I'm wondering if you guys ever experienced your RC jerking or maybe a better term sputtering even when the trottle is in constant speed. Since I'm the 2nd owner and since I bought the bike, I notice my RC jerk or sputtering a lot especially if I'm on a lower RPM, even with the correct gears. I've been riding sportbikes for many years and went thru many bikes but I never encountered this kind of sputtering, so I'll say it is not me at all. Thou, this is my first V-Twin sportbikes, most my bikes before were Inline-4. Anyway, the worst is when I'm in a lower gear like 2nd or 3rd even with the right amount of speed. Unless if it's design like that since the torque is in low-mid range? Any ideas what's goin on??? :confused:

Oh btw, I also notice my bike ran smooth (no jerking or sputtering) when I'm on the mountain twisty. But then when I come down then it will start the jerking again. Also, on a hot weather, the bike will just jerk or sputtering again!

Forgot to add from my previous thread, my bike is pure stock, no modification as far as the 1st owner. I only added a slip-on exhaust. But the sputtering is already exist before I added the slip-on.

I don't know if we're talking about the same thing but my bike jerked real bad in the lower rpm's really anything below 4K. Then I changed the gearing and it doesn't do it anymore.

sounds like a fueling problem if it ran fine at elevation........

Well first off, RC51's don't particularly like to be lugged around.
I know mine doesn't like me much at 3000-3500 RPM with lightly cracked throttle in 2nd or 3rd gear when behind cars in traffic.

And frankly, I feel sorry for it too.
Like a thoroughbred, they love to run.
If I run mine at 4000 or above, it runs fine.

Is the reason the bike no longer exhibits the behavior in the mountains due to the engine being under more load than on level terrain?

What year is your bike?
The SP1's had 4-hole injectors that might cause fueling issues at low RPMs.
That's why Honda went to 12-hole injectors on the SP2s to try and atomize the fuel better.
Under more throttle, either bike should run fine.

IMHO, it is probably the tune. That would explain the change in performance at elevation and temp differences. Many people will get a pipe and you need a new tune usually after that, and the problem largely goes away. Most RC-51’s exhibit these problems stock from what I hear and I can see how. There are differences in the SP-2's that will help in that area also as mentioned. A chain conversion will help too. That will keep it from wanting to load up and lug as much. Good luck and don't get discouraged. They do not all run that way and it can be fixed pretty easily.

Fuel-air-mixture is too fatly the voted of Honda.
With the right Map to the Powercomander is then OK.

Das Kraftstoff Luft Gemisch ist von Honda zu fett gewählt .
Mit einem Powercomander und einer richtig abgestimmten Map ist es weg.

That looks like a good board, sr2-e. VTR1000.de Germany Forum

Pc3 will help tremendously!!! Best $250 you'll ever spend on your bike anyways.

Yo Lead you not talkin to me no more bro???

Thanks for all the inputs/suggestions! I'm humbled to hear all your inputs. Anyway, the bike is 2005. I think all that problems you guys indicated make a lot of sense and surely it can be one of those item. For example, the cause of the problems (sputtering/jerking) indicated by JGOS929I, and SubSailor are pretty close to what I'm suspecting. Then I started thinking maybe I need PC3 to have it tune right or check the Fuel line suggested by SR2-E. Correll1000, and Leadfinger. However, I started questioning myself like since the bike is stock and no modification per the 1st owner, then why it is acting like this? So, I'll check your suggestions and hope to fix the problems. I'll keep you guys posted. Thanks again guys!

No. I don't talk to anyone. Thanks. =)

????????????

With 13,1-12,9 Air Fuel it is better.
If too lean, then very aggressive the gas assumption.

Mit 13,1-12,9 Air-Fuel ist es besser.
Wenn zu mager, dann sehr agressiv die Gasannahme.

With 13,1-12,9 Air Fuel it is better.
If too lean, then very aggressive the gas assumption.

Mit 13,1-12,9 Air-Fuel ist es besser.
Wenn zu mager, dann sehr agressiv die Gasannahme.

Correct. I believe most Dynojet centers try for 13.2:1 air/fuel ratio as that is suppose to be optimal.

The best is, brought it with a WBC on the street .

Mit einer WBC auf der Strasse eingefahren ist das beste.

The bike has more performance and less petrol consumption.
The Air RAM effect is not available on the test bed.


Dabei hat das bike mehr Leistung und weniger Benzin Verbrauch.
Auf dem Prüfstand ist der Air Ram effekt nicht Vorhanden.

I need to plug in my PC3 to my computer and install the software to see what tuning and datalogging I can do. I do not have a laptop with serial so it is a PITA. I need to get a PC serial card.

there are adapters serially to USB.
es gibt Adapter mit seriel zu USB.

but not everyone works properly.
Aber nicht alle funktionieren richtig.

here my adapters serially

Thus far it sounded like I might need the PC3 to solve the problems. Please excuse my ignorance, but any recommendation of what brand or type of PC3 I need to get for my 2005 RC51? Thanks in advance!

Its all good man. Just go to powercommander.com and that will get youstarted.
You can find one all over the net at different websites for cheap. Make sure u get apcIII usb.

Thanks Jgos929. I'll check PC3 APCIII, and hope that will eliminate the jerking/sputtering on my RC. I'll keep you guys posted. :-) Again guys, I really appreciated all the suggestions and the discussions on this tread and trying to help out with my RC problems. Thanks!!!

After you get the bike re-tuned, you might still want to raise the gearing. Mine has the stock 16/40 gearing, and a PCIII, and is still a little jerky at 3-3500 in a tall gear, unless you are reeeealy smooth on the throttle.

Its not a big deal with me, as I'm pretty decent at throttle control, but even still, I'm strongly considering a 15t countershaft.

Thanks Snarf. I'll will definitely keep that in mind once I get the PC3. Funny that your bike is acting the same way as mine. I'm pretty close to your RPM situations, about 3 - 3500 tall gear, that is where the real jerking/sputtering occur! The worst jerking/sputtering situations happen when you are in stop-and-go traffic (I think hot or cold weather doesn't really matter). A lot of time when that happens I look at my friends bike next to me and their bike run really smooth! :-(

So, numerous times I was so close to sell my RC but I couldn't if I started thinking about the handling, the torque, and the sound. I still think it is one of the best bike out there and met all other sportbike riders wanting one. So, it is hard to give it up, so I decided to find a way how to fix this jerking problems.

Man definetly dont sell it! If you dont want to spend the money on the PCIII right now, just get a smaller countershaft. It'll disguise the fueling issues the stock tune has, be releiving so much of the load on the engine in those low-speed, low RPM, hi gear situations.

Ive never ridden a stock mapped RC, but I bet its kinda sketchy, especially with the tall gearing.

Another trick you can do is just to slip the clutch just a very small amount in slow speed stuff.

Keep your index and middle fingers on the clutch at slow speed [i do it all the time], so in case you unexpectedly have to slow down ad get caught in a taller gear, you can pull the clutch a minute amount.

Try it- it helps a lot!

I have the same problem when stuck in traffic myself.

Big twins (especially high-performance twins) just naturally have issues when lugged below their optimal rev range.
Those two big 500cc pistons cause large pulsations in the intake tract at low RPM.
I'm amazed the FI on the RC51 works as well as it does.

To put it in perspective, imagine your bike with carbs instead of FI.
You would have far more fueling issues (i.e. spitting, backfiring, fuel wetted air filters, etc) at low RPMs than you do now.

Try and keep your engine around 4000 RPM and up, and she will love and reward you.

I find mine a little bitchy off idle. I live on a dirt National Forest road and I have to put-put down the road 15-18 mph avoiding pot holes, splashes, and cow pies. Once off the road, undiscernable. I have an '03, and I run 15F and a 42R sprocket.


John

SubSailor, you just brought something interesting topic in regards to big twins (on sportbikes). I wonder if Duc (Ducati) has the same issues (lugged, jerking, or sputtering)??? Too bad I don't know anybody that ride Duc's to ask, but it would be interesting to find out thou. Anyway, since I just spent few $$$ this month on my RC, I'll wait till next month and definitely will get the PC3. I bought new Sargent pillon, Panasonic Camcorder (Flash Drive), and Camcorder mounting from Sportbikecam. I can't wait to do the next run and record the trip. I guess I have to suck it up the jerking for now till I get the PC3. Beside, been riding like that for almost 2 years so what's the difference a month from now. :-(

I believe Ducati has spent a lot of time and money fine tuning their FI systems. So I would incline to believe they run quite well.
I've ridden a 999 and it was a sweet engine, and pulled cleanly and strongly from low RPM.
But most Ducati riders don't tend to lug their bikes either I've noticed.
However, the next time I talk to them I'll ask what their average in-town RPMs are as a comparison and how their bikes behave.

The early Buell FI systems were notoriously sensitive to intake tract pulsations and would backfire into the airbox at times.
The improved Delphi units on the XB series are much better.

My RC like to backfire in the air box... Scares the crap out of me sometimes. lol
Well I've put a fender elem on mine. I havent been on here in a spell.

My RC like to backfire in the air box...

Never had that happen to mine.
What circumstances occured to cause that?

1st gear parkinglot speeds.

Pc3 will help tremendously!!! Best $250 you'll ever spend on your bike anyways.


on top of that you can usually find a custom map to upload from your pipe manufacture. Try that, it should help and would be an excellent investment for you first mod and well worth the money.