Triumphrat

JohnD

Let's say that you are interested in getting a Thruxton or Bonnie and doing some speed work on her. Something like Thruxtonboy has done in his thread, "More Powerful Thruxton", ie. big bore, pipes, porting and polishing, big valves, better carbs etc. That last part is the question, better carbs? In the U.S. the 2008 twins still have carbs while Europe has switched to fuel injection, but the rumor is that we get F.I. next year.

That brings up the question: is extra performance easier or cheaper to achieve with carbs or F.I.? If F.I., it would be better to wait for F.I. models to arrive in the U.S. This question is also relevant in other countries because there are pleanty of older models with carbs on the used market.

If one can use the stock F.I. (another question in itself), it seems one can then save buying expensive aftermarket carbs. From a style standpoint carbs certainly look good (especially with velocity stacks), but I have read that the F.I. is hidden in throttle bodies that look like carbs to preserve the original look.

So what is the better hop-up choice: carbs or F.I. ?

Pokeyjoe

I haven't seen many posts regarding mods and FI. To a certain extent, the FI system will be able to keep up with your mods. The O2 sensor will read the lean exhaust and richen the mixture. At some point, you will need bigger injectors and the FI system itself may need to be tweaked. You can either be a pioneer and teach us all what it takes to mod an FI bike, or get a carb model and access the resources here to set it up.

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John

Some people are like Slinkies. They're really good for nothing. But they still bring a smile to your face when you push them down a flight of stairs.

sweatmachine

carb model.

Unless you're willing to wait for the aftermarket to catch up.

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alright alright alright

Bonnie cafefighter!

JohnD

Thanks Pokeyjoe and Sweatmachine. I am hoping that since Europe already has the F.I. models, that the aftermarket is already hard at work. That maybe someone there has already been a pioneer, and will give us in the U.S. a report.

propforward

pull the EFI off and put carbs on perhaps - there are quite a lot of stock bonnie carbs available cheap, then again there are flat slides, which is why there are stock carbs available in the first place.

Unless they've changed the cylinder head fixings I can't see why going to carbs would be that hard. I suppose the tricky bit would be any nonsense with firing sparks. But I should think putting a carb model igniter on wouldn't be difficult either.

Be a pioneer on the EFI trail!

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If you go flying back through time, and you see somebody else flying forward into the future, it's probably best to avoid eye contact.

mikeinva

I dont know what size throttle bodies they are putting on the bonnies.In the next few years i think efi will be much better then carbs .But someones needs to learn what to do with the efi first.Re map them bigger throttle bonnies and so on.

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Why do I feel young on my bike

killian101

correct me if im wrong...FI model has some sort of computer to it...right? You can mod that...but id go with carb.

Soulrebel

Go EFI, start doing your tuning now, sourcing throttle bodies/injectors, fuel maps etc. By the time EFI comes to the states, you will be selling kits like NewBonneville.

OKcarburetor

EFI. Not even a question. Better all around for everything.

I'd love to convert mine.

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"I never vote for anyone. I always vote against."
W.C. Fields

Baltobonneville

Then why is your name OKcarburetor?

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Marty
2005 Bonneville Blue 790cc, AI removed, Staintunes, Unifilter, no snorkel, 120/40/Thrux needle/1 shim/3 turns, fly screen, tacho, D9 gauge panel, center stand, Ikon 7610s, Hagon fork springs, gaiters, Pirelli Sport Demons, 3 seats.