Power/Speedo problem

brian48130 · 05-04-2004, 7:19 PM

My vfr has 20k miles on it (only about 500 mine). I noticed recently that it would stagger when the throttle was wide open. I've been meaning to open it up and check the carbs. I just took it for a ride today after replacing the battery, and when warming up in neutral the speedo started jumping all over the place. The tach was jumpy too, not nearly as bad though. You could feel the power was really on-and-off too. I was desperate to ride (my cbr's clutch snapped and the vfr battery had been unreliable), so I took it out. The problem seemed to be worse with low throttle, and didn't come back again until it was wide open. I thoght the carbs needed to be cleaned, but with the speedo bouncing around from 0-160 I'm thinking the problem might be something else. I can't imagine what, though, maybe it's two different problems. Any suggestions?

I can't afford to take it to a shop right now and I NEED my motorcycle fix.

RPinOZ · 05-05-2004, 7:49 PM

Quote:

Originally Posted by brian48130

My vfr has 20k miles on it (only about 500 mine). I noticed recently that it would stagger when the throttle was wide open. I've been meaning to open it up and check the carbs. I just took it for a ride today after replacing the battery, and when warming up in neutral the speedo started jumping all over the place. The tach was jumpy too, not nearly as bad though. You could feel the power was really on-and-off too. I was desperate to ride (my cbr's clutch snapped and the vfr battery had been unreliable), so I took it out. The problem seemed to be worse with low throttle, and didn't come back again until it was wide open. I thoght the carbs needed to be cleaned, but with the speedo bouncing around from 0-160 I'm thinking the problem might be something else. I can't imagine what, though, maybe it's two different problems. Any suggestions?

I can't afford to take it to a shop right now and I NEED my motorcycle fix.

Brian my last bike was a 96 VFR750. What you describe sounds like the reg/rec is about to fail or has or the battery may have dropped a cell. Low battery voltage causes the wild movement of the speedo which is electronic. It may also cause running problems like you describe. The R/R is the achilles heel of this bike which is otherwise pretty bulletproof (apart from the tendency of the tail section plastic to crack up). I'd get the bike to an autoelectrician or check out the US VFR list faq for diagnostic procedures.
Cheers
RP

brian48130 · 05-06-2004, 8:45 PM

It died completely today. The problem was the battery terminals were loose. I tightened them up, no problems now. I haven't rev'ed it up real hard, so it may still have the lugging problem with full throttle.

I already had the r/r go on me a month ago. I replaced it with a new one from Honda, that had cooling fins. I superglued a 60mm PC fan onto it and wired it into the taillight like I had seen somewhere online. The new part was really expensive, though. I can't believe it wasn't recalled, I hear it's a really common problem.

brian48130 · 05-06-2004, 8:49 PM

Oh, by the way. I noticed some smoke coming from the tailsection when my r/r died. It was running fine the whole time. I thought the slipon was melting the plastic, and I poured water on it...

I figured it was electrical after it failed to go out. Somehow no fuses were blown. The r/r was so fried i was able to stick my finger through it and it was nothing but ash (except the metal).

RPinOZ · 05-06-2004, 9:14 PM

Quote:

Originally Posted by brian48130

Oh, by the way. I noticed some smoke coming from the tailsection when my r/r died. It was running fine the whole time. I thought the slipon was melting the plastic, and I poured water on it...

I figured it was electrical after it failed to go out. Somehow no fuses were blown. The r/r was so fried i was able to stick my finger through it and it was nothing but ash (except the metal).

When mine went I was out in the mountains. We stopped to look at the scenery and then the bike wouldn't start of the starter so I push started it. The speedo was moving like you described. I got another 4 or 5 k before it died completely. There was a little patch of molten metal on the inside of the tail fairing and a hole in the R/R. I replaced it with a new OEM one with a big heat sink and routed a 3' length of 1" pre-heater hose from the right fake ram air intake through the frame to the R/R. Here's a pic
http://www.ozvfr.net/gallery/Richard-%40-WP/aaj
Looks ugly but you don't see it once the fairing is on and I got about 20,000 miles out of that R/R before the bike got rear ended and written off. I tested it and it made the R/R run about 20 degC cooler in ambient temp of 30 degC.

brian48130 · 05-08-2004, 12:42 PM

Quality work. I'm surprised it fits under the fairing, though?

The PC fan makes a cool humming sound, though

After having a couple fuel injected bikes I'm always dissapointed to turn the key on the vfr and hear nothing.

CBRVFR · 05-08-2004, 12:51 PM

I carry a spare on the bike, so the original will never burn out.

brian48130 · 05-09-2004, 1:35 AM

Just how often do these things fail?

Good to see yet another person from Ann Arbor.

CBRVFR · 05-09-2004, 11:57 AM

I guess there were some bad replacements that weren't reliable at all, and some of the old honda ones might fail within 20K.. OTOH, there are high mileage bikes out there with the original.

The RR failures stand out because they are virtually the only weak link (from a longevity/reliability standpoint) on the bike. It's annoying for VFR owners who ride tens of thousands of miles per year. My '92 has only 30K miles, because it's never had the garage to itself. It's got the original plus the spare, which is the new finned and - pentium fanned model. . A lot of guys add a voltmeter so they can more effectively obsess about tenths of volts, but I personally think that just causes the RR to fail.
(What, no faith? )

We should ride sometime - PM me when everything's runnin'

Dave

brian48130 · 05-09-2004, 4:21 PM

Quote:

Originally Posted by CBRVFR

I guess there were some bad replacements that weren't reliable at all, and some of the old honda ones might fail within 20K.. OTOH, there are high mileage bikes out there with the original.

The RR failures stand out because they are virtually the only weak link (from a longevity/reliability standpoint) on the bike. It's annoying for VFR owners who ride tens of thousands of miles per year. My '92 has only 30K miles, because it's never had the garage to itself. It's got the original plus the spare, which is the new finned and - pentium fanned model. . A lot of guys add a voltmeter so they can more effectively obsess about tenths of volts, but I personally think that just causes the RR to fail.
(What, no faith? )

We should ride sometime - PM me when everything's runnin'

Dave

Cool, will do. I just need to fix my battery and tighten the slip-on.