So you fancy a bit of a 'Mongrel' then?

This is the place to start.... Now unfortunately for us mere mortals for whom 'bike butchering' is not a natural process, Mr Haynes doesn't produce a manual like the one to your right (bloody shame, I say!)

So, we have to do it the hard way... or do we...?

It occurred to me that there are a fair number of 'RG / YPVS Hybrids' out there already, and that the people who built 'em must have a few hints and tips, if we could get them to part with them. So after a bit of badgering, Nick (NuttyNick from the RD Forum) was persuaded to let me have the photographs he thoughtfully took while building just such a machine, and provided some choice tips on construction & solving the problems we are likely to encounter.

Read on for one account of how it was done.....

Disclaimer: This was how Nick did it. All the information is to the best of his recollection – Do NOT blame him if yours goes wrong. Also, all pictures show a first build – So don’t worry about odd sized bolts and the use of cable ties etc. The bike will be finished with nice brackets etc. after a shake down run!

Step 1

Find yourself a good chassis, preferably from a Mk1 or Mk2 (twin discs), as they have a nice eighties shape!

Step 2

Find yourself a good RD350YPVS motor. You will also need the carbs (with some sort of K&N type filter), the complete wiring loom with ALL boxes eg: YPVS control boxes, fuse box, powervalve servo, flasher unit with canceller, switchgear, ignition switch (with key!) coil & Tacho (Cable or electric).

Don’t forget you will need a clutch cable and throttle & YPVS cables and one for the tacho if its cable driven. These all cost money – so try to get them thrown in as a job lot.

Step 3

Find a local engineer to machine up some spacers for you.

The front engine spacers are as follows:

1 x 50mm long, with an ID of 10mm.

1 X 18mm long with an ID of 10mm.

For the rear you will need:

2 x rear engine plates, approx 35mm long with a 10mm hole at either end 27mm apart. Both plates 9mm thick. I had mine made of 10mm plate and had to file them to fit.

Like this.

Step 4.

Remove the bodywork, fuel tank, seat, side panels etc to give you access to the motor and electrics. Drain and remove the rad – put it somewhere safe, you’ll need it later.

Remove the exhausts, carbs, and electrics from the motor. Do NOT try to prise the airbox out of the frame – it won’t come out of the frame until the engine is out!

Remove the rest of the wiring loom from the bike including the ignition switch. Remove the clocks and ditch the RG tacho. The YPVS tacho will sit in the hole nicely so don’t panic! Do not cut any of the loom at the back of the clocks, use the block connectors from the RG loom later so that everything is a nice plug in job. Remove the switchgear and all Cdi / fuse boxes and the coils.
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