Author Topic: EFI to Carb  (Read 14280 times)

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cyrusb

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Reply #15 on: June 20, 2012, 02:00:24 pm
I don't think performance is what the original poster is after. Gee, a whole 27hp! If a carb befuddles you, then FI is the answer. Remember, this is the classic forum, where guys bought this bike BECAUSE it has a carb, points, cable brakes,non unit construction etc. It is these features that makes these bikes unique. And although it lacks the blazing performance of the new bikes, it more than makes up for it in it's "oil lamp" simplicity. 
2005E Fixed and or Replaced: ignition, fenders,chainguard,wires,carb,headlight,seat,tailight,sprockets,chain,shock springs,fork springs, exhaust system, horn,shifter,clutch arm, trafficators,crankcase vent.


mustangdave

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Reply #16 on: June 25, 2012, 11:52:03 pm
I have an 05 that I just get a hoot out of tinkering with...I went through a number of issues as I've sorted the bike out...finally got the carb set up going GREAT...the bike runs like nobodies business...IF I didn't want to tinker I woulda bought an EFI model...as it is I wouldn't have it any other way...wrenchin is cheap entertainment and keeps me out of trouble.
I rode Japanese bikes as a kid...then I grew up and got some British Thunder


cassiopia

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Reply #17 on: April 22, 2020, 01:41:06 am
I have been under the impression that a carb would produce more torque. 


Adrian II

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Reply #18 on: April 22, 2020, 11:12:22 am
Modern EFI Bullets have an 8.5:1 piston, which by itself would account for the power output advantage of new bikes over the fifties iron barrel.



I think the stock 500 Redditch Bullet (we can ignore the Woodsman and Westerner models) was only 6.5:1. You can also factor in the 1⅛" (28mm) Monobloc carb and the old-style hemi-head combustion chamber instead of the EFI's more modern design which RE (India) carried over from the AVL/Electra-X 500. Also the "S" cams were only a touring cam, regardless of what they have since been shown capable of doing for the Electra-X. The Big Head Bullets might have managed 27bhp, I'd have to check.

My '57 old 500 was in a lower state of tune than my old Electra-X and it showed. I gather the current owner has it running at 7.5:1.

A.
Grumpy Brit still seeking 500 AVL Bullet perfection! Will let you know if I get anywhere near...


ace.cafe

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Reply #19 on: April 22, 2020, 12:43:44 pm
I have been under the impression that a carb would produce more torque.

The throat(venturi) size of the carb, or EFI throttle body size, will give approximately the same torque curve results if they are the same size on the same engine. It more-or-less sets the air speeds in the inlet.
Typically smaller throats give more low rpm tq, and larger throats give more upper rpm tq, within certain limits of the rest of the engine design.
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ddavidv

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Reply #20 on: April 22, 2020, 01:12:18 pm
The HP gain is the result of the UCE engine, not so much the EFI though the latter may improve burn efficiency.

I come from an automotive background. It's been dyno proven that an EFI system vs a carb on a street spec engine offers no tangible performance advantage with both properly tuned. What the EFI does is tune on the fly, whereas the carb is limited to whatever the air temp or altitude is.

I've read of various bike guys going from EFI to carb for 'reliability' because they fear EFI failing on the road in a way they can't easily fix. The theory is you can disassemble a carb and clean it but can't fix a failed pickup or control module. What they ignore is the failure rate on those components is so negligible it's probably not measurable.
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eskasteve

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Reply #21 on: April 22, 2020, 04:02:10 pm
One of the biggest advantages to a carburetor system is it provides the owner the ability to make his or her own adjustments. These tweaks only require simple hand tools along with the appropriate knowledge regarding what you're trying to accomplish. Sure FI provides more precise fuel metering but at the cost of the owner being able to easily and cheaply make modifications. RE is the embodiment of simplicity from a bygone era of motorcycling that unfortunately is long gone. Emission standards, though, have bitch slapped quite a bit of that simplicity to the curb. Heck, my last dirt bike, a 2010 Husqvarna 450TE, was fuel injected. Because it was street licensable it had a catalytic convertor and a very annoying lean run stumble. It was unridable at slower trail speeds as delivered. Out came the cat and a Power Commander was installed. Then it was off to the DynoJet approved dealer to get the initial settings loaded into the Commander. About $500 total. Credit where credit is due, that bike ran incredible after that. DyboJet gave recommended programs that an owner could load with their own laptop to compensate for any new changes.
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Paul W

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Reply #22 on: April 22, 2020, 04:03:49 pm
It's a similar argument for and against points ignition as opposed to electronic; it boils down to personal preferences.

In the past I've had various cars with distributors and points. I found the weak point to be the condensers. For one car in particular I got really tired of having to buy two or three condensers at once in the hope of getting one good one. For me, modern electronics are better; they're usually fit and forget.

My 2004, iron barrelled Bullet Electra 350 has possibly the best of both worlds. It came out of the factory with a carburettor but TCI ignition so there are no points or distributor to worry about; the ignition is powered by a magneto which runs off the left hand end of the crankshaft, similar to the present UCE engined Bullets. I found a spare TCI ignition module (cost just £12.99!) and put it in my spares cupboard in case the original fails, but I'm really not expecting to have to use it.
Paul W.


Adrian II

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Reply #23 on: April 22, 2020, 09:13:57 pm
Quote
powered by a magneto

I wish the factory wouldn't call it that, it's a permanent magnet alternator!

A.
« Last Edit: April 22, 2020, 10:52:19 pm by Adrian II »
Grumpy Brit still seeking 500 AVL Bullet perfection! Will let you know if I get anywhere near...


Paul W

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Reply #24 on: April 22, 2020, 10:21:48 pm
[qupte]powered by a magneto

I wish the factory wouldn't call it that, it's a permanent magnet alternator!

A.

Seeing as we both know, I don't think it matters too much. Many modern similar setups are similarly called "magneto" ignition.  ;)
Paul W.