Carb vs Direct Injection 125s (what to choose?)

Hey all.

There's a lot of controversies about scooters when it comes to what kind of engine to choose, years ago there were only carburettor versions available (same as with old cars), then started to show up fuel injected versions. I am not sure how many scooters around with direct injection, but I have been the owner of Suzuki Katana R (DiTech) for almost a year and have no issues so far.

What I've found from others, that injected engines are prone to tuning and harder to work on as well as parts are more sophisticated making them scarce and more expensive to buy.

In this thread I would like to discuss in more detail about current scooter market and how many of you would choose carbed or directly injected scooters, and why? So this thread would be as a guide to others considering their next scooter, same as I am looking to up scale in a few months time and thin of what could be my next scooter in 125cc range.

I am considering between Gilera Runner ST 125 and other (maxi) options such as Yamaha X-Max 125 and Honda Forza NSS125.

Wonder what would be your pick in terms of reliability and ease of maintenance (maybe tuning)?

Thanks a lot for your guidance!

 

My choice comes to between Gilera Runner St 125 for it's name stood in time, reliable Piaggio LEADER engine (easy to maintain and tune up) or Honda Forza NSS125 for it's great design, great fuel economy data (not sure about it's maintenance or insurance group, what engine it's got, must be Honda's?).

 

ive got a Honda sh injection cant fault it beats a carb every time, down side you cant sort it out if it goes tits up

 

Isnt it as simple and replacing the injectors?

 

Presumably it's not only injectors, what can make your scooter go 'tits up', could be high pressure fuel pump or a fault in ECU...

 

And the money you pay to find out which of those expensive things it is!

 

Still, the purpose of this thread is not being met here, assumptions are not explanatory at all, what we want is clear opinions. Thanks.

 

the way i would think of... an injector system needs an ECU, which means it will have diagnostics of some sort, easy to find faults with diagnostic systems.
carbs, they have a billion different componants. less fuel efficiant, and it seems ive spent my life adjusting them, i have never had to adjust an EFI scooter.....
im not a huge fan of gilera/piaggio either, the quality is crap considering the price, why pay for a brand when its just shoddy cheap crap? i mean i know most are made in the same factories etc, but at least with hondas/sym, they use water tight connections, and the exhausts last more than 1 winter......

 

The problem I've found with injected scooters is that there is nobody locally who has the equipment to do the diagnostics. Yes we all know about the gameboy cartridge thing, but can you find one? Not me. And without access to the proper diagnostics, the home mechanic, however much experience they have, will just end up chasing their tails.
It's expensive to change things willynilly on them on the chance that it will cure it.
And if you are lucky enough to have a dealer nearby who has the equipment, the price they charge is quite high.

And not all scooters use the same diagnostic software, just like cars. Plus the fact that just because the software says it is one thing, doesn't necessarily mean that that is the fault.
Another example, on injected scooters, the fuel pressure has to be around the 150psi mark, or above the piston compression ratio. How many home mechanics have the correct tool to measure fuel pressure? Do you go and buy the tool just in case?
I know someone who had the Peugeot Jetforce that was playing up. He took it to the dealer for a diagnostic and it turned up nothing. I told him to change the filters just to rule them out of the equation and before changing anything else. Guess what, ran like a dream. What looked like a good clean air filter was actually the cause of the problem.

For a small bike, I personally, would stick with a carbed model.


If you have an injected scooter and it is running nice, then enjoy it.

 

aye. there are pros and cons, working for a main dealer i havent thought much about the whole lack of tools thing, those jet force ones are hardly injection anyway, its just loads of trash thrown into a harness and shoved in a stupid frame...... same as the ditech.....
the yamaha system is very good, of all the ones ive serviced, and looked after over the years, i think maybe 9 have had EFI problems, and that was right out the box, so warrenty covered it (the ECU had a fault and the fuel pump wouldnt turn on).

 

HUH???
There are loads of scooters out there with carbs. Injected scooters were a failure from the off.

 

over 50cc and its EFI, pretty much anything else is carb.
carbs work,
EFI works,
both offer about the same fuel consumption for small engines.

 

they dont go wrong, the only injector fault ive ever fixed was an ECU fault, which was a warrenty job anyway

 

yeah they do, EFi's, compressor pumps fail and if the fuel pressure isn't above that of the piston compression the damn things WONT GO

 

ive never seen that, or are you refererring to that peueot/suzuki/piaggio system? because that was just shit, its noty EFI its a freaking nightmare am i right?!

 

Piaggio system, as found on the runner ditech stuff

 

yeah, thats just a massive fail....

 

I am a bit 50/50 on the subject
In therm of injection lets not mix what piaggio did with the 50 cc Ie ditech or pure jet (direct injection) which was pretty good when it was working but when it wasn't was a real pain in the back
The one on the later 125 / 250 / 300 are pretty good
I can add I have seen few Yamaha and Honda injection having issues it is mainly due to the fuel pump packing up some time electric connection to relay or injector
The only problem I would say with injection (not the direct one) you can find piggy back ecu or new ecu to upgrade them but the actual throttle body stay the same size which could end up restricting the engine it s not like a carb when you pass from let say a 12 as standard to up to a 32mm
But newer bike are mostly injection now days and there would come a point were a new bike won't have carbs due to environment rules like the two stroke might end up dying for good eventually
The good point is that injection keep on adapting with the engine needs so no rejetting due to cooler air or different altitude
But you need specific tooling to fix it and even with the correct diagnostic equipment (game boy) it is difficult to make sure that it is the exact problem
The carb is more tunable , easy to replace , to clean but you have to know what you are doing as if you get it wrong that will cost you the engine and it will need tweaking eventually with weather change
I which my tmax was injection and my agility 125 as a bigger carb fitted
Injection engine tend to be more smooth and torquier across the all rev range

 

I've had fuel injected bike and car engines for many years and never had a problem, if your fuel pump dies you are screwed whatever delivery system you have. IMHO if you're not a spanner person injection is your best bet by far.
From what I've been told as of next year all EU registered bikes and scooters will be injected anyway, and anything of 125cc and above must have ABS.