Cannot rev past 6500 RPM under load

[n00bzi11a]

Sorry, have just re-read your opening post and realise you have already done that check, at least that is one thing it isn't but I would also do a continuity check from the unit to the ICU to rule that out as an issue as well.
Re the oil and fuel level warning lights, are you getting 12v on the red/ black wires? This also feeds the advance unit as well so an issue here may explain both problems?
If you do then have you checked the diode block?

Regarding the 12V on the red/black wire, I've never tested it
I think I do because if the ignition toggle switch is on the off position and I try to crank the engine, both bulbs light up as they should.
The diode block is that rectangle made from some kind of hard resin under the seat with an plug on it?

 

[n00bzi11a]

Where's your fuel switch now? In On-position or Res?

It has been always on the ON position . I don't recall trying the other position to check for any change during the stutters but I can try it.

 

[Radioguylogs]

I'm not sure if the breather is ok but riding without the fuel cap on didn't change anything.

That rules out the gas tank ventilation as the problem- it was easy to test.

 

[MaxMidnight]

Another issue that can or cannot be related. I don't seem to have a functioning fuel or oil light. When I hit the red kill switch, sometime the bike takes a while to shutdown (i think the relay or whatever is called, under the left scoop of the bike is acting weird) and only when the kill switch is on the off position (whether the engine still remains running or not) i get a slight slow glow from both oil and fuel lights.

This is the issue I was referring to but you seem to have sorted that?...or have I misunderstood the problem?

The diode block is #32 on the diagram below and is located near the headstock on the LH side.

 

[motoboy]

Make sure the float bowl hoses aren't pinched underneath the air box?

 

[Mr. Max]

Hows the spark plugs, are they all same colour etc? Might be worth to check them. On front cylinders spark plug wires are crossed (from left coil to right cylinder and vice versa) those are put wrong way many times.

 

[Jack Hammer]

My plug wires are not crossed and the bike works flawlessly. I have OEM coils and mounted in original location. The wires are not long enough to cross over. Nothing modified there in mine. Two factory versions?

 

[Fire-medic]

My plug wires are not crossed and the bike works flawlessly. I have OEM coils and mounted in original location. The wires are not long enough to cross over. Nothing modified there in mine. Two factory versions?

Mr. Max is just stating the OEM wiring arrangement: left front coil as you sit on the bike fires the right front cylinder, and right front coil fires the left front cylinder.



To help recall 'which cylinder is which,' start with the left rear cylinder and draw a capital letter 'N,' that's 1-2-3-4 or LR-LF-RR-RF with you being 'in the saddle.'

 

[Jack Hammer]

My arrangement is different, every coil fires to the cylinder below it and plug wires are not crossed. I wasn't questioning Mr Max, only wondering if there's two different setups. I didn't see any hacks in my wiring loom when I built my bike. The crossing over part was news to me.

 

[Fire-medic]

That's not the way the USA bikes are wired. Not aware of that (your setup) being the way it is for other countries' bikes. What country is your bike designed for? It says on the headstock badge, assuming it's still there.

The nylon 2-connector for each coil is on the outside of the front coils, behind the air scoops, and the high tension lead to each sparkplug is at the midline side-to-side of the bike, just behind the steering head, where the left coil fires the right plug and the right coil fires the left plug.

I think this is a good time to ask for pictures. I'm not the only person who is very interested to see the wiring to the coils and out of the coils to the sparkplugs.

 

[Jack Hammer]

Mine is originally a UK full power bike. I don't know much about it's previous history besides it was fully loaded with a shitloads of high end aftermarket stuff. The guy I bought it from had no idea. Even though I can say that I am fairly knowledgeable, there still were few very nice internal surprises in the bike. I bought it on the spot very fast. Some surprises still to discover obviously, coil location and direct HI wires conversion might be something but I begin to wonder about many things in my bike, as if it was some kind of a test mule in it's past. But then again, this thread is not about that.

 

[n00bzi11a]

This is the issue I was referring to but you seem to have sorted that?...or have I misunderstood the problem?

The diode block is #32 on the diagram below and is located near the headstock on the LH side.

View attachment 88235

I really have no idea what does de diode do. I only recall seeing it just hanging around. I'm going to put it on the check list for this weekend and search around for what is it's function.

 

[n00bzi11a]

Make sure the float bowl hoses aren't pinched underneath the air box?

The routing is good with those hoses. I've even did a test run without them and had no changes. Also the breather itself (where the hose connect on the carb) have been cleaned.

 

[Jack Hammer]

A diode is like a one-way valve, it let's electricity flow one way, preventing it the other way. A regulator.

 

[n00bzi11a]

Mr. Max is just stating the OEM wiring arrangement: left front coil as you sit on the bike fires the right front cylinder, and right front coil fires the left front cylinder.

View attachment 88257

To help recall 'which cylinder is which,' start with the left rear cylinder and draw a capital letter 'N,' that's 1-2-3-4 or LR-LF-RR-RF with you being 'in the saddle.'

About the Ignition wiring. I've been thinking about it but didn't change the order of anything since it only starts to get upset at 6.5k RPM and under load (in neutral i can rev it to around the redline without any issue, and I need to be carefull with the throttle not to over rev the thing)

I Can assure that in the front, the left coil is connected to the right cylinder and vice versa. The small plugs that feed the coils, I seem to recall that they are not long enough to reach each other.

However in the rear, each small plug that feed the coil can be mismatched... I've never changed to be honest. I'm thinking about doing it But I'm a bit affraid that it could detonate or something like that

 

[Jack Hammer]

That dude that was supposed to know what he was doing to let you buy this can of worms... He owes you a lot of money or at least ten big favors. Hope you bought the bike really cheap.

 

[n00bzi11a]

That's not the way the USA bikes are wired. Not aware of that (your setup) being the way it is for other countries' bikes. What country is your bike designed for? It says on the headstock badge, assuming it's still there.

The nylon 2-connector for each coil is on the outside of the front coils, behind the air scoops, and the high tension lead to each sparkplug is at the midline side-to-side of the bike, just behind the steering head, where the left coil fires the right plug and the right coil fires the left plug.

I think this is a good time to ask for pictures. I'm not the only person who is very interested to see the wiring to the coils and out of the coils to the sparkplugs.

I'll try to take some pictures and post them.

This Vmax was bought in France, but I'll need to confirm on the badge. Is the same one that has the VIN right?

 

[n00bzi11a]

That dude that was supposed to know what he was doing to let you buy this can of worms... He owes you a lot of money or at least ten big favors. Hope you bought the bike really cheap.

I really don't want to talk about it to much because it leaves me a bit unconfortable... It was the cheapest registered bike in the country! However this doesn't mean it was that cheap...

 

[MaxMidnight]

I have no idea if it is possible to check that your ignition is advancing with a strobe on the Max without dumping a load of oil.
Has anyone tried it?

 

[Jack Hammer]

The flywheel cover plug off while running the engine, bike stationary.