Polaris reeds

[Suzukidave]

Hi Richard after you had a chance to look over the parts i sent you what did you think of running the reeds that way .

[tz375]

Hi Dave,
I love what you did, but there is no way I can see to make that work. 50% or more of the reed area faces straight into the water jacket. I need to play with it some more to mock up possible flow paths.

It's quite possible that I can rearrange water passages back there where they don't do much.

[Suzukidave]

My plan was to machine in just a bit further and weld the boxes right to the back of the aluminum surrounding the bore , then open up a nice big lower port like i did to the other reed block and a nice boost port or 2 .This would have worked better with the Arctic Cat 6 petal reeds though i must admit . It does get the reeds in past the stud openings nicely though

[ja-moo]

Sorry if I posted this before, but you can get carried away with reed sizes, and go backwards on motors not designed for them. Bigger is not always the "best".

My comparitively tiny stage 1 reed conversion for the H2's (750) produce over 87 rwhp with only a stage 2 port..........

[tz375]

Good point John, but we need those large reeds to get up over 180 horses at the crank... On the GT motor, smaller reeds start to become an issue at say 120 and Arctic cat reeds will struggle at around 150 or so crank HP.

You can see why we need all that reed area can't you. We're talking Suzuki here. Known for big HP, not some wimpy little H2.

Did I go slightly over the top there?

Realistically, if an RZ can makes say 70HP with stock reeds, then a triple of the same cylinder size should make 105. We're not talking Brett deStoop 200+mph monster motors here. I haven't tried a motor with reeds that are too large. One might speculate that at lower levels of power, they might not lift as well and that might hurt the bottom end. I don't actually know. In my experience, larger reeds on a motor that is not reed restricted makes little difference. they seem to work OK but maybe are slightly less snappy/responsive.

[ja-moo]

Good point John, but we need those large reeds to get up over 180 horses at the crank... On the GT motor, smaller reeds start to become an issue at say 120 and Arctic cat reeds will struggle at around 150 or so crank HP.

You can see why we need all that reed area can't you. We're talking Suzuki here. Known for big HP, not some wimpy little H2.

Did I go slightly over the top there?

Realistically, if an RZ can makes say 70HP with stock reeds, then a triple of the same cylinder size should make 105. We're not talking Brett deStoop 200+mph monster motors here. I haven't tried a motor with reeds that are too large. One might speculate that at lower levels of power, they might not lift as well and that might hurt the bottom end. I don't actually know. In my experience, larger reeds on a motor that is not reed restricted makes little difference. they seem to work OK but maybe are slightly less snappy/responsive.

Is there a bull around here?..........

The RZ is a much different and much more modern design, so hp capabilities are higher. And I'm sure with some tweaking, high 90's are possible with my little reeds. Just sayin......

The problem with huge reed set-ups is not the reed lift, but the necessary transition taper into the port, plus the added "area" to the crankcases (good is some cases... get it...lol)

And a drag tuner (h2's) just uses a 6 petal reed, and is getting 240 plus crank hp...........

[tz375]

I'll see your 240 and raise...... Just kidding.

Is there a bull? You ask. Well I'm bullish about the potential of a GT750 to make big HP numbers if that's what you mean


240 is a big number from a conventional design. That's impressive, but I suspect it is not exactly close to stock.

Although the H2 is limited in terms of transfer port shape, it at least has two each side for a total of 4 stock per cylinder and the GT has 1 each side pointing way at the back for a nice street cruising performance and the twisted ports restrict exhaust, transfer and intake port shapes. Is that enough excuses or do I need a few more?

Just out of idle curiosity, what sort/size reeds are they using at that level of performance and where do they put the extra ports? I have seen Henry's motor (on KTW) and some of the bolt on boxes plus the SE bikes, but are we talking Ebos by any chance?

[ja-moo]

I'll see your 240 and raise...... Just kidding.

Is there a bull? You ask. Well I'm bullish about the potential of a GT750 to make big HP numbers if that's what you mean




240 is a big number from a conventional design. That's impressive, but I suspect it is not exactly close to stock.

drag racer, stock 64 hp, I would agree.......

Although the H2 is limited in terms of transfer port shape, it at least has two each side for a total of 4 stock per cylinder and the GT has 1 each side pointing way at the back for a nice street cruising performance and the twisted ports restrict exhaust, transfer and intake port shapes. Is that enough excuses or do I need a few more?

You have a long path, and mine longer, a 250 triple roadracer....LOL

Just out of idle curiosity, what sort/size reeds are they using at that level of performance and where do they put the extra ports?

I can't say, but Henry's motor is a "sorta" copy ......

I have seen Henry's motor (on KTW) and some of the bolt on boxes plus the SE bikes, but are we talking Ebos by any chance?

No Ebos, good ol American ingenuity!.....

[tz375]

250 triple eh? You need any S1 spares by any chance? I have a complete motor plus spare top end That I picked up cheap that I keep tripping over in the shop. Comes with a free set of instruments and seat hump. Perfect for that Cafe Racer project ( can't believe how heavy that thing is, but I digress).

It's all junk - I mean great stuff. For the right price I could be persuaded to let it all go to a good home. PM me if you have any interest in a "spares package".

I could drop it off with Randy Illg if you are ordering an S1R frame kit to go with it.

I'll have to drag (pardon the pun) myself along to at least one of the SE races this year with spy camera in hand to suss this out.

Just to put that 240 in perspective. That's twice the HP Kevin the Hatchet is making and his makes twice what a stock GT makes! That's a steep hill to climb.

[Suzukidave]

For 240hp makes me wonder if its not on happy gas

[ja-moo]

250 triple eh? You need any S1 spares by any chance? I have a complete motor plus spare top end That I picked up cheap that I keep tripping over in the shop. Comes with a free set of instruments and seat hump. Perfect for that Cafe Racer project ( can't believe how heavy that thing is, but I digress).

It's all junk - I mean great stuff. For the right price I could be persuaded to let it all go to a good home. PM me if you have any interest in a "spares package".

I could drop it off with Randy Illg if you are ordering an S1R frame kit to go with it.

I'll have to drag (pardon the pun) myself along to at least one of the SE races this year with spy camera in hand to suss this out.

Just to put that 240 in perspective. That's twice the HP Kevin the Hatchet is making and his makes twice what a stock GT makes! That's a steep hill to climb.

I have 4 motors, but just one set of cylinders. I could use another set.... Are they early or late cylinders?
And the real perspective to me is the GP 500's make the same hp and are streetable........

[ja-moo]

For 240hp makes me wonder if its not on happy gas

The guy is good!, no bottle...............

[tz375]

Early or late? How do I tell? I was planning on boring them to 54mm having them plated and slipping in a set of RS125 pistons for a little cubic advantage, but I already have way too many projects.

If you can point me to the differences in early Vs late, I'll check them for you.

[Suzukidave]

Sorry if I posted this before, but you can get carried away with reed sizes,

John , if you think the Polaris reeds are too much your going to love this

[ja-moo]

I was having lunch with Hurley Wilvert today, (for those tha don't know of him, he was a factory H1R and H2R rider for Kawasaki, and took the "official" 3rd at Daytona in 1974 on a H2R. The scorers actually missed a pit stop by roberts and scored Roberts 2nd.... ) He raced a lot of different bikes, and even a TR750 back in the day. We talk bikes and racing all the time, (of course) and I brought up you guys and all the mods you are doing, especially the reed conversions. He said that was interesting as he was clocked at 180 mph on his TR, and said it was about 120 hp. The bike was pretty much the stock racer, but with some of his personal mods. He said hell, I didn't have any of that stuff back then, and still went pretty fast........