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Guessing Kawasaki wouldn't like it much.

VForce John got back to me and said to expect a 7/8 hp drop at the wheel by removing the spring. He also does UCU re-flash for $250. If any of you guys that have removed the spring and have the opportunity to race or climb against someone that is stock I'd like to hear the results. I have a friend with two (he and his wife) and might take mine out and race them.
So VForce John says it is alright to remove it? would like to make sure it is safe to remove it before I do so.

Thanks!!
 

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So VForce John says it is alright to remove it? would like to make sure it is safe to remove it before I do so.

Thanks!!
Not John, James from JBS performance recommended it. I believe he’s also coming out with new clutching and spring options for the krx also. Here’s his video showing the rpms with it removed
 

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Discussion Starter #23
VForce John (Johnny Miles) is who I've been asking about it. He says he's working on a clutch mod for the KRX that should put it at 80-84 with 31" tires but requires the ECU mod. I don't need to go that fast but I would like a 10-12% taller gear.
 

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VForce John (Johnny Miles) is who I've been asking about it. He says he's working on a clutch mod for the KRX that should put it at 80-84 with 31" tires but requires the ECU mod. I don't need to go that fast but I would like a 10-12% taller gear.
I need to go that fast😬
 

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Discussion Starter #27
Took the spring out of ours last night. It's easy to do and takes about 30-45 minutes. Like it so far and don't notice a power loss. Certainly not 7/8 hp loss. Will ride over the weekend and report back after road test.
 

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Took the spring out of ours last night. It's easy to do and takes about 30-45 minutes. Like it so far and don't notice a power loss. Certainly not 7/8 hp loss. Will ride over the weekend and report back after road test.
MOKRX, I’ve seen the video from JBS Performance on this and was thinking about giving it a shot. Then I saw your post and had to try it. So, like you said 30 minutes and done, nothing to it. I don’t want to speak to soon but I’ve ran my twice now since removing primary spring and I’m almost certain this was the best move I’ve made. I see no HP loss, in fact I think it runs faster than before. Engine runs noticeably cooler so it’s more comfortable in the cab and engine is quieter with the lower RPMs. Nothing but improved riding experience so far and I’d highly recommend this mod. It’s easy to do, costs nothing, and takes care of several minor issues!
 

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Pulled my primary spring today, like others have found, it really lowers the RPM's in the middle range. Only downside seems to be that engine braking is cut in half seems like.

Approximate RPM's before and after:

speed before after
5 mph 3000 3000
15 mph 4500 4000
20 mph 5000 4500
30 mph 5800 4800
40 mph 6500 5200
50 mph 7000 6500
60 mph 8500 8200


Machine seems much quicker, as it's now "geared lower" and accelerates harder with more tire spin.

All this is with the stock ECU. Sending mine off to Vforce John next week for stage 2 tune. Going to try a gutted cat next too.
 

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Great explanation here what we're accomplishing with the earlier shift points:


The beauty of a CVT is that you can match shiftout RPM to optimum engine RPM, relative to power output. This mod is lowering shiftout RPM somewhere below optimum. It will absolutely rev less at a given speed and be quieter as a result. If this were a 5 speed car and best possible acceleration happens at 6500 RPM, you are effectively shifting at 3500-4000rpm, like you would on a casual drive, vs a drag race. So for a casual ride it is easy to see why folks like this. It makes the machine quieter and less obtrusive. Here is the downside. 1. Decreasing shiftout RPM reduces belt clamping force. So the likelihood of you slipping/overheating/breaking a belt under load increases. 2. Shifting out well below peak power decreases acceleration/felt power. The engine is making just as much power but if it shifts before you get there, you are only feeling the HP made at that RPM. It may feel the same at part throttle but lined up for a drag race to a stock machine it will be noticeably slower. No idea if you will be happy with it or not, that's a personal question, but that is how a CVT works and what you are doing with this mod.
 

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I wonder how this mod would deal with a tune on the machine. I personally don’t feel a power loss from it but there might be some. Still haven’t found a negative to the spring removal yet.
 

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I was wondering that myself. I don’t have a tune in it so I’d feel much better about putting the spring back in if I ended up not liking this change.
 

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I've put in a couple calls to John but it goes right to voice mail..........was going to ask him just this question.............sending in ECU later this week.
 

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I was wondering that myself. I don’t have a tune in it so I’d feel much better about putting the spring back in if I ended up not liking this change.
I haven’t heard a person say they miss the stock feeling. I’m still on stock tires but I will most likely run 33s at some point. The machine is just so much more enjoyable now. Hoping for an updated secondary spring to take the rpms down even further (as long as it’s still reliable). The krx still seems plenty torqey enough to climb and crawl over anything.
 

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I've put in a couple calls to John but it goes right to voice mail..........was going to ask him just this question.............sending in ECU later this week.
Is it mandatory to run an aftermarket exhaust with a tune? I may be in the minority saying this but I enjoy a somewhat quieter machine, 15 years ago I would say the complete opposite !
 

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Discussion Starter #38
Rocky Heap,
Thanks for giving the before/after rpm/speed figures. I still want to line up with some friends that have these that are stock and see the difference. Our machine (wife's) didn't seem to loose any low end. My wife did several hole shots and thinks it feels about the same. I'll be curious to find out how you like the tune and clutch mods from VForce.
 

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Rocky Heap,
Thanks for giving the before/after rpm/speed figures. I still want to line up with some friends that have these that are stock and see the difference. Our machine (wife's) didn't seem to loose any low end. My wife did several hole shots and thinks it feels about the same. I'll be curious to find out how you like the tune and clutch mods from VForce.
It's exactly the same from a stop. This does nothing until the CVT starts to shift out around 10 mph. It also has no effect over about 50. It will noticed rolling along with a another KRX and both getting on it the same time. This is why people like this mod, it lowers cruising RPM with no ill effects at top or bottom.
 
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