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Discussion Starter · #1 ·
So this is my first post, and I want to preface this by saying I am NOT an engine guy, I just love to ride. Now to the issues.

I had been having an oil leak which turned out to be that notorious brass tube at the bottom of the air box. Found that answer here on the forums. I fixed that up and almost immediately started noticing that the bike was running DIFFERENT. Like, it used to feel like it was chugging in the 4k and lower RPMs, but now it feels like it's working hard in that range. Running RPMs always felt comfortable in the 5-6k range, and now that feels HIGH. The power in the bike still feels like it's there, but the RPM ranges are weirdly different. NEXT is that I'll get home after riding home from work (about 7 miles) and the exhaust from the rear header, right at the header is glowing red. I feel like this is a concern but I don't know how to diagnose this or what I would do to correct it. Can anyone explain like I'm five?
 

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So this is my first post, and I want to preface this by saying I am NOT an engine guy, I just love to ride. Now to the issues.

I had been having an oil leak which turned out to be that notorious brass tube at the bottom of the air box. Found that answer here on the forums. I fixed that up and almost immediately started noticing that the bike was running DIFFERENT. Like, it used to feel like it was chugging in the 4k and lower RPMs, but now it feels like it's working hard in that range. Running RPMs always felt comfortable in the 5-6k range, and now that feels HIGH. The power in the bike still feels like it's there, but the RPM ranges are weirdly different. NEXT is that I'll get home after riding home from work (about 7 miles) and the exhaust from the rear header, right at the header is glowing red. I feel like this is a concern but I don't know how to diagnose this or what I would do to correct it. Can anyone explain like I'm five?
Is the engine light on?
 

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So this is my first post, and I want to preface this by saying I am NOT an engine guy, I just love to ride. Now to the issues.

I had been having an oil leak which turned out to be that notorious brass tube at the bottom of the air box. Found that answer here on the forums. I fixed that up and almost immediately started noticing that the bike was running DIFFERENT. Like, it used to feel like it was chugging in the 4k and lower RPMs, but now it feels like it's working hard in that range. Running RPMs always felt comfortable in the 5-6k range, and now that feels HIGH. The power in the bike still feels like it's there, but the RPM ranges are weirdly different. NEXT is that I'll get home after riding home from work (about 7 miles) and the exhaust from the rear header, right at the header is glowing red. I feel like this is a concern but I don't know how to diagnose this or what I would do to correct it. Can anyone explain like I'm five?
No real connection between the brass breather tube and how it will run. Coincidence. That condition is hard to diagnose but being the rear is now glowing and running poor in that range, it sounds fuel related, as in not enough for that cylinder. Could be low fuel pressure output or an injector issue. I would start with testing the fuel pressure at the fitting, right side of throttle body. A GM pressure tester with an R12 fitting can be rented at some auto shops. Should come in at 57-62 psi and not drop like a stone when the pump shuts off. A very slow drop over a minute to about 1/2 the pressure will not cause problems. Getting a Service manual is a great step for self repair and maintenance.
Do you have any codes shown on the speedo? Do you have an aftermarket tuner on this bike? Most common is the PCV. It will be located close to the ECM under the rear seat. If so, remove it and test the running without it installed. Sometimes they can go flakey and cause running issues. If neither fuel psi or tuner seems to be the problem, it might be a bad rear cylinder injector.
Data logging the bikes sensors should be done also to see if something shows up. Check to see if your front throttle body shaft isn't cracked at the screw holes, tps side. The above order of things to check isn't exact. Just go with process of elimination.
Ron
 

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Discussion Starter · #5 ·
No real connection between the brass breather tube and how it will run. Coincidence. That condition is hard to diagnose but being the rear is now glowing and running poor in that range, it sounds fuel related, as in not enough for that cylinder. Could be low fuel pressure output or an injector issue. I would start with testing the fuel pressure at the fitting, right side of throttle body. A GM pressure tester with an R12 fitting can be rented at some auto shops. Should come in at 57-62 psi and not drop like a stone when the pump shuts off. A very slow drop over a minute to about 1/2 the pressure will not cause problems. Getting a Service manual is a great step for self repair and maintenance.
Do you have any codes shown on the speedo? Do you have an aftermarket tuner on this bike? Most common is the PCV. It will be located close to the ECM under the rear seat. If so, remove it and test the running without it installed. Sometimes they can go flakey and cause running issues. If neither fuel psi or tuner seems to be the problem, it might be a bad rear cylinder injector.
Data logging the bikes sensors should be done also to see if something shows up. Check to see if your front throttle body shaft isn't cracked at the screw holes, tps side. The above order of things to check isn't exact. Just go with process of elimination.
Ron
Thank you! I'll look into this. I don't know how much of this I'll be able to do on my own, but I'll definitely check into it! I appreciate your help!
 

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Just to follow up on this, I solved it! Turns out the engine does really funny things when the o2 sensor is unplugged. I reseated it and it's running like a dream again!
Generally an unplugged sensor will force the ECM to go open loop in the calibration. Rich, not lean, as a form of protection. This can make the flame travel further down the pipe making it glow. I'm surprised you didn't an O2 code. You should have seen that right away.
Ron
 

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Discussion Starter · #8 ·
Generally an unplugged sensor will force the ECM to go open loop in the calibration. Rich, not lean, as a form of protection. This can make the flame travel further down the pipe making it glow. I'm surprised you didn't an O2 code. You should have seen that right away.
Ron
Yeah there were no lights or warnings at all. Was really strange.
 
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