GT750 reed intake idea's

Suzukidave · Post by **Suzukidave** » Mon Dec 21, 2009 9:55 pm

Richard , wouldnt putting that large a bore in the GT block cut into the alrady small transfer passages ?

ja-moo · Post by **ja-moo** » Mon Dec 21, 2009 10:30 pm

tz375 wrote:
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.

You can just raise the boost ports to open first.............

tz375 · Post by **tz375** » Mon Dec 21, 2009 10:32 pm

Yes Dave, it probably would, but it would pull tree stumps straight out of the ground

It wasn't a serious suggestion. More of an idle thought. Though we know that Brett has gone to a much larger bore and his motor reputedly is capable of 200mph, so he has worked out how to get around that problem on his 1000cc motor.

I happened to slip an Arctic Cat ZRT reed cage into an old RM250 barrel and the reeds appear to be the same size. Different bolt patterns but the same size.

On the RM250, the reeds on that year were barrel mounted and the reed cage is in the perfect spot to get good flow into the boost ports and the two rear transfers. Very similar to Tom's GT250 porting job but a smaller boost port I think.

The Arctic Cat by comparison is not so nice. The reeds obscure the boost port and it badly needs a reed spacer to pull them back to improve flow.

durgam · Post by **durgam** » Thu Dec 24, 2009 7:38 pm

Got the goods in the mail on wednesday. Thanks Fred. Ill get to work on the cage right after xmas.

Buffalo-guy · Post by **Buffalo-guy** » Fri Dec 25, 2009 1:00 am

That's great Kris. It is actually 11:58 here, so where you are, it's already Dec 25. Merry Christmas to you and yours, and do enjoy your time off. Have a fabulous 2010. That goes for everyone here on the board. Time for bed. Santa's coming!! Cheers.
Fred

Suzukidave · Post by **Suzukidave** » Fri Jan 01, 2010 11:34 am

Hi Kris , any updates on the custom reed boxes ?

Suzukidave · Post by **Suzukidave** » Mon Jan 11, 2010 5:15 am

durgam · Post by **durgam** » Mon Jan 11, 2010 10:44 am

Ive got a good start on the design. I started later than i wanted too, sorry. How do you guys want to mount these. Stock spigots, or weld???

durgam · Post by **durgam** » Mon Jan 11, 2010 10:52 am

vertical too right?

Angle on the cylinder side?

Post by **Suzsmokeyallan** » Mon Jan 11, 2010 11:22 am

What id like to see is them made so they bolt on from the inside of the reed block onto a plate thats been welded to the back of where the cylinder intakes were.
Also if you could make them so they carry just enough rise when viewed from a side that a set of carbs (type to be decided on) will clear the clutch hump on the right side and allow the carbs to sit nearly level without them having to be tilted forward too much.

durgam · Post by **durgam** » Mon Jan 11, 2010 1:51 pm

Ill do what i can for the clutch hump and what not. Ive got a motor, but its not in a frame and im not exactly sure how it 'sits' in the frame. Does anyone know the lean angle of the motor? From there I can make them more accurate for what you want.

durgam · Post by **durgam** » Mon Jan 11, 2010 2:05 pm

Do you want me to make the plate also?

Post by **Suzsmokeyallan** » Mon Jan 11, 2010 6:42 pm

If you can make a plate to fit across the three cylinders thats even a better deal.
It will save having to look around for a plate when you have the reed boxes made up.
When the engine is mounted in the frame on a stock bike the lettering on the clutch cover (2200cc) is more or less horizontal to the ground.

durgam · Post by **durgam** » Mon Jan 11, 2010 8:24 pm

That helps on the angle situation, thanks Allen.

I can do a single plate. I can do what ever you want. A fully machined plate, a bare plate for you to machine, or a machined plate with these welded to it. I will have to get somebody else to weld it, as im not nearly skilled to weld aluminum.

All this depends on the mounting surface of the cage. Ive got the rest of it done, and modeled up. We just need to come up with a common process to mount these buggers and I can start making them.

Somebody earlier mentioned trying to angle them down to line them up with the port direction. This will help clear the clutch hump, Correct?

durgam · Post by **durgam** » Mon Jan 11, 2010 8:37 pm

I looked through some earlier replies in this post and found the pic of the Kawi cage design. I can Duplicate that to a Tee. With the holes on the inside like you mentioned earlier. They would be small though like a 10-32 or a 5mm if you prefer metric. And bolt to maybe a 5/16's thick plate that can be welded on to the cylinder by you guys. Or all three bolted to a single plate. I can get the spacing from my cylinder unless somebody here already has the info on the tip of their tongue...