though. Check out Pablo83's build, similar ideas are used.
 
You'd be surprised how many engineers can't draw! :eek: I agree, high pipes are definitely what I want, but I couldn't photo chop out the old ones, so for clarity, I left the low pipes in. I'll work on that some more maybe, perhaps I can go really old school and use some white out!
 
Signed up, but I'll be back for more later.

In the meantime, do a Google image search for "GR650 tracker". The first one is a yellow GR with right side high pipes

Great start Joe. .
 
Thanks Big Rich! I think I've seen every custom GR out there at this point (since there aren't very many). I think something like this, only two pipes is the look I'm after.

SPEEDTRACTOR_0461_MR2_low-662x425.jpg


So, here's another one with a bit more photo chop and sketch.

GR650+Concept+2+Side+View.jpg


I like the look of straight pipes, I think reverse cones aren't where I want to be. We shall see.
 
In for EFI updates... Ive done a lot with megasquirt in turbo VW's and have long thought of doing what you are here, throttle bodies from a liter bike into a custom manifold on stand alone.. need dyno access for tuning though, would be kinda tough to tune a bike on the street, without crashing anyway hahaha

I think the worst part of the whole deal would be getting a crank trigger setup and a dang fuel pump modded into a vintage looking tank.
 
Haven't done much on the bike yet, but I have done a ton of planning and purchasing on ebay. I'm using an external fuel pump from a Honda TRX700. Looks like this:

TRX700+Fuel+Pump.JPG


Its about the size of a sour cream container, so I have to find a place for that. My bike won't exactly have the "see through the middle" look!

So here's what I have acquired so far for the EFI conversion:
Ninja 650 throttle bodies + injectors
Ninja 650 throttle cables (push/pull)
Ninja 650 wire harness
TRX700 fuel pump
New Stator from Electrosport
Solid state Rect/reg from 2007 Yamaha R1 (50 amp)

I've also got two rear wheels from a KLR 250 for a rim conversion to 17" front and back. Need to get spokes on order from Buchanons and get rims/hubs powdered before I can assemble.

Still need a couple of sensors (head temp sensor, IAT sensor, MAP sensor, Ox Sensor), the Microsquirt, and the intake adapter. I'll be working on the design of the adapter in the coming weeks. But I sold by BMW dual sport which freed up some $$$, so more purchases will happen quickly after the holidays.
 
have you compared that to the size of a good old stock inline pump from a car? pics make it hard to tell but most in line pumps for cars are shorter then a pop can and about half the diameter.
 
Great project! Not only does it look good according to my taste, it's exciting EFI wise too! A few comments and questions.

1) When using rear rim in the front, check recommended tire width charts for it and see if the recommended tire fits between stock forks. Maybe youve done it but im just sayin... My rear is 2.50 and i think it would never fit to front, 2.10/15 is pretty much max i can do. I could have fitted wider rim if i had wanted to, but since the tyre is even wider than the rim, i couldnt have fitted the right tyre and it would have looked ugly-thin and funny on that wide rim.

Also, it seems like an easy job choosing the tyres but its not ;D Problem is, different widths, they look different on the rim and you really know only after youve fitted them. Or maybe im the moran here :D Tyre measurements, the width and height of the wall, make a whole lot of difference about the overall looks and style of the bike, so you must choose wisely, my friend.

2) About battery pack. If size is important, check this (or maybe you have already and its common knowledge in this forum) : http://www.youtube.com/watch?v=UTDctiyUa9E I think you can manage with 8 cells but 10 is even better.

3) EFI - id never use it myself but it sure is really exciting technologically. Does it have air flow sensor built in the throttle body already? How smart is this thing? Can you adjust basic settings (2 cyl, ccm etc) and you think it will start and you can customize the maps afterwards?

Cheers!
 
im building my own A123 pack as well but I only need a 4cell

with microsquirt you can adjust every setting in the map there are also a ton of base maps to choose from to help you get it running initially.. Its a lot easier then most people think just takes a lot of hours reading hahaha
 
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