Once Cylinder Missing Swtiches Front to Back

[jbasford]

Anyone ever have this crazy problem.... One cyclinder is cutting out, but it switches. Sometimes front, sometimes rear. I check by pulling the sparkpug wire to see if the bike still runs when I pull one off.

Any idea of what could cause this or what I can check/ replace to fix the problem. Everyonce and a while It will run on both Cyclinders, but not long enough to realy be ridable.
Not sure if its related, but the tacometer stopped working, and I notice when its running on once cylinder it charges at 12.5V and when both actually kickin it jumps to 13-13.5V.

[AMCQ46]

those voltages dont sound right and even if it is not the cayuse of your mystery misfire you should start to look at the charging system.
1) new Reg/Rec
2) check the connectors to 1) to see if they have overheated.
3) check wiring back to the generator. the 2 yellow wires.

then check the connectors to the 2 ECU's by the tail light bulbs.

did the bike have an alarm fitted / removed? could be you have some dodgy wiring hidden under some insulation tape

[sirch345]

I'll wait for jbasford to get back and read this, then I'll move this to the "Workshop" section".

I agree with AMcQ, you need to sort your charging out first regardless, as 12.5 volts is below the required limit.
It should be reading between 13.5 and 15.5 volts with the engine running at the battery terminals.

Chris.

[tony.mon]

and I notice when its running on once cylinder it charges at 12.5V and when both actually kickin it jumps to 13-13.5V.

Or to put it another way, once it's getting the right voltage, it runs fine.....

[jbasford]

The terminals pluging into the rectifire are a little burned (melted at end)
I replaced the rectifire
The wires/plug to the ECU's look fine.
I replaced the large ECU box (I thought the little one just controled blinkers and lights??) I replaced the coils
Still same problem.

When you say genorator. Do you mean stator. I think it is ok, I was told checking wires from the rectifire if I have continuity between the 3 yellows and the green ground does not have continituity to the yellows the stator is good.

I dont see any evidence of an alarm system, but the previous own did splice an integrated tail light.

Any ideas of what to look at next

[Ckennedy]

Almost sounds like a fault in the loom. Lloyd had similar trouble a little while a go and replaced the whole loom and replaced the breather pipes for the tank I think and all was right as rain.

Might be the same problem. I'm sure he will be along at some point to say

[lloydie]

Think mine was just the breather being the wrong size and wrong location

[VTRDark]

See the following:
http://www.vtr1000.org/phpBB3/viewtopic ... 31&t=28771

and give the charging system a thorough going over before anything else, including replacing any burnt plug connectors, earth's etc. You may as well check the engine earth at the same time.

(:-})

[Furrybiker]

Love your Freudian slip "rectifire" so true!

[sirch345]

The terminals pluging into the rectifire are a little burned (melted at end)
I replaced the rectifire
The wires/plug to the ECU's look fine.
I replaced the large ECU box (I thought the little one just controled blinkers and lights??) I replaced the coils
Still same problem.

When you say genorator. Do you mean stator. I think it is ok, I was told checking wires from the rectifire if I have continuity between the 3 yellows and the green ground does not have continituity to the yellows the stator is good.

I dont see any evidence of an alarm system, but the previous own did splice an integrated tail light.

Any ideas of what to look at next

Now moved to this section.

Having now carried out the above work, what voltage readings are you now getting at the battery terminals with the engine running? Is it still fluctuating?
You readings from the alternator (stator as you call it) test sounds fine.

Chris.

[darkember]

Bad plugs

[jbasford]

When you say loom. Do you mean wireing harness? I found someone parting out one. So he is send me the wire harness. I'll let you know if that makes a difference.

Breather Pipes? What adjustment is their in that. Isnt that just the welded tube coming out of the bottom of the tank.
Spark plugs are new

[VTRDark]

When you say loom. Do you mean wireing harness?

Yes both are the same. It's reasonably easy to change the complete loom. You will need to remove the carbs and cowl to run the TPS/Fan wires across. Take pictures so you remember where things run/connect to, otherwise there's pics I have uploaded on the form somewhere. Sorry I have no time to right now to search and link to them.

(:-})