Hitchcocks Forum

A mate of mine has bought a custom made bike minus the engine. From the wiring loom (absolutely minimal), it seems like it was fitted with a Royal Enfield twinspark engine.

We are trying to fit a 2018 Bullet single plug engine. It was fuel injected but this has been replaced by a carburettor.
For the moment we have got a twinspark tci unit with the throttle position sensor connection vacant.

When the engine is turned over we get about a million sparks at the plug instead of the one needed somewhere around tdc.
I guess there is a mismatch between the tci unit and the crank sensor in the engine.

Any info on how to, or what is needed to fix this problem gratefully received.

After a bit more searching it seems the engine may need the ecu to run.
I guess the ecu does all the advance/retard and there is no way to adjust the ignition timing manually even if we could modify things to get only the one spark as required from the crank sensor and trigger mechanism.

The rotors are different.
You probably need an earlier tci rotor with a single ignition point instead of the efi one which has 20 odd on the rotor plus a main one for ignition.
Or, see if you pick up an efi ecu.
There are some sensors that, if not fitted, will stop an efi ecu from functioning though.
Roll over sensor is one them.

Thanks for the info, I would prefer to not use the ecu, the bike has no sensors on it at all.
Getting a single spark seems like it should not be a problem, getting the timing and advance retard sorted is a different matter.

Try the alternator rotor and TCI box for an Electra-X, these were used in our hosts' original carb conversions for the EFI Bullets.

A.

For anybody interested in this, I found a post on this forum about this exact problem

viewtopic.php?t=9427

I will ask Hitchcocks directly about this now I understand the problem a bit better.

My knowledge about Enfields has increased a thousand percent today, the last one I owned was a Crusader sports in 1971 and I wish I still had it. I paid £17 10 shillings for it.

Thanks Adrian, you posted while I was typing my reply above and I didn't see your post

My year 2004, home market 350 Bullet Electra has a 12 coil stator and a single “tag” magneto rotor.

It is controlled by a simple TCI controller which has two electric sockets, a two pin and a four pin.

The later bikes had an 18 coil stator and a lot of “tags” on the flywheel.

The more commonly found controller on most other bikes has an extra socket, which I believe is for the side-stand down sensor.

Thanks for the info, I have enquired at Hitchcocks about which bits and pieces they can supply and then we can decide which way to go.