Hitchcocks Forum

I am thinking of converting the EFI system on my 2018 C5 to carburation with our hosts kit. I run a standard exhaust set up and don't plan to change this. reason for change is that i understand carburetors and have no understanding at all of EFI systems. I may in the future install other exhaust tuning etc.

I know a few folk on here have done this conversion and the only negatives i have heard are that the MIL light stays on and the throttle twist goes not go fully round. I can sort the MIL light easily by taking the bulb out, but has anyone experienced a fix for the throttle issue?

Also is this a good conversion for a standard set up? ie: i wont loose any power/performance????

Thanks

The throttle does go all the way round, its just the with efi its half a turn from closed to full open.
With a carb conversion its 3/4 of a turn from closed to full open.
So more wrist action required.
I fitted an Amal conversion and the bike was dyno run and gave 4 more rwhp than standard efi but I did have a free flow exhaust though.
Fuel consumption was very slightly worse by about 5%.

Thanks Haggis for all the points mentioned, that's good to know about the throttle too.

Did you do the conversion yourself, does anything need fettling during the job to make it all fit/work?

It was all very straight forward.
The only thing that puzzled me for a few minutes was the throttle cable.
Efi has two cables, one to open the throttle and another to close the throttle.
This means the twist grip body throttle tube has two cable nipple holes.
When I fitted the carb with its one throttle cable I thought it would go in the place where the opening cable went but that made the cable too loose, like a missing spacer.
I then found the using the second position that the old closing cable used worked just fine.
Also the tap that came in the kit was very poor quality so I bought a better one.

Thanks Haggis, did you fit a fuel filter between the fuel tap and carb inlet? I would be keen on doing this one I assume that the piece of fuel hose is very short.

Theses a decent filter on the tap i bought and there is also a filter in the carb where the fuel line connects.
Not had any problems.
I use stuff called Freeline petrol hose, used a lot by go-kart racers.
Doesn't harden or go yellow.
You can pick it up from ebay.

Haggis you mentioned that with a carb the throttle turn is 3/4 rather than the 1/2 with the EFI. A 3/4 turn actually sounds like quite a lot of wrist action. I have just measured my EFI throttle turn and it is 1/4 turn to fully open, do you think the carb throttle turn is actually 1/2?

Could well be 1/4 and a 1/2.
I'll measure later on today.
The the carb is definitely much more travel than efi .

I can confirm its 1/4 turn for efi and 1/2 turn for amal carb.

Excellent many thanks for checking the twist travel Haggis