[RJ_RC51]

Hi everyone,
I am a new owner of a 2002 RC51 with 5600 miles on it. The title was clean and adult owned without any issues. It ran beautifully on my 25 minutes test ride. After the ride, I was convinced this was the bike for me and bought it. On my way back home after picking it up, the bike started to die on my repeatedly after I pulled in the clutch lever or in nuetral. I was not very fun ride home especially when you make a turn as you have the clutch in and the thing dies on you. After many attempts to start it back up once home, the battery discharged. After recharging the battery, the bike started but would not idle and kept stalling. I purchased new plugs for it and installed it last night (Thursday). The old plus were fouled and black. I also emptied the tank and put fresh fuel with octane booster and Stabil once the plugs were changed. With the new plugs, it started up on first try and repeated the stop and start sveral times and it looked promising...............Now today, it started first try this morrning, but once the bike warmed up the it started stalling again. About 6 times this happened on the way to work. I had to repeatedly play with the throttle so it would keep alive. I also had to pull the choke out a bit to raise the RPM. I am fearing that there is something worse wrong with the bike since it has brand new plugs. Has anyone had any experiences like this and what the fixes were done. I don't have warrantly and much money to spend as I paid cash for the bike. I've been owned and ridden many motorcylces in my time, but never experienced anything like this. Your help is much appreciated.

[DVIII]

mabye the battery is old an the R/R is bad?

[RJ_RC51]

What would the battery have to due with fouling and stalling th bike when it idles down below 1000 RPM's? The battery has great voltage and amprage. What is an R/R? Thanks......

[DVIII]

Honda's are notorious for bad Regulator/Rectifier's

It may be the reason the bike is stalling and not starting back up consistently.
My RC hasn't had this problem but my F3 did and your issue sounds like what my issue was.

Fouling plugs may not be due to this, may be so... can't tell you for sure.

[onealrc51]

I hate to say this, but this sounds nearly identical to the problem I just recently had fixed on my 03. I bought the bike, it ran fine, then all of a sudden the plug - it was just the rear plug on mine, began fouling consistently. Turns out that a tps control on the throttle body assembly was the culprit. Problem being, you cannot replace just that part, you have to replace the entire assembly. It is about a $1500 part retail.. Before getting my problem fixed, I raised the idle, played with the choke, and never let it rev below about 2k at lights and when in neutral and it would not die. Let it go below 2k, and on its face it would fall. Mine also got to the point that it would not start, it would sound very close to starting, but like it was not getting enough fuel. Once it did start, it would keep dumping fuel to the rear cylinder causing the plug to foul. I spent the money, cost me about 1500 total and 5 weeks at the shop, but it runs great now. Hope this helps bud.

[aussie-sp1]

gday mate. im sorry but onealrc51 is spot on. we both had this problem. replacing the throttle body because they dont sell the tps sensor seperately is the answer. I followed his advice and my problem was cured also. I wasted $1600 on listening to what the mechanic thought the problem was. I replaced every sensor and serviced the injectors with no result. I bought a used throttle body from a wrecked bike for $650 and im riding again. read our forum "running rich" and u can see what we went through.

[aussie-sp1]

Im willing to bet my left testicle that this is the exact same problem.

[vitzaa]

sounds to me like it might be the same problem... but here's what i would do...
1. dont use octane booster, you'll mess up the ratio and probably end up doing more harm than good, just use 91/92 octane and you'll be fine.

2. its VERY common that the wires under the gas tank get pinched and after a while they create the problems you are having... to me it sounds like that needs to be checked first. your bike doesent have enough miles for the sensors to start going out... honda is very reliable... check the simple stuff first before you start spending the big $$

[sheepofblue]

Given you needed to change the fuel the injectors could be varnished. Try running it for a bit if possible it might clean out.

[RJ_RC51]

Ok here is the verdict. Just got my bike back this week. The problem was not the throttle body or TPS like others have suggested. At first the bike shops diagnosis was the idle screw not adjusted properly. They said they readjusted the idle screw and was running fine. I asked them did you run the bike for more then 5 minutes and let the temp go above 200 deg Fahrenheit? They didn't and ran more tests and it idled rough and died on them as predicted. After their second diagnosis this time using the F1 codes it was throwing a code for the TPS. They called Honda to investigate further and found a heavily leaking Fuel Pressure Regulator. Needles to say, after waiting for two weeks, I get my bike back and is running like a champ. I now appreciate why I purchased this bike. I have rode the bike for 50 miles since and love every second of it. A simple $50 dollar part (FPR) was all it required as well as new plugs and a gasket set. I hope OnealRC51 and Aussie that your mechanics ruled out an FPR before suggesting a new throttle body. Thanks everyone.

[i<3my00rc51]

Originally Posted by aussie-sp1

Im willing to bet my left testicle that this is the exact same problem.

Oh shi*t hahahah time for operation testicle removal hahahhahhaha jk

[onealrc51]

my fpr was changed and that did not solve my problem - the regulator was not responsible for the rich condition it was due to the throttle body tps not working and dumping fuel in the rear cylinder causing the fouling of the plugs constantly. i'm glad you got it all worked out though!