Frame up builders

[limeex2]

I started building resto-mods many-many years ago. The Forum helped me bring back my old race bike back to life, and a better life at that. I need advice on my final build. I'll be trying to recreate a 85 Kevin Schwantz GS700 Superbike. https://www.classicbikehub.uk/From-T...rst-superbike/ It won't be perfect, but it is the last of the parts I have collected over the years and after recently retirement, I want to build my last Resto-mod.

About me. I was an amateur road racer, not that good, but developed many good habits and a few bad ones. The good, riding skills, slowing down on the street, working on GS's for about 4 years, many new life long friends and memories and a life long addiction to motorcycles. The bad. The addiction got worse with retirement. Lol. I stayed in the motorcycle industry for to long, but in doing so I meet many gifted people in the M/C industry and became very spoiled to perfectly running and drivable bikes.

A while back I bought a GS1100. Cheap. Non-runner. Tons of good mis-matched parts. To keep it short, It has ES body work, with factory weld fairing mounts, leading axle forks, Canadian meter set up, I believe a 80 or 81 tank ("Indents" for knees)., seat and tail section from a 80/81. This is the base I will start from.

Starts with the chassis. It is straight but will need modifications. I will be using a 99 Triumph Sprint Sport front end assembly. I had it, so it was basically free, it's RSU, fully adjustable, forks are long enough to work around ground clearance other issues and killer brakes. Rear end. Usual Bandit rear end, but....From the ZRX I sold, I ended up with a set of Ohlins piggy backs that weren't sold with the bike. I do NOT want a single shock. From the ZRX forum, I acquired upper and lower shock mounts.

Because of these parts and tons of others, I have a chance to change the chassis set up with modern parts and the geometry will need to be changed as well as Yoshimura style frame bracing ect. I don't want to slap a bunch of parts together, As explained in my addictions, I want them to work in harmony with each other, and work like a modern street/superbike, not a slapped together 80's parts bike. So first off, who does frame and chassis work/ modifications like this? I E-mailed a well known ZRX builder, but haven't received an answer, which tells me either the answer is no or someone I don't want to deal with.Yes I realize this will not be cheap, and you guys need to know I still do NOT know how to post pictures. Thanks!

[unfocused]

I have x2 frame up builds.

1 - 77 GS750 that had a bored 750 engine that's no longer in one piece. I swapped in a 78 GS1000 engine. The rest is basically stock.

2 - I have a 77 GS750 frame. 95 Katana GSX750 engine and 2002 GSXR suspension. Only mods is the rear section on the frame which is obvious.
Complete Katana wiring, ignition, exhaust and 93 ZX11 gearsets. It runs but has not been ridden just yet.

Email yourself the pictures on your phone ( I text to email.) Then drag into the box below (click and hold on the email attachment, then drag over)

Resized_20240124_170554.jpg

[limeex2]

The frame will need and possibly more than I am unaware of:
Steering stops.
Frame bracing. Enough to help stiffen and handle extra traction and horse power loads, but not stiff like a sport bike. Some flex is good for lousy Mn. roads. Like modern Triumph's.
Upper and lower shock mount relocation. It will affect (I believe) Rake/trail and other aspects that are out of my knowledge level.
At minimum, I will also need a new steering stem, possibly a new upper triple clamp to be able to mount the gauges.

[bitzz]

I will suggest you talk to Byron Cox, formally of CMR Racing, now Cox Custom Fabrication. He is in Trenton, Ontario, just the other side of Toronto.
He made all the frames for Team America that went to Philips Island (and probably a third of the other bikes in the big show, and sponsored the race for a few years), and has LOTS of GS experience, is a virtuoso welder AND has a frame rack.
I know of no one in North America that has more frame building experience... and I keep track of that sort of thing...I'm a big fan of custom frames.
CMR built me a TZ lowboy frame, custom swing arms for TZ's, a TR750 frame, modified a RS250 frame for a XT motor, modified on a Yetman frame for me (the only Yetman CB450/500 frame out there).
I knew Denis Curtis, CMR's founder, since the '80s, when he ran the race program for Trev Deely, the Canadian Yamaha distributor. Sadly Denis passed a couple of years ago.
If you tell Byron I sent you... be prepared to get sworn at.

[limeex2]

Spent lots of time searching the internet while on my morning coffee buzz. Framecrafters in Illinois is a little closer (6 Hrs from home) and has been around for awhile also. They have added many other services besides straightening frames. More research is in order. Having trouble finding the link to the Yosh bracing article. Hoping our friends from New Zealand chime in. Very knowledgable fellows also.

[GregT]

I've scratch built quite a few frames - and braced a lot of stock ones for racing. Finding someone to modify a frame for street use is becoming a can of worms in a lot of places around the world. Here any deviation from stock requires an engineers certification before it can be registered for the street. I believe it to be even tighter in Europe.
If you do ask race frame builders, I suggest you supply a copy of any relevant local laws/rules the work will have to comply with.
I'm sure someone will come up with a link to the Yosh frame bracing for you. Just remember that it's very easy to waste a nice stiff frame with compliant suspension by fitting flexible wheels....The best handling tip back in the day was replacing wire wheels with cast.

[limeex2]

It will have a Bandit rear end, Modern Triumph RSU front end. Triumph wheel is from Arashi, who also make Suzuki wheels. The even look them same. The bike is titled. What happens after that is my created problem. VIN is good, motor # matches... If Minnesota gets picky, I'll have the kids title it in Wisconsin. I do not want a stiff frame for the street. I don't believe I need all the braces, just the proper ones to match the build. Looking for Rake/Trail/wheel base specs to follow as now is the time to do it. Leaning towards a ride like a ZRX or well sorted FZ1, Bandit etc. All day comfy but can remove chicken strips if asked or while I still can.
No disrespect to any war veteran, but Minnesota roads almost resemble no mans land in WW1 or if one has ever been to Jamaica... Thanks!

[limeex2]

I need help finding a good link to the Yoshi frame mods. links were all expired. Some one had a great picture posted, but I'm coming up empty. Who's got a name of a good frame builder. It's a hodgepodge of parts that will work, I want it to handle modern, and it will with proper supervision.

[dorkburger]

You'll have to scroll down a ways, but there is frame bracing info in there. Lots of fork / wheel / swingarm swap info as well.

https://oldskoolsuzuki.info/archives/category/the-vault

[Buffalo Bill]

You should look through the member resources in race and trackday club web sites. They welcome questions like yours, and they can answer with a business referral.

[limeex2]

You'll have to scroll down a ways, but there is frame bracing info in there. Lots of fork / wheel / swingarm swap info as well.
https://oldskoolsuzuki.info/archives/category/the-vault

Thanks for the link, that's the one I was looking for.

[limeex2]

You should look through the member resources in race and trackday club web sites. They welcome questions like yours, and they can answer with a business referral.

The above article on bracing is very informative as far as bracing goes and what I was looking for. It's not going racing and for a street bike, it will not need the full gusseting. I have found that Framecrafters in Illinois can straighten and do frame work, but I need to find out about their knowledge in this type of build, specifically rear shock placement, angles and other items get the handling I am looking for with the parts I have. I don't want to turn into a cf because of the desire to use up my parts.

[Shin-Ken 1074]

I've scratch built quite a few frames - and braced a lot of stock ones for racing. Finding someone to modify a frame for street use is becoming a can of worms in a lot of places around the world. Here any deviation from stock requires an engineers certification before it can be registered for the street. I believe it to be even tighter in Europe.
If you do ask race frame builders, I suggest you supply a copy of any relevant local laws/rules the work will have to comply with.
I'm sure someone will come up with a link to the Yosh frame bracing for you. Just remember that it's very easy to waste a nice stiff frame with compliant suspension by fitting flexible wheels....The best handling tip back in the day was replacing wire wheels with cast.

Very good points there Greg regarding going too far with frame bracing when in some cases other things can solve the problem. An example of "other things" being the solution is the swing arm. Not so much of an issue with most bikes built in the last 10- years or so however, some early 1980's machines did suffer some handling issues. Best example from my part of the planet is the SZ and SD 1100 Katana, frame was O.K., swing arm not so much. There is a good reason why the South African SZ 1100 Katana race machines were supplied with chrome-moly swing arms and not the usual aluminium swing arm. No other market got the moly swing arm from Suzuki, but fit a swing arm from one Mr. K. McIntosh and it was transformed, in a good way! Yes, I still have my SZ model steel Katana McIntosh swing arm, it is not to leave the family!

With Ken's swing arm installed there was no need to brace the Katana frame in racing or street use.

McItosh by Max Mutarn, on Flickr

[Rob S.]

So what's the reason?

[Shin-Ken 1074]

The South African Team Suzuki race Katana were fitted with chrome-moly swing arms as a factory part to provide improved handling over the stock aluminium swing arm. At the time, frame and swing arm modifications were not permitted in production racing however, as the chrome-moly swing arm was fitted by Suzuki at Hamamatsu for the South African SXZ Katana 1100 it was deemed a "Factory Stock" part and allowed to be used on the "Production E27 spec" SXZ race Katana.

These swing arms were based on the GS1000 steel swing arm but they are not GS1000 swing arms. Two ways to check if it is a Saffer chrome-moly swing-arm;

1) Weight it, lighter than the stock steel GS1000S swing-arm.

2) The X stamp pattern on the pivot box section is also unique to the chrome-moly swing arm and is different to the steel swing-arm stamp pattern.

This is a genuine South African E27 SXZ with the chrome moly swing arm.

Saffer SXZ moly swing arm by Max Mutarn, on Flickr


Saffer moly 2 by Max Mutarn, on Flickr