Project FrankenPig

Honda CB500 Racer Special

Part 4 – BMW S1000RR Shock

The BMW shock fits more or less straight into the VFR400.

The BMW shock fits more or less straight into the VFR400.

I was going to fit the rear shock from a VFR400 NC30, and indeed I’d ordered one (and it’s now for sale again!), not least because this particular one had all the lower linkage attached, which I need either way. Then I came across this thread on the 400Greybike forums, explaining how to fit a BMW S1000RR (a current superbike) rear shock to a VFR400, which is almost what I am doing. So I bought one, for £60! It’s brand new. Ridiculous.

BMW S1000RR rear shock

A brand new 2015 rear shock from a BMW S1000RR superbike, literally. This came off a Buildbase BMW being prepared for BSB.

Part 3 – TZ250 Seat Unit

Shinya Nakano's Chesterfield Yamaha YZR250 from 2000

Shinya Nakano’s Chesterfield Yamaha YZR250 from 2000

I’ve wanted to fit a Yamaha TZ250 ‘droopy’ seat unit to a bike for about 15 years, since seeing the Chesterfield YZR250s of Shinya Nakano and Olivier Jacque in 2000. I’ve struck out several times in the past when looking for one as they’re not easy to come by (remember that), a fact backed up when the only one I could find on the internet was in Imatra …Finland! It was reasonably priced at £70, although the shipping made it £100 – a little bit of a stretch, but it’s what I wanted and they’re hard to find aren’t they?! Delighted with my purchase and keen to see how it may look on the CB500, I got on my computer, created the FrankenPig mock up image and posted it to Facebook, almost immediately one of my racing friends piped up and said “I’ve got one of those TZ seats you can have for £40”, Wonderful, I thought. So now I have 2 😉 Thanks Josh.

TZ250 Seat Unit - red/white

The Josh Leaning supplied TZ250 seat unit plonked onto FrankenPig. It’s going to require some major surgery to make it fit, but that’s the whole point innit. Sort of.

Part 2 – CBR600 F3 Yokes

Anybody thinking about fitting some adjustable (preload & rebound) forks and a twin disc braking setup from a CBR600 F3, to their CB500, will be delighted to know that it’s a piece of cake.

It took less than 10 mins to swap the yokes over, with zero modification required. The stem and headrace bearings are exactly the same as the CB500’s, which all means the forks and front wheel (from a VTR1000 Firestorm) will now also bolt straight in when they arrive next week. Happy days.


A straight swap for the CB500 yokes, these CBR600 F3 jobbies will hold 41mm adjustable forks. They also need a lick of paint (ahem)

Part 1 – NC30 Swingarm arrives

The NC30 swingarm arrived today, so I was straight out in the garage before breakfast to see if it would fit. The CB500 swingarm is 220mm wide at the frame pivot and I’d been reliablyish informed that the NC30 arm was 202mm, as it turned out it was more like 215mm but that meant it should fit – and it did, with a little wiggle room to spare…

NC30 arm first fitting

NC30 arm went straight in using the CB500 spindle for it’s first fitting. An NC30 spindle will be needed for correct fitment.

NC30 arm room

A little space left over which will allow the correct alignment of the sprockets. Then shims can be made to take up the slack.

In order for the NC30 rear shock to fit, the expansion tank for the cooling system and the battery will need to be relocated, not to mention top and bottom shock mountings made and welded in place (not by me).

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