Trifield 500

DESIGNER / MAX REINERT

As described in the 1967 MotorCycle magazine, the Trifield was the best iteration of the powerful triumph engine and the agile Royal Enfield frame.

1960

In 2013, I acquired a frame, wheels, a fuel tank and a Triumph 5TA engine together with a set of period instructions to build a Trifield. So I put the music on and went to work for the next two years...

From a pile of parts to reaching 77 mph at the Brighton Speed Trials, the oldest UK motorsport event - this page details how I got there...

It all started from the bottom-end of a 5TA block and some Royal Enfield tubes making a chassis.

Luckily, I was working at the time for Cosworth, the legendary engine company, so I had easy access to the right equipment and knowledge to rebuild the top-end of this 1960 masterpiece.

The New from Old Stock valve seats, springs and valves were all nicely fitted and the valve seat cut accordingly.

The intake ports have been slightly optimised whilst the carburation has been upgraded to a pair of Amal 626 carbs.

The exhaust relies on a pair of new swept-back headers and some period Pride & Clark megaphones which arrived in their original packaging.

The chassis was the most problematic item.

First, the Royal Enfield frame had to be modified to work with the engine plates and the 5TA lump. Luckily my period instructions described in detail which holes to drill and material to remove.

Then there was the fork...

The initial combination of yokes, fork and wheel resulted in a wheelbase that was a tiny bit too long.

But the summer of 2013 was nice and warm so the wrong fork wasn't going to stop me from attending an 1000 bike event at Mallory Park. I ended up wearing my Dad's Lewis leather suit and a borrowed crash helmet as my helmet was missing the ACU sticker...

As you can see below, the fuelling wasn't yet sorted.

Once this pickle was sorted, the bike took another dimension through its look. The picture below was taken 35 weeks after I first touched the frame with my spanners. You will also notice the 1960s world famous beacon slicers on the front drum.

That same year, the Trifield was invited to join the Goodwood Revival Mods & Rockers parade but due to professional commitments, I couldn't attend. It would have been great to see this unique Café Racer in its element.

2014 saw the Trifield take a premium spot at the Bike Shed Show in London. Click on the image below to watch a video of the event.

During the 2015 Brighton Speed Trials, I struggled a lot, mainly due to very disparate fuelling between the two cylinders.

Nevertheless I managed to ride to the venue (and back)

but the starts were chaotic. Luckily, my mate Daz was always around when it was time to bump start the beast.

I found out later that one of the two Amal 626 carburator bodies was porous!

By swapping it with a NOS part from the USA, the bike worked a treat.

Since then I ride around Cambridge with one of the most pretty Café Racers.

In 2016, I once again took part in the Brighton quarter mile event, but this time with higher hopes.

Hopes that culminated in a 77 mph terminal speed in my second run. I achieved this with a massive smile on my face. Those ten very intense seconds made all the hours spent building this period Café Racer worth it.