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Discussion Starter #1
Hey all,

I'm having an interesting experience with a dyno shop. If I'm crazy and wrong, please let me know. The bike is an SP1 with power commander. The shop I took the bike to came recommended from a friend. They claim that the clutch switch being disconnected is keeping the bike in "start up enrichment". I call bulls__t in a big way. it has been that way for quite a long time with no issues, and nothing comes up in searches both on this site and webbernet wide. I explained to them that that was not the case, and if it were, why would it have a choke? The other thing that has me intent on pulling it out of there is that they claim that they cannot tune with the SP1 PCII, that it is "ancient technology". Unless someone can tell me I'm wrong or missing something, I'm getting that thing out of there tomorrow...

Whatcha think?
 

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So holding the clutch in is what is making my sp1 use so much fuel..What a load of BS...It stops you from looking like a fool when you hit the starter button when the bike is in gear.
As for the pcII it is old tech with limited tuning ranges..
Maybe someone here can point you in the direction of a good tuner and a pcIII
 

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The clutch switch is complete BS. All it does is interrupt a ground.
A pc2 is older, but I can not see why a shop couldn't tune it, tell them to dust off their old manuals and get to it. My guess is that they are trying to get you to buy a newer version.

Hopefully LDH will tune in with his insight, he's the one to ask and one of the few I'd blindly trust working on mine. Now if only he was wasn't on the other side of the country:rolleyes:
 

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Discussion Starter #6 (Edited)
Just talked to the Dyno shop, and he states that there is an ignition spike at ~5k and ~10k. While common understanding says that the clutch switch only interrupts the circuit, wiring diagram shows both wires from the clutch switch going into the ECU. I'm unsure why, but there must be a reason....

The clutch switch is open and the bike cannot be started in gear which means the ECU sees the clutch as engaged, but...

I'm going down the road with them and reconnecting the clutch switch even though I know it's crap, won't take long. Also, I'm going to a PC V since it is more modern, slicker tech. I'll keep you posted.
 

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Discussion Starter #7
...and LDH, I know I shoulda just brought it to you guys, but I had a friend already going to this place and he praised their skills. I promise to call you soon and buy something. I repent. :)
 

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PC II is very old, to be fair, I hadn't even heard of it and have mad my bike 8 years!
I have a PCIIIR and even that's got old tuning software, which requires a serial port connection, but as there's nothing wrong with the way the bike runs I won't be changing it.
I guess PC II software is old and like my PC IIIr has far fewer fuel cell map adjustments than a PC III USB or newer. PC II software may no longer be available either. So going to a newer ECU makes sense for several reasons.

The clutch switch is just a safety, it has nothing to do with start-up enrichment, but in any case it's good to have it connected.

Tuners are like dentists. Few people really know a good one because they don't have enough experience in this work themselves to quantify. :D
 

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Don't be so quick to discount the clutch switch.
I had a Suzuki TL1000s. I chucked the clutch switch and the bike never ran right, until I put a new switch.

I don't believe it was bullshit on my Suzuki.
It may not be bullshit on the Honda either.
 

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I have no clutch switch connection on my SP2, as I run a Brembo master cylinder which come without a switch. There's no difference in how mine runs now compared to before; I just can't start it if the bike is in gear, that's all.
I doubt a PC II has any different parameters than an PCIIIR with regard to this safety switch. It's just an on / off micro switch to stop the bike being started in gear unless the clutch is pulled in... It has nothing to do with fuel enrichment.
 

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I talked to the tuner earlier today. The clutch switch is a valid issue on Suzuki's, but not on Honda's.

I wish I had time to go up there and look at the bike because this is a very odd problem, but not unheard of. Many similar instances have popped up with various RC51's over the years. Most common culprit is a battery connection that seems tight, but is just loose enough to vibrate loose at specific rpms causing a stumble. I've seen similar problems come up with bank angle sensors going bad.

I've also seen aftermarket airboxes and aftermarket airfilters cause similar fueling problems on RC51's. As I understand it there is also a custom exhaust on this particular bike that could also lead to a hesitation at specific rpms based on the dynamics of the exhaust. Again I haven't actually seen the bike just going off what I was told inititally.

Another more recent problem are these new Li-ion-whatever-the-fuck batteries that everybody wants. Most of them are so cheaply made that they cause real performance problems for Fi controlled bikes as I have reported in this article
http://www.rc51.org/battery.htm

My last thought would possibly be the Fuel Pressure Regulator as they also tend to go bad on these aging bikes, but the symptoms expressed aren't typical of a bad FPR.
 

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Discussion Starter #13
Thanks for the reply LDH! Yes, the exhaust is custom-ish. Erion header to a dual "shotgun" side mount. I'm under no illusions that the changes I have made will make gobs of power or anything of the sort. This bike has simply turned into a long term experiment for me. If I want gobs of power, I'll take out the CBR. :) I have made a bunch of mods to it that have mediocre results historically. I have turned multiple inserts for the exhaust that will provide various levels of backpressure/flow variations. Those are for future exploration. I have the bike being tuned so that I have a solid baseline on which to test further modifications. Purely exploratory. At a minimum it will provide some more data for the archives, and perhaps a decent map to provide folks with similar mods...
 

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Thanks for the reply LDH! Yes, the exhaust is custom-ish. Erion header to a dual "shotgun" side mount. I'm under no illusions that the changes I have made will make gobs of power or anything of the sort. This bike has simply turned into a long term experiment for me. If I want gobs of power, I'll take out the CBR. :) I have made a bunch of mods to it that have mediocre results historically. I have turned multiple inserts for the exhaust that will provide various levels of backpressure/flow variations. Those are for future exploration. I have the bike being tuned so that I have a solid baseline on which to test further modifications. Purely exploratory. At a minimum it will provide some more data for the archives, and perhaps a decent map to provide folks with similar mods...
The Erion full system had the worst mid-range dip in the history of the RC51




With that in mind and the fact it corresponds to the problem tuning area I am willing to bet that is the root cause of your tuning problem
 

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Discussion Starter #15
Good to know. Thanks again, we'll see where it ends up. In the end it's all reversible...
 

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Discussion Starter #16
Update:

As I said before there was an ignition spike at 5k. No more. LDH advised the shop that the lithium battery can have some effects like this. They switched the battery out and sure enough, the spike is no longer present. Holy hell, man....You are one bad mother. Thanks again!
 

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That is so awesome you found the culprit and one more piece of information I will add to my catalog of errors I have come across with all these new superlight batteries.

Thanks for taking the time to post up the resolution. It's easy for me to tell people what problems I have encountered, but when others post up the exact same issues it really helps reinforce the credibility of what I am saying and get the real point across to consumers.
 

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RCx2 - Not sure if I missed it, but what brand lightweight battery were/are you using?
 
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