Author Topic: GSXR Front end swap opinion/discussion (Read 1734 times)

Jake750 · « **on:** December 09, 2019, 01:38:26 PM »

Just got my hands on a 2015 gsxr 750 front end suspension and about to order the conversion stem from cognito moto to install on my 78 cb750f.

This is a fairly common mod so I figured people on here would have first hand experience. I know its mostly a mod that is done for cosmetic reasons (those sweet sweet inverted forks). But if anyone has done a gsxr front end swap on a cb750, how do you like it? And is there a noticeable impact on ride comfort/performance? Andd is there anything I should be aware of (like speed wobbles or something)?

All info/opinions/2 cents welcomed!
Thanks.

seanbarney41 · « **Reply #1 on:** December 09, 2019, 06:33:45 PM »

imo it only looks cool if modern swingarm is done too, and 17" cast wheels with modern sticky rubber. To me, it looks really out of place and corny with spoked wheels. As far as performance, you are just moving the weak link around, from the forks to the steering neck/frame. Plenty of good front ends from the 80's and 90's that are right side up, not too short so as to cause geometry problems and won't overwhelm the frame.

Or let your old bike be an old bike. Old bikes are fun too!

calj737 · « **Reply #2 on:** December 09, 2019, 07:20:08 PM »

The swap is fine. If you use the GSXR stock offset, you are changing the rake and trail geometry from CB stock. Also changing to 17” wheels front and back helps restore it, but it is different. Personally, I don’t find the change problematic on the CBS I’ve ridden with the swap. I do make sure to move the clip ons out for better control.

I prefer the swap with spokes. Different strokes...

Jake750 · « **Reply #3 on:** December 10, 2019, 09:09:29 AM »

Quote from: seanbarney41 on December 09, 2019, 06:33:45 PM

imo it only looks cool if modern swingarm is done too, and 17" cast wheels with modern sticky rubber. To me, it looks really out of place and corny with spoked wheels. As far as performance, you are just moving the weak link around, from the forks to the steering neck/frame. Plenty of good front ends from the 80's and 90's that are right side up, not too short so as to cause geometry problems and won't overwhelm the frame.

Or let your old bike be an old bike. Old bikes are fun too!

What do you mean by moving the weak link to the steering neck/frame?

Xander^ · « **Reply #4 on:** December 10, 2019, 04:56:51 PM »

also been thinking of doing a front end swap... was looking to keep CBR 600 front end to have it all around honda.. any big differences between GSXR vs CBR?

Jake750 · « **Reply #5 on:** December 10, 2019, 05:14:50 PM »

Quote from: Xander^ on December 10, 2019, 04:56:51 PM

also been thinking of doing a front end swap... was looking to keep CBR 600 front end to have it all around honda.. any big differences between GSXR vs CBR?

One thing I noticed was that the gsxr's were way more available. Ive had my eyes on ebay for the last 2 months looking for a decent front end that was cheap and I saw very few if any cbr 600 front ends. Always a decent amount of gsxr's tho.

seanbarney41 · « **Reply #6 on:** December 10, 2019, 05:17:15 PM »

Quote from: Jake750 on December 10, 2019, 09:09:29 AM

Quote from: seanbarney41 on December 09, 2019, 06:33:45 PM
imo it only looks cool if modern swingarm is done too, and 17" cast wheels with modern sticky rubber. To me, it looks really out of place and corny with spoked wheels. As far as performance, you are just moving the weak link around, from the forks to the steering neck/frame. Plenty of good front ends from the 80's and 90's that are right side up, not too short so as to cause geometry problems and won't overwhelm the frame.

Or let your old bike be an old bike. Old bikes are fun too!

What do you mean by moving the weak link to the steering neck/frame?

ok, you have seen the frame of a gsxr (or any sport bike in the last 20 years)? You obviously are familiar with the forks that attach to them. Imagine the amount of force that front end is capable of generating during cornering and braking. You know what the 35mm noodles on your 550 do when asked to withstand this amount of force. Go try this right now. Hold the front wheel between your legs, grab the bars backwards and try and turn them. You can flex those forks without taxing your muscles too awfully much, can't you? So most of that cornering/braking force (actually can't even be generated by a 550's puny amount of braking force and tire grip)is being absorbed by
those 35mm forks flexing. This is why your 550 cannot do the things a gsxr does. Now imagine generating a gsxr amount of force with gsxr forks on your 550 but they are not attached a gsxr frame. Compare your 550 frame to the gsxr frame. Guess what. Your 550 is still not gonna do what a gsxr does.

I am not saying there will be no performance improvement. I am saying the amount of improvement will be much less than what a superficial estimate might be. To me, that's just not worth it. Think you can do one of these swaps for less than $1500? For $1500 I bought a whole running, riding 1986 Suzuki GSXR 750 (which didn't even come with upside down forks lol) Say you make a mistake in the conversion and it ends up costing $1000 more. Plenty of early 2000's 600's around for $2500 if ya look.

Maybe this is all a "looks" thing for you. That is fine. Personally, I would rather ride my bikes. That is about all I ever really want to do these days.

You did ask for discussion. I am just opening some points that many may have over-looked.

low-side · « **Reply #7 on:** December 10, 2019, 05:19:34 PM »

Jake, Sean is saying that it will handle better with the Gixxer front, but it's still a 70s bike with 70s geometry and strength. I think that you'll feel the limitations of the stock swingarm before you'd notice anything else.

Bodi · « **Reply #8 on:** December 10, 2019, 05:40:23 PM »

Kinda like putting a 440 Hemi in a Pinto. The car will twist and lift a front wheel off the ground when you floor it.
The original frame is pretty good for a 70s bike... but it's a wet noodle compared to a modern sportbike's. I doubt that the stem will break off if you do a panic stop with a modern front brake... but I won't say it's impossible.

seanbarney41 · « **Reply #9 on:** December 10, 2019, 05:52:25 PM »

oh hey...I found a really nice gsxr1000 frontend for sale cheap!
youtube.com/watch?v=ab3xdVk9G8I

Xander^ · « **Reply #10 on:** December 10, 2019, 08:10:59 PM »

can someone clarify the stock offset and what type of offset triple top youll need if you do gsxr and cbr front end?

Don R · « **Reply #11 on:** December 10, 2019, 10:01:36 PM »

Quote from: seanbarney41 on December 10, 2019, 05:52:25 PM

oh hey...I found a really nice gsxr1000 frontend for sale cheap!
youtube.com/watch?v=ab3xdVk9G8I

Oh man, you get all the good parts! L0L!

tacc13 · « **Reply #12 on:** December 11, 2019, 02:39:11 AM »

No idea how they ride, but purely from an aesthetic point of view and just my opinion, I'm not a fan of the USD forks on the old bikes. To me it's like putting huge rims and rubber band tires on a 67 Mustang. I wouldn't mind doing a CBR600 swap from the last year they ran conventional forks.

Jake750 · « **Reply #13 on:** December 11, 2019, 08:44:39 AM »

Quote from: Xander^ on December 10, 2019, 08:10:59 PM

can someone clarify the stock offset and what type of offset triple top youll need if you do gsxr and cbr front end?

+1. I would also like to know this

SF · « **Reply #14 on:** December 11, 2019, 02:50:29 PM »

Nicholas or anyone else at Cognito Moto will be able to tell you what you need.

Sent from my iPhone using Tapatalk

nicks2319 · « **Reply #15 on:** December 11, 2019, 05:50:57 PM »

Is the stem required on the 750? For my 500 I just used new bearings and used the gsxr stem. Only needed the conversion hub for laced wheels.

Shtonecb500 · « **Reply #16 on:** December 11, 2019, 09:02:35 PM »

Quote from: nicks2319 on December 11, 2019, 05:50:57 PM

Is the stem required on the 750? For my 500 I just used new bearings and used the gsxr stem. Only needed the conversion hub for laced wheels.

yes.

scottly · « **Reply #17 on:** December 11, 2019, 09:34:55 PM »

Quote from: Jake750 on December 11, 2019, 08:44:39 AM

Quote from: Xander^ on December 10, 2019, 08:10:59 PM
can someone clarify the stock offset and what type of offset triple top youll need if you do gsxr and cbr front end?

+1. I would also like to know this

Stock offset for a K7/K8 F2/F3 750 is 50mm, as well as 550s. Early 750s had a 60mm offset.

Xander^ · « **Reply #18 on:** December 12, 2019, 09:05:28 AM »

Stock offset for a K7/K8 F2/F3 750 is 50mm, as well as 550s. Early 750s had a 60mm offset.
[/quote]

hmmm thanks, going to have to really study this. thinking more about it, i would need to measure the fork lengths and then figure out the new front wheel size to keep it all similar to stock, or lower, lower looks nicer hehe. there are choices/variations of front wheels for this conversion i've seen, not sure what the performance differences are? is it just for front end height choice?

Jerry Rxman Griffin aka MuthaF'er · « **Reply #19 on:** December 12, 2019, 11:38:09 AM »

I'm looking into this too. I will probably go 05 - 06 with a 17" front as the first step. Not sure what the real differences are with the later models though?? Spokes perhaps? Get the front settled and look at the rear. Could leave the F rear alone?? or convert it also.

low-side · « **Reply #20 on:** December 12, 2019, 12:25:48 PM »

You could go for something really special and adapt Morris mags or something along those lines. Probably be a bit pricey, but it would be a great and unique look.

Jerry Rxman Griffin aka MuthaF'er · « **Reply #21 on:** December 12, 2019, 12:31:26 PM »

Not to hijack but my concerns were using the 19" front on 17" forks. I currently have gold powdered Lesters on the stock front/rear.

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Author Topic: GSXR Front end swap opinion/discussion (Read 1734 times)