GT750 reed intake idea's

Buffalo-guy · Post by **Buffalo-guy** » Fri Dec 11, 2009 3:32 pm

I have sent Durgam (Kris) an AC reed cage and intake manifold as a guage to build with. Hopefully it gets there soon. Merry Christmas all!!! Am I being politically incorrect here? Tough!
Fred

Suzukidave · Post by **Suzukidave** » Fri Dec 11, 2009 5:27 pm

Thanx Fred and Merry Christmas is good in my book

Post by **Suzsmokeyallan** » Fri Dec 11, 2009 8:05 pm

Merry Christmas is the way to go for me as well..................

TLRam1 · Post by **TLRam1** » Fri Dec 11, 2009 9:09 pm

Merry Christmas!!!!!! works for me, why should someone be able to take that away...

durgam · Post by **durgam** » Sun Dec 20, 2009 6:29 pm

Fred, post office tried delivery on thursday and friday, but nobody was home. Ill have to wait till tuesday to pick up the package.

Oh well, Im off work till after the new year, But ive got the proper software here at home, so I can get right to work on it.

tz375 · Post by **tz375** » Sun Dec 20, 2009 6:48 pm

I have an Arctic Cat top case and reed block from Kevin. They are all measured up and I'm working though the block sizes and angles. the castings are really nice and the reed blocks are fine for a street motor.

Suzukidave · Post by **Suzukidave** » Sun Dec 20, 2009 7:03 pm

Richard , what size Cat did the case come from as the 900~1000cc Cats use the same size ( looking ) reeds and the engine is rated at 180+ HP .

tz375 · Post by **tz375** » Sun Dec 20, 2009 9:47 pm

No idea Dave,

I'll dial in some Arctic Cat type bore and Stroke dimensions and see how that works out. Suffice it to say that I'm a long way short of those sorts of numbers.

But the GT has a lot less port area than an Arctic Cat triple, so that's not a great surprise.

Maybe I need to throw out all the bike sized exhausts I ran through so far and start to look at those fatties they use on sleds

Suzukidave · Post by **Suzukidave** » Mon Dec 21, 2009 11:48 am

Soon as my lotto money comes in i am going to have a complete block recast with all the right stuff

tz375 · Post by **tz375** » Mon Dec 21, 2009 1:14 pm

Sounds like my plan - now where did I put that old Lotto ticket?

I did check on line and it seems that Arctic cat did the same thing as Polaris and used the same reeds on all of their triples.

Boyeson and V-Force are listed for ZRT 600, 800 and 1000cc Thundercat.

The 'cat has 64.6mm stroke and 81mm bore, so it is capable of sucking in all the air and fuel it needs. A quick tweak of the numbers last night with those reeds I was able to get to 145 with more to come, but that's a much larger piston and it runs at much higher revs.

I'll have to design a new pipe now to explore power at the 9k and above range, but so far I'm not seeing any advantage for a race motor. The differences below 5500 are quite staggering though.

Suzukidave · Post by **Suzukidave** » Mon Dec 21, 2009 4:24 pm

Yeah .. thats what most say that have added reeds to there performance motors , that they got back a bunch of the lost mid range grunt . Now that GS tranny might pay off for Kevin in that 1 ~2 shift so the engine doesnt drop out of the sweet spot the more he narrows the power band for more HP .

tz375 · Post by **tz375** » Mon Dec 21, 2009 4:51 pm

What you talkin bout - narrow band...

He'll have over 120hp for at least a couple of hundred revs.

Be good if we could eh!

That's a good point about the GS box though. It won't drop into quite such a large hole between gears. Can it handle all that power though?

I'd like to see a straight cut primary set with the box spinning faster, but that's just me.

Of course I still can't fit any size of reed boxes between the new frame rails I added, so I have to rethink the frame on the monoshocked bike.

Suzukidave · Post by **Suzukidave** » Mon Dec 21, 2009 6:10 pm

I would think the GS box thats back cut while hes swaping it out would be at least as strong as a GT box . As much as they raced the GS bikes in the day they were the big guns in town i bet there are some drag trannys floating around out there ?

Suzukidave · Post by **Suzukidave** » Mon Dec 21, 2009 8:15 pm

Yeah .. the Arctic Cats do have a bit more transfer area

tz375 · Post by **tz375** » Mon Dec 21, 2009 9:45 pm

Notice how small that rear boost port is though. It's similar to the XCR Polaris at around 18mm wide. The main and auxiliary ports are quite large and similar sizes, so that's a huge advantage over a GT cylinder.

The boost ports do help but they also push a lot of mixture straight out the exhaust if they are too large. That means that we can't make up for our lack of transfer area by adding huge boost ports unless we are really clever with chamber design.

When i was seraching for something on-line I discovered some 85mm sleeves for a 1098 big bore Thundercat. Hmmm