High rpm stumble - Honda RC51 Forum : RC51 Motorcycle Forums
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 13 (permalink) Old 07-29-2012, 09:59 PM Thread Starter
Senior Member
 
Join Date: May 2011
Location: Griffin, GA
Posts: 317
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
High rpm stumble

Hey guys, so I went out riding last weekend after a couple of additions to my rc, 520 conversion 15/40 sprockets and new Dunlop rubbers but anyways I haven't rode it in a few months and after I rode for a while breaking in the new tires and running the old gas out I filled her up and started putting her through the paces and I immediately noticed a stumble around 8800 rpm it just feels like there is a huge power drop off after that and I find myself short shifting it, it wasn't doing this before it sat up for a couple of months, Have y'all ever encountered this I'm gona try a couple of things, new plugs and filter changes and maybe send the injectors off for cleaning and flow matching . I'm not that familiar with the rc fuel injection yet does anyone know what kind of injectors it has ie in the throttle body or multi-port? Thanks
RickyBobbyv8 is offline  
Sponsored Links
Advertisement
 
post #2 of 13 (permalink) Old 07-29-2012, 11:12 PM
Senior Member
 
Join Date: Oct 2009
Location: Northern California
Posts: 161
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
8800 rpm is extremely close to the 9000 rpm rev limiter. Both injectors are located underneath the butterfly used in each throttle body. Yes, you say the rev limiter is @ 10K. Not in the US. You need to remove the soft rev limiter, so you can get to 10K where the hard rev limiter is. Since you changed the gearing you"re up on the limiter quicker and on a faster acceleration curve.

Last edited by rc51 Red Rider; 07-29-2012 at 11:16 PM. Reason: added information
rc51 Red Rider is offline  
post #3 of 13 (permalink) Old 07-30-2012, 10:05 AM
Senior Member
 
jondog9's Avatar
 
Join Date: Aug 2010
Location: Northern CA
Posts: 8,653
Mentioned: 15 Post(s)
Quoted: 317 Post(s)
+1

That was my thought too. RBv8, I bet your hitting the soft rev limiter. That's just what it feels like. Unless you know the soft rev limiter has been removed. Then you hit the hard-rev-limiter at 10,200.

If you want to disable the soft-rev limiter, which a lot of folks do, here's a link to do that.
http://www.rc51.org/mod.htm

John, 2000 RC51 #000100

jondog9 is offline  
 
post #4 of 13 (permalink) Old 07-30-2012, 11:23 AM
Moderator
 
SubSailor's Avatar
 
Join Date: Oct 2008
Location: Sarasota, FL
Posts: 6,456
Mentioned: 24 Post(s)
Quoted: 88 Post(s)
The soft rev limiter starts retarding the ignition advance, so you lose power (around 5+ HP).
The hard rev limiter cuts out the ignition for each cylinder, and you will definitely know when it kicks in.
SubSailor is online now  
post #5 of 13 (permalink) Old 07-30-2012, 05:33 PM
Lifetime Premium
 
madbuyer's Avatar
 
Join Date: Sep 2010
Location: Indy
Posts: 8,335
Mentioned: 17 Post(s)
Quoted: 226 Post(s)
Quote:
Originally Posted by SubSailor View Post
you will definitely know when it kicks in.


Ha...You just may kiss the wind screen if your not ready for it too.

http://store.scottsms.com/RC51-soft-...t-RC51-SRK.htm

This kit will fix you right up.



The very first schoolbook that was written had God all over it. --Dave Mustaine
madbuyer is offline  
post #6 of 13 (permalink) Old 07-30-2012, 05:39 PM
Senior Member
 
jondog9's Avatar
 
Join Date: Aug 2010
Location: Northern CA
Posts: 8,653
Mentioned: 15 Post(s)
Quoted: 317 Post(s)
Quote:
Originally Posted by madbuyer View Post


Ha...You just may kiss the wind screen if your not ready for it too.

http://store.scottsms.com/RC51-soft-...t-RC51-SRK.htm

This kit will fix you right up.
Is scottsms with Mike and Rogue? It looks like he's selling a copy of Mike's page for $10? Is there something else?
You can get that same page by clicking on the link in my previous post...

John, 2000 RC51 #000100

jondog9 is offline  
post #7 of 13 (permalink) Old 07-30-2012, 06:44 PM Thread Starter
Senior Member
 
Join Date: May 2011
Location: Griffin, GA
Posts: 317
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Thanks for all the info guys, I'll be doing the soft rev delete soon, does anyone know why the U.S. Models have it, I tried doing some research on it but seems like a big secret?
RickyBobbyv8 is offline  
post #8 of 13 (permalink) Old 07-30-2012, 08:11 PM
Senior Member
 
Clutchless45's Avatar
 
Join Date: Feb 2012
Location: Oak Harbor, Wa.
Posts: 198
Mentioned: 2 Post(s)
Quoted: 2 Post(s)
Hard rev Limiter

Quote:
Originally Posted by madbuyer View Post


Ha...You just may kiss the wind screen if your not ready for it too.

http://store.scottsms.com/RC51-soft-...t-RC51-SRK.htm

This kit will fix you right up.
Hope you get it sorted. The hard rev limiter is no joke. I didn't know what it was when it happened to me. I thought I broke the engine. It threw me out of the seat over the bars enough to where I kissed the windscreen on the outside. I went straight back home and had to read up on it after checking the bike over. It was kinda like the first time you orgasm. Your just doing something that feels really good then right when you don't think it can get any better something happens that scares the shit out of you and you think you broke it.

Colt
00 RC51 #1119
97 CBR F3
Clutchless45 is offline  
post #9 of 13 (permalink) Old 07-30-2012, 08:31 PM
Senior Member
 
Join Date: Oct 2009
Location: Northern California
Posts: 161
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
0nly Motorcycle Consumer News spoke of this issue in their April 2003 test. It surely is a reliability insurance issue for the manufacturer. The fact that removing the soft limiter has not lead to increased failure rates, even a decade later, is a testament to the build quality of the motor.
rc51 Red Rider is offline  
post #10 of 13 (permalink) Old 07-31-2012, 02:09 AM
Lifetime Premium
 
madbuyer's Avatar
 
Join Date: Sep 2010
Location: Indy
Posts: 8,335
Mentioned: 17 Post(s)
Quoted: 226 Post(s)
Quote:
Originally Posted by jondog9 View Post
Is scottsms with Mike and Rogue? It looks like he's selling a copy of Mike's page for $10? Is there something else?
You can get that same page by clicking on the link in my previous post...
Not sure?? You could go here http://www.easternbeaver.com/ and just make your own too.



The very first schoolbook that was written had God all over it. --Dave Mustaine
madbuyer is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Honda RC51 Forum : RC51 Motorcycle Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome