Digs

Proper build, love it

Bikeshed show 2025 23, 24 & 25 May 2025 Worship motor show - Sunday 28th September 2025

Zzr1400 front end works with a stem swap, k3 1000 stem works well. Also zx10r BFF forks work.

I’d place money it’s the resistor on the ignition barrel. It’s an anti-theft feature. Check the resistance between the (if I remember rightly) orange and red on the barrel.

It’s all very tight fitting wider rims or larger offset carriers/wheels in a slingshot frame. I had to do a lot of modifications to get my 6” rim to work and some single shear calculations to make sure I still had enough material left.

I’m assuming it’s a typo and he meant 6”

So I’ve put a 6” rim in two slingshots, they’re not k4 rims but zzr1400. I needed to machine down the rear sprocket carrier to make it work. You need to find out the distance from the wheel centre to the inside face of the sprocket. For a standard slingy wheel it will be 100mm, ideally you should aim for 105 with 6” rim to not run too close to the tyre. Also bare in mind you may want to run a 525 or 520 chain to help with the clearance if you run a larger offset. Picture here shows how much I had to remove.

I’ve no interest in restored or stock bikes, they do nothing for me. I do however agree that the variety is what makes a show, and - while it’s not my thing - I’m always keen to chat to the guy with the rattiest bike with the worn grips, they’re normally the ones that do the most miles anyway.

Bit of penetrating oil and some heat, that’ll get it out.

So my suspension setup is quite a bit different to any of these bikes stock. I made my setup for maximum adjustability in terms of motion ratio and swingarm angle. I’m using a shorter shock (309mm from memory) from a 2018 gsxr1000r and have different linkage plates for different applications. There were definitely issues with parts fouling to start with, and I did change shock a few times but it’s all resolved now. I spent a lot of time in cad going through it all. But that’s just the way I like to work.

Good work so far, and you can check that very easily. Unload the suspension and place a scissor jack or similar under the rear wheel. Measure every 5mm of shock travel and compare that to rear wheel travel. Once you’ve done that plot a graph with the data and you’ll have your motion ratio.

Cheers @KennyKak much appreciated. Yeah mine was a little different to the design shown above. The mount was a little further back and quite a bit lower to suit my use case. This probably shows it best. I also machined out the central part of the mount and machined out a couple of slots on the underside for the lower frame mounts which let it sit directly on the lower frame rail. Finished mount looks like this. Happy to modify my cad model and share it here to match the mount shown in this thread.

There’s a bit of ‘works well enough for me’ with the k series swap. In my view you need to actually do some work: cad, spreadsheet or pen and paper to make sure whatever you setup has a proper motion ratio and can transfer the loads properly. Moving the lower mount down and closer to the original k series geometry is a good idea, as is spacing the top mount out. It’s not the only way to do it, but it is a good way.

“I recently saw a person making some spacers to install modern GSX-R rims, versions K - L, it seemed like a pretty clean job to be able to replicate.“

Love that fillet brazing, looks mega.