Help with motor selection

[88workcar]

1. There is no replacement for displacement, NEVER FORGET THAT.

2. The 30lb diff is nothing compaired to the size and power potenial between a 70 and a 90.

3. 70 has 2.33 gearing, 90 has 2.0, 2.33s are for low end power, 2.0 is for speed. You can swap the 90 gear into a 70 housing (and vice - versa) but even modded the 70 will struggle to turn the 2.0 gear. And it has been proven many times that tall gear and low pitch is better for speed than low gear and high pitch.

4. The 70 and the 90 share reed cages, but with the 90 you get bigger pistons bigger carbs.

5. As far as reliability goes, I have s held my 90 at 7400rpm for over 7 miles at one time. I do it regulary. The yammi will take the abuse. Also on a 90 you have detatchable connecting rods, easyier to balance, work on, swap out in case of a failure.

6. The are ways of making a 90 into a 15" motor, takes some work and thought, but has been done many times.

7. Right now I am running a completely stock 90, with just a lightened flywheel. I can turn my big 27 cleaver right at 6000 and run 72mph on gps, STOCK. Do that with those small motors! If I run a smaller pitch it will sometimes go to 6400. When I have a modded powerhead I have spun 7400 and with proping right have been to 78mph, BUT modded gets there a whole lot quicker. I was suppose to make the attemp to break 80mph this year but I have been too busy to even start. I make 2 rides this year thats it.

Go with the 90 you will love it. http://youtu.be/KQyBnDBagdc

[88workcar]

7. Right now I am running a completely stock 90, with just a lightened flywheel. I can turn my big 27 cleaver right at 6000 and run 72mph on gps, STOCK. Do that with those small motors! If I run a smaller pitch it will sometimes go to 6400. When I have a modded powerhead I have spun 7400 and with proping right have been to 78mph, BUT modded gets there a whole lot quicker. I was suppose to make the attemp to break 80mph this year but I have been too busy to even start. I make 2 rides this year thats it.

Go with the 90 you will love it. http://youtu.be/KQyBnDBagdc

I have a correction, Just got a new GPS, I went out and got disappionted. Big wheel, 5900 with STOK motor, 67.6mph. Been two yrs sence I did the bottom, may need a little tlc there. But it is what it is.

[JohnsonM50]

I have a correction, Just got a new GPS, I went out and got disappionted. Big wheel, 5900 with STOK motor, 67.6mph. Been two yrs sence I did the bottom, may need a little tlc there. But it is what it is.

Seems as easy to lose alot of speed as it is hard to gain a little

[Karl Kretzmann]

Here's a Pic of our sponsored ArgoCat in the European Championships.

[88workcar]

Very Nice rig, I would love to have a tunnel. What are the specs on that rig?

Yea M50, and I try hard to be honest about it all. Now I have some new found encouragement to get back to work. Today I ran a 26 cleaver that works out on the slide rule to be a 27p instead, and this is the same set up that I ran at our bogalusa race with only a 20p on it. How fast was I LOL.... Hope Santa sends me a new strong powerhead, I sure miss the good one, I am a long way from 7400rpm.

[JohnsonM50]

Very Nice rig, I would love to have a tunnel. What are the specs on that rig?

Yea M50, and I try hard to be honest about it all. Now I have some new found encouragement to get back to work. Today I ran a 26 cleaver that works out on the slide rule to be a 27p instead, and this is the same set up that I ran at our bogalusa race with only a 20p on it. How fast was I LOL.... Hope Santa sends me a new strong powerhead, I sure miss the good one, I am a long way from 7400rpm.

Agreed, there might be a thrill in pad-n this or that on the rig but not on the #'s

[nate22]

88workcar thanks for posting very helpful and informative post.

Karl Kretzmann your boat look amazing very nice rig, and very fast. I have herd the batboats can get into the low 70s with a worked 90hp but no were near 80mph.

Wow you guys race in 4 meter waves, even 2 meter waves sound undo able for that boat, how did you manage in that mass

Were i'm from the race will get called off in anything like that. I guess we need to grow some balls like you guys