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Author Topic: Higher Rev;s combined Threads.  (Read 3842 times)

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Offline Soos

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Re: Higher Rev;s combined Threads.
« Reply #25 on: October 03, 2009, 05:42:50 pm »
I SOOOOOO miss my rev limiter the dyna2000 unit I was running(before it fried)!!!!!!!!!!!!


The safety factor of high RPM shifting was AWESOME!
Seriously looking into one for my daily rider.




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Offline mlinder

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Re: Higher RPM's allowed when upgrading valve springs?
« Reply #26 on: October 03, 2009, 07:11:21 pm »
If he's shifting at 8k max, though, Jerry, chances of hitting 12k are pretty slim.

You're sure right about that. I was probably TRYING to shift somewhere north of 9000 when I missed 2nd and the tach needle went ballistic. Main thing I was trying to allude to was this is one very expensive thing stronger springs will prevent if he misses a shift at higher rpms. I don't think stronger springs will do much for a stock engine unless you miss a power shift above 9000 as I did.

I was somewhere above 9k at wot when my clutch slipped. 15k at least. Somethign broke, still haven't looked at what, though. It did get me home, though, an hour at 70mph. I'm guessing the spring itself broke.
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Offline KB02

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Re: Higher Rev;s combined Threads.
« Reply #27 on: October 04, 2009, 06:09:09 am »
Mike did Stage II porting on my head and I am running a webcam 41a grind Cam. I also running stock rods so I know that 12k would be a bad idea.  ::) But, yeah, the incidental missed shift is basically why I am wondering.
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Offline mlinder

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Re: Higher Rev;s combined Threads.
« Reply #28 on: October 04, 2009, 08:16:30 am »
I may be wrong, but it is my opinion that the cb750 bottom end (as well as the 650/550/500s) are fine with frequent forrays into the 11k plus area.
Doesn't mean you'll make power there, though.
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Offline MRieck

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Re: Higher Rev;s combined Threads.
« Reply #29 on: October 04, 2009, 08:47:47 am »
I may be wrong, but it is my opinion that the cb750 bottom end (as well as the 650/550/500s) are fine with frequent forrays into the 11k plus area.
Doesn't mean you'll make power there, though.
That's for sure
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Offline turboguzzi

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Re: Higher Rev;s combined Threads.
« Reply #30 on: October 04, 2009, 12:16:24 pm »
If my electronic GSXR tacho is anything to go by (I expect it to be way more precise than a stock mechanical), I often go into 12K in my 500, with some 13K peaks,

that said, you can see how power falls down after the peak (its about 10.5K in rpms). 

therefore, I can hardly believe that a 750 will peak at more than 10K, 9K would be more likely, just to put numbers in the right proportion. Maybe Kos can confirm :-)

Sure, stronger rods are always nice but I rather stop the engine from hitting 15K with the preset 13.5K limiter of my GSXR ignition. Whatever you do to a sohc valve train, you will never match the GSXR valve float ceiling: dohc, bucket followers, small ti valves vs. big valves and springs that need to return valves AND rockers.

 


Offline mec

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Re: Higher Rev;s combined Threads.
« Reply #31 on: October 04, 2009, 12:46:38 pm »
@TG:
do you use stock conrods in your 500?

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Offline turboguzzi

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Re: Higher Rev;s combined Threads.
« Reply #32 on: October 04, 2009, 01:31:45 pm »
MEC, I am on shot-peened stock rods

BTW, had a look at your old dyno charts and you seemed to peak HP at 8800 right?

TG


Offline mec

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Re: Higher Rev;s combined Threads.
« Reply #33 on: October 05, 2009, 12:13:46 am »
that´s right.
1000ccm engine power peak at 8865rpm
stock 836 engine at 8048rpm

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