Rear cylinders not firing at idle

[MANA1]

I'll post another video tomorrow after the carb clean and with the rear coils disconnected. Coil #1 makes little difference to the way the bike idles. Don't want to piss off my neighbors running my bike this time of night. Thanks for staying with me in my pursuit of snuffing out this monkey. What did you guys think about the first video??

 

[naughtyG]

TBH to me it didn't sound that bad at all, but it's hard to tell from a vid..

You should talk to Sean and/or Kyle, they may be able to arrange a complete carb rack swap so you can make sure your problem is carb-related!

 

[Rusty McNeil]

Spark plugs are new, wires and caps swapped out. Secondary coil test on coil #3 tested 30.9 instead of the spec 13.7 ohms. Swapped out the rear coils but it made no difference. Its strange how the rear cylinders seem to fire with half the power compared to the front.

Have you checked your coil grounds, if not mistaken I believe the core bar is also the other end of the high voltage (Secondary) part of the coil.

Did you mean "13.7Kohms or did you really read 13.7 ohms secondary?

Are you reading them thru the plug wire or removing the wire and reading direct to the little prong down in there?

Having them plugged into the TCI also effects some readings, whcih I'm sure you probably already know.

 

[MANA1]

I took the readings from the plug wire to the coil connecter 13.7 k ohms on #1. Stripped carbs and used a piece of guitar wire (high e) and was able to get a little bit further down the passage that leads to the A/F screw. Put the carbs back on and low and behold..... same shitty idle. Sorry guys, I was to pissed off to take another video. Decided to get a case of beer and drink and stare at my bike. Maybe giving Mr. Max the "evil eye" will scare it to work right. Lol. If anyone has a working spare rack of carbs I could borrow I would be eternally grateful. My only other option is to take my carbs to a Suzuki stealership and get bent over.

 

[sdt354]

Can someone who has had this problem tell me how you resolved it.

Covering the rear carbs make no difference in the idle of my bike. Covering #2 or #4 makes the engine stumble. I get gas on my hand and I can feel a slight vaccum but not as strong as the front carbs. Could not find a vaccum leak anywhere. Would'nt a major vaccum leak increase the idle??

Found out something weird..... rechecked my float level (again):ummm: on #1 carb (problem carb) and it was 22mm. turned the key off and on to activate the fuel pump and got a reading of 12mm. I tried blowing air into the clear measurement tube and the level changed back to 16mm. Guess I need to replace the float needle assembly.

You might be on to something there. The needles could cause flooding, enough to foul the plugs. I hope this resolves the issue. Don't forget to sync when done.
Steve

 

[MANA1]

Have you checked your coil grounds, if not mistaken I believe the core bar is also the other end of the high voltage (Secondary) part of the coil.

Did you mean "13.7Kohms or did you really read 13.7 ohms secondary?

Are you reading them thru the plug wire or removing the wire and reading direct to the little prong down in there?

Having them plugged into the TCI also effects some readings, whcih I'm sure you probably already know.

Not sure how to check the "coil ground". Could you explain. :confused2:

 

[Rusty McNeil]

Not sure how to check the "coil ground". Could you explain. :confused2:

It's pretty much going to get its ground through the mounting points. To check it.

Remove the plug wire
Put and ohmmeter across the Plug wire point on the coil and to the metal mounting bar or the coil. Should read cool resistance here of around 13kohms
Do the same check again using the Plug wire port and a ground point on the chassis, perhaps the ground wire by the oil fill hole or what not
The two reading should be about the same, any increase in that number indicates the mounting point for the coil isn't well grounded.

I ended up running a hard ground from every coil mounting point to the same system of grounds tying my engine, the frame, the separate ground I ran to the r/r, and to the battery negative.

Hope this helps

EDIT!
I'm wrong and will admit it. I just did some checking and discovered that the core/mounting bar on the coil is common to NEITHER side of the coil.
The high voltage side of the coil gets its ground through one of the two primary leads back through the TCI.
If your checking high voltage side of coil from plug wire port to one of the unplugged primary leads, and doing this with the primary connector unplugged, it should give you true coil resistance. If your doing it from plug wire port and a grounded chassis point (primary lead connector plugged in) and the number is higher then it's probably a poor cnnection on the primary lead system back to the TCI or the TCI itself.

Sorry for the bad info.

 

[MANA1]

Appreciate any info that comes my way. I think I was able to double tap the monkey. Spent a hour doing the shotgun proceedure, figured compressed air was cheaper than a mechanic at the stealership. Rechecked every plug connection and ground wire. Yanked the fuel pump and gave it a good cleaning (very fine rust particles was caked on the inside) used some cotton swabs and cleaned thoroughly including the inlet and outlet pipes. Slapped everything back together and......praise the gods of war, Mr.Max fired on all cylinders. After a quick sync my bike is now 90% back to normal. Thanks a bunch for all the help.

 

[MANA1]

I found the last piece of the puzzle that was causing my excessive fuel consumption. Long story short, my coasting enrichner plungers on #1 and #2 carbs were not closing all the way. I put my finger on the hole on top of the carbs and even with the choke lever fully closed I could feel the vacuum on my finger tip. Now Mr.Max is 95%. I just need to figure out the best rr to replace my fried oem rr. Any suggestions? Also if anyone is using the cop from a r6.

 

[naughtyG]

If you found rust dust inside any components of your fuel system you really need to double-check your tank as if it's rusty your problems will only come back. You must either replace the tank, or seal the rust with a product such as POR-15.

Any modern RR will do as they pretty much all do the same job - convert 3-phase alternative current to 12V DC. If you get a Vmax one make sure to get the newer finned version, and it helps to run both a negative and a positive wire straight to the battery (eliminating the shit crimps in the OEM harness). Ask Sean Morley (one2dmax) for a new one, or Kyle Clegg (CaptainKyle) for a S/H one.

Also ask Gannon (88vmx12) any COP question - he knows best which model works.

 

[MANA1]

Your right about my tank, been fighting with fine rust particles for awhile now. Guess I need to bite the bullet and yank the tank and seal it once and for all.
I am leaning towards getting a rr and coil set from a r1 or r6. My old rr was purchased from a dealership 3 years ago and cost me a pretty penny. Hoping the r series rr will last a little longer.