Trying to make a mean looking thruxton

grumple

New Member
Hi all. Here's my medium arse project. I know this is the big arse projects section, but I think this is pretty minor compared to the things others are doing. I've been reluctant to post, just because this is the first time I’ve wrenched on a bike, and I don't really know what I’m doing, other than making it all up as I go. And it can be a bit intimidating posting in the same forum as some of these amazing builds. Not through any fear of ridicule or 'look at this noob' kind of thing, just hard to see what I'm doing in my leaky old garage as comparable. But it was this thread: http://dotheton.com/index.php?topic=14841.0 which inspired me to not be intimidated/shy/whatever and just post it, and try to be a bit more active here.

Anyway, on to bike stuff. I know a lot of people might not like the idea of modifying a thruxton. I can kinda understand that, as I bought her because I love how she looked stock, before I'd even thought of doing any modifications. My only criteria for buying this bike was something that was okay for 2-up riding (unlike my CBR600RR which I sold to buy this bike), so really I could have bought anything, but I was sold on the thruxton.

I didn't take a pic when I first got her, but here is a pic of the stock thruxton anyway as a reference:
2009_thruxton.jpg


I could tell though, that there was a mean shaped bike in there, under the extra bulk and formality. It was like some pool hall punk, dressed up in a business suit with a sensible haircut trying to look respectable. I thought that the stock front end was way too cluttered with the gauges and headlight mounted too high, the stock bar end mirrors were ugly (I bought the model with the handlebars rather than the clip ons, which might explain a few things). The rear fender stood out way too much, the indicators too bulbous. There was too much chrome and plastic, and she was *way* too heavy. I guess overall, she looked too 'conformist' or something, which really rubbed me the wrong way when I could see that mean looking bike underneath (also, not to steal the credit for someone else's work, it was this bonnie http://i79.photobucket.com/albums/j158/sweatmachine/DSCN0461.jpg?t=1253929249 on the triumph rat forums which got me started on using the mag wheels instead of spoked. I like spoked, but the weight saving, ease of fitting dual brake discs, and in this case the look of mag wheels was what I wanted).

Ugh, too much talking, here's some pics of where she is now:
thrux3.jpg


thrux2.jpg
 
The SV650 front end was almost a perfect fit. The bearing were identical, but I did have to shim the top steering bearing by about 1mm so I could tighten the top nut with enough pressure on the top bearing. I had to grind off the steering stops on the SV650 lower yoke and then drill and tap some new holes to put in a couple of bolts for new steering stops.
P4100458.jpg

P4100459.jpg


These work pretty well, however they're in slightly the wrong spot, as I can have probably another couple of degrees of steering before my hands on the bars hit the fuel tank. Haven't quite worked out how to do this yet now that I've already drilled the holes.

The outer diameter of the SV650 rear axle (but only the 1st gen I think, i.e. 1999 - 2002 model) is identical to the thruxton's rear axle, so that swap was nice and easy. However, I did have to reverse the rear wheel, as the brake and chain sides are swapped on the SV650. The main reason I went with the SV650 wheels though, is that they're unidirectional (not sure if that's the right word), i.e. they look the same spinning forwards or backwards. The hard part though was getting the rear wheel centred in relation to the frame. I've had to put a lot of spacers on the brake side, and push the chain side almost right up against the inside of the swingarm. Even now though, the rear wheel is off by about 2mm. I think it'll be okay to ride, but I am going to have to get the sprocket carrier machined to get the wheel dead centre as soon as I can.

I've had to get a new rear disc made which fits the SV650 wheel and the thruxton caliper (the diameter of the SV650 disc is too small to reach the caliper). That worked out okay, and the company who did it for me were excellent. I'll post a pic when it arrives (should be this week).

Getting the suzuki controls to work with the thruxton's wiring has been a challenge. The stock bars on the thruxton are a 1" outer diameter, but most clip ons are 7/8", so that forced me to use all new controls. In hindsight, I wonder if an easier option would have been to get some 1" clip ons instead, use the stock thruxton controls except the master cylinder, and try to get a new master cylinder which could handle dual discs to fit. Oh well.


I'm still struggling with all this wiring, and as I have the EFI model thruxton, it seems like I have twice as many wires to deal with.
P4040449.jpg


Because the old regulator/rectifier was mounted on the front forks, I had to get a new one, which I think I'll mount under the battery box. This also meant *more* rewiring :'(

The digital speedo thing is just temporary until I figure out if I can make an analog speedo work
IMG_0409.jpg


I'm also going to try to do the wiring in such a way that I can run the bike with the side covers off. This'll mean getting a smaller battery (some of those A123 cell things) which I'll try to hide somewhere under the seat. I'll also have to mount a new rear brake reservoir somewhere.

And I gotta apologise for not taking more pics. I'll take more from now on, I promise!
 
I likes it. Looks a bit more "pool hall" now..lol.

What did you do with the old front end? I have been looking for one of those.
 
Why the sv 650 front end? after riding a gs 500 and a sv 650 i found i thnk the gs 500 frontend is better. and it suck on its best day.Seems to me the triumph front end would be better. I like the mags. I like spokes too. but the mags give it the mean look.
 
Thanks for the comments, guys :)

alpinaclone, my plan was to try out the thruxton front end on my new kz650 build this weekend, partly as a possible option, partly just to see what it looks like. If it's not even close to fitting, I'll PM you and let you know what I've got re. the thruxton front end (I think it's all there, but the lower yoke and steering stem might not be in the best condition after a failed steering stem swap experiment, and some of the wiring and controls might have been canibalised).

thompsonmx100, yaa, in hidsight I would have gone with a different front end, probably something a bit more modern and adjustable. I used the SV650 front end though, because a) I knew it had been done before on a bonnie and I wasn't brave enough at the time to pioneer something new, b) SV650s parts are pretty readily available, and c) I get the 'bidirectional' wheels (still don't know what to call them). After I finally got my front brakes working last weekend, I noticed I get some seriously crazy brake dive, around 2", just from walking my bike around my driveway! I've either got some dud forks, they're *way* undersprung, or my bike is *way* heavier than a SV650. I'll have to come up with something soon (new springs, way heavier fork oil, etc), as right now, yup, the triumph front end is better.
 
I'm pretty sure this is the first new bike I've seen someone dig this far into. There's nothing 'medium arse' about this project. The moment you begin swapping out front ends and re-wiring a complicated bike like this, it becomes a huge arse project.

Looking great so far!
 
Hahaha hind sight is 20/20. Your bike is probably a little heavier than the sv 650 and they just kinda stink they are undersprung. I have my buddies forks preload crunk down and they still dive. There is solutions out there for them. My gs forks ride in the last 2 inches of stroke but they are stiff there.
 
grumple said:
I'm still struggling with all this wiring, and as I have the EFI model thruxton, it seems like I have twice as many wires to deal with.
ihatewiring.jpg

To me, the above defines a big arse project!
 
Yes, do keep me posted about that front end.

As far as the SV forks are concerned; preload the hell out of the springs with a spacer under the fork cap and throw in some thicker weight oil. I doubt that a Bonnie is substantially heavier than an SV, with some free adjustments I am sure that they will get the job done.
 
if that's first gen SV650

check these out. they are supposed to transform that front end.

basically generic Racetech emulators.


http://www.debrix.com/41mm-Fork-Damper-Valve-2000-up-Harley-FXST-Softail-p/24-0361-vt.htm
 
Nothing 'Medium' here mate!

I think the friction you sensed regarding modifying a Thruxton was in turning one into a bobber when there are zillions of Bonnies out there drying for just that.

I second the emulators, as well as uprated springs. The SV forks are quite soft as noted but with springs and emulators you'll be way ahead of the game.
 
I LOVE THE BIKE MAN, these are one of my favorites!

check this out i have a feeling yours will look similar
 
gribbs said:
Anyway to fix the pics that are not working???

Oops. Sorry about the pics, I'll try to fix them tonight.

Wish I had an update, but I'm almost at a standstill with this wiring. Trying to redo the wiring harness on an EFI bike is doing my head in. Everything appears to be connected correctly, and the bike kinda starts up, but runs *really* badly. I get some smoke smelling like unburnt fuel coming from the right-hand exhaust. The left-hand header is cool to the touch whereas the right-hand one gets warm. Something must be wrong somewhere, and the computer is trying to compensate for where I messed up. Oh well.

I did get some new fork springs and cartridge emulators which I'll put in this weekend. My thruxton is about 30kg heavier than the SV650 (and apparently the SV650 forks are undersprung to begin with), so this definitely needs doing. I'm hoping 15wt fork oil will work, but if it's too stiff, I'll go with a combination of 10wt and 15wt.
 
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