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SyntheticReality said:
What would installing Muzzys adjustable cam sprockets do? Increase hp? if so, how much?
What they would do is give you a better ability to adjust the timing of the cams. Increase horsepower? Depending on the state of tune your bike is in, you MAY gain about 2 horsepower.

BTW : Go here... www.redmonkey.com/7r

Search around and read the "Performance" section. Lots more info there then just asking minor questions concerning miniscule possible gains in horsepower by slapping on this and that part. You want REAL power from her? Either install a 94 to 97 ZX-9R engine, get the crank and rods from a 93-95 ZX-7R engine and stroke it out (like I did), install N2O (like I may :lol ), or get a different bike. May not be the answer you are looking for, but the facts are the facts. We ride antiquated, under-powered, heavy-ass bikes.

What year ZX-7R do you own anyway? You have no info listed for it.
 

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Discussion Starter #3
It's a '99 Why would a '97 engine with a 95 crank be more powerful? How much HP do you push? And I really don't know what it means to stroke it out. Wasn't the engine the same from 96-03?
 

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Some times due to factory tolerences the cams could be off 2-3 degrees. Did you ever wonder why one bike may run harder than yours. Degreeing the cams will allow you to
adjust them to the exact factory specs OR you can move the torque curve up or down in the rpm range by retarding or advancing the cam timing. If you have done any machine work--- RE: surfacing block or the head surface it should degreeded
 

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SyntheticReality said:
It's a '99 Why would a '97 engine with a 95 crank be more powerful? How much HP do you push? And I really don't know what it means to stroke it out. Wasn't the engine the same from 96-03?
OK, here we go. Ready ?

Adding the connecting rods and crankshaft from the 93 to 95 ZX-7R's to a 96 to 2003 ZX-7's engine would increase the displacement of that engine to 850 cc's. The reason ? The engines from 93-95 were still 749 cc's, BUT the architecture of their design was that the pistons (bore) was smaller in relation to the length of the connecting rods. So it was a considered a "Long Stroke" engine.

For the 96-03 engines, Kwak changed them to a "Short Stroke" setup to gain higher RPM horsepower, and to try to catch up with Suzuki (which they failed miserably at, I may add). The pistons (bore) was b***** than the 93-95, yet the connecting rods were shorter, still yielding 749 cc's of displacement.

Now savvy racer types soon realized that most Kwak parts (and most other manufacturer's as well) are modular. Meaning that footpegs that fit the 95 ZX-6R's also fit the 03 ZX-7R's and 98 ZX-9R's. Sooooooooooo...Adding those parts to the newer engine worked out lovely.

It's a bolt in affair that yields about 138 to 145 Rear Wheel Horsepower, and 85 ft #'s of torque, depending on camshaft and tuning.
 

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toddman35 said:
How does the stroker kit effect the top end on the bike? I would imagine that you couldn't rev it up as high, but would like to know for sure.
Top end powerband is reduced to approximately 11,500 RPM. That's 1,000 RPM less than it was before it was stroked. So the power gained DEFINATELY offsets the negligable loss in "Top end."
 

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Discussion Starter #9
So all you have to do is bolt in the lower end from the older model and you have a stroker? no other work required? I'd like a detailed explaination of what has to be done. I am very interested in doing it.
 

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toddman35 said:
Thats not bad at all. As long as we're off topic still, what kind of rwhp numbers are stock bikes putting down? I believe they are rated at ~106 crank hp, but I have no idea what kind of drivetrain losses bikes have.
Actually Todd, the ZX-7R's are rated at 125 crankshaft HP. The result is about 106 to 110 rear wheel. If the bikes made @ 106 at the crank, we'd put down about 85 to the rear...YIKES !!!
 

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ZX7ROU812 said:
Actually Todd, the ZX-7R's are rated at 125 crankshaft HP. The result is about 106 to 110 rear wheel. If the bikes made @ 106 at the crank, we'd put down about 85 to the rear...YIKES !!!
Ahh, as you can see I'm new to the 7r scene. :D Is there a common drivetrain loss % for these bikes? It seems like 15% is fairly accurate. :dunno
 

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Now I know where I was misled. I was looking at the redmonkey site and under the specs they've got the following listed...

Claimed Power (Crank) 123 bhp @11,500rpm
Claimed Power (Rear Wheel) 109 bhp @11,500rpm

I was under the assumption that bhp was always brake hp, IE at the crank. I must have misread it.
 

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The stroker kit sounds interesting, however, do the stock 38mm carbs bottleneck the larger engine, and have you dynoed your bike yet?
 

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Zippy said:
The stroker kit sounds interesting, however, do the stock 38mm carbs bottleneck the larger engine, and have you dynoed your bike yet?
Stock sized carbs are are on my bike Zip. I just messed around with the fueling settings. If anything, the 96-03 ZX-7R's should have come with 36 mm carbs ! They're too big for the 749.

Last time she was dyno'ed she laid down a 138 rear wheel HP run. That day, the dyno was being optimistic by about 5 HP I think, and I didn't have her dialed in 100 % (was a little lean on the mains). So i figure those two facts wash each other out. So I just say about 138 !
 

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toddman35 said:
Yeah, but Bhp is at the crank correct? At least I've got a some what reasonable excuse - I think. :D

Yep.

BHP is NOT RWHP. It's power measured on an engine dyno, not a chassis dyno.

Also keep in mind when Manufacturers list the "Dry Weight" of their bikes, there are NO liquids in it. NONE ! No fuel, no oil, no coolant, no brake fliud, no fluids in the forks and shocks. NADA, ZIP, ZERO, ZILCH ! BONE dry !
 

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Discussion Starter #18
So where can I get a walkthrough of how to build a stroker and a list of parts I need? How much will it cost me if I do the labor myself?
 

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ZX7ROU812 said:
Stock sized carbs are are on my bike Zip. I just messed around with the fueling settings. If anything, the 96-03 ZX-7R's should have come with 36 mm carbs ! They're too big for the 749.

Last time she was dyno'ed she laid down a 138 rear wheel HP run. That day, the dyno was being optimistic by about 5 HP I think, and I didn't have her dialed in 100 % (was a little lean on the mains). So i figure those two facts wash each other out. So I just say about 138 !
Nah, all the specs sheets I've seen have them listed as 38mm CVs, it might depend on where you're measuring.
138 is Damn impressive. I imagine your 7 moves OUT. Given the new weight/power ratio, it's competitive with the new line of 600 SS bikes.
 

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Zippy said:
Nah, all the specs sheets I've seen have them listed as 38mm CVs, it might depend on where you're measuring.
138 is Damn impressive. I imagine your 7 moves OUT. Given the new weight/power ratio, it's competitive with the new line of 600 SS bikes.
They are 38mm CV's. I'm saying they SHOULD have been 36's, as the 38's are actually TOO big for the stock engine, as anyone who has jetted the bike can attest to the pain in the ass they are to set up correctly. ALWAYS too rich somewhere in the powerband !

Yeah, she moves out pretty good :) . 600's ? They have NO chance. Even the new 636 ZX-6R's and GSX-R 600's. I have friends with each. I TROUNCE them. The only bikes I can't hang with are the newest crops of the liter bikes. My bike is faster than my friend's 2003 GSX-R 750. Now whether it's the bike or the rider, I'm not sure. But a win is a win... :lol

And given the fact I've replaced all the heaviest items on the bike (Titanium exhaust, no emmissions, lighter bolts, carbon air ducts, etc), it SHOULD weigh CONSIDERABLY less than a stocker. So the power/weight ratio should be nice.
 
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