running on 3 cylinders

[Hellboy]

Hi guys,

My Max starts and runs every time, but sometimes the right rear cylinder is not firing. It's funny (haha) that it runs so well that I had trouble being sure if it was running on all 4 or not. I now know the bike well enough that I can recognize it immediately. The strange thing is that all I have to do is pull the lead off of the plug and the put it back on once or twice and then it's fine??? I can hold it just at the top of the plug and here it ticking, a little farther and it kicks in and then sometimes when I click it all of the way on it quits. Do it again and then it's O.K. and doesn't stop until the next time or sometimes it won't do it again for weeks. Any ideas?
I'm using Nology hot wires and iridium plugs, all in what seem to be very good condition. There is the coolant hose clamp on that cylinder that touches or almost toucher the lead same as the front left, Arcing maybe? I've been very careful and have ruled out the coil side of things. I've pulled the coil side of the lead off and it is definitely sparking on that end. I look forward to any of your ideas or input.

I didn't know if this should be an engine or electrical topic so I posted it here.

Matt

 

[blaxmax]

It sounds like it is either the wire not twisted far enough into the housing or you are arcing off the hose clamp.

 

[scuff]

dielectric grease maybe that would help?

 

[Hellboy]

Thanks, because the wires came assembled, it didn't really occur to me to check the wire into the housing as far as being pulled out a bit. I think I'll also find another type of clamp if I can't get this one turned enough not to touch.
Don't know about the grease but I'll look into it, if it doesn't hurt, then why not?

Matt

 

[jfeagins]

Does any of this wierdness coincide with the fan operating on & off?

 

[Hellboy]

Does any of this wierdness coincide with the fan operating on & off?

No, it's always from a cold start after sitting.

 

[one2dmax]

The nology wires used to advertise that they needed to be run with a non-resistor type plug if I remember correctly.

 

[Hellboy]

The nology wires used to advertise that they needed to be run with a non-resistor type plug if I remember correctly.

I will check that Sean, thanks.

 

[Hellboy]

A quick update.
I found that my v-boost was actually only working intermittently. Squeezing the control box would cycle it open but then it wouldn't finish the cycle until I released it. Anyway, I unplugged it and now the bike has been running great and starting on all 4 cylinders. Maybe a coincidence??? I was thinking that any electrical problem might be able to cause other random electrical problems ie; spark???? Rode the Max 250 miles today with the wife on back with no problems whatsoever, touch wood.

Matt

 

[blaxmax]

A quick update.
I found that my v-boost was actually only working intermittently. Squeezing the control box would cycle it open but then it wouldn't finish the cycle until I released it. Anyway, I unplugged it and now the bike has been running great and starting on all 4 cylinders. Maybe a coincidence??? I was thinking that any electrical problem might be able to cause other random electrical problems ie; spark???? Rode the Max 250 miles today with the wife on back with no problems whatsoever, touch wood.

Matt

If you have a carb sync tool i would put it on and check the vacuum of the cylinder that was not getting as much gas. Set all a/f mixture screws to the highest vacuum you can get them. Then sync the carbs.
It sounds like when the venturi was partially open one cylinder was pulling more vacuum therefore sucking more gas.
I have my v-boost open at all times but i close it to set a/f and sync.
Good to hear that it's running well.

 

[Hellboy]

I do have a Synch Tool. I'll give That a Try , thanks for the input.

 

[Hellboy]

If you have a carb sync tool i would put it on and check the vacuum of the cylinder that was not getting as much gas. Set all a/f mixture screws to the highest vacuum you can get them. Then sync the carbs.
It sounds like when the venturi was partially open one cylinder was pulling more vacuum therefore sucking more gas.
I have my v-boost open at all times but i close it to set a/f and sync.
Good to hear that it's running well.

I've done what you said and do not see any difference In the vacuum from adjusting the A/F screws. I've have tried from 2-4 1/2 turns with no real difference in vacuum??? I'm back at about 2 1/2 turns. They are all synched and I've got 21 cc/hg at idle, 27 at 2000RPM and 34 at 3000RPM. The shop manual says it should be 7.9 inches at idle which is 20cc/mg so It's very close. Anyway, thanks. It is running well and I'll wait for the new V-boost control.

Matt

 

[blaxmax]

Some guys try to find the happy medium between stumbles at each end but with a carbtune mine pulls highest vacuum between 2 and 3 turns out at 1200 rpm.
I used one of these on a valkyrie last week and it worked very well.
I did bench sync them first though.
http://www.homedepot.com/p/Ryobi-4-to-600-Degree-Non-Contact-Infrared-Thermometer-IR001/100674438

 

[Hellboy]

The nology wires used to advertise that they needed to be run with a non-resistor type plug if I remember correctly.

Thanks Sean, I have gone back to a standard non-resistor plug and it is running nicely. Don't know if that has anything to do with it, but it certainly hasn't hurt.

Matt

 

[Hellboy]

O.K. here I go again. My bike is running beautifully once I get it on all 4 cylinders. I thought I had this sorted but it is actually still starting on only 3 cylinders sometimes, most times now. The non running cylinder is random, usually the front left or rear right but not always. I've removed the Nology wires and I'm using Iridium plugs at the moment. I've used standard plugs, non resistor plugs and iridium with the exact same symptoms. I think it has something to do with resistance. If I pull the plug wire off of the problem cylinder and just hold it just at the top of the plug but not quite off, it will then fire and run nicely. If I push it back on it will stop, almost remove it and it's good and so on. If I leave it almost off until it warms up, I can then push it on and it will then keep firing and all is well. All I can think is that by pulling the plug wire I am increasing resistance and then after the bike warms up I would guess the resistance is also increased with the heat??? Is this possible and if so, would it be due to the ignition control unit failing? It's not that big of a problem now that I know how to get it running every time in just a few minutes but I certainly want to fix it. Any advice would be appreciated.

Matt

 

[lethal dose]

Do the affected cylinders kick in once you get past 1/4-1/2 throttle?

 

[Hellboy]

Do the affected cylinders kick in once you get past 1/4-1/2 throttle?

No they don't. I can rev it quite high and it remains on 3.

 

[Hellboy]

By the way. Once it is warm after riding it will then start on all 4 after stopping. Only seems to be from cold.

Matt

 

[lethal dose]

Have you tried swapping coils around?

 

[Hellboy]

No I haven't due to the fact that at some point each cylinder has done it, I didn't see the point.

Matt