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menace
23rd May 2004, 22:38
Ok i know this is probably a stupid question or whatever... BUT as im brand new to biking im just curious about somthing...

Do most motobikes run carbs or have I missread something?

If they do i dont get why? :blink: It seems pretty old technology and i dont know too many car tuners that still fiddle withcarbs, its mostly electronic injection and such. This makes it easier to map and even have a few diferent maps for different conditions/needs/wants. Its just plug and play...

Anyway im just curious... And probably wrong... <_<

pete376403
23rd May 2004, 22:46
More and more bikes are running injection, but usually rhe bigger, more expensive ones.
Carbs, although old technology, are pretty refined and they do work well. Factories build bike to sell and they don't really care too much about people who want to change them from stock, ie mess around with fuel maps and so on.
Consider also the economies of scale - cars sell by the 100's of thousands, if not millions. Also they sell for a lot more than bikes, so 1, they amortise the cost of developing expensive electronics over a lot more units and 2, as a percentage of the total cost of the vehicle, the injection cost is a smaller part.
FWIW, the first mass marketed injection system on a bike (GpZ1100) was based on a Nissan (Bluebird IIRC) system. U+It was pretty crude and tended to fry its electronics. The preferred fix was to replace it with carbs.

Motu
23rd May 2004, 23:05
Most bikes have carbs,but fuel injection is making inroads on top of the line models.Like you say it's a bit of a puzzle - fuel injection is used for two reasons...emissions and costs - it is waaaaayyy cheaper to make fuel injection components,a carburettor is horendously comnplicated to make and difficult to spell correctly.It goes out of tune,wears out and needs adjustments.The odds are stacked completly against carbs - but they are still used....I guess the old technology is in place and working well,why change.

riffer
24th May 2004, 08:34
Yeah, its funny.

I can remember as a kid when my dad and I pulled apart and rebuilt the motor in mum's Herald 13/60 and he was trying to explain the difference in the motors between the car motor and the one in his GS550.

He was telling me how tehnology most often appeared in motor cycles first and told me how cars would one day commonly have things like electronic ignition and overhead camshafts.

Seems its almost like motorcycle technology is only advancing on the top-of-the-line models mostly now and its kind of stagnated on the cheaper models.

Still, as you said Pete, economies of scale and all that. :yes:

Motu
24th May 2004, 08:53
But all they have to do is transplant the car system to bikes - all the development work is done,Bosch controls everything about how it's done.The only hard part with multis is multiple throttle bodies and air flow meters,but that's been done on cars as well.You don't need special bike injectors,TPS,CTS,MAF,MAP whatever,all this stuff is cheap - it's the suppliers,I guess Mikuni says we'll supply job lot number x for $$,doing the same for an injection system would involve more components to source,price and supply - just comes down to costs.

James Deuce
24th May 2004, 09:25
One of the big factors in getting fuel injection to work on a bike is the fact that the "feel" of the throttle is vital. A slight off idle hesitation is no more than a possibly undetectable glitch in a 1.5 tonne car, where that hesitation could result in an accident for a 200kg bike. Triumph's (Hinckley - the new Triumph) first 600 had fuel injection and it suffered from inconsistent fuelling at part throttle settings, which is what most people use most of the time in real life.

The expensive late model bikes get a lot of R&D these days, but it is trickling down product ranges for the Japanese manufacturers.

Motu
24th May 2004, 12:32
From what I've seen (and hey,I could be very wrong) bike systems are basicly incomplete - not closed loop and usualy missing idle control because of multiple throttle bodies,in a single induction impulses play havoc with airflow meters.If you try and control idle speed with spark advance and injector pulses only - poor low speed and off idle control problems are almost gauranteed.The top end of the market and they cut corners because it's ''too hard'' duh.

menace
24th May 2004, 14:35
Ok guys thanx for that. It clears out a few things... Im not saying carbs are a bad thing because there are a lot of cars that still run them (think ported rotaries... ;) ) But for variety and ease of tuning EFI is soooo much easier... IMO... :) Granted the intial cost might be steep but once it comes to modifing i dont know... :)

Motu
24th May 2004, 14:58
Well,electronic engine control will keep the engine in tune for a hell of a long time compared to points and a carb,but if you want to modify then the carb is an easier option.Money no object,then a tuneable engine manement is the way to go.I was down at Possums a few years ago and they had a WRX on the 4x4 dyno they were tuning with the so called Possum Link - fuel and ign could be altered all the way,performance gains without touching anything else were huge - but you could buy another car for the cost of that sort of set up.

menace
24th May 2004, 18:20
Well,electronic engine control will keep the engine in tune for a hell of a long time compared to points and a carb,but if you want to modify then the carb is an easier option.Money no object,then a tuneable engine manement is the way to go.I was down at Possums a few years ago and they had a WRX on the 4x4 dyno they were tuning with the so called Possum Link - fuel and ign could be altered all the way,performance gains without touching anything else were huge - but you could buy another car for the cost of that sort of set up.


Tehehe no offence but the the link system are not the greatest. IF i was going to dish out money for a CPU it would probably be a motec ok so they cost around 3 grand BUT the thing is you can use the comp again and again... (as in plug them into your new toy after your finished with one... )

Now motec is prety much top of the line... But if ur after something as almost as good you get haltech and get someone who can tune them and ur set to go go GO>.. :D :yeah:

dangerous
24th May 2004, 21:09
I have had injected bikes for over 8yrs (CX500 Turbo 1982 and a Moto Guzzi 1100 sport 1997) and think that its the best thing since sliced bread. The CX was fultless started from cold and always ideled at the push of the button were as thw Guzzi being Itiallian was a bitch when cold and often stalled when hot and had a slower responce but this is still faster than a carb to respond.
I recently brought a 03 VTR storm and it fells so slow to respond in comparision and you have to do the bloody warm up thing with the choke etc. Give me a ECU and injecters anyday :yes:

ps: I rechiped the Guzzi so easy and it ment more power and better mapping.and to ulter the mixture (which I never had to do) you plug in a diognostic puter and diled up +3% rich and un plug

menace
26th May 2004, 18:55
Ok can someone explain why carbs would be more "responsice" than an equalent injector setup? :o :spudwhat:

dangerous
26th May 2004, 19:50
Ok can someone explain why carbs would be more "responsice" than an equalent injector setup? :o :spudwhat:

"responsive" would that be?..... Well they'r not. A carb can prodcce more power that an inj however they are not as economical or set up as well.

eg: a carb can not adjust mixtures by its self when it comes to altitude, air temp were as a inj will so inj is suited in all terains were as carbs can only be set up for one type of condition. make any sence?

Inj is almost instent were carbs have mechanical parts which take time to open which means a lag between 'action and responce'

Aleph
26th May 2004, 20:30
I do not know the answer but is it anything to do with the fact that on a bike everything is going to get wet and temperature variations will be much greater than in cars.

pete376403
27th May 2004, 10:01
Injection can be "too" responsive. Some of the early setups are more like an on/off switch. When you have a high power/lightweight vehicle (ie a 600 or better sports bike) this can make riding round town very jerky. With a carb, when the butterfly opens the air speed change is almost instant, but the heavier fuel takes a little time to get going (hence accelerator pumps and so on) but the power increase becomes a little more controllable.
Could this be why the new setups use two butterflies, one before and one after the injector?

pete376403
27th May 2004, 10:05
[QUOTE=dangerous
Inj is almost instent were carbs have mechanical parts which take time to open which means a lag between 'action and responce'[/QUOTE]
Hmmm.. the mechanical part in a carb is usually the butterfly, which most injection setups also have. the slide in a CV card WILL respond almost instantly to vacuum, but is damped to prevent this happening (recall the oil reservoir in the top of a Stromberg or SU carb)

menace
27th May 2004, 18:48
A carb can prodcce more power that an inj however they are not as economical or set up as well.


Ok are you sure about they produce more power? I dont see how this can be true... Maybiee you mean the power delivery or somthing similar. I dont think carbs or injectors have much to do with peak power, that would be more compresion rating related...
:o
I would think that carbs or injectors are only a way to get the fuel suplied TO the chamber, so they dont have much to do with it...
:o

BTW i do understand the the mechanical differences between the two. But chears for saying them anyway... :)

Jackrat
27th May 2004, 19:55
I'm personaly all for anything that makes life easy for the home tuner.
Electronic Ignition "great" Fuel injection "not so great"
Fuel injection is pretty cool but it's taken me years to understand carb's so I don't have to go to shops for a basic tune.
Us thick buggers need things to stay basic :o
Like I can set the timing on a manuel points system with an out of tune AM radio but I don't know the first thing about fuel injection maping an such.
Hell I even got a hammer under my bike seat.

jrandom
27th May 2004, 20:03
I'm personaly all for anything that makes life easy for the home tuner.
Electronic Ignition "great" Fuel injection "not so great"

awww I dunno. Fuel injection *would* be great if the chip emulators and control software were easy to come by. The present generation of petrolheads are all pretty au fait with 'puters it seems, surely running a program up on a laptop and plugging an emulator into a DIP slot wouldn't be too hard. Once that's up and running it should just be a matter of clicking on buttons and going for rides around the block. I know quite a few guys that do just that with their cars, much tider than swapping jets around.

menace
27th May 2004, 20:28
awww I dunno. Fuel injection *would* be great if the chip emulators and control software were easy to come by. The present generation of petrolheads are all pretty au fait with 'puters it seems, surely running a program up on a laptop and plugging an emulator into a DIP slot wouldn't be too hard. Once that's up and running it should just be a matter of clicking on buttons and going for rides around the block. I know quite a few guys that do just that with their cars, much tider than swapping jets around.

Thats exactly what i mean... Although i would leave it to the pros to do my tuning but just save a few maps and 'tis all good. :Punk:

Jackrat
28th May 2004, 10:38
awww I dunno. Fuel injection *would* be great if the chip emulators and control software were easy to come by. The present generation of petrolheads are all pretty au fait with 'puters it seems, surely running a program up on a laptop and plugging an emulator into a DIP slot wouldn't be too hard. Once that's up and running it should just be a matter of clicking on buttons and going for rides around the block. I know quite a few guys that do just that with their cars, much tider than swapping jets around.

LOL,Yep I just ain't the current generation.Mate I don't even know what a au fait is, let alone an emulator or a DIP slot. :o

Motu
28th May 2004, 12:15
LOL,Yep I just ain't the current generation.Mate I don't even know what a au fait is, let alone an emulator or a DIP slot. :o

A DIP slot is where you put the DIP STICK - jeez,you really are ignorant Jack,anyone would know that.

bungbung
28th May 2004, 13:47
an au fait is one of those fancy auckland coffees.

menace
28th May 2004, 14:28
LOL,Yep I just ain't the current generation.Mate I don't even know what a au fait is, let alone an emulator or a DIP slot. :o


I think "au fait" i think means that we ar computer literate... Which is probably the case as we are all here on the internet...

And emulator is prty much the interfase you would use to acess the ECU so you can play around with the ingnition ratios ect... :) DIP slot is just a way to physicaly conect to the ECU


Happy with the computer lesson?

Posh Tourer :P
28th May 2004, 14:32
funnily enough, au fait translates pretty well to OK if you use it in context. It is in an old boring language (French) so i would have thought you would have known in Jackrat :Pokey: j/k

dangerous
28th May 2004, 18:26
Thats exactly what i mean... Although i would leave it to the pros to do my tuning but just save a few maps and 'tis all good. :Punk:

Thats just it....... you never have to tune a thing with inj. The only time that the system needs tampering with is when someone wants to make more hp or with the Iti stuff a replacment chip for better running and thats only ever done once, and most Iti stuff is well sorted now at the factory. Its that simple.
I have done over 40000km on my 97 Moto Guzzi 1100i sport and I never touched a bloody thing were as the carb sports would need a tickel up every 5-10000 km to keep em runing sweet eg: winter would need different tuning to summer but with inj the ECU (puter) does it all by its self.... just great realy :)

pete376403
29th May 2004, 20:14
I got my GS1100 in 1990. (and it was pretty old already). I have never messed with the carbs, apart from pull the float bowls once to see if there was any crap in there. Even after I replaced the foam air filter with a K&N, nothing would convince me there is anything to be gained by altering jetting.
Sometimes on a cold morning I'll wind the idle speed up a bit.
Nothing at all wrong with carbs if people leave the damn things alone.

dangerous
29th May 2004, 22:52
Thats true Pete, I guess that I'm compairing Itialian carbs (big bulky vintage Deloto's) which can be a real pain in the ass when combined with a high compression V2 to keep tuned.
Mind you there early inj wasent much better :apint:

ps: note that I have gone back to a jappa with carbs :whistle:

pete376403
30th May 2004, 17:55
Jawa speedway motors used to come standard with a big Del'Orto, and the thing with those was to have two big frame mounted float bowls. It used to be a standard scene in the pits, people altering the fuel level by moving the bowls up and down, trying to get the things running right. All my troubles ended when I put on a 40mm Mikuni - the f*ckin thing would even idle. Starting was a breeze - put the choke on, and with the bike on the stand, give the back wheel a flick. The Mikuni and the Mitsubishi magneto where probably the best parts of that bike.

Skunk
30th May 2004, 22:29
I think the reason EFI has taken longer to get to bikes is because the bikes are more sensitive to incorrect fuelling because of their power to weight ratio. The early computers could not sample all the data required and map it to a fuel amount fast enough to produce smooth power.

I may be wrong but I believe that good systems sample the thottle postion, thottle movement, air density/velocity and map that to the ignition timing and fuel.

Someone correct me... :o

dangerous
31st May 2004, 19:08
I think the reason EFI has taken longer to get to bikes is because the bikes are more sensitive to incorrect fuelling because of their power to weight ratio. The early computers could not sample all the data required and map it to a fuel amount fast enough to produce smooth power.

I may be wrong but I believe that good systems sample the thottle postion, thottle movement, air density/velocity and map that to the ignition timing and fuel.

Someone correct me... :o

Yes and no..... the first sentence I would agree with, the second sentance I would not but that would depend on how 'early' you are talking eg: the GPZ11 was a bit dodgy however a mate has one and it runs just fine with a modded motor. My 82 CX 500tc was inj and one of the first to come out of Japan and it is as good a set up as inj today better than my 97 Guzzi 1100inj altough the number of senses has been lowered the CX had 11 were as now they are down as low as 5-7
As for the last sentance correct but you can also add engine temp (cyl head) and fuel flow.

Lou Girardin
31st May 2004, 20:13
Well,electronic engine control will keep the engine in tune for a hell of a long time compared to points and a carb,but if you want to modify then the carb is an easier option.Money no object,then a tuneable engine manement is the way to go.I was down at Possums a few years ago and they had a WRX on the 4x4 dyno they were tuning with the so called Possum Link - fuel and ign could be altered all the way,performance gains without touching anything else were huge - but you could buy another car for the cost of that sort of set up.

Motu, heard of Power Commanders? Much cheaper than a Link too.

Motu
31st May 2004, 22:09
Yeah,and there are systems you can get off the net and build your own.But this is one I saw in action,and anyway - I was talking to Possum about it,that's a good memory.

You can run fairly low on your inputs - say engine speed,MAP for air flow and TPS,then add more and more from there,the more inputs,the more outputs,the better it runs - simple as that.As I mentioned way back,bikes have nowhere as many control systems as a car,they are never going to be as good until they spend the money - it's all done,the modern car is very sophisticated,bikes are not a big money earner,they don't get the good stuff.

menace
1st June 2004, 15:53
I think the reason EFI has taken longer to get to bikes is because the bikes are more sensitive to incorrect fuelling because of their power to weight ratio. The early computers could not sample all the data required and map it to a fuel amount fast enough to produce smooth power.

I may be wrong but I believe that good systems sample the thottle postion, thottle movement, air density/velocity and map that to the ignition timing and fuel.

Someone correct me... :o


Thats all good but i think that the current microcontroles that are coming out have not problem calculating the inouts and otutig what is needed...

Hoon
1st June 2004, 18:03
A good carb tuner can make carbs do anything EFI can do. EFI is definately better for the average biker especially with all its sensors to adjust on the fly but performance wise for a given day at a given track - carbs can do just as well if not better so I've been told.

One area where carbs are still in the stone age tho is the accelerator pump which squirts raw fuel into the barrels when you twist the throttle to overcome the lag until the fuel reaches the cylinder. EFI is more precise hence better response, fuel economy and emissions.

While stripping my carbs in the weekend with my mechanic mate we were talking about EFI and he also agrees that carbs are all good. He also says that a lot of mechanics coming through these days don't know how to tune carbs...only EFI so he ends up doing most the carb work at his job.

Dr Bob
4th June 2004, 09:21
Yeah, its funny.

I can remember as a kid when my dad and I pulled apart and rebuilt the motor in mum's Herald 13/60 and he was trying to explain the difference in the motors between the car motor and the one in his GS550.

He was telling me how tehnology most often appeared in motor cycles first and told me how cars would one day commonly have things like electronic ignition and overhead camshafts.
.......

Fuel injection (at least for diesels) was commercial in 1927, the Merlin spitfire engine had overhead cams (not to mention nitrous injection), at the same time Messerschmitt used fuel injection and superchargers were old hat.