Fuel Injection Discussion, 2T And 4T

[b40rt]

#142 comparing performance, weight.

I have 30 year old carbs that still perform well so replacement cost not really an issue.

[atomant]

All of this just because Dadof2 says EFI is no good for a trials bike This argument is futile because you are not comparing like for like . The only similarity is that they both deliver fuel into an engine. The mechanics are obviously much different and with this comes a whole lot of other parameters to consider. EFI is FAR superior to a carburetor in a sport where you could possibly need a variety of tune-able options to meet the terrain/climate/conditions of a trial on a weekly basis. You can even control how the fuel/air is delivered through a section if you want to.

Weight is not even worth considering as there isn't a rider here who could make use of any advantage of a few grams here or there.

And regards the cost, what about the costs of maintenance? Riders do not take that into consideration - They might like to fettle away in a shed playing with this and that but it all costs ( marriages mostly )

EFI is here to stay and all you will see carbs on in the future is chainsaws/lawnmowers/hedge-cutters and the like !

IMHO

Edited January 28, 2015 by atomant

[dadof2]

If peak power does not mean anything why does the FIM restrict 2T to 1/2 the capacity of 4T?. A 4T may hook up better, this might be because the of the power characteristics, because they have less power or a combination of both.

You cannot compare just the cost of the throttle body, there is the more complex or separate ECU, fuel pump, potentiometer, larger alternator etc.

And No, I did not say EFI is no good for a trials bike. My point is that on a 2T trials bike EFI has not demonstrated any competitive advantage and the added cost and complexity is a disadvantage.

It may be that EFI can never work properly on a 2T because of the residual fuel in the crankcase. It may be that to get the advantages of fuel injection onto a 2T it has to be high pressure direct injection (as on watercraft) but that is a whole different and expensive ball game.

[atomant]

And No, I did not say EFI is no good for a trials bike. My point is that on a 2T trials bike EFI has not demonstrated any competitive advantage and the added cost and complexity is a disadvantage.

Errrr, so it's no good on a trials bike then!

It may be that EFI can never work properly on a 2T because of the residual fuel in the crankcase. It may be that to get the advantages of fuel injection onto a 2T it has to be high pressure direct injection (as on watercraft) but that is a whole different and expensive ball game.

"EFI is working on an OSSA and a VERTIGO.. did I miss something ?

Edited January 28, 2015 by atomant

[0007]

If peak power does not mean anything why does the FIM restrict 2T to 1/2 the capacity of 4T?. A 4T may hook up better, this might be because the of the power characteristics, because they have less power or a combination of both.

You cannot compare just the cost of the throttle body, there is the more complex or separate ECU, fuel pump, potentiometer, larger alternator etc.

And No, I did not say EFI is no good for a trials bike. My point is that on a 2T trials bike EFI has not demonstrated any competitive advantage and the added cost and complexity is a disadvantage.

It may be that EFI can never work properly on a 2T because of the residual fuel in the crankcase. It may be that to get the advantages of fuel injection onto a 2T it has to be high pressure direct injection (as on watercraft) but that is a whole different and expensive ball game.

Well Dad I realize now that you simply cannot grasp the long term value of progress, it's not an insult, I have met your kind before, at some point it probably happens to everyone

here in North America you can race a 250 2t in the 4t class but you wont win anything, you can watch it happen, the 4 strokes killed off the 2 strokes lap time wise even before EFI came about

But this is about EFI, how can You say

"It may be that EFI can never work properly on a 2T because of the residual fuel in the crankcase"

Wha?

EFI is just a cool precise electric carb, no Venturi just electronic fuel delivery, what has that got to do with residual fuel anywhere?

It may be true that it offers no competitive advantage right now, I will give you that, it will not make me ride much better

Let's move along, you can keep your carb but don't try and stop the future from happening

[atomant]

Of course it gives a competitive advantage. You can change the set-up from section to section and even in a section as I just mentioned. It HAS a competitive advantage over a carburetor . Just ask Toni Bou eh ?

Edited January 28, 2015 by atomant

[b40rt]

Well Dad I realize now that you simply cannot grasp the long term value of progress, it's not an insult, I have met your kind before, at some point it probably happens to everyone

here in North America you can race a 250 2t in the 4t class but you wont win anything, you can watch it happen, the 4 strokes killed off the 2 strokes lap time wise even before EFI came about

But this is about EFI, how can You say

"It may be that EFI can never work properly on a 2T because of the residual fuel in the crankcase"

Wha?

EFI is just a cool precise electric carb, no Venturi just electronic fuel delivery, what has that got to do with residual fuel anywhere?

It may be true that it offers no competitive advantage right now, I will give you that, it will not make me ride much better

Let's move along, you can keep your carb but don't try and stop the future from happening

Lambda sensors Edited January 28, 2015 by b40rt

[sectionone]

I'd like to see oil injection come back like the twinshock autolube systems that everyone took off to save weight. You get the advantage of running 100:1 in sections to 20:1 at highway speed.

[dadof2]

I agree the 4 strokes started beating the 2 strokes before EFI, It was as if all the major manufacturers let 2T development stop, perhaps in the expectation of emissions legislation. With regard to lap times the big improvements are due to suspension. When I watch both outdoor and stadium the speed with which the riders get over the bumps is much faster than it used to be, try hitting things like modern suspension does on a 20 year old bike and you would be thrown all over the place. On firm but moist clay type going an 88 CR500 comfortably out accelerates a 2014 Yam 450, same thing on supermoto tyres on a tarmac hillclimb course. Do the same test on a sweeping climb with stutter bumps and the yam leaves the CR for dead.

The reason I think it will be difficult for EFI to work properly on 2T is because the residual fuel in the crankcase breaks the close link between where the fuel is metered and where it burns. EFI is at its best when linked to Lambda, MAF and knock sensors. Lambda sensors will soon become inaccurate because of 2T lube pollution and also the amount of unburnt fuel that passes into the exhaust and burns there rather than in the combustion chamber. It is very difficult to find room for an effective MAF sensor on a trials bike. Having the timing adjusted by knock sensor timing will not give the right power characteristics for trials.

I am not against progress, but what is progress and what do most riders want from the sport?

I remember 100 National karting, used to have entries of 100 + when is was heavily cost restricted, then some said they wanted progress, less cost restriction, more performance, the sport collapsed, lucky to get 20 on the grid.

Same in twin shock MX. started as a bit of fun for lads on cheap old bikes who were not bothered about going as fast as monoshocks could. Then dealers and importers started entering with top line riders on fully restored / tuned bikes. All the lads on the "bangers" gave up and left the big spenders with no one to race nor provide marshals.

New technology especially when accompanied by higher costs does not necessarily progress the sport.

[lotus54]

Sorry- 2stroke EFI works flawlessly.

I have one in my garage.

Have you ever even ridden one?

More complicated? I don't think so, but I find it very rare for people to really understand how a carburetor works. Even more so EFI of any sort.

I'm very much sold for a trials bike.

1. Packaging. Easier to get components in better locations.

2. No fuel leakage/flooding when tipped over (let's not talk about crappy OSSA Explorer fuel cap)

3. Multiple MAPs available. Easy switch to change how the bike runs.

4. Automatically adjusts for temperature and elevation.

5. Better running consistently (just my experience)

I understand those that don't want it. That's ok- but it does work.

[0007]

Conspiracy?

If you recall the YZ 400 was produced to compete in the 250 2 stroke class not open class (so the comparison you pose is Moot) and it wasn't long before no one raced a 2 stroke anymore, I was a service rep for Yamaha when that happened and I can tell you that both the 2T and the 4 T had the same suspension technology

I cannot argue the point of expense, some of this does raise prices, but again, I bet people thought the world was ending with single shocks, and CDI and cartridge forks and Disc brakes and the list goes on

And for the record I like the character of a bike that is imperfect like our current carb bikes but I have no doubt they will get cleaner and smoother and have better fuel economy and last longer with EFI

I don't buy the more expensive thing when your engine lasts 2 or 3 times as long and you don't have to fix it

[johnnyboxer]

All of this just because Dadof2 says EFI is no good for a trials bike This argument is futile because you are not comparing like for like . The only similarity is that they both deliver fuel into an engine. The mechanics are obviously much different and with this comes a whole lot of other parameters to consider. EFI is FAR superior to a carburetor in a sport where you could possibly need a variety of tune-able options to meet the terrain/climate/conditions of a trial on a weekly basis. You can even control how the fuel/air is delivered through a section if you want to.

Weight is not even worth considering as there isn't a rider here who could make use of any advantage of a few grams here or there.

And regards the cost, what about the costs of maintenance? Riders do not take that into consideration - They might like to fettle away in a shed playing with this and that but it all costs ( marriages mostly )

EFI is here to stay and all you will see carbs on in the future is chainsaws/lawnmowers/hedge-cutters and the like !

IMHO

Agreed

EFI is great

All my bikes are EFI now & I would not go back to carbs .....by choice

[dadof2]

As I have already pointed out I have not said EFI is no good for a 2T trials bike so I would appreciate it if people gave up posting this misrepresentation of my view.

[biffsgasgas]

As I have already pointed out I have not said EFI is no good for a 2T trials bike so I would appreciate it if people gave up posting this misrepresentation of my view.

You stated this Dadof2

"EFI clearly has advantages over Carbs regarding emissions,performance and to a lesser extent consumption. But against this EFI has much higher initial cost and complexity. To make EFI work well it needs a MAF sensor. This is fine on cars were there is plenty of room and electrical power. As far as I know neither the 4RT, Ossa or Vertigo has a MAF sensor, relying instead on more compact but less effective pressure sensing. The more you compromise EFI to make it fit a trials bike and reduce costs the less any potential advantage over a carb."

I am confused about your view.

[hrmad]

EFI bikes seem to run though, ossa have even a got a 2 year warranty on theirs and reports from 4rt owners seem to be positive. FI will continue to be developed, hopefully with owner access to diagnostic equipment. A lot of companies still use carbs and you have a lot of choice. So what's the problem?