High Speed Miss at 65mph

[Joan & Jack]

I ride a 2013 PCX 150 with 4400 miles. Approximately 1/3 of my 12 mile commute is on a six lane interstate (I-4) east of Orlando, FL. I get merged into the right lane and ride in that lane to my exit. This week at 65 mph my PCX has a big time "miss" If I back off the throttle a smidgen and the mph drops to 63 or below, it purrs like a kitten. I am puzzled. Anyone experience this phenomenon?

I put some "Sea Foam" fuel additive in the tank last evening. That has not improved the miss. It seems like the engine is starving for fuel, more so than being an ignition problem.

Thanks,
Jack Ferrell
Deltona, FL

[j.d.b.]

Yes, you're describing fuel starvation. Sounds like it's time for a pump or at least a look at a possible constriction in the fuel supply line(s). I've experienced that on two cars, though they were clogs in the filters back then.

[gn2]

Maybe its the speed limiter kicking in...?

[tbln930]

Yep - If it is the original belt I bet 65 mph is about it.

[maddiedog]

You can also check the spark plug, in case it's running lean for some odd reason.

The PCX (when it hits the limiter) backs off very quickly and feels like a miss.

[j.d.b.]

I see these things have a diagnostic jack. They apparently have OBD, as well. Has anyone here ever hooked up a scanner to a PCX?
To the OP: Does the MIL (check engine) light come on and/or blink when the miss happens? The manual describes a procedure how to read any stored codes by blinking the MIL. Do you have a manual? If it has multiple misfire, it should store a code (unless it's hitting the rev-limiter). In most modern OBD's the MIL will flash when multiple misfire is detected (unless it's hitting the limiter). These appear to have halfway decent OBD systems. You could take it in to service if all our "help" fails to ID the trouble.

[fish]

Speed limiter....or an angel slowing you down on a little PCX out in the freeway!
Probably nothing wrong with this scooter.
Fish

[Pcxdemon]

+10 speed limiter..

[you you]

I see these things have a diagnostic jack. They apparently have OBD, as well. Has anyone here ever hooked up a scanner to a PCX?
To the OP: Does the MIL (check engine) light come on and/or blink when the miss happens? The manual describes a procedure how to read any stored codes by blinking the MIL. Do you have a manual? If it has multiple misfire, it should store a code (unless it's hitting the rev-limiter). In most modern OBD's the MIL will flash when multiple misfire is detected (unless it's hitting the limiter). These appear to have halfway decent OBD systems. You could take it in to service if all our "help" fails to ID the trouble.

Where is the OBD port situated?

[iceman]

I see these things have a diagnostic jack. They apparently have OBD, as well. Has anyone here ever hooked up a scanner to a PCX?
To the OP: Does the MIL (check engine) light come on and/or blink when the miss happens? The manual describes a procedure how to read any stored codes by blinking the MIL. Do you have a manual? If it has multiple misfire, it should store a code (unless it's hitting the rev-limiter). In most modern OBD's the MIL will flash when multiple misfire is detected (unless it's hitting the limiter). These appear to have halfway decent OBD systems. You could take it in to service if all our "help" fails to ID the trouble.

Where is the OBD port situated?

From memory, the service manual indicates you have to remove some panels and bits to get to it as it's usually attributable to major rather than minor problems. You can by these MIL codes scanners but they cost about £400 for good ones or cheap Ebay ones (do they work?). The flashes are a starting point - there is more info available to the scanner. Not often anyone on this forum has has a major MIL malfunction though.

[sendler2112]

Come on you guys. At 65 mph it's obviously just hitting the rev limiter like we have discussed many times. There is no need for any diagnostics. He can change to DrPulley sliders to get a few more mph in final gearing. Or go for the NCY variator and drive face to get 6 mph more when in a tail wind.

[j.d.b.]

To "You you": the manual shows the port located left of the battery's positive terminal.
Now, then. The O.P. WAS able to travel at 65 mph before this problem began. It is possible he's hitting the rev-limiter, but, it's also possible there's another problem(s). We're all just guessing at this point. O.P., have you done any further checking?

[sendler2112]

The O.P. WAS able to travel at 65 mph before this problem began.

Normal belt wear gradually diminishes the top gear ratio more and more with increasing mileage. He has 4,000 miles on the bike and can still hit 65 mph at the rev limiter. This is really good belt wear. And perfectly normal to feel the rev limiter fade in and out at these high speeds.

[j.d.b.]

So, O.P. what have you found? Enquiring minds want to know.....