Front-End Swaps - Non-Suzuki Options?

[Guest]

It?s looks like I?ll be rebuilding my front shocks this off-season, but since I have a few other bits to address as well (master brake cylinder) upgrading to a modern(er ) front end might fix a few problems all at once?

I?ve read a few threads on swaps, but all used GSXR/Bandit parts; my question is whether other brands have been/can be used or not? I.E. - Could i use a full R6 or CBR RR font end on my ?82 GS650e with some finessing or are the bearing/sleeve/spindle setups too different?

I wouldn?t be using the instruments, but if I can get a donor front-end that has a complete front brake setup then why not use that too?

Just thinking out loud, but I?d appreciate any feedback if you have it.

 

[Guest]

The first obvious thing (to me, anyway) is that you will most likely inherit a 17" front wheel meant for radial tires and it won't be a simple thing to get the original GS wheel to work, if it will work at all. If you want to also fit a 17" rear rim for radials then that isn't much of a problem but that adds the rear conversion work to your list of things to do.


Mark

 

[zed1015]

Anything can be made to fit anything else if you have the skill and tools.
I've done many modern front end upgrades and swingarms too.
Unless you are lucky and a bearing conversion does the trick then usually it's a stem mod or swap to get the donor yokes in and some alteration of the lock stops.
Consideration needs to be taken to the length of the new forks as most modern ones tend to be shorter and may need extending either internally , externally or by way of stepped yokes otherwise you will end up with a head shaking ,exhaust dragging deathtrap that will tank slap you to death at anything approaching 100mph.

 

[Rob S.]

...deathtrap that will tank slap you to death at anything approaching 100mph.

But over 100 will be okay, right?

Actually, I learned years (decades) ago that when the high speed wobble starts (I rode a Z1) the last thing you want to do is hit the brakes (makes it worse). 'Accelerate' out of it. I used to give it gas and ride the rear brake at the same time.

I never realized there were that many issues. I'm sure I've read about members swapping in CBRs or newer Suzis. Let us know how it goes.

 

[Who Dat?]

One slight modification here:

Anything can be made to fit anything else if you have the skill, tools and money.

 

[Grimly]

It's crossed my mind a couple of times that if the front end on the currently most-used GS850 gets to the stage of needing another major rebuild, I might swap in the entire front from an XJ900F, as seen in my sig. Not only is it several years younger in design, it feels it too. Also get opposed piston calipers in the package, as well as a fork brace. Both fork diameters are 37mm, and they're about equal length. The only downside, if you could call it so, is the XJ uses an 18" wheel, but meh.

In fact, it was the pretty decent handling of the XJ that prompted me to sort out the wallowing mess that the GS had become, after years of gradual deterioration.
A happy accident of acquistion saw me with a set of GS1000 forks, which were 19mm shorter than the 850G's ones, and that shortened the trail just a touch, compensating nicely for the weight of the fairing. Once these were fitted with modern springs, fork brace and diy pre-loaders, everything became quite nice again, especially when allied with the Showa air shocks on the rear (all hail King Hardly, and his devotees of needless upgrades).

Moving on another ten years or so (given that the XJ900F was originally designed in the early 80s), I might look at one of the earlier Bandits, the 1200 being favoured as a front end donor by a few on here. However, that would mean messing around with different yokes, etc.
I don't think I'd bother with GSXR fronts, too short and getting too far away from a relaxed cruisery feel.

 

[slayer61]

Originally Posted by zed1015
Anything can be made to fit anything else if you have the skill, tools and money.

One slight modification here:

Or friends with skill, tools and money!

:-\\\

 

[Guest]

Thanks for the feedback all

I might look at one of the earlier Bandits, the 1200 being favoured as a front end donor by a few on here. However, that would mean messing around with different yokes, etc.

I was looking into a 2004 SV650 setup (forks/triples/stem/bearings/controls) that is up for sale on FB nearish to me. According to the interwebs the front suspension travel is 20mm shorter than my GS (130mm vs 150mm) but I couldn't find an overall length to compare for some reason. Unfortunately the forks are 41mm so using my stock triples would be out...hence the interest in a full front end. What are the chances that a.) The sv650 triples will fit my GS stem and/or b.) the SV650 stem can be used with my GS head tube? I've got my eyes peeled for Bandit parts, but nothing of note yet.

everything became quite nice again, especially when allied with the Showa air shocks on the rear (all hail King Hardly, and his devotees of needless upgrades).

Using cast-off stock Harley rear shocks? I'd never considered it, do you just find ones that match the OAL and slap them on, or is it more involved than that?

But over 100 will be okay, right?

Originally Posted by zed1015
Anything can be made to fit anything else if you have the skill, tools and money.
Or friends with skill, tools and money!
:-\\\

too true

Cheers

 

[Grimly]

I'm fairly sure I got a couple sets of Dyna shocks, at 13" eye-to-eye. For use on the GS, I had to shim the shock eyes in the rubber, but that was trivial. Only slight embuggerance is the 850 bottom eye is offset, but it's not been a problem so far, in many thousands of miles.

 

[slayer61]

I'm fairly sure I got a couple sets of Dyna shocks, at 13" eye-to-eye. For use on the GS, I had to shim the shock eyes in the rubber, but that was trivial. Only slight embuggerance is the 850 bottom eye is offset, but it's not been a problem so far, in many thousands of miles.

Grimly can I use that word? It's perfect for daily conversation when discussing projects & POs!

Well my friend, what embuggerance did you find on the project today?

 

[Chuck78]

Anything can be made to fit anything else if you have the skill and tools.


Consideration needs to be taken to the length of the new forks as most modern ones tend to be shorter and may need extending either internally , externally or by way of stepped yokes otherwise you will end up with a head shaking ,exhaust dragging deathtrap that will tank slap you to death at anything approaching 100mph.

WHAT HE SAID ^^^^^^^^

Bandit 1200 forks from the 1990's are long, Honda VT1000C Superhawk forks are long as they stick up over an inch above the stock triples to have clip ons mounted to the fork legs above the triples.
Yamaha YZF600 forks also are taller but oretty thin. R6 forks are paper thin, they buckle, crease, and tear when crashed.
Kaw ZRX forks may do well but are quite heavy. Those are tall modern retro sport touring bikes.

The triples are another thing. Custom billet triples will certainly do it.
You need to keep 18" wheels at minimum if not stock 17" or 18" rear and 19"front, vs modern 17". Your bike's frame ride height and engine (width) are designed around the stock wheel size and suspension height. The triple clanp offset is spec'd specifically for the rake of the frame and the diameter (or radius, rather) of the front tire.

If you ignore these engineering details and think you can turn your back on factory-ish engineering, think again, you'll have a very sub par machine.

 

[Chuck78]

These 750+ 4 cylinder engines are quite wide. With 18" wheels front and rear, taller shocks, and almost stock front end height, I scrape my feet & the stator covers just playing in the tight corners on twisty roads. With proper tires sized for my rim widths (non-stock), I run to the very edge of the rear 130/80-18 RoadAttack3 radial on a 3.50-18 rim (2.15-18 stock), and almost to the edge of the 100/90-18 front on a 2.50-18 rim (1.85-19 stock).
If you put 2" shorter forks and wheels 1" & 2" smaller diameter on a GS, your cornering clearance will be absolute garbage, defeating the purpose of upgrading for better performance.
Even almost scraping my stator cover, my lean angle us nothing compared to a modern 17" wheel sport bike whose forks get swapped onto vintage bikes frequently.

Stock wheels or 18"/18", taller upgrade forks, proper triple clamp offset around 45mm to 55mm, these factors are essential.

A 2" thick billet block could be machined into an offset upper triple clamp to make a set of 43mm cartridge forks work on a Yamaha VMAX 1200 triple clamp if you wanted to find someone to machine something up for you... I'm considering this for a set of GSXR1100K forks. Bandit 1200 forks in GSXR1100K triples with an 18" front wheel or the 41mm VT1000C Firehawk forks in GS1100GK triples might be the easiest swap, but you'll still need to deal with the 20mm axle vs 15mm GS. The bearing size yo run a 20mm axle in a GS wheel is nearly obsolete and has smaller balls, so a GS axle or 17mm axle might be a better bet.

 

[Chuck78]

I made a long post/thread several years ago of cartridge fork and triple clamp options to retain acceptable geometry. Look that up. Modern cartidge fork options for 18" wheels or something similar was the title.