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scott.n
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Need advice...

Post by scott.n » Sat Oct 16, 2010 5:51 am

Hi all, i have been told later model KR's had a powervalve system, did it make much power difference? Can anyone help me source the parts to upgrade to these?. Is it possible (without too much difficulty) to fit larger carbs?, say, off a KX? :idea:

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Luders
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Post by Luders » Sat Oct 16, 2010 7:49 am

Firstly, what bike do you have?

The KR-1 and 1S had power valves, but you can't add these to a KR.

Power valves do make a significant difference to power delivery and performance of the 1 and 1S.

Carbs can be upgraded, but we need to understand the context and rationale of what you are planning and on which bike.

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Post by scott.n » Sat Oct 16, 2010 8:06 am

Luders wrote:Firstly, what bike do you have?

The KR-1 and 1S had power valves, but you can't add these to a KR.

Power valves do make a significant difference to power delivery and performance of the 1 and 1S.

Carbs can be upgraded, but we need to understand the context and rationale of what you are planning and on which bike.
Yeah i have a KR1, but i'm talking about an 85 model KR250, apparently kawasaki released an S model, with powervalves! I'm considering buying an 85 KR, just wondering what can be done (if anything) to increase power, because the KR1 models are easily beefed up! I'm not going to race, just like a good run though the hills when i get a chance! After buying an aprilia and hitting the hills, the taste came back!! So i restored my 91 RGV, got hold of a KR1... going to need a bigger garage!!! Two strokes rule!! :D

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Luders
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Post by Luders » Sat Oct 16, 2010 9:37 am

Sorry it's a bit early here and wasn't fully awake when I replied to your original post.

There was a power valve model, take a look at this topic...

viewtopic.php?t=197

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ScottaKR
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Post by ScottaKR » Sat Oct 16, 2010 4:34 pm

Hi Scott,
The parts to upgrade to the S model engine specs are VERY hard to get, even our resident Tandem Twin guru Tim (AKA Strokerboy) has only managed to get about half of the bits needed.
If your just after some extra power to make your weekend ride a bit more enjoyable, your probably better off getting the combustion chambers optimised (mainly the squish band), some port-work done, some good pipes, or perhaps all three.
As for fitting bigger carbs, youll have to make new manifold adaptors and carb to airbox pipes, and use something like the RGV Mikuni's which are a similar style (angled throat) but are 34mm or so. At one point I was trying to sort out a 300cc conversion, but I never got past the basics, but I think it had potential.
In short, there's a lot more potential to be had out of these little things than was realised by Kawasaki, even in when they made the S version, and a good tuner should be able to release some of that potential for you.
KR250 Tandem Twin (Naked) :mrgreen:
KR1 Red/White
KR1S Track Bike (has been put on hold for now)
ZXR750 H1 (Winter project)

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StrokerBoy
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Post by StrokerBoy » Mon Oct 18, 2010 2:09 pm

Yeah, I've managed to get all the S bits apart from the control box but haven't done anything with them yet. :roll:

As ScottaKR said, if you're trying to pep-up your standard KR then that's not the best approach anyway. The KVSS powervalves were all about midrange rather than any extra top-end. You should be able to apply conventional tuning knowledge to get more out of one, there'll be decent gains I reckon but it'll be a bit more work than a simple reed-valve parallel-twin. The factory issued a KR250 tuning manual for racers but I've not managed to get hold of a copy yet.
Kawasaki KR250 Tandem Twin (x4) & KS-II 80,
Yamaha RD350LC,
Suzuki GSX-R750RK & RB50 Gag.

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Post by scott.n » Tue Oct 19, 2010 1:23 am

StrokerBoy wrote:Yeah, I've managed to get all the S bits apart from the control box but haven't done anything with them yet. :roll:

As ScottaKR said, if you're trying to pep-up your standard KR then that's not the best approach anyway. The KVSS powervalves were all about midrange rather than any extra top-end. You should be able to apply conventional tuning knowledge to get more out of one, there'll be decent gains I reckon but it'll be a bit more work than a simple reed-valve parallel-twin. The factory issued a KR250 tuning manual for racers but I've not managed to get hold of a copy yet.
That manual would be sweet, i'll try to track one down, cheers :D
"There is no substitute for a well tuned two-stroke"

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Post by TwoStroke Institute » Sun Oct 24, 2010 10:45 pm

The S looks to be just a KIPS resonator, A Zeeltronic or Ignitech will power that no problems.

The KR has some serious potential in it, Changing the disc timing will give a big top end kick.There is a lot you can do to the ports. All of which will give far to much HP for the frame to handle
crochet & croquet

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StrokerBoy
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Post by StrokerBoy » Wed Oct 27, 2010 1:58 pm

TwoStroke Institute wrote:All of which will give far to much HP for the frame to handle
So, exactly the right amount then ? :lol: I miss my GSX-R1100... :cry:
Kawasaki KR250 Tandem Twin (x4) & KS-II 80,
Yamaha RD350LC,
Suzuki GSX-R750RK & RB50 Gag.

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Post by TwoStroke Institute » Sat Oct 30, 2010 6:50 am

:D
Would like to see a tricked KR in a KR-1/RGV/NSR/TZR/RS/TZ frame would make an awesome track bike.
crochet & croquet

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