Running On 3 Cylynders...

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Dreamster66

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Running On 3 Cylinders...

Just yesterday my 85 vmax seemed to lose power and after futher checking I found that the left rear cylinder isnt working.
I pulled the plug..... excessive amount of black carbon build-up on it. (NEW NGK plugs all the way around.)
I cleaned it and reinstalled..... seemed good after that, but a few minutes later....BAM..... happening again!
I get spark at the plug wire....but when I pull the plug wire from the plug....donesnt even die down and btw....I had just done the "shooting the shotgun" on the carbs last week plus resynced the carbs after I was done. (ran awesome after too!)
I even pulled the carb cover on that one and check to make sure nothing was plugging it.
I'm at a loss..... if anyone wants to give me ideas or even let me phone them to try to fix it I'd really appreciate it.
Randy
 
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Buster Hymen

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Dreamster66 said:
Just yesterday my 85 vmax seemed to lose power and after futher checking I found that the left rear cylinder isnt working.
I pulled the plug..... excessive amount of black carbon build-up on it. (NEW NGK plugs all the way around.)
I cleaned it and reinstalled..... seemed good after that, but a few minutes later....BAM..... happening again!
I get spark at the plug wire....but when I pull the plug wire from the plug....donesnt even die down and btw....I had just done the "shooting the shotgun" on the carbs last week plus resynced the carbs after I was done. (ran awesome after too!)
I even pulled the carb cover on that one and check to make sure nothing was plugging it.
I'm at a loss..... if anyone wants to give me ideas or even let me phone them to try to fix it I'd really appreciate it.
Randy

If you can pull the spark plug wire and the motor doesn't die down, I suspect it's an electical issue and not the carb. I know you said you are getting a spark at the end of the plug wire but try switching coils with the other cylinder and see if the problem follows to the other cylinder. I remember reading about a problem with a coil that was just marginal and would produce a spark when tested but when all hooked back up, it wouldn't work properly. Give it a try and let us know what happens.
 

one2dmax

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Sounds like you may want to do the shotgun again. You may have dislodged some more crap to plug the circuit up. However, You can also swap coils and or wires to see if the problem moves to another cylinder. You may want to trim about 1/2" off the wires where they plug into the coils as it is common for corrosion to build up in them.

Sean Morley
 

1FK00

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If it's ignition, it could be anything from the pickups, the '85's have four separate pickups, to the spark plug wires and anything in between. Not to ruin your day but the same thing happened to me a couple of summers ago and with a bit of ocilloscope work, I determined that it was the ignitor. Big bucks even from places like FlatOut. I did the exchange with RMSportmax for $175 and it works great. I think it's actually $25 cheaper now.

http://rmsportmax.com
 

Dreamster66

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coils didnt do anything for it.
I swapped the plug wires around on them(the ones that sit above the battery)
You dont have to change the wire connectors too...right? just swap the plug wires.
The plug gets wet and black....alot of carbon....I clean it and put it back in..... a few later...bam....doing it again!
Think I can do the shotgun on that single carb to see if that is it?
 

Dreamster66

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ok....just got thru doing the "shotgun" on that carb again.....cleaned the plug.... even tried a different plug.
Nothing!
I can "suffocate" that carb with a rag.... runs same...not even dieing out -even a little!
pulled the plug wire from the coil...started it....looks like a nice spark happening but doesnt die down at all.
I am at a total loss!!!!
If anyone wants to pm me or email me their phone # so I can call and describe and possibly eliminate some things, I'd really appreciate it!
(I live in Corning NY.... figured me calling would be my 25 cents.... I AM DESPARATE :Flush000: )
Randy
 

one2dmax

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You might try re-syncing the carbs. You would be surprised at the funny things that happen when they aren't in total sync.

Sean
 

Calimus

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Do a compression check just for piece of mind. If for any reason you arn't building proper compression, you can have all the spark and fuel you need and get nothing.

Anyone have the compression numbers for the Max handy? My clymer is at home.
 

mikemax04

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It should be about 150-160 just as a guess. What's really important is to take a compression check of all the cylinders and compare. All should be the same within 10-15lbs. You could also have a stuck valve or no clearance in the valves in that cyl., if it lacks compression.
 

robstabobsta

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hi, in my experiance, coils are known to die when they get warm, mine had identical problems that u describe, av ad loads of yams over the years and a few have suffered the dreaded spark/no spark syndrome
tip o the month for you
do the coil over plug mod and be done with it
sorted my max out straight away and it wasnt expensive and real easy to do, i used gsxr coil ova plugs but the consensus is that all will work, mine is a 1990 with almost 60 thou milles on clock:biglaugh:
 
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