Ignition Problem?

slammp · 06-13-2008, 9:10 AM

Ok here we go. I have searched all of the related threads on this and am looking for input. The other night I am riding doing 30-40 hard acceleration from a stop light. I get a shotgun blast back fire followed by violent bucking (like the engine was losing power and getting it back repeatedly). It is only under hard acceleration; if I back off it smooths out. I am also experiencing rough idle. I used to idle at 1200rpm, now it is at about 1000 and it's not steady kind of uneven sounding. Here's what I know:

2001 rc51
- Battery is fine (I use a tender) and the connections are verified tight.
- I looked under the gas tank for anything pinched (nothing).
- All electrical connections are tight.
- new spark plugs, pulled them and they look fine.
- new exhaust, no leaks, I checked.
- I dont think it's the fuel filter because in my mind the backfire indicates unburned fuel not a lack of it.
- I am thinking Regulator/Rectifier but that is a guess and I do not know how to test that.
- I am also wondering if it could be the Converter Unit or one of the coils?

Looking for suggestions.

Thanks

Red Rider · 06-14-2008, 10:48 AM

Does it have a PowerCommander?

slammp · 06-16-2008, 10:57 AM

I have a PCIIIr. I pulled that, checked the connections and reset it. Now the problem gets worse. I also checked the throttle bodies to make sure they were tight. Put everthing back together, let it warm up and ujusted the idle to 1400. Everything seemed good and it was running fine for 20 minutes then the same thing happened only this time it sounded like someone had plugged both tailpipes. I drove it back home and parked it and had grey smoke from the left pipe and under the gas tank on both sides.

I let it sit for a couple hours and restarted it, no smoke, running a little rough?

Would a blown head cause the off/on power surges I am feeling?

What about the exhaust sound (it was really quite whne the power dropped)?

HRace · 06-21-2008, 10:05 PM

Its a fuel problem. How many miles on the bike. Serviced recently? Sounds like the fuel injectors are partially clogged. Any other mods, Flapper valve, pair system removed?

slammp · 06-21-2008, 10:20 PM

ended up being a bad power commander. I did not know that could make the engine smoke but it did. It is off now and the bike is running fine.

HRace · 06-21-2008, 11:02 PM

That sucks. Installed wrong or did it just fry? I have a PCIII USB on mine never had any problems

slammp · 06-22-2008, 10:30 AM

No its been on for years, just ended up losing its memory off and on (I guess it got senile).

01'BLADE · 08-07-2008, 11:24 AM

Hi HRace / slammp

I'm experiencing the same issue as slammp with the exception of the exhaust smoke, i too have a PCIIIr, and when i'm hard on the throttle i experience the on/off bucking at around 8k-9k rpm. If i back off and then smoothly go to the bar with the throttle it's okay (with the exception that my friends blow by me down the straigthaway). I'm curious (hoping) this may just be a mapping issue, i'm not going to even pretend to understand how that stuff all works, but you guys seem to have experience with fuel systems. I have the m4 full header system and a k&n filter with the air box flapper removed, and i'm running the map from the power commander website for the m4 full system with stock air filter. They don't have a map for the m4 full with K&N filter and i don't know if the map is made with the flapper mod or not. Anyways, i could get a custom map down the street here for about $280.00 but don't want to waste the money if my pc is fried. Could be a possibilty that i just need a custom map? Your comments are appreciated.

Red Rider · 08-07-2008, 12:45 PM

Disconnect the PC and see if the problem goes away. If so, get the custom map (and ditch the K&N). If the tuner is any good, it will be worth every penny and should correct the problem.

slammp · 08-07-2008, 12:58 PM

I will agree with Red Rider. Since removing the Power Commander my bike has been fine. Keep in mind I also have a full system (Hindle) and the flapper and pair mods have been done. The bike runs great the only complaint (if I actually had one) is that the exhaust temp on the left hand pipe is considerably hotter than the right one - but it has not effected anything and the airflow coming from both is equal.

HRace · 08-08-2008, 11:34 AM

Quote:

Originally Posted by 01'BLADE

Hi HRace / slammp

I'm experiencing the same issue as slammp with the exception of the exhaust smoke, i too have a PCIIIr, and when i'm hard on the throttle i experience the on/off bucking at around 8k-9k rpm. If i back off and then smoothly go to the bar with the throttle it's okay (with the exception that my friends blow by me down the straigthaway). I'm curious (hoping) this may just be a mapping issue, i'm not going to even pretend to understand how that stuff all works, but you guys seem to have experience with fuel systems. I have the m4 full header system and a k&n filter with the air box flapper removed, and i'm running the map from the power commander website for the m4 full system with stock air filter. They don't have a map for the m4 full with K&N filter and i don't know if the map is made with the flapper mod or not. Anyways, i could get a custom map down the street here for about $280.00 but don't want to waste the money if my pc is fried. Could be a possibilty that i just need a custom map? Your comments are appreciated.

Go back to the stock air filter. I had a problem with a BMC air filter. Very similar to what you are experiencing. I replaced the stock filters and everything went back to normal. If you have the extra cash though I would highly recommend a Dyno tune. I know they are pricey but in my opnion worth every penny. I get 135hp and 83 ft. lbs. at the rear tire and I have the exact set up that you have with the exception of a larger volume airbox. With a proper tune you should be getting around 128HP or so at the rear tire
Good luck