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Discussion Starter · #1 ·
The first I heard of bumping the redline up was when I had my ZX10R Derestricted. I think most people were bumping the redline up 500-1000rpms. My bike was a 2012, so people had been doing this without issues for a year before I was having my bike flashed. I was sceptical and decided to bump my redline up 1k rpms and never had any issues.

I've seen guys on this forum bump their H2s redline up 1k rpms and I haven't been able to find anyone having problems with it. The H2 SX SE has a redline of 12k rpms and looks like the power is still building all the way to redline once it's derestricted. So in theory revving a little longer will build more boost and more power. But how do you know how far you can push it?

The H2 SX (SE) has the same valves as the H2 but different springs and cam. The bore and stroke are also the same but the compression is different.
 

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Hmmmmm i had to make this decision recently....for possible 5 bhp raise rev limit to 14,000 rpm. Tuner would'nt unless i begged him not bothered what anyone else says or thinks i dont know exactly the gain theres more cons than pros i feel so i passed on it. Im full stage 2 with 265bhp at rear wheel
 

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14,200 is where the stage 2 stops.The actual limit is about 14,500(where they set it).I don't think Brock's would be raising that if it was gonna damage anything.HOWEVER...he does say...installing this kit(ECU flash and mapping/timing),you need to pay attention to the maintenance schedule of the H2R.It will be similar.But not completely.And it's probably not expected that anyone getting this is gonna be running around up at 14K for any extended time.I know I won't.Gotta use some common sense with this.

"Im full stage 2 with 265bhp at rear wheel"...I'm really curious what mine is making.ZX10R midpipe and CTshort Akra muffler(no DB killer installed).Pretty sure it's well above the factory setup.Haven't been able to ride her since I installed the stage 2 power kit.That's yet to happen...in July.Some of you guys that did this mod,how did yours feel after the install?Could you feel the power difference?Torque?
 

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The other thing that needs considering when increasing the rev' limit is the shape of the power curve.
 

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set 14k for 2015 H2... I think if I sum up all the time I have been over 13 is less than 1 minute... usuarly 1-4 gears I shortshift at about 12-13k just to avoid the TC to detect the front wheel up and cut acceleration.
 

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H2 madness. That all sounds like what my tuner said and what woolich told him but he was not keen on raising rpm. Im glad he did'nt im not that bothered. And as for maintenance i dont think that will help if its gonna go bang then in that red zone is where its gonna happen. I road race so i will never be up there. Mostly average 120-160mph with odd run upto 180'ish.
 

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Yeah...having it raised is kinda,well,'useless'.I don't ride anywhere near that either...Once in a while I'll open her up to that.Rarely.No real point in it.Just extra stress on the motor.Definitely don't want that.

Your speeds sound like mine...yep.I ride like that also.Kinda dangerous actually,but I try and do it safely.Certainly never around traffic.I really think the steering damper works awesome.That's one thing I have confidence in for sure.I know it's helping.Frontend has NEVER gotten squirrely or twitchy in any curve or surface I've ridden.Love it.
 

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Totally agree it is thee best handling bike ive ridden very confidence inspiring weather here is terrible and ive passed police here at 170 on a lunch break. NO i did not stop! Ha ha yeah were all pretty safe here we go out early am. Start at 5 a.m be home for noon or somedays 2pm its quite tiring 8hrs riding fast.
 

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Discussion Starter · #9 ·
I haven't been around this forum for long but I haven't seen anyone have issues with bumping up their redline on the H2 or the Zx10R. But the SX SE has a different motor, different valve springs, cams, pistons, rods etc.

So with the power building up to the 12k rpm redline in the de-restricted sx se is the only way to decode if it's safe to try it out and see what happens?
 

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Not debating this at all. Unless you plan on doing 200mph plus i just dont see point and motor issues can develop over time and/or may not at all. I just wont be bumping rpm as for me its a needless risk
 

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Discussion Starter · #11 ·
Not debating this at all. Unless you plan on doing 200mph plus i just dont see point and motor issues can develop over time and/or may not at all. I just wont be bumping rpm as for me its a needless risk
This isn't on the H2 which is obviously a proven bike. I'm talking about the H2 SX SE which is heavier. I do intend and enjoy going to the 1/2 mile and mile races as well as the 1/4 mile drag strip. So I'm interested in doing it. The question is directed more for people who have bumped their redline because there are many that have or those that do tuning and have determined it to be safe. How do you know what is safe and what is not safe to do. Is it just run out on the dyno bump it up a little at a time until it shows power loss from valve float and back it off a little? Or is there a better way to determine what is safe?

It's been done for years on lots of bikes. It wasn't common in the past because most bikes started dropping power before redline. But after derestricting modern bikes many are still building power up to redline and can still make a little more beyond redline. Looking at the deristricted SX SE graph I attached to the first post it looks like it will still build power beyond redline. I want to get the most out of my bike that's why I'm asking.
 

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The most important thing when is comes to redline is VALVE FLOAT. That is the real reason for 4 and 5 valves per cyl. 2 valves that flow well are too heavy and remember objects in motion tend to stay in motion, objects at rest tend to stay at rest. So the real problem is do the valves close completely, and worse not follow the cam profile (valve keeps moving toward the piston and maybe hits). So raising the rev limit just may be a detriment. Where do the valves start to float? I sure wouldn't want it happening to my bike. Many a motor has been turned to junk from over revving. The bad part is it may not show up on a supercharged engine as dramatically as a normally aspirated engine, and by then it is too late. EEEK!!!. Be safe, don't over do it.
 

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Thanks ted. Forums can be a pain sometimes and life in general. I usually keep myself and my opinion to myself. I fo not have the time to justify or the energy to type out my resume on here ha ha ha i am merely stating that "i" think its a piss idea and it is not for me. But anyone who has or who wants to that is fine your bike and life to do as you wish. Ted if i take a trip to vegas i must meet you and pick your brain you seem a cool guy
 

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Just to add @ cOoter i aint saying you do not have a valid opinion i just want to stress that mine is not an instruction i am "just saying" if you are or feel you will use it then sweet but guy that tuned mine builds turbo bikes for a living and pretty sure hes did the 1st h2 if not ever than 100% 1st to mess with one in uk and he stressed that for the gain the risk could outweigh that. The h2 really boogies around 12000 rpm it is awesome up there and insane to keep front down lol
 

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Discussion Starter · #15 ·
Just to add @ cOoter i aint saying you do not have a valid opinion i just want to stress that mine is not an instruction i am "just saying" if you are or feel you will use it then sweet but guy that tuned mine builds turbo bikes for a living and pretty sure hes did the 1st h2 if not ever than 100% 1st to mess with one in uk and he stressed that for the gain the risk could outweigh that. The h2 really boogies around 12000 rpm it is awesome up there and insane to keep front down lol
I'm just trying to figure out the best way to determine what's safe and what's insane. It worked fine for my ZX10R but by the time I had done it others had been doing it for a while on that motor. Someone else was the first to venture into the higher revs. Did they just bump the revs up and hope for the best or was there some science involved in determining how high to push the limit? Was it just luck that the bikes were able to handle the higher revs?

The H2 SX redlines at 12k compared to the H2 at 13k. I would assume that the H2 SX can handle a little higher revs but it's just that, an assumption. I'm trying to find out how others have decided if its worth trying or not for some more power. If the H2 SX had the same valve springs, pistons and cams as the H2 I'd feel comfortable trying to bump up the revs 500-1000 to see how it does. But with a totally different motor I'm trying to decide if I'm comfortable trying it.

I know there are people that say there's no issue with bumping the revs others say it's a crazy idea. I'm trying to find the best way to determine if I'm going to try it based on science rather than opinion. I'm more interested in the why it would or wouldn't work. I appreciate your reply and I understand that to many people the risk isn't worth the reward. To me it's worth trying to get a better understanding to make an informed decision that I understand. Rather than baseing my decision on what someone's opinion is without knowing how they got to that decision.
 

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Thanks ted. Forums can be a pain sometimes and life in general. I usually keep myself and my opinion to myself. I fo not have the time to justify or the energy to type out my resume on here ha ha ha i am merely stating that "i" think its a piss idea and it is not for me. But anyone who has or who wants to that is fine your bike and life to do as you wish. Ted if i take a trip to vegas i must meet you and pick your brain you seem a cool guy
Thanks,
I live in Reno though.
Here is the thing about me, I am full of $hit about most everything. BUT when it comes to motorcycles and slot machines it pays to listen to me.
 

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I'm just trying to figure out the best way to determine what's safe and what's insane. It worked fine for my ZX10R but by the time I had done it others had been doing it for a while on that motor. Someone else was the first to venture into the higher revs. Did they just bump the revs up and hope for the best or was there some science involved in determining how high to push the limit?
There can be.

For example, mean piston speed at redline is a pretty predictible limiting factor. It might not be what comes first, but there are values you aren't going to get past, not if the engine's going to hold together long.

I remember back in 2006 Yamaha decided to lie that their new R6 was such a huge advance over others that the redline was (allegedly) 17,500 rpm and the limiter was at 18,000. Easy enough to do! Just claim it in your press releases, tell it to the bought-and-paid-for presstitutes, and order your engineers to program the tachs to read 1000 rpm high, 2000 rpm high, whatever is needed to fool your customers whom you obviously have zero respect for, the same respect you have for the truth.

Only problems were, the mean piston speed vs rpm could be calculated and it could be seen this was impossible. Not that a 600 operating at that rpm couldn't be built, but they obviously hadn't built such a motor yet for some reason decided to promote heavily that they had. So they were called out on it in forums, saying Yamaha you are lying because simply from piston speed there's no way this bike's redline is past 16,000. And then second, sooner or later someone would hook the bike up to a dyno, and the dynograph would show the real rpm off of the ignition. When that happened, it turned out the bike was turning only 15,500 while displaying 17,500 on the tach, and the limiter kicked in at 15,800.

Showing an example of, piston speed is one basis you can confidently and accurately predict that a limit rpm can't be this, but could be that.

The H2 and also the H2 SX have the same stroke as the ZX-10R, so with regards to mean piston speed could plausibly handle the same rpm. Of course, piston weight, rod weight, and rod strength are factors that can make some modest difference in how much can be gotten away with.

BTW, the factory limiter value of 13,000 for the H2 is what you'd expect from mean piston speed. A 14,000 limit with a flash gives the same mean piston speed that F1 engines had back when they were spinning 19,000 rpm!

As Ted said, valve float is another potential limiting factor. I don't know the science behind predicting that but I'd bet others do: knowing valve lift, valve weight, cam profile, and the valve spring strength could allow predicting onset of valve float.
 

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There can be.

For example, mean piston speed at redline is a pretty predictible limiting factor. It might not be what comes first, but there are values you aren't going to get past, not if the engine's going to hold together long.

I remember back in 2006 Yamaha decided to lie that their new R6 was such a huge advance over others that the redline was (allegedly) 17,500 rpm and the limiter was at 18,000. Easy enough to do! Just claim it in your press releases, tell it to the bought-and-paid-for presstitutes, and order your engineers to program the tachs to read 1000 rpm high, 2000 rpm high, whatever is needed to fool your customers whom you obviously have zero respect for, the same respect you have for the truth.

Only problems were, the mean piston speed vs rpm could be calculated and it could be seen this was impossible. Not that a 600 operating at that rpm couldn't be built, but they obviously hadn't built such a motor yet for some reason decided to promote heavily that they had. So they were called out on it in forums, saying Yamaha you are lying because simply from piston speed there's no way this bike's redline is past 16,000. And then second, sooner or later someone would hook the bike up to a dyno, and the dynograph would show the real rpm off of the ignition. When that happened, it turned out the bike was turning only 15,500 while displaying 17,500 on the tach, and the limiter kicked in at 15,800.

Showing an example of, piston speed is one basis you can confidently and accurately predict that a limit rpm can't be this, but could be that.

The H2 and also the H2 SX have the same stroke as the ZX-10R, so with regards to mean piston speed could plausibly handle the same rpm. Of course, piston weight, rod weight, and rod strength are factors that can make some modest difference in how much can be gotten away with.

BTW, the factory limiter value of 13,000 for the H2 is what you'd expect from mean piston speed. A 14,000 limit with a flash gives the same mean piston speed that F1 engines had back when they were spinning 19,000 rpm!

As Ted said, valve float is another potential limiting factor. I don't know the science behind predicting that but I'd bet others do: knowing valve lift, valve weight, cam profile, and the valve spring strength could allow predicting onset of valve float.


Interesting about Yamaha, I don’t remember that at the time but it was insane to think they’d get away with a 2000rpm lie.
Almost as bad as Kawasaki saying in 2015 the H2 would be ultra exclusive and available in very limited numbers..!


Sent from my iPad using Tapatalk
 

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There are some very informed comments on this thread which talk about valve float and mean piston speed. The first consideration should be whether the power rolls off or continues to rise with revs. On my H2 the peak power is just over 12,000rpm and it does roll off, so a reflash giving extra revs would be pointless. Ok, that's just me talking about my bike which is fairly stock, it may be different for others.
 

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One of the things that make the H2 a bit unique is the forced induction. A normally aspirated bike only flows so much, and increasing the rpm may yield no gain and in many cases a loss. Where the H2 just forces more and more in until the impeller cavitates or the blow off valve says enough.
 
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