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Hi guys,

Well I put up a post a few days ago about removal of anti dive units on an 88 GSXR1100 front end. I got great response and advice.

Now here is my issue, before I send my forks to Lindemann Engineering over the winter to have them reworked to eliminate the anti dive units and replace them with aluminum caps I have had machined I have given thought to finding an inverted front end that can drop straight into the triple tree of my 86 750. Can this be done and what would be the best year inverted front end to use. I have thought about getting an 89 front end because I could use my Nissan 4 pot calipers without the brackets I need for them to fit my 88 GSXR1100 front end that has 17 inch wheel (17 out back too).

Since I am in Canada to send off to Lindemann is gonna set me back a few bucks, I have connections to used stuff that may be a better alternative and will also improve the look and handling of the bike.

All feedback is welcomed, I have been told 90-91 are a straight drop in but I need to find out for sure fromn those who have done.

The Ghoul
modded 86 GSXR750
How do you post a pic of your bike here???
 

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A buddy of mine used to race ama superbike (Brad Von Behren) back in the early '90's recommended the forks off of a '93 1100. He said they were identical to the factory forks Yoshimura was using except for one part...they had an aluminum internal rod vs the stock steel rod. As for compatibility, All, yes ALL the front ends are interchangable among 400, 600, 750, and 1100 between the years 1985 and 1995. I've heard from RG/RGV riders that they love to put USD's from gixxers on those older 2-strokes before the USD's became standard. In '96 they changed to an aluminum steer tube on the lower triple clamp and it changed the size of the upper bearing. I was fortunate to find a brand new set of Showa legs from a '94 750 that came annodized blue. They look really nice for my 7/11. The key items to remember are the forks and triple clamps, the front brake calipers, and the front wheel with rotors. They all make up a useful front end. Hop over to http://www.tidepool.com/%7Etetrault/ for data on changing wheels and rotors. Be patient and you'll find what you need.

Hope I helped.
 

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Hi guys,

From what I can remember, from '90 onwards the 750 and 1100 had USD forks. The 1100 has 43mm and the 750 ummm... a little smaller (I think - perhaps Jeff could shed some light on the correct sizes). My '90 1100 has the 43mm USD's and I've just changed the springs for the progressive type. Mucho improvement!
 

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the ghoul,

I think bcklrcr missed part of your question. All front ends from '85 to '95 are interchangabe, but he is talking about the complete front end.

You must change your triple trees to go to inverted forks. The inverted forks will not slip into your triple trees. If you find a complete front end, it will be an EASY swap.

Good Luck!
 

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Cherry and Earl are right, I assumed you meant the entire assembly. The clamp diameters on the 1100's are larger on the fork tubes than the 750's. So if you find an 1100 triple you then have to use 1100 fork tubes. I was trying to ease your mind about the physical swapping of the triples with regard to the brearings.
 

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Aside from the bearings, the only other thing to note is that the air/oil bikes have steering stops that are inside the frame stops. The H20 bikes have steering stops outside the frame stops - you can use H20 triples and forks, but you may have to adjust the stops on the lower triple and frame.

I would hunt up a 91 1100 front end.
 

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Discussion Starter #7
Guys,

If I understand correctly then I can look for a 91-93 GSXR1100 front end? Or would it be better to find a 91-93 GSXR750 front end as my bike is an 86 750. I want the entire front end so I can just drop it in. Do I have to replace the triple clamp on my bike. Sorry for the confusion but I ma a bit new to this but think I got it.

the ghoul
 

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Discussion Starter #8
Ah I haver it now the entire front end off a 91-93 would be the way to go, if I just get the USD forks I need to replace my triple tree/clamp correct.

Which would be better the 750 or 1100 front end . Is the 1100 front end not longer??

the ghoul
 

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Yup, you've got it.

I don't think the length of the fork legs are different(I haven't measured them) but the diameter of the legs are different. For example, the 750 uses 50mm clip-ons with the Showa legs, the 1100 uses 52mm(or is it 54mm?) I do know the clamp diameters of the 1100's triple are larger. I'll bet it means there more resistant to flex too. Ah... to be big AND stiff...that could come in handy controlling alot of mass...like during stoppies.
 

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As far as I know, the 90-92 1100 forks are 50mm at the top, then bulge to 52mm at the lower triple. bcjohn is right about the 93 and up 1100 being 52mm, then bulging to 54mm at the lower triple.

I had best success with 92 1100 in my 85 750 frame. Straight bolt in, and the longer 1100 forks allow for clip ons over the top triple, if you want.

mark
 

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Yeah, the 1100's are 52mm (eg, my '93). Stock, you could get a lot of judder on hard braking, that the mags blamed on the frame. I fig'd that couldn't be correct, given the cast chunk right behind the steering head. Seems to be correct given that the judder went away after I put in some custom hd triple trees. So, what I'm trying to say is that the lighter weight of your machine should balance pretty well with the forks.

I've heard some folks say that the earlier frames will flex some with the USD, but again - is this track or street? And, as I discoverd, was it really frame or triple clamp strength!

Also, the '93 forks are 41mm.

Good luck on your customization.
 

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"Yeah, the 1100's are 52mm (eg, my '93). Stock, you could get a lot of judder on hard braking, that the mags blamed on the frame. I fig'd that couldn't be correct, given the cast chunk right behind the steering head. Seems to be correct given that the judder went away after I put in some custom hd triple trees. So, what I'm trying to say is that the lighter weight of your machine should balance pretty well with the forks."
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I wonder if the sensation felt was the electric anti-dive kicking in? Or were you using the custom triples with the old forks?

I know on my racing bicycles the aluminum fork has that vague feeling while the steel forks and the carbon fiber forks are solid and precise. I try to never race the aluminum one in the rain, it gives no feedback in those conditions.
 
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