Forum

[Cranky]

Hello Gentlemen . I have recently acquired an RE EFI 500, now I am not a stranger to Royal Enfields as I went to India and bought a 350 Iron Barrel in Chennai in 2008. My recent purchase a 500 EFI was bought with the intention to convert it as I had heard the EFI was pretty poor stuff.

So I cut it all out and bought a carb and stuck it on. I have just got it running today and will tinker with jetting tomorrow. I know that you will say but but what about-- yes there is lots of what abouts and I did cut out the loom and modified the flywheel. Big job and it got real technical but it runs.

[Adrian]

I know that you will say but but what about--

Just what will we say, precisely? Mmm?

I'm fine with EFI to carb conversions, chopping the loom IF YOU KNOW WHAT YOU'RE DOING is one thing, at least you weren't chopping the frame!

A.

[Haggis]

You seem to have went a bit ott?
I fitted a carb to my C5 efi and unbolt all the efi stuff but did not have to cut anything or modify the flywheel/rotor.
Bike runs fine with the carb and I can revert back to efi should I need to.

[Rattlebattle]

Same here, though I am intrigued to know what you actually did, particularly re the generator rotor.

Though I’ve no intention of reverting to EFI, I prefer to have the option easily to reinstall it if I have to, should the MOT regs change in future to include emissions testing or, like happened to diesel cars, specific changes from standard be outlawed (as Germany wanted to do a while back, mainly because they were the only ones equipped to implement the draconian MOT test). Fortunately the proposal was rejected but given the current green agenda I wouldn’t bet against something similar being put for are again.

[Cranky]

I did not use the ECU I cut everything that had anything to do with the EFI. I fitted a small motorcycle TCI unit often called incorrectly a CDI. Keeping the the 28 tooth flywheel would give multiple sparks per rotation, well I assume it would.
The flywheel was ground down and all teeth removed. I then welded on a 50mm tab with trailing edge at TDC. You must not weld longer than 2 seconds and dump it in cold water. The tab was then turned down at my local happy lathe shop to 13.5mm --thats the inside of the rotor to the top of the tab. I have trigger gap of 12 thou.

Im going to get the strobe on it today to see what advance I have if any but I think its not far off as it will kick back sometimes if I kick start it. But the jetting is way out and it wont pull above 2500. I need to richen up a bit and this is proving difficult. Ive raised Fuel level 2mm and enlarged the idle jet and its getting better.

[windmill john]

Well you’re far cleverer than me, reading what you’ve done makes my head spin

But if not pulling above 2500rpm, how do you know it’s carb and not advance? Or have you tried it in different gears to get a different affect?



John

[Rattlebattle]

Impressive! If you have the carb jetted as if it were an ordinary conversion like most have, I doubt that this would cause it not to run above 2,500rpm. More likely the timing, but I guess you’ll soon find out. Presumably the TCI has its own fixed advance curve? Great that you’re doing this differently though; way more adventurous and skilled than me! Do keep us posted.

[Adrian]

Our hosts' original EFI to carb conversion used the Electra-X alternator rotor (flywheel???) and TCI, but latterly they have found a way to get the EFI's existing ECU on-side.

Nuking the whole installation and starting from scratch is cool if you can get it all to work properly. A bit gung-ho, but hey...

So I cut it all out and bought a carb and stuck it on

What carb did you settle on?

I've noticed that there is an Indian supplier selling 33mm CV carbs with throttle position sensors to convert 2009-2017 EFI bikes, the TPS apparently works with the ECU's ignition circuitry, which (allegedly) has a better ignition curve or range of curves than a plain TCI.

Hmm. Could be an Electra-X performance upgrade there, they only had a 29mm carb but the inlet port will take bigger carbs.

Sorry about all those TLAs (Three Letter Acronyms).

A.

[Cranky]

Using the ECU with all the bits still connected and stuffed up under the seat or tank is not what I wanted. The ECU will still be trying to read all those bits like TPS , MAP, OX sensor, eng temp etc this has to mean your ECU is not giving the correct ign timing and I am surprised the MIL light is not on. May be you know more about this than me.

I found today that my reading from the hall effect sensor must have been insufficiently clear to the TCI. I had seen on youtube an American guy saying that a .47 micro farad capacitor gave a certain amount of retard, so I tried it. I looked in my biscuit tin marked 'Electronic bits'.

I tried a big horrible thing from a TV and some others until I crocodile clipped in a small capacitor ,--- looked like a blue smarty with 2 wires ,---value unknown and Bingo it ran 1000 RPM faster at idle and was very responsive to throttle with a very lively engine. After re adjusting RPM and mixture It idled so quietly.

Gentlemen --at the moment I do not understand what has happened here but it seems like sharpening the Sensor/ pulsor/ trigger message was what the TCI needed .

I used a VM 32-33. I bought it off Lazada --same as Ebay here in Thailand. It was 20 quid. and the TCI units are 2 pound 50 pence.

The VM 32 fitted into the original rubber mount of the EFI throttle body.

Thats about it apart from the TCI not liking the RE ign coil reading at 4.5 ohms . I bought a small bike coil from the ubiquitous motor bike shops for 3 pound fifty and had a reading more to the requirements of a CDI or TCI.


Thing about the CDI or TCI units you need to be DC and not AC. An Ac unit will need 3 phase supply through a rectifier or a Charge coil in the flywheel magnets and the RE does not have this. A DC supply from the kill is as per RE original to the ECU.

[windmill john]

I thought Einstein had died, but apparently he lives in Thailand....

Still, a very interesting thread that I’d like to learn more from.



John