2nd hand PCIII?

**2wheeljunkie** · 23rd May 2010, 14:32

Originally Posted by Zim_Invader

hate all you want... carbs are brilliant!

hermmm................................

**Zim_Invader** · 23rd May 2010, 14:40

Originally Posted by 2wheeljunkie

hermmm................................

shoosh! .

**Slyer** · 23rd May 2010, 14:43

Fuck carbs right up their fucking arse.

**jono035** · 23rd May 2010, 14:45

Originally Posted by Zim_Invader

hate all you want... carbs are brilliant! if it weren't for them, u'd not have your injection systems! appreciate the foundations of your machine design kiddos. wait, so is it more expensive to dyno tune a carbie? i didn't know that... i thought u could always get around that by just tweaking them as needed. meh. so i've learnt something new.

Sure, and automobiles wouldn't be here if it wasn't for horses and carts, so you should really get one of those instead of your fancy newfangled carbed bike.

With an injected bike, you don't need to tune the bike at all for low/medium throttle because it's running closed loop and self-tuning from the oxygen sensors. For full/high throttle you can do a pull, look at the results, adjust the tuning and repeat with the entire process taking stuff all time. Doing the same thing with a carbed bike requires the carbs to be removed and dismantled.

Carbs don't exactly have a huge amount of positive sides when it comes down to it.

**Slyer** · 23rd May 2010, 14:47

Apart from being cheap.

**2wheeljunkie** · 23rd May 2010, 14:48

zim = 0 , kb = 1.

**jono035** · 23rd May 2010, 15:00

Originally Posted by Slyer

Apart from being cheap.

They aren't though, they're freakin expensive compared to an injection system when you're making em a few hundred thousand at a time...

**reemit** · 23rd May 2010, 15:44

Originally Posted by Slyer

Fuck carbs right up their fucking arse.

Well said that man,

couldn't have explained it any better!

**Zim_Invader** · 23rd May 2010, 15:54

Originally Posted by jono035

Sure, and automobiles wouldn't be here if it wasn't for horses and carts, so you should really get one of those instead of your fancy newfangled carbed bike.

hmmmm.. don't tempt me too much.. imagine popping a wheelie on one of those? lol.

**motorbyclist** · 28th May 2010, 14:49

Originally Posted by Zim_Invader

hate all you want... carbs are brilliant! if it weren't for them, u'd not have your injection systems! .

IIRC, diesel engines had mechanical injection from their very beginning; so is isn't too difficult to imagine a petrol world without carbies....

carbies are a less complex system in that they have lower technological overheads and few moving parts, but rely on a careful balance of several factors (some of which change with temperature and pressure) and are an open loop system, making them prone to "two-stroke-itis" type problems

**Real_Wolf** · 28th May 2010, 15:19

Originally Posted by motorbyclist

IIRC, diesel engines had mechanical injection from their very beginning; so is isn't too difficult to imagine a petrol world without carbies....

carbies are a less complex system in that they have lower technological overheads and few moving parts, but rely on a careful balance of several factors (some of which change with temperature and pressure) and are an open loop system, making them prone to "two-stroke-itis" type problems

Diesel engines need the compression, so carbs would be quite a hassle to design for them.

As for the carbs, this makes me wonder how hard it would be to put in some feedback in the loop to make carbs more reliable

**jono035** · 28th May 2010, 16:16

Originally Posted by Real_Wolf

Diesel engines need the compression, so carbs would be quite a hassle to design for them.

As for the carbs, this makes me wonder how hard it would be to put in some feedback in the loop to make carbs more reliable

I think you've got that backwards...

Diesel engines are simple enough that they don't NEED carbs. The fuel/air mix in a diesel engine doesn't need to be carefully regulated because the diesel burns slowly and there is no danger of pre-ignition due to the diesel self-igniting under pressure. Maintaining that pressure requires both high compression and high manifold pressures, so a butterfly valve can't be used to control the engines power output. It's not that a carbs would be a hassle, it's that they're inappropriate and entirely un-necessary.

As to the problem of a feedback loop, just what exactly are you going to 'feed back' as such? The feedback loop within a injected engine is the oxygen sensor which is inherently an electrical device. To provide the feedback you would then need to electrically control the jet needle height which is basically an over-complicated fuel injector!

**AllanB** · 28th May 2010, 16:28

Meh carbs are old news. Next you'll want to go back to setting a set of points for your timing! Gawd I changed a few of them and used to carry a very small file for the occasional roadside clean! Well over those days now.
Walk up to the bike, key in, push buttom and VAROOOOOMMMMMMMM. No tickling, kicking or cursing.

**jono035** · 28th May 2010, 16:38

Originally Posted by AllanB

Meh carbs are old news. Next you'll want to go back to setting a set of points for your timing! Gawd I changed a few of them and used to carry a very small file for the occasional roadside clean! Well over those days now.
Walk up to the bike, key in, push buttom and VAROOOOOMMMMMMMM. No tickling, kicking or cursing.

There are a few engines out there that don't even use points, they just rely on a magnet passing a coil to generate the spark, can't imagine that's particularly great above a few hundred RPM...