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Discussion Starter #1
I want to lower the stock front in order to give the bike's lines a more even look.

How much can you slide the forks up without jeopardizing safety, if at all?
I tested it out and it looks killer, but I want to be sure I'll be safe before keeping it that way and getting on it...

Thanks!

[ This message was edited by: mase on 2006-12-04 23:46 ]
 

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I remember a few months ago this coming up and it seemed that Brent over at NewBonneville knew how low, seems an inch was too much and maybe I recall 1/2 inch was the max before you risk horrendeous woe. Perhaps someone with better memory than I could chime in????
 

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the general consensus is 10-15mm is safe enough...watch your horn though, if you lower it too much it will hit the front fender, especially if you have a larger aftermarket horn.

I solved this problem by mounting my horn under the gas tank, out sight but nearly just as audible.
 

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Look how close the horn is to the fender. The forks have lowered about 15mm. The horn WILL hit the fender on a big bump, when it hits it can severly upset the handling. READ: knock your ass down.



Here the horn is under the tank, and out of the way of the fender. It's very easy to do, no rewiring or anything. You can even use the stock horn bracket which is a flat piece of 1/8'' plate, and don't tell anyone but I used a drilled bottle cap for a washer which gave a little flex, and a single bolt...I can't remember the thread or size.
 

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Discussion Starter #5
Thanks guys!

Sweetmachine, you're bike is def inspiring! I love what you did to the headlight brackets and acheives a more linear look I'm trying for.

Good call on under the tank, I'll give it a look and see if I can fit the nautilus horn I have (similar to yours).

did you adjust the pre-load in the rear too?
 

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Wow,
what a statement your bike makes sweatmachine guy!!!

With only subtle alterations, you've created one of the cleanest Bonnie's EVER. A chrome cam cover would be 'too much', discrete front turn signals while keeping my MUCH LOVED art deco rear indicators, and that Black headlamp housing..... jeez I Love that! Not to mention my regret for having rid myself of the Pred's..... But surprise of surprises, I find myself agreeing that some old fashion & bulbous gaiters would be unbecoming to such a clean machine.

Truly a Gentleman's Bonnie.
 

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i think i lowered mine around 3/4'' with no problems at all. had my first sweeping turn at around 100 MPH last week and it felt great. Make sure that they are exactley even though.
TJ
 

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Thanks Pat, maybe one day I'll sell it to a nice gentleman that befits your comments! Until then this bastard heathen hooligan is the pilot!

Since that photo I've installed matching turn signals in the rear, in the stock housing. I have a set of fork (dork) gaitors in my garage just waiting to be installed, I like the fat look they give to the front end.

I too love the black headlight housing, everytime I see a bonnie in person that still has the chrome headlight I remember why I painted mine.

Pat, in case you missed the thread a while back I cut 1.5'' out of the bottom of my headlight brackets and welded it on top of them, to lower the headlight, then I lowered the gauges about 1.5'' too.

Thanks for the nice comments guys. Clean and subtle was exactly what I was after...now my mission is to get 85-90 rear wheel hp out of this bad boy.
 

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Before



and after.




I have the Ikon Bonnie shocks under the tree that will be lowering the rear by 1''. I can't wait for Christmas morning to put them on!


[ This message was edited by: caspianthruxton on 2006-12-05 08:41 ]
 

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I wanna be a 'bastard heathen hooligan' too when I grow up.....
I'm mistaken for neither a gentleman nor a hooligan, giving off mixed signals instead. I haven't quite figured out if it's ME who's confused 'bout what I am.... or the rest-o-the world.

I don't think I remember catching what you did to lower stuff up front, it works though THAT'S fersure! Well..... gaiters it is then; personally I could NOT have a Bonnie without 'em. With regard to switching out the art deco's on the back.... well, they DO stick waaaaay out there. I'm fired up about altering mine to make them shorter and Blacker.

And given how much fun I had on a BMW putting 79 horsepower to the rear wheel, a Bonnie with that kind of power would be intoxicating. However I would limit my engine mod's to only that which would assure me absolute uncompromising reliability. I won't have any money to do ANYTHING though, given as I have just accepted pretty significant monthly car payments. It I do anything to promote more horsies, it'll be via an air box removal and ZARD exhaust system (if it's as good on the Bonnie engine as it's claim on Bonnie racers).
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Sorry 'bout hijacking a thread about lowering the Bonnie. I'll make up for it by submitting my two-pence worth:

I lowered my FZ1, and the ONLY way I would do it to the Bonnie would be via the same method (but I won't). I lowered my Yamaha by having the internals of both my front tubes and rear shock lowered. At the same time, I changed out the springs to better match my weight, and had things revalved. The bike now handles like it's on rails, I can stick FILLED Krauser hard bags on it for a trip across the nation, and I would like to think the bike is lower.... but for MY 24" inseam, it's not. All the comfort zone of the factory's initial sag has been eliminated, and it's a FIRM ride even on the smooth tarmac. My poor riding habits (read, 'not very smooth') is now arrested and not telegraphed to the road when I'm pushing the envelope... and THAT'S a good thing. But even with a lowered saddle and an inch lower front & rear, I'm still tippy-toe'ing one foot at a time.

All I'm suggesting is that if you're gonna mess with the factory geometry of a machine, there are compromises that will be made. The bike may 'feel' fine, it may even 'feel' like it's got a lower/better center of gravity, but with an altered suspension it may not rear it's ugly head and act up until the very WORST moment. I suppose if you ride smoothly, never touch down, and ride at sane speeds, your bike might behave. BUT that unannounced decreasing radius with a dip right at the apex..... even at a "safe" speed, could get real ugly REAL quick.

I'm sorry, I just want folk to be scared of mod'ing the suspension for cosmetic reasons.
Rant off.
:hammer:
 

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You're right Pat, there's a lot more at play in the geometry than's evident. I figure there's a little room to wiggle, the Thruxton has the same frame/rake, but an 18'' wheel out front instead of the 19''er. I figure there's not much difference, but fit a tall tire on a 19'' wheel and a short one on an 18'' there could be a significant difference...

That being said, I did lower mine for looks, the quicker handling is just a selling point, plus with the lower headlight it makes the forks look really short and there isn't much space between the headlight and the fender which is exactly how I think a bike should look. Leaned forward and short looking forks sure do give a mean stance.
 

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When i lowered the front of my thruxton it really helped the bike feel more stable entering a turn. It's just like any mod you will do to your bike. It could be fine for a long time till you really need it to work and it might fail you. I say try what you feel comfortable with. Everyone should be careful, but also don't let it hinder your sense of adventure. Cause at the end of the day that's what it's all about. Also a person's size and weight can completely change a bikes geometry. I'm 6'0 190LBS and i carry my weight pretty evenly so i like the lower feeling.
 

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Also putting on or taking off extra weight on the front or the back of the bike can have an effect on handling characteristics. IE: putting a bunch of tools on the bike, fairings, after market exhaust, sissy bars, etc, etc.......
I guess my point it that it's everyone's personal preference and that every mod that we do has more of an effect than we might think.
TJ
 

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I lowered my Bonnie 1/2 " in front and put Hagon Shocks on the rear which lowered it 1.25 " in th rear. I did this because I'm short and I wanted to be able to put alittle more foot on the ground at stops. It did help and I like the looks.
 

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Discussion Starter #15
thanks guys for the food for thought.

I lowered the front today about 5/8" and looks great. I'll see if I noticed any difference...
 

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Discussion Starter #16
hey sweetmachine,

do you happen to have a pic of your horn mounted under the tank?
I can't seem to find room with the relay looking box that goes to the spark plugs (?) in the way...
 

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I don't have a pic, what you're talking about is the coil. sitting on the bike, my horn is closer to the rider than the coil and in between the spark plug wires. You'll have to remove the tank to do it. There are a couple of threaded holes in the back bone of the frame, I think they were for the Air Injection (long gone in my case), I used those holes to mount the horn bracket.
 

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Discussion Starter #18
ah, gotcha. that's what it is. I still have my AI... : \
 

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I put my Ikon Bonnie shocks on last night and it Made the bike feel a lot better. It doesn't feel as top heavy to me anymore and it feels a lot more comfortable going into turns.
I really think that this something to look into if you have a Thruxton.
TJ
 
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