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Surging at 3,500rpm


DanV

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Appreciate the help everyone

 

1999 800 bone stock expect for exhaust and air filter (added at 8,000 miles)

12,300 miles

Oil and coolant changed less than 100 miles ago

Temp while riding 185

Mileage normal

Gas age: old with stabilize

 

I have a recent development at low end rpm which occoured on the way to work today. I'm very familiar with the normal low end bog/slog on these v4s and this is different. Half way into my ride things changed, now when taking off until 3,500 it feels like I'm running on 2 cylinders and the sound is very similar to a 4 stroke dirt bike and different from the normal tone. Then at around 3,500 there is a significant surge of power and she runs and sounds like normal (with a second expected surge at 5500 as everything opens up)

 

Issue occours in first and second  gear and, while not as severe, can still be heard when in neutral and rolling on throttle

When at low rev the ride roughs up some, with pulsing inconsistent "power" but then 3500-4000 hits and it's back at full strength like nothing is wrong. Definitely not following the normal power band I'm used to with this bike.

 

Cant tell if idle is different or if my brain is playing tricks on me, wanting it to be different.

 

First step will be to change the plugs as I assume they are original

but coming into the end of season I don't think I'll go through another tank to run injector cleaner

 

Thoughts?

Not interested in moding for better performance, just want to return to normal

 

Thank again

 

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Some good maintenance for a nearly 20 year old bike that's done a lot of sitting would be to check for water in the fuel, and for my money remove the injectors and have them  bench cleaned.   Injector cleaner is fine for maintenance,  but does little for deposits that have built up over time.  Not saying that's the issue,  but even if it's not it's money well spent.   

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#1 Check the basics plug wires, vacuum lines, all thaaaat.

 

#2 I'd be checking the fuel filter.

 


I'd use winter to perform a full service though, including a throttle body sync, and if you're feeling adventurous, take off the injectors and send them to be cleaned and flow tested. 🙂

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How old is the battery?  I mean really?  How old is that battery?  How much sitting has that battery done?

 

Have you addressed the 5th Gen weak battery charging wiring?   Trouble in this area is inevitable with the 5th Gen VFR800 (gonna happen eventually, along with death and taxes).  Some 5th Gens go longer before having the issues, others have it at relatively low miles, but it's coming.  Installing a "VFRness" is a very good idea.

 

You'd be amazed at the problems a bad battery can cause.  And one of your comments, saying that things got worse during your ride, is a common indicator of a battery issue.

 

The 5th Gen's PGM-FI ECM is a pretty advanced unit for its time, but one thing it does not do is compensate ignition coil "dwell time" for low battery (electrical system voltage).  The ECM does compensate (correct) the fuel injector control pulse width (injection time) for low battery voltage.  If your battery is going bad and dragging down the bike's electrical system while you're riding it will negatively affect the performance of the spark plugs because with lower system voltage the coils will not reach full "saturation" during the ECM-commanded dwell time.  You may be experiencing intermittent weak spark plug performance (or a situation that just gets worse the longer/farther you ride it).

 

Bottom line analysis (disclaimer - opinions are like assholes, everybody's got one):  Problems that obviously/noticeably vary during operation, during the course of a ride, are often battery/electrical problems.

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Thanks guys, I'm going to dig in

 

Had battery tested today, tested fine but had a charge of 91% which is odd since the ride home was 35min which should have more than charged.

 

I replaced the R/R at around 5,000 miles.

 

Does this change anything?

Going after the plugs once my newborn gives me a free Saturday (should be sometime around 2028)

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31 minutes ago, DanV said:

Thanks guys, I'm going to dig in

 

Had battery tested today, tested fine but had a charge of 91% which is odd since the ride home was 35min which should have more than charged.

 

I replaced the R/R at around 5,000 miles.

 

Does this change anything?

Going after the plugs once my newborn gives me a free Saturday (should be sometime around 2028)

 

Grab a multimeter and test your charging at least (check on the battery terminals - engine hot and cold.) should get 13.6-14 @ idle and 14-14.6 at 5k rpm. If you do, probably move on to some other other suggestions as charging sounds good.

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I was just checking that

12.1 on idle

14.0 at 3500 and at 5000

So while not textbook I'm thinking there is a good current coming in

 

I also noticed that I must have topped off the oil a bit much. On the center stand I'm right at top line in the window.

I saw someone mention in other posts I may be drowning the motor. Think I need to drain a bit?

 

Plugs are on order

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1 hour ago, DanV said:

I was just checking that

12.1 on idle

14.0 at 3500 and at 5000

So while not textbook I'm thinking there is a good current coming in

 

 

Beware, Regulator/Rectifiers are sneaky things.  A failing R/R will sometimes give a good (enough) reading when the unit is cool, but after you've ridden for a bit and the R/R heats up its performance can change a lot (and usually for the worse).

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12.1 at idle is discharging the battery, technically.

 

Full stator test time.

 

1) Resistance to ground on all 3 legs. Should be infinite (aka no continuity to ground)

2) Check VAC output of the 3 legs (A to B, B to C, A to C) 25-35VAC at idle to 60-80VAC @ 5k rpm
 

Repeat test when the engine is at warm temps (i.e. the fan has kicked on at least once.)

 

Note, stators grounding can cause weird electrical issues with ignition, similar to what you describe. Ask how I know? 🙂 

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Thanks man

Started breaking into it. Figured I'd check voltage at battery with a new multimeter (didn't trust other one) and while I was testing, found another piece of the puzzle

 

Started up and at idle 14.0 holding steady (sounded good/normal)

 

Within 1min at idle dropped and DANCED between 13.0 and 13.5 and started running rougher

 

Figured I'd take video to show. By the time I got the camera set up now had dropped to 12's and dancing again. Sounding rougher

 

In the video I am adjusting the rpm via choke level and holding them steady (you can hear the surging) 

 

Once I take it up to 3000 we are at 14.1

 

Didn't get to check stator VAC, as the kid woke up and needed to go feed him

 

This change anything? Im not an electrical guy but that seems like RR right?

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Without the stator test, it is impossible to tell; I have money on the stator having continuity to ground, but I could be wrong.

 

The reason being is the RR can only convert what AC power it receives to DC, so if the regulator is not getting enough juice, it can't do it's job.

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So maybe I'm just not smart enough...

 

Assuming these are the wires coming off the stator since they are the only group of three going into RR

 

At idle all combination read 10

At 4000 rpm held at 10 but sometimes 11

 

Leads me to think I'm not doing this right

 

Connections we're shot so I put temp jumper wire on and checked. Same results

20180916_145855.jpg

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I think you might have a problem with your measurements (your multimeter testing results).

 

If I remember correctly you're supposed to disconnect the stator from the motorcycle's electrical system for testing.  If you test with the stator still connected to the R/R (and as a result, connected to the entire bike's electrical system) you'll get strange/unreliable results.  I remember reading explicit directions in one of my motorcycle service manuals to insure the stator is disconnected from the system for testing.

 

That's what Urbanengineer is referring to:

 

4 minutes ago, Urbanengineer said:

Under the right side cover is a natural colored plug with 3 yellow wires coming out of it. Unplug it there and see if it tests as mentioned, but do understand the bike can’t run forever with the stator unplugged. Nothing is charging the bike. 

 

However, the picture in your last post makes it look like somebody "hard-wired" the stator into the bike's electrical system, so you can't quickly disconnect the stator.  Is that correct?

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Yea you will definitely need to unhook the stator connector from the regulator (bike runs on battery only at this stage.) Then test wire 1 to wire 2, wire 1 to wire 3, and wire 2 to wire 3. Make sure the multimeter is on AC 

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Yes the connections were soldered in by shop who installed RR (unknown why)

 

The jumper wires were to remove the corroded connections but when tested all connections were same as operating connections

 

Will test tomorrow with stator disconnected

 

Thanks everyone!

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Did you repeat the test across all 3 legs? Is that what you are getting from them all?

 

Also, you need to test resistance to ground. it should be infinite

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Continuity test with stator disconnected from RR

 

All three legs tested against ground (multiple bolts) no tone. Bike running and off

 

When tested against each other all showed continuity

 

I'm not really sure what this means...

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Hmmmm, it sounds like you don't really know what you are doing.

Nothing wrong with that, a lot of people don't get electricity.

Voltage from stator is checked in AC volts, from ground to each winding.

Stator must be disconnected from RR.

At idle and 5000rpm, so you should end up with 6 readings, 3 for idle and three at 5000.

You want 25vAC or more at idle, and 60vAC or more at 5000.

Continuity is only checked with engine stopped, if it's running you can blow fuse in meter depending on type.

You also need a reading for resistance, not a tone. It needs to be infinity and nothing else.

I'll add that my bike (with lights on) drops to 12.8vDC at idle on a hot day, it allways reads 14.1vDC at over 2000rpm no matter the temperature.

It's been like that for years without a problem.

I have soldered connectors and upgraded wiring using an RR from a 2013 FJR1300 (FH020).

 

 

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2 hours ago, VFROZ said:

Voltage from stator is checked in AC volts, from ground to each winding.

Stator must be disconnected from RR.

Woops sorry VFROZ, might have you on a technicality here.

AC voltage from the Stator has no reference to ground, the 3phase windings and voltage generated is isolated from ground. AC voltage must be checked phase to phase across the three yellow stator output wires with NO meter probe to ground, as you've rightly stated disconnected from the RR.

So just as the AC voltage is isolated from ground, so to the windings = NO continuity to ground with any of the three wires.

Cheers.

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You’re dead right. 

Checked between phases, not to ground

Fingers went into gear before brain was engaged. 

Like the bloke needed more confusing. 

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Checked resistance to ground with ignition off on all three and got no reading at the 20 and 200 ohm setting just to be safe

 

Volatage at idle 1,500 rpm

A-B: 18.1

B-C: 18.0

A-C: 18.1

 

Volatage at 4,000 (don't have hands to work throttle and test)

A-B 41.2

B-C: 40.1

A-C: 42.0

 

Able to hit throttle and see 5,000 for a quick measurement

A-B: 44.3

 

Safe to assume, based on what you've said, while maybe not shot my stator is not putting out what it is supposed to?

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