what carb? :rtfm:

Carb a shortend name for Carburetor. Definations below.

A mechanical device found on the intake side of the engine which mixes fuel and air to create the volatile mixture that gets ignited in the engine.

or

Carburetor
A device through which air and fuel are atomized and drawn into the engine. It meters the proper proportions of fuel and air to form a combustible mixture and varies the ratio according to the engine operation.
OK I am an old g~t but a throttle Body is a Carburetor whether your feul metering is controlled by an electronic injector, or a mechanical needle/Jet.

:occasion14::occasion14::occasion14::rant2:

A few years back I was looking for a cheap XTX air box, I was going to gut both chambers & fit a pod filter off a Raptor, the uprated pod filters.

I am still looking for a cheap air box.

I my world a throttle body & a carby are to very different things.

I conceed :smile[2]:. But you know what I mean, we have the same problem with my Sons WR250F (and it does have a carb). All the restrictions are arround the Air Box having to wrap around the Monoshock.

Just had another thought, I recall some of the Sports bikes (cannot remember which one) used to have ram air, the same as the F1 cars of a few year ago, would you be able to use that approach to get a positive air preasure into the Air box?

You usually need a air speed over 180kph before you get any ram air effect.

I do agree the XTX & R have a poor air box design.

Ok I guess we are not normally at those speeds to get the benefit...:fairy:

I recall but not where at the moment that someone had made an effective Electric turbo charger that uses less electricity HP loading than the HP gain it gives. I will try to think where I say it but it was likly to be in www.Gizmag.com, I will check and see. :3chat:

Found it http://www.gizmag.com/electric-super...er-boost/9364/. They called it an electric supercharger.

Hi Kenny,

Great to have another Guru on the forum. Like many others, I am keen on extracting more power from my engine but (and again like many others) am not as technically inclined as yourself, Kev and Freez on this forum. Therefore, it would be great if you could consider "packaging" a power-up sollution that makes it as clear as possible what is required in terms of cost and effort, what the expected (or better promised) gains will be and critically - what the downside / risk is to engine life and reliability.

If you are able to do this - it would make is wonderfully easy to decided on what option best suits my (and I presume others) requirements.

I for one am really looking forward to what you can come up with.

Cheers

First, let me thank you for the compliment! To be grouped with the likes of Kev and Freez is quite an honor! I hope to earn the reputation.

Okay, the first thing on the agenda is to get everyone in a different mindset. So here goes...... This engine design is tested and proven in the Raptor market as an absolute dead reliable engine. The are no real inherent weaknesses. Anything that would be considered a weakness is readily replaced by stronger aftermarket parts. The only real failure I have seen is the factory piston(in race conditions), and occasional cylinder wear. This is few and far between in extreme conditions, on very high hour engines.

If you watch the Raptor forums and realize that there are hundreds,if not thousands of modded Raptors out there......the fact that everyone is shocked at the occasional catastrophic failure says a lot. We have guys routinely spraying nitrous without drama. I have a half dozen or so 70+ horsepower stock bore engines getting the snot beat out of them regularly without issue. These engines rely on a factory rotating assembly and plated cylinder. We are working on a new cam which should put us at 80 hp on the same builds. We are only concerning ourselves with specific power output since durability is never really an obstacle. Enough said.

That leaves us to power output, which there are many weaknesses in factory form because of production compromises. Almost anything you do to this motor is worth power, and that part in return will add cumulative gains as the build gets more aggressive. For example, a good performance oriented valve job alone can be worth a stunning 30 CFM gain (@28"). Our CNC ported head is worth over 100 CFM of improvement. This will bring about the obvious question of port velocity. This is not your average motorcycle engine. This engine has a rod/stroke ratio of 1.6:1 and lack of velocity is not a problem, as a matter of fact, we need to add runner volume. I will go into my design theories at a later date. At the moment I need to get a cam and supporting hardware so I can design and start producing the parts for these......Then we can get a couple of different dyno proven packages together.:028:

Kenny my offer still stands if you want to borrow my complete standard XTX cam, I will post it over to you.

Otherwise, I am sure I will find you one that you can buy, if you want to go that way.

We have one major problem on the Xt's that you don't have to worry about on the Raptors which could put a damper on the engine mods we can do.

The Xt's rev limiter kicks in at 7200 RPM, where the raptor spins all the way till 9000 RPM.

At this stage, we are not sure if a raptor's ignition module from dynojet (powercommander) or the Dynatek ignition will sort out the problem.

The Xt also run coded keys and more advance ECU's with anti theft protection that the raptor don't and if you cannot get the RPM limiter extended, then even the plain old stage 2 or 3 Hotcams become useless on the XT as you cannot reach the RPM peak those cams are designed for, let alone a special high RPM cams with major port work added.

Also, and this is maybe useless info, but I did some spot checks with just some basic tools and the Xt�s cam (lobe high and width) is closer to a Grizzly 700 stock cam than the 700 raptor�s stock cam. I would not be surprised if Yamaha used the same type of cam setup for both.

Also, the Xt does not suffer from the same ignition mapping problems as the raptors, so if we can sort out the limiter problem, we can do some major work on the XT�s