Starting my first ever project. GSXR 1000 front end on a GS

**SqDancerLynn1** · 02-21-2004, 10:36 PM

From what I have heard from others It is usually the 3 mounting bolts that break You should take it apart first

**GER144** · 02-21-2004, 11:44 PM

Sounds like you have a cool project there Mookie! Keep us posted how that front end works for ya on that 1150.

**Anonymous** · 02-22-2004, 02:12 AM

Today I just won an auction for an '02 GSXR front end

Sweet front end. Get it rebuilt and resprung to suit your bikes weight and it will be incredible. You will have to watch ground clearance with it. Current sportbike forks are WAY shorter than your stock GS forks (likely 4"+ shorter). Combined with a 17" wheel, your front end will be sitting a good 5" lower than stock, which is going to cause some cornering issues if you like to rip it up in anything other than a straight line. OK for a drag bike or cruiser, though. And it will look very cool.

Mark

**Guest** · 02-22-2004, 02:48 AM

sounds kool dude.

could you post the outside diameters of the forks @top and bottom triple? and the lenth of those forks from center axle to the top of the tubes...not the top of the adfusters?

cheers,

katman

**Gerry** · 02-22-2004, 07:22 AM

Sounds like your going to have some fun. Good luck and keep us posted

**robinjo** · 02-22-2004, 07:33 AM

Sounds like a very cool project!

Originally posted by mark m

Today I just won an auction for an '02 GSXR front end

Sweet front end. Get it rebuilt and resprung to suit your bikes weight and it will be incredible. You will have to watch ground clearance with it. Current sportbike forks are WAY shorter than your stock GS forks (likely 4"+ shorter). Combined with a 17" wheel, your front end will be sitting a good 5" lower than stock, which is going to cause some cornering issues if you like to rip it up in anything other than a straight line. OK for a drag bike or cruiser, though. And it will look very cool.

Mark

The 1150 came with a 16" front wheel as standard so he will probably come to the same height wheel when he uses a 17" 'cause the 16" used a higher profile tire, I am curious about the lenght of the 1000 forks though

**Anonymous** · 02-23-2004, 03:49 PM

The 1150 came with a 16" front wheel as standard so he will probably come to the same height wheel when he uses a 17" 'cause the 16" used a higher profile tire, I am curious about the lenght of the 1000 forks though

Good point on the 16" wheel, I missed that. That is a bonus in his favor for the ground clearance issue.

I have a 99 GSXR600 front end in my basement and the forks are 28.5" long from axle center to the top of the tubes. Forks haven't gotten any longer since then. Current sport bikes have very short forks and low steering heads compared to the 80's bikes. This makes swapping forks difficult without a lot of work. OTOH, my 97 ZX-9 forks are about 31.5" long, so they are not too far off. They could be internally lengthened about 10mm and that is getting really close then. I think that the early 90's GSXR1100 USD forks are similar lengths to my 9's forks. The reason the 1100 forks and my 9's forks are longer is that the clip-ons are above the top triple, not below it. To allow that, they are a good 1-1.25" longer than other USD forks of the era.

Mark

**Robert Corrie** · 02-23-2004, 06:22 PM

85 gs1150 fork length extended 32 1/2" 01 gsxr750 fork length extended 28" even. That dimension is to the TOP of the fork tube. 1150 wheel with metzler lazer total 23 " tall. gsxr wheel tire combo 23 1/2" tall. You are going to need to replace the stem in your triple with the 1150's and make a custom drop top for it also if you want to keep your ground clearance. I'm in the middle of installing a complete 01 gsxr 750 front end on my 85 1150.Came up with a trick to keep the fork length.Machine "extensions" for the top of the fork tubes.Get the total length you want, screw them into the top of the fork, put a spacer inside the fork to match, install cap.Bingo,modern forks on ancient bike!

**Guest** · 02-23-2004, 06:55 PM

93gsxr 1100 forks are 30inches 92 gsxr 1100 forks are 29.5 inches.

I have the 93's and I use zx clipons so I can go under the top triple for more lenth. the 750's are 2mm smaller all round.

thanks for the info on the zx9 forks....could you post the diameters @ the triples??? I believe they are 52 top and I don't know the bottom but if they are 56 they are a great alternative to gsxr fork tubes.

cheers

**Anonymous** · 02-24-2004, 09:50 PM

could you post the diameters @ the triples???

They measure 52mm from top to bottom of the triple area, with no step anywhere in there. That means they could be used in the GSXR triples with a shim to take up the clearance in the bottom clamp. They measure 30 1/4" from the axle center to the top of the tube as it sits now and I had about 20mm of static sag last I checked, so the extended length would be right around 31" from center of axle to top of tube.

The damping is not the greatest as they come, though. There is way too much compression damping and the rebound adjuster has a very steep taper that means it is very hard to find the right setting. One setting could be too soft, the next click too hard with nothing in between. I am going to get the forks and shock rebuilt and revalved this year to solve the damping rate problems. As well, I am installing a set of 2000 GSXR compression pistons in place of the Kawi items to get big flow holes for less high speed compression damping. This is a sort of poor man's Gold Valve modification. If I could put Axxion valves in instead, I would do that, but the price is too steep for me at the moment.

Let me know if you want more info on them.

Mark

**Anonymous** · 03-02-2004, 12:06 AM

I'm getting a little worried about the ground clearance issues now.

I haven't had a chance to measure my stock forks yet but when it's said they are 33 inches is that from the top of the tube to the middle of the axel? If so then you are correct about the shortness of these new forks. I just got them in the mail today and they are about 28.5 to 29 inches long.

I figure I won't miss an inch or 2 in ride height but much more than that and I'm going to start grinding stuff way too early. So, here's what I'm thinkin, If we are measuring from the same points and the wheel size differential isn't that much then that basically means I'm still going to have to find another 2 inches minimum in clearance. If I remember correctly (my poor GS is stuck up north in a friend?s garage right now) the clip-ons for the GS are mounted above the triple clamp thus taking up about an inch or so of the top end of the fork. I can just ditch the GSXR clip-ons and get some dirt bike risers, drill some holes in the new triple, mount some drag bars and that should get me at least an inch.

That leaves me short another inch. Any ideas? I know that when I do the rear of the bike I'll probably jack it up a little (or a lot) so that should clear up a little more clearance in the front but probably not much more than a 1/2" or so. But that's stage 2 of the transformation and I haven't even really thought that far yet. Another way I could clear up a little room is if I got a 4/2/1 exhaust setup which should be a little flatter than the current 4 into 1 that's on there now. The suspension is also going to be what I would guess to be a fair bit firmer as well so there should be decidedly less dive when under braking or turning conditions.

I still will need another inch or so. What do you guys think? Is this going to be possible? I'd hate to have to get some custom made triple clamps made (if there is even such a thing made that can give me more room) since I?m not made of money. Is there such a thing as extending the sliders? These things are so nice I?m going to have a hard time selling them. There has to be a way but I?m not really sure what to do at this point.

check out these beauties :twisted:

The brakes on these things made my jaw drop! And in person the tubes seem wider than they are tall! There has to be a way of getting these blingin' forks to work with this bike. And I need this bike for twisties not straight lines so it can't grind hard parts too obscenely early.

What do the strong minds of GS world think?

**Anonymous** · 03-02-2004, 12:01 PM

The brakes on these things made my jaw drop! And in person the tubes seem wider than they are tall! There has to be a way of getting these blingin' forks to work with this bike. And I need this bike for twisties not straight lines so it can't grind hard parts too obscenely early.

New bike stuff is just awesome to look at; huge fork tubes, massive brakes and it all weighs about nothing...Very nice.

Anyway, as for your clearance issues:

1. Bridgestone (http://www.motorcycle-karttires.com/) gives the OD of various front tires as follows:
100/90-16 - OD=23.1"
110/90-16 - OD=23.8"
120/70-17 - OD=23.8"
So it looks like at worst your new front tire will be the same OD as the old one. Very good.

2. Your forks can be internally extended by about 10mm by changing the top out springs and/or spacers (I am not sure exactly which is in the GSXR forks you have). Unfortunately, this will cost some money for the pieces and installation from a suspension tuner. But you will gain nearly 1/2" right where you need it.

3. A longer shock is a MUST, because the new 160 or 180 rear tire you will be using is about 1" smaller in diameter than the old one, so you lose another 1/2" at the back. I have a buddy who runs +1.5" shocks on his Katana with no stability issues at all (with 17" rims and a katana 600 front end), so consider at least +1" of rear ride height. You can apparently use a GSXR shock from the early 90's, which opens up a lot of choice in the aftermarket, especially for shocks with ride height adjustment.

4. Yes, you can get custom triples made. The top one would have a gullwing type droop to clamp lower down and raise the front end up. Cost would be pretty obscene, though. They would look SOOOO cool if you did it, which will balance off some of the cost...

If you really want to do this, I would be willing to do a 3D model of the piece for you to take to a CNC shop, but they will want a pretty steep price to machine a set of clamps for you, even with the model in hand.

5. Someone mentioned making a longer endcap to replace the stock Suzuki piece and allow clamping higher up. Not the best solution, as it loads the threaded connection between the cap and tube (which was not really designed for that), but if you keep the amount you use this for to a reasonable level (say 1-1.25" at most), I would think it would work OK. Especially for a street bike that will not see a road race track and slicks. If you wanted to try this, I would also be willing to help you with modelling of new end caps for nothing.

If you think those brakes make your jaw drop looking at them, wait until you try them out with good pads, braided stainless lines and a sticky 17" front tire. You should be able to leave retina prints inside your face shield! 8O

Mark

**Anonymous** · 03-02-2004, 02:36 PM

Awesome Ideas! I'd be very interested in finding out some more specifics on both of those oprions. To be honest I don't have a ton of money to throw around and it looks like those fork extenders that you mentioned sounds like a more affordable option but I also am guessing that would also depend on how much those fancy triples would end up costing (of which I have no idea, but "obcene" doesn't sound good)

Yes, I am planning on jacking the back end up a bit I'd say at least 2 inches. I've heard the Hayabusa's have longer shocks but I haven't really begun to research fully my options concerning the rear yet.

I think That all I'm going to need to really get is an additional inch of room from the forks (not including the additional internal fork spacer and all the other mods). So how to the extended endcaps function? Would that also require me lengthening all the internals so that I can still adjust everything or would they just be covered by the now longer endcap?

BTW-these are exactly the kind of ideas I'm looking for- Thanks!

**Anonymous** · 03-02-2004, 03:04 PM

To be honest I don't have a ton of money to throw around and it looks like those fork extenders that you mentioned sounds like a more affordable option but I also am guessing that would also depend on how much those fancy triples would end up costing (of which I have no idea, but "obcene" doesn't sound good)

I would expect a set of triples (just making a new upper triple is not that great of an idea, since they should be either line bored together or CNC'd to ensure that the holes are dead true to each other, between the upper and lower clamps) made from aluminum to run $500-$600 USD at a minimum, unless you happen to know someone who will do it for beer money.

I've heard the Hayabusa's have longer shocks but I haven't really begun to research fully my options concerning the rear yet.

Check out http://www.ohlins.com/ for info. Go to "Motorcycles", then "Mounting Instructions". They generally have overall lengths and stroke for the shock, so you can look up shocks for different model bikes and compare their dimensions to give you an idea of what should fit OK.

So how to the extended endcaps function?

I haven't thought hard about it, but I think I would set them up with the preload adjuster and rebound screw set down into a counterbore, at the same height as the stock Suzuki caps and an outer sleeve area that extends up above the adjusters to clamp onto. Then you would simply thread them into the forks like normal and put the triple clamp onto the extended portion. Did that make sense? :?
In order for me to model the caps, I would need a bunch of detailed dimensions from your stock caps so that I can correctly get it set up. Send me a PM if you want to talk more about it and find out what you would be in for. They still wouldn't be cheap, but they should cost significantly less than a full set of custom triples.

Mark

Starting my first ever project. GSXR 1000 front end on a GS

Starting my first ever project. GSXR 1000 front end on a GS

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