bitzz

AP CP2195 They're making them again. Not quite the same, they now are ambidextrous. A more modern 4 pot is a FAR better choice... even a 2 pot Yamaha caliper off a RD is a better choice

I've seen pics of that first bike, the frame and suspension supplied by Suzuki, modeled off the XR69, with Kayuba shocks, mounted at 45 degrees, not even close to the GS750 setup. It lost the KYB shocks pretty quick.

NEVER put a hole through a tube. That mount has to be built into a gusset, and the plates of the gusset have to welded to the tube like the original was. Engineering 101.

If you get the shocks in at exactly 45 degrees, in the triangle of the lower mount, upper mount and the swing arm pivot, the forces put on the shocks will "graph" linear as it goes through travel. It's easier to tune the shocks.

Here's a pic of the last CMR frame. CMR did all the frames for Josh Hayes and Team America. Team America mostly used a FJ Yamaha motor but the frames are the same. They're not much different from a GS frame... except they're 4130... and the 6 points of connection at the head stay

I thought the saying was "There's no replacement for displacement" ... but we've proven the replacement is compression and RPM. More compression and RPM is better than displacement... and so is squish design, and flat top pistons

Replacing the headbolts on your 40 year old bike, that is known for head leaks, is probably a good idea Weld nuts on and spin them out. Make new ones from 10mm drill rod. Can you still buy aftermarket head bolts for these bikes? It used to be a popular "upgrade".

2 valve? Is the Yosh kit still available? The Wiseco kit uses soup can sized pistons and stock thickness rings, where the Yosh kit uses lighter pistons and 1mm vented rings from a GSXR. MUCH BETTER. (and Total Seal makes GSXR rings). Neither are "low compression". Custom barrels/pistons (JL will make you 4 pistons for not much more than off the shelf) and you can hog it out to 4" if you wanted.

The 2 valve GS bikes usually have a roller bearing bottom end, and have next to no oil pressure, 17psi at full chat IIRC The 4 valve GSx bikes usually have a shell bearing bottom end and DO require oil pressure. You want 30psi at idle and to gain 10psi for every 1000rpm to a max of about 80psi on a GSx.

http://www.motorcycles123.com/mc123_images/honda_common_service_manual_1.pdf is a good start.

...jus so ya know: Harley's have Brembo brakes. Russell makes universal hoses, with threaded ends which makes them easier to customize. Pick the hose length and which ends you need, and they're made in USA

Threaded inserts get a bad name. Installed correctly they work well. They were not designed for thread repair, that was an after thought, they were designed for the aerospace industry to use to make aluminum connections stronger. The inside thread is steel so it doesn't pull out as easy, and the insert increases the size of the fastener, making the connection stronger, more surface area in the connection interface. The people that tell me that helicoil are crap are the people that just ham fisted or galled the thread out of their oil pan or spark plug, where my aerospace machinist friends swear by them.

Swap front wheels with one with a speedo drive

Pretty sure your get to choose your muffler https://www.hindle.com/road-race/mufflers

Being Canadian, Hindle is my default choice. I bought my first Hindle exhaust in 1983 or 84. Still have it. I have the first GS1000 Hindle pipe (that's my GS on their website... it doesn't look like that anymore). I think I have had a Hindle pipe on every 4 stroke racer I've run I won't make any performance promises for them, but Team USA uses Hindle pipes. I'll tell you they're no better or worse than any other REAL aftermarket performance pipe, and a LOT lighter than anything from back in the day... and it's 4 to 2 to 1, so it has better mid-range than anything that isn't. Fit and finish is good, and they're the cheapest pipe for us Canadians. What's not to love?