7-11 swap, 8v 750 vs 16v vs gs1100e - Rickman CR900

[Chuck78]

20 years ago, a guy in Georgia was rebuilding a Rickman CR900 frame that had the typical cracked braze joint(s) at the headstock which occurred on these frames regularly when ridden very hard in a racing environment. The Rickman Predator series were an updated frame with additional bracing up front.

well I have purchased this frame since the guy passed away a long time ago and it has been sitting in storage ever since. I was told that he had reconfigured the frame with additional headstock bracing and GS1100E engine mounts. I have read that the lower triangular mounts were the only difference between the 16 valve 750 and 1100. Looking at all of my 8v GS 750 engines and spare frame, he has the new engine mounts much further forward than my engines. Will an 1100 drop in a GS 750 8-valve frame just the same as a 16 valve frame?

I was really hoping to do a kick start only 894cc 11:1 GS750 based engine in this CR900 chassis. if it is only one bolt-on motor mount & one that is brazed on that need altered, then I may just add an additional brazed-on mount for the 8 valve engine and make it so that I could bolt on either. If I get the frame's nickel plated finish re-done, it would be nice to have both options without having to do any more metal work!

[Chuck78]

I know that the 1100 engine is probably just as light as the 750 if not slightly lighter, but I have all this 8 valve stuff &4 spare engines, and am fanatical about it. I had considered the 1100 or 1150 engine, because it is absolutely the ultimate vintage 4-cylinder engine, but then I thought about how much more likely I would be to want to twist the throttle open far too much. A stock 750 with minor mods is already plenty fast! A little more highway-speed torque would be nice, but I can deal.




Yes that would be 14 Suzuki GS1100E swing arms in crates at my house! The Georgia junkyard was really good to me!

[Fjbj40]

Hoarder you are!

[Chuck78]

Well I have been "coming across" several spare gs750 77-79 engines that I decided to hoard since the parts aren't getting any easier to obtain.. the swingarms I only kept 2 of, gave the rest to our awesome Vintage Japanese Bike Parts & Salvage shop/warehouse here, the Rice Paddy, $20/ea (all bearings were shot & rusted, no axle adjusters included), and they gave me as payment for transporting 600 miles, a better GS400 seat than the one they were previously selling for $130! Flat 78 seat for my 79 GS425 project. Good trade, good buddies.

Any pointers on the 1100e vs 8v motor mounts???

[GregT]

Is that frame still plated ? Have the headstock reinforcements just been welded over the top of the plating ? How ? Bronze or fusion weld ?
Before anything was welded onto it, it should have been deplated IMO...The metallurgy involved with what is a high quality tube is a trap for the unwary.
Your bottom engine mounts are easily accomodated with custom plates made to go on the existing mount points on the frame.

[Chuck78]

Yes the copper&nickle plating was removed from the areas where the additional bracing and mounts were brazed on (not welded). the rest of the frame remains nickel plated, although some areas were rubbed completely bare from the side covers, and other less visible areas were left to neglect and rust.

I really would like to get this thing on the road just with some really serious buffing and polishing and clear coating over the areas of bare metal. Then down the road after I have gotten fun enjoyment and much road testing out of it, then strip it down another winter and have it re-plated with the copper/nickel finish. Finding a good competent nickle plater that will not use an acid solution that will eat away all of the braze joints is going to be a challenging process.

[Chuck78]

Your bottom engine mounts are easily accomodated with custom plates made to go on the existing mount points on the frame.

Greg, are you saying then that the other engine mount points on the 8 valve 750 and 1000 are the same as the GS1100E?



I need to start another thread about this Rickman on multiple forums in regards to parts. I am hoping to use a GS hub/D.I.D. alloy rim spoked wheelset on it, but it appears that the axle may be 11/16" - troubling if I want to use this 2nd generation Rickman CR extremely heavy duty rigid CR900 swing arm ((earlier CR750 (CB750 models) had much more flimsy swingers)) and this very nice original Lockheed underslung brake caliper and original master. Also having trouble finding Lockheed rebuilt parts, pads, m.c. res. cap, swingarm pivot parts, a photograph of the missing left rearset shifter mounting parts, etc... quite the rare beast! A $25 ebay copy of the assembly guide & parts list may help a lot, but sourcing parts may be more of a challenge.

Edit: Aha! in addition to the Lockheed name on the caliper, there was also a logo that I did not recognize which I now realize was a cursive AP, almost the same logo that is still currently use for motorcycle racing brakes! Although, the master cylinder has a different logo that looks more like a stretched out "H" & no Lockheed marking unless it's on the back side.

http://www.apracing.com/%255Cdrawings/2014%2520Product%2520Catalogue/2014%2520Motorcycle.pdf

Also found where my shifter lever mounts as I suspected, but missing the pivot and linkages, everything except for the pedal!

[Chuck78]

http://www.diablocycle.com/GS750-Lower-Engine-Brackets-Unfinished.html

http://www.diablocycle.com/GS750-Lower-Engine-Brackets-Unfinished.html

GS750 Lower Engine Brackets to convert 750 to an 1100 or 1150 - SOLD AS A SET ONLYLower engine brackets fit 1980-82 GS750 to install a 1980-1986 GS1100/GS1150 engine.

GVW-711

7/11 Brackets Powder Coated Textured Black
$35 USD including worldwide postage

7/11 Brackets Unfinished
$32 USD including worldwide postage
I thought I has seen something.

Under Misc Suzuki Parts

this only addresses 80-82 750 16v swaps

[GregT]

Greg, are you saying then that the other engine mount points on the 8 valve 750 and 1000 are the same as the GS1100E?

They should be pretty close. i know putting an 1100 into a GS1000 was pretty simple.

Replating...I've nickelplated a couple of frames, scratchbuilt ones though. Any acid used is simply a wash prior to it going in the plating bath, and that's only to degrease the surface. It won't affect the bronze welding at all. If you do replate, sequence is strip any existing plating (in the plating bath but reverse polarity) then beadblast using very fine bead to produce a satin finish on the bare metal. Then usually its just straight nickel plate. Most platers won't bother with a first coat of copper these days. Probably not really necessary for nickel.

[Chuck78]

what exactly is the alloy of rod used to do the brazing on these frames? I thought it was more brass than bronze.

[dorkburger]

Diggin this project...

[GregT]

what exactly is the alloy of rod used to do the brazing on these frames? I thought it was more brass than bronze.

Both are alloys. Bronze welding is a generic term used to describe the joining of metals by building up a fillet of bronze weld on the joint.
The rods used can be quite complex alloys for good flow and fillet strength. Often containing Nickel and manganese - and sometimes Silver as well.
Brazing is used to describe the process where a mainly brass based rod is drawn into a prefluxed joint when the workpiece is heated.

The Rickman frames were Bronze welded. My understanding is that they used a Nickel bronze rod. As a side note, an awful lot of them were welded by Kiwis in the UK, there to gain Motocross experience. I've met two of them who between them were there for around 8 years...

[dorkburger]

http://www.thegsresources.com/_forum/showthread.php?228546-Scratch-built-GS

Chuck, I had this thread in mind regarding your brazing questions, but couldn't remember it. It just resurfaced.

[Chuck78]

Thanks, Glen! I somehow missed your replies due to junk mail folder filters changing... that drag frame build is wild!

I got some 41mm vtr1000f Superhawk forks for almost nothing, probably have to use 01-02 gsxr1000 6 piston tokico calipers for clearance to my spoke wheels, smaller pistons on those. Using honda CB1 296mm rotors that are basically a bolt on to gs hubs, I need a 7.25mm spacer between the rotors and hubs to make the skinny gs wire spoked hubs work with these forks.

Biggest dilemma is 20mm axle forks vs 17mm GS axle, bigger bearings & custom spacers and try for a modded gsxr 17" wheel speedo drive??? Or run a GS axle & machine adapter bushings with a clamping slit in them to adapt to the larger fork?

Also the 2nd Gen Rickman swingarm used an 11/16" (17.4mm~) rear axle, GS uses 20mm. I think I can machine a 1.3mm wall thickness adapter sleeve to make it work

[Chuck78]

"Bronze Welding" is much more common in Europe, as evidenced by the drag bike link from a GSR member that Glen pointed out, numerous UK welding forums, Rickmans, Harris, Egli frames, etc... in the US it is held very skeptical in most people's minds aside from the custom high end bicycle frame market.

Glen, I'm sure you can vouch for this.. in my extensive BMX days from 14 years old into my 20's, I brutalized a lot of heavy duty dirt jumping frames, race frames, etc, all 4130 cromoly TIG welded steel. They ALWAYS broke on the metal immediately adjacent to the weld... frames, handlebars, etc... even my 6061 t6 aluminum PK Ripper racing frames, broke 3 of those on the metal directly adjacent to the weld. Precise heat control with a TIG and proper heat treating after welding is very critical.

With bronze welding, you don't have to get the steel as hot to the point of embrittlement, since you are not fusion welding with steel. This allows the parent metal to stay much stronger. This is VERY CRITICAL with high grade lightweight high strength steel. Thicker mild steel is not as critical.
With bronze welding (looks like bigger TIG welds, can do with uncoated rods and TIG machine also) and fillet brazing (similar but bigger smooth puddle vs stacked dimes look), you can get a very large spanning bead for more strength, and the joint can flex slightly more than tig, where the TIG would just cause major stress and crack the weakest point of the parent metal...

There are a lot of racing motorcycle and car tubular steel chassis that have been oxy/fuel bronze/braze/fillet-braze -welded together. Those terms are used when you make a fillet instead of "sweating" a joint together as with tube/lug fittings.

The size of the fillet will vary with the strength of the filler rod. Brazing is basically an adhesive attachment since the parent metal isn't melted so lower strength (usually more ductile too) rods will need a bigger fillet for more surface area than will a high strength bronze rod. Here's a typical oxy/fuel bronze weld fillet.




The ERCuSi-A AWS/SFA5.7 rod is claimed by one manufacturer to have a minimum tensile strength of 50ksi (but doesn't give a yield strength), with 65% elongation in 2 inches and a Brinell Hardness of 80-100. SAE 1018 hotrolled has a UTS of 58ksi and yield of 31.9ksi.

The little bit of TIG brazing with the above rod I've done gave me the impression that the rod doesn't "wet out" or "tin" as well as the high strength oxy/fuel rods like Eutectic 16 or Messer MG130 that I've used to build some race motorcycle frames. The high strength rods may also have nickel or silver in them.

You do want to avoid overheating the steel as you can get intergranular penetration of it by the bronze which will degrade the strength.

http://www.weldability-sif.com/media...ig_brazing.pdf

http://www.weldability-sif.com/media..._technique.pdf

http://www.weldability-sif.com/media...03_gasflux.pdf

http://www.weldability-sif.com/media...ng_brazing.pdf

Sifbronze 1 and 101 are what were typically used on the English race frames with oxy/fuel.

cheers,
Michael
Last edited by Michael Moore; 09-29-2010 at 02:45 PM.