A pic from the latest Moto Gp test

[DJ Down Under]

The latest test is at Catalunya...here's the Suzuki guys..er..I mean galls....I like John Hopkins seat warmers.

It all starts soon...I can't wait...Rnd 1 - Jerez (Mar 26)...that's next week...:eusa_clap:

DJ

http://www.mcnews.com.au/motorcycleracing2006/motogp/mar/catalunya_mar3-5/gallery_g/images/pit_girls.jpg

[Dallara]

Well, it took me quite a while 'cuz I kept getting distracted by John Hopkins' new team manager and chief engineer shown above...

But I finally did get around to making note...

Am I the only whose noticed THREE sparate levers on the left handlebar?

I've seen a bunch of the bikes with two, with the second most often being an actuator for the rear brake via the bar, but's what the third lever in the pic for?

(if you look carefully you will see there is the clutch lever, a trigger-finger lever right next to it, and then appearing literally above the grip is a third)


http://r1150r.smugmug.com/photos/60117348-O.jpg


Anybody have a good clue?

Thanks!

Allan (Dallara - NACD)

ps - Wonderful pic, DJ

[supermotoC]

rear brake lever - Many MotoGP riders use them now, as do World Supermoto racers. You get a mini master cyclinder & you don't lose the brake pedal.
The trigger lever is the brake lever - the "other" lever (I think) is an optical illusion of cabling (electronic?) running down the frame spar.

[DarthRider]

Don't know about that but the black "adjuster knob" looking thing is just that...for take up on the front brake lever on the fly.

Dave

[DJ Down Under]

Could it be a front/rear bias thingie..?

Also...have you guys seen this little Rossi vid...it sure gets me excited..:045: ...http://www.vsocial.com/video/?d=18178

also....I just finished watching the A1 race from Laguna last w/e and there was snow on the sides of the track...geees..I couldn't believe it.

Was I seeing things?

btw..that extra lever has been around a long time......here 'tis

http://members.optusnet.com.au/~djp1/mypic2207.JPG

[Dallara]

Collyer...

I know one is a rear brake lever, as I said in my other post... And I most certainly could be mistaken in there being a third lever.

Hell, I used to race two-stroke flat-trackers when we had a second lever on the clutch side. It was for a compression release. It was used for slowing into turns back when rear brakes were outlawed by the AMA on dirt trackers.

DJ...

Ya' know, DJ - You got me to thinking. It was Mick Doohan who introduced the left-side rear-brake lever to GP racing. Since he was from the smae part of the world as Burt Munroe I wonder if that's where he got the idea!

Cheers!

Allan (Dallara - NACD)

[supermotoC]

I know one is a rear brake lever, as I said in my other post... And I most certainly could be mistaken in there being a third lever.

DOH! Missed that part. Compression release? Maybe - my Duke II has one for kick starting - but lets hope NO ONE kickstarts one of those monsters. Maybe a slipper clutch engage-disengage? Possibly a parachute release system?

Seriously, it may be a measurement tool for headshake or ????

[Dallara]

It ain't gonna' be no compression release on a four-stroke GP bike...

Compression releases on four-strokes are used to assist starting, and since they are starting MotoGP bikes with external starter which have absolutely no problem spinning those engines over there isn't a need for a compression release of any kind... and certainly not on four- and five-cylinder engines.

Only one TWO-STROKE motorcycle engine family ever used a compression release for starting purposes... Some 400cc and 501cc square-barreled Maico's. They located a small compression release in the rear of the cylinder half-way up the cylinder higher than the top of the exhaust ports. When actuated this had the effect of reducing the compression ratio by half ot make them easier to kick over. As soon as the engine lit you simply released the lever and *bang* the engine was running at full power capability. Worked like a charm, and I always wondered why no one else used such a system on big, open-class two-stroke singles...

Compression releases were used on TWO-STROKE flat-trackers as a braking mechanism. At one time brakes of any kind were outlawed by the AMA on flat-trackers. The AMA felt that someone applying brakes entering a short track (1/4 mile), half-mile, or mile dirt oval corner would cause a huge pile-up, and dirt trackers were supposed to know how to slow down by *pitchin' the bike sideways*... However, when TWO-STROKE 250cc singles started being run in the class it was quickly discovered that a TWO-STROKE did not have the engine braking that the four-stroke Harley/Aermacchi Sprints and Triumph/BSA four-stroke singles, and as such they were hard to *pitch-off* on corner entry. Two-strokes don't have near the amount of mechanical parts whizzing and whirring around as four-strokes, and when you chop the throttle on a four-stroke it loses revs and slows down right now. TWO-STROKES, OTOH, not only don't slow down, but because of their pumping characteristics actually maintain a small bit of drive when the throttle's closed. Add to that the flywheel effect of the rear wheel easily overcoming the mechanical friction of the two-cycle and the damn things don't feel like they slow down at all...

Enter the compression release, which was no more than a tiny four-stroke style poppet valve with an external spring hooked to a cable and a two-fingered lever just below the clutch lever. When this lever was pulled and the little valve opened it forced the rear wheel to try and pump a large volume of air through a little, bitty hole, which slowed everthing down right quick, and added four-stroke-like engine braking drag to the TWO-STROKE singles. Made a damn distinctive noise, too... Which is almost impossible to describe... a sort of BZZZZZZZZZZZZZT-that-that-that-that-that-brrrrrrrrrrrrrrrrrrrrrrrr... and they dumped tons of two-cycle oil and fuel mix all over the top of the cylinder head externally, so the engine looked all greasy after a heat.

They were fun to use, effective, and dead simple and reliable. They were spark-plug sized, and installing one was as easy as drilling a hole, tapping it for threads, and screwing in the valve. At one time they so effective and so common that some manufacturers started delivering the engines with a hole already drilled and tapped and with a plug in it that you could remove and install your compression release.

Okay, enough about old flat-tracking compression releases...

Back to your regularly scheduled programming.

Cheers!

Allan (Dallara - NACD)

[Bones]

I could have sworn I either read about or heard about compression releases for four stroke singles to ease starting (dirt bikes), but perhaps I am mistaken. And I thought I saw a similar thing on a four stroke single KTM recently, but I wasn't really studying it.

Dallara, any ideas what those are?

Jeff

[Dallara]

Bones...

From my post immediately preceding yours...




Compression releases on four-strokes are used to assist starting...



Yes, Bones. Compression releases on four-stroke singles have been used for decades to assist starting. First used to allow rolling the engine over just past TDC with little effort or chance of kickback... Then the compression release was closed and the rider had a full engine rotation to build up flywheel momentum and inertia before a big single tried to light its fuse. Let the rider get some momentum on the way down, too, so if the engine did decide to bite back he was less likely to have body parts damaged.

Later all sorts of *automatic* versions of this type of compression release were developed by the Japs to try and aid starting. Honda, for instance, tried no less than about four completely different designs on it's XR-500's, 600's, and 650's. One even had the valve opened into a small plenum chamber to effectively increase compustion chamber volume - i.e. lower the total overall compression ratio (this was used on the early RFVC beginning in 1983, but was quickly superceded by another system within two or three model years).

Many four-stroke singles still come with compression releases, but very few with automatic set-up's any longer... primarily because of the gain in acceptance for electric starters even on dirt bikes. BTW, compression releases can also be used on four-stroke singles to clear a flooded combustion chamber... And not just big four-stroke singles used compression releases. Again, Honda used various types of automatic compression releases all the way down to 185cc two-valve singles.

Okay, now back to your regularly scheduled programming...

So, DJ... Ya; think that Suzuki can get back in the hunt for a MotoGP win this season?

Cheers!

Allan (Dallara - NACD)

[DJ Down Under]

So, DJ... Ya; think that Suzuki can get back in the hunt for a MotoGP win this season?


I know it's a long shot..but..this guy could be a real dark horse in Moto Gp this year...and he's an Aussie..:023:

DJ

http://www.mcnews.com.au/motorcycleracing2006/motogp/mar/catalunya_mar3-5/gallery_g/images/pit_vermeulen.jpg