Cafe Racer prop choice

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04-10-2019 | 09:03 AM

ancho

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From: Merritt Island, FL

Cafe Racer prop choice

Hoping for a little guidance here - thanks in advance.
1991 Cafe Racer, Bravo 1, Currently spinning Bravo 1 4-blade 26P.
Rev limiter on new engines has been set at 5800 but I am barely seeing 5000. Depending on conditions / trim that will get me to low 70s. This is with fresh 550ci motors - dyno sheet below.
Wondering what direction to go in, if any.

04-10-2019 | 09:44 AM

VortechSS

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From: Stilwell, KS

IMO, it sounds like you're pretty well set now. 15% slip and 70mph at 5000 rpm isn't bad. 24s would push you backwards to 70 at 5400ish. Those engines should live a long life turning 5000.

04-10-2019 | 09:48 AM

ancho

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Appreciate the input - thanks!!

04-10-2019 | 01:38 PM

VortechSS

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Thinking about this over lunch, you shouldn't have any problems turning 26s with that kind of power. Might check some other things out to see what the deal is. Assuming drive ratio is 1.5?

04-10-2019 | 01:45 PM

ancho

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Yeah, I posted in the general tech forum as well - sounds like maybe starving for air at top end. Got a few things to look into. And yes, I believe the drives are 1.5

04-10-2019 | 04:56 PM

Wildman_grafix

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I forget do we know for sure they are not messed with?

04-10-2019 | 07:07 PM

ancho

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Quote:

Originally Posted by Wildman_grafix

I forget do we know for sure they are not messed with?

The props? They were cleaned up when the motors were done so I assume they are true to pitch now

Last edited by ancho; 04-12-2019 at 08:02 AM.

04-11-2019 | 08:17 PM

seafordguy

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I would think with that power you could spin 26's to redline easy......

I've had labbed 26's North of 5000 before I rebuilt my motors. Can't comment after the rebuilds unfortunately because I haven't spun them that fast, but I never put out that kind of power....