Rev Limiter, options?

Spoony · Post by **Spoony** » Mon Sep 21, 2009 12:13 am

Once my 23 race bike is back together, I want to get a rev limit on it to avoid more destruction. Sure I can be 'careful' but last destruction wasn't caused by downshifting to hard or similar, it simply popped out of gear, pretty hard to catch when your full throttle already near 14k rpm in 5th! While I've never had this happen on any of my Gixxers, I've heard mention this can happen with Honda's, so would rather be safe.

Anyone fitted a limiter or can recommend one?

leopard_pagan · Post by **leopard_pagan** » Mon Sep 21, 2009 4:27 pm

hmmmmm most people want to go the other way and get rid of the limiter.
i "hear" the resistor mod removed the safety net of the limiter = no use to you.
on my bike i removed the disk from the light sensor inside the speedo, this has left the safety limiter in place as this weekend i was showing someone what hitting the limiter sounded like. BUT racers tend to remove the speedo.

so.. my suggestion would be to keep the speed limiter in place, remove the disk that sets it off, seal it from water and plug only that back in to the loom leaving the rev limiter still in place. ........

i am assuming you have a later NC23 that uses the resistor mod? the earlier ones dont need the resistor and instead have a different CDI unit thats programmed different.

Post by **Cammo** » Tue Sep 22, 2009 12:49 am

leopard_pagan wrote: on my bike i removed the disk from the light sensor inside the speedo, this has left the safety limiter in place as this weekend i was showing someone what hitting the limiter sounded like. BUT racers tend to remove the speedo.

The rev limiter is in the cdi.

The easiest way to lower it would be to buy an aftermarket adjustable cdi, you can set the rev limit from your laptop/pc.

Not sure if there's a model for the nc23 out there, check with Rick Oliver or Graeme France.

No rev limiter will save you if you downshift too hard. I learnt that one once.

Pleiades · Post by **Pleiades** » Tue Sep 22, 2009 3:53 am

Stickshift wrote:The rev limiter is in the cdi.

The easiest way to lower it would be to buy an aftermarket adjustable cdi, you can set the rev limit from your laptop/pc

Is it possible to lower/raise the rev limiter on the HRC NC29 CDI? Think mine comes in at around 15K (oddly enough, I'm generally too busy to look at it when it's in that range...), just thinking there might be times when I'd prefer to go easy on the thing. I find that the controlling the right wrist thing is a little ineffective...

Post by **Cammo** » Tue Sep 22, 2009 5:10 am

Pleiades wrote:Is it possible to lower/raise the rev limiter on the HRC NC29 CDI? Think mine comes in at around 15K

No. The rvf hrc one I had limited it to 15500, +1000 over standard.

The aftermarket fully adjustable units are the easiest way to change timing, rev limit etc. Not legal for racing in Oz though!

Pleiades · Post by **Pleiades** » Tue Sep 22, 2009 5:48 am

Stickshift wrote:No. The rvf hrc one I had limited it to 15500, +1000 over standard.

The aftermarket fully adjustable units are the easiest way to change timing, rev limit etc. Not legal for racing in Oz though!

Well, I'll leave it alone then. Don't want to start cheating just yet

leopard_pagan · Post by **leopard_pagan** » Tue Sep 22, 2009 3:55 pm

"The rev limiter is in the cdi."
yes i know it is.
lets say you want to race your bike.
remove the speedo/dash to loose the unwanted weight = the need to then bypass the speedo limiter however you want to do it. thing is i have heard (? any truth in this?) that using the resistor or a Mbox will also increase the RPM limit.
Spoony here wants to keep his in place. as you have mentioned, doubtful he can lower it on a NC23.
so.. if you remove the speedo/dash as before but KEEP the speed limiter electronics, remove the disk that cuts the beam at 112mph (no good if your racing!), seal the electronics somewhere safe. re-connect that back to the loom.
this way you still get over 112mph but the signal is being sent to the CDI and the original RPM limiter is in place.. as far as the CDI knows.. nothing is out of place....
if that kinda makes any sense? it may.. or may not work.

Waza4 · Post by **Waza4** » Tue Sep 22, 2009 5:24 pm

An oil cooler might help solve the gearbox problems as most gearbox problems like that are caused by high temperature. On a fast technical ride if someones gear box goes to pieces we stop for a smoke and a natter ,give it 20 minutes to cool off and its ready to go again.

Spoony · Post by **Spoony** » Wed Sep 23, 2009 6:41 am

Thanks for all the replies. I've found this http://www.dynatekuk.com/drag_racing_rev_limiter.html" onclick="window.open(this.href);return false; 12,000rpm max but apparently now can be set higher with dip switches.

The bike was setup before I bought it so am not 100% sure what CDI etc it is running, I think theirs some customised stuff. I do have a speedo though so will have a look at that and see if the loom still exists to reconnect it.

112mph, 400's go faster than that?

lol

stimpy · Post by **stimpy** » Wed Sep 23, 2009 10:54 am

many factors would have come into your nc23's engine blow up...have you worked out what it was yet?
ive raced mine for years stock...only recently adding ram air with nc29 carbs and a stock set of downpipes...
and to this date,its recorded the fastest times for a nc23 in aus
its always running in the top 8 on a national level with a stock rrj cdi where the super quickbikes are hrc equiped 29s,zxrssp and fzrs and is maybe a second off the pace of the 2 top guys on rockets...whether there bikes are actually within the rules is debatable.
why would you want to lower the rev limit when the thing is making power from 11-14500 is all i want to know?

all i can say is,make sure your motors built right,regular oil changes(mines done after every round)then i cant see you having probs apart from a freshen up every year.

they are old,only 400cc and the power they make isnt mindblowing no mater what you do..super bigbore would be fun i admit..
stimpy

Rev Limiter, options?

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