Vmax running issue

[Maxmadd]

Hi there, another newbie to forums here!
I have an 85 vmax with a bad missfire/splutter between 3-6rpm that clears with more throttle.
So far I've had the carbs removed, diaphragms replaced and sliders checked. Carbs were cleaned and refitted then set up on the bike.
I've replaced the stator that basically blew up! New battery and replaced the air box with pods and fitted new plugs.
Did the wire from R/R direct to battery pole as recommended. I have good battery power and supply for charging etc but theres still the misfire/splutter.
Check/replace coils?
The previous owner added an additional vboost switch to work at 3000rpm but if I switch that on when riding the misfire/splutter gets worse?
Not sure if that mod is effecting the bike even if turned off?
Also the flasher relay is apparently faulty but it also works the CDI unit as bike wont run without it so maybe this is also causing an issue? Have purchased new relay anyway to get indicators working (am thinking of wiring in a universal flasher relay just to get it through MOT while I wait for new relay to arrive).
My friend whos an electrician did suggest replacing the R/R as this my of been damaged when stator blew as they normally over power before going bang?!
Anyway, sorry for the lengthy post but any ideas or help appreciated

 

[Fire-medic]

Throw a multi-meter onto the battery or the leads to the + and -- wires from the R/R to it. Read the voltage at idle, and then at say 4-5K RPM. If it's much-over 14 volts DC your R/R is going to cause battery problems, overcharging. Refer to the factory service manual:
http://vmoa.net/VMX12-Service-Manual01.pdf
I suspect that your switch to pods has something to do with the rough running mid-range. I don't think the VBoost switch has anything to do with the problem, but if you eliminate it, and things improve, it did! Go-ahead and eliminate the switch, and see what happens.


NOTE: there is an overlap on this schematic!

 

[StevieJ]

Hi there, another newbie to forums here!
I have an 85 vmax with a bad missfire/splutter between 3-6rpm that clears with more throttle.
So far I've had the carbs removed, diaphragms replaced and sliders checked. Carbs were cleaned and refitted then set up on the bike.
I've replaced the stator that basically blew up! New battery and replaced the air box with pods and fitted new plugs.
Did the wire from R/R direct to battery pole as recommended. I have good battery power and supply for charging etc but theres still the misfire/splutter.
Check/replace coils?
The previous owner added an additional vboost switch to work at 3000rpm but if I switch that on when riding the misfire/splutter gets worse?
Not sure if that mod is effecting the bike even if turned off?
Also the flasher relay is apparently faulty but it also works the CDI unit as bike wont run without it so maybe this is also causing an issue? Have purchased new relay anyway to get indicators working (am thinking of wiring in a universal flasher relay just to get it through MOT while I wait for new relay to arrive).
My friend whos an electrician did suggest replacing the R/R as this my of been damaged when stator blew as they normally over power before going bang?!
Anyway, sorry for the lengthy post but any ideas or help appreciated.

The V-boost switch mod shouldn't have anything to do with it... Sounds like one of your four carbs has a valve catching at a certain point...or blockage on one or more of your fuel lines... There is a fuel line block under your carbs that can get gummed up and needs to be wire reemed every once in a while...

 

[02GF74]

I have an 85 vmax
Also the flasher relay is apparently faulty but it also works the CDI unit as bike wont run without it so maybe this is also causing an issue? Have purchased new relay anyway to get indicators working (am thinking of wiring in a universal flasher relay just to get it through MOT while I wait for new relay to arrive).

According to the manual, the early models have a combined flasher relay and starter relay.
The flasher unit has automatic cancelling so by fitting an after market unit you will lose that feature.... not a biiggie as long as you remember to turnthe flasher off.
When you say the flasher relay is apparently faulty - which part of it is not working - the turn signal or start relay?

It should be possible to bypass the starter relay but obviously that loses the safety feature such as the engine running when in gear and the side stand down.

.... and here's the diagram with no overlap.

 

[John Dooh]

According to the manual, the early models have a combined flasher relay and starter relay.
The flasher unit has automatic cancelling so by fitting an after market unit you will lose that feature.... not a biiggie as long as you remember to turnthe flasher off.
When you say the flasher relay is apparently faulty - which part of it is not working - the turn signal or start relay?

It should be possible to bypass the starter relay but obviously that loses the safety feature such as the engine running when in gear and the side stand down.

.... and here's the diagram with no overlap.

HI,

I've a similar problem. Yesterday my BIke ran in 3 x starting, after 8 months of doing nothing in the garage...
I have a 1985 California model and the only thing i've changed in my electric system, are the original flash bulbs for LED turnsignal lights. and my taiil lihght for a LED light.
With the resistors etc it worked for almost 10 years...

SInce last year i stalled my bike in the garage after noticing my flashlights did not work anymore.
I wanted to replace the Turnsignal Relay and bought a second hand thing which they said it was similar to the original.

After connecting it, it still did not work. Replaced the "faulty" original back. And now my bike does not start anymore.
All my lights and dasboard lights, horn works fine.
When turning the key...i don't hear my vboost working. Check the Ill Switch, Side stand connector.... my green neutral light is working fione.
It looks like i start it with my side stand out or when i'm a a gear, or my clutch handle is out. (al the 3 emergency **** )

Is it possible that by connecting a relay that was not right could cause this issue?
I'vve ordere an original Relay no... but i'm anxious it won't'start.

All the fuses 4 under the cover and themain fuse neaur the battery are just fine.

PLease help...

John

 

[one2dmax]

Sounds like the kill switch is not working if you have no vboost or fuel pump when first turning the key on.