Right rear cylinder intermittently loses power

[gr8ded1]

Hi All, I'm new to the forum but have owned my '85 max for about 5 years.

I'm hoping someone has gone thru what I've gone thru and knows how to fix my issue. Since I bought the bike it has intermittently lost power around 3500 rpm.

I've replaced all the coils, plug wires, plugs, pickup coils. I even changed the entire wiring harness. Other work I've done is replacing the reg/rect and carb cleaning/sync.

The bike has kerker 4/2/1 and stage 7 jet, not sure if it's relevant but I figured more info is better.

I think the only option I have left is cdi? PLEASE HELP!!! I love my bike, but I'm on the verge of smashing it with a sledgehammer

I know it's losing spark in that cylinder because we put a spark tester on it.

 

[[email protected]]

http://www.vmaxforum.net/showthread.php?t=10124

 

[gr8ded1]

Thanks Mike. If I can't find the answer through other users here in the forum I'll definitely get in touch with Shawn before spending a cpl hundred on another part I may not need!

 

[gr8ded1]

Am I really the only person to have gone through this? I hoped I'd at least find suggestions as to what it may be.

 

[johnpclynch]

Could it be corrosion in your connectors like I had?
http://www.vmaxforum.net/showthread.php?p=195930#post195930

PS: Am I correct in saying that the right-rear cylinder is the same connection used for the RPM gauge/vboost trigger?
when you loose power does the gauge flick about the place? (ground short)

 

[95spfldmax]

Hi All, I'm new to the forum but have owned my '85 max for about 5 years.

I'm hoping someone has gone thru what I've gone thru and knows how to fix my issue. Since I bought the bike it has intermittently lost power around 3500 rpm.

I've replaced all the coils, plug wires, plugs, pickup coils. I even changed the entire wiring harness. Other work I've done is replacing the reg/rect and carb cleaning/sync.

The bike has kerker 4/2/1 and stage 7 jet, not sure if it's relevant but I figured more info is better.

I think the only option I have left is cdi? PLEASE HELP!!! I love my bike, but I'm on the verge of smashing it with a sledgehammer

I know it's losing spark in that cylinder because we put a spark tester on it.

It sounds like you already swapped out most everything in the ignition system. You might be ready to try the ignitor next. Sorry I couldn't be more helpful.

 

[gr8ded1]

My gauges don't jump around, the bike just feels a bit flat.

Forgive my ignorance, igniter=cdi box? Or no? Just want to make sure I'm swapping out everything possible!

I'm pretty sure the connectors are ok, but not positive...I'll check first thing when I'm home from work today

Please don't apologize! Everything you guys tell me will be checked if it hasnt been already!

 

[jfeagins]

Are you 100% sure of your fuel pressure?

Perhaps you are running out of gas as you approach higher RPMs?

You should be able to tell by the cycling of the pump when you first turn the key on. If it clicks repeatedly each and every time you turn it on, perhaps one, or both of the little one-way rubber valves in the pump has come loose and causing it not to supply enough fuel.

Just a thought........

 

[alorio1]

If its loosing spark on that one cylinder, my guess is its the CDI ignition control. Sean Morley will send you one and if thats the problem you buy it. Check with him to make sure I have my info straight on this.

 

[gr8ded1]

I think my fuel pump is ok, I get the clicking the first time I start the bike in the am, but not everytime. Also, the spark tester showed the intermittent loss of spark(only in that cylinder).

A friend of mine who is a mechanic thinks my stator may be failing and thinks this may be causing or contributing to the issue.

I'm leaning towards most of you guys' suggestion of tci/ignitor I've replaced damn near everything else!

I'm going to pm Sean and another member offered to loan me a tester...fingers crossed!

 

[one2dmax]

Email me directly. [email protected] - need address and year of bike with a request to borrow the electrical loaner stuff.

Sean

 

[alorio1]

Just for the heck of it you could swap coil connections and swap plug wires and see if the problem goes to the other side. If problem remains the same you could have a carb related problem or fuel delivery issue or even low compression on that cylinder....just a thought.

 

[gr8ded1]

Email sent Sean, thanks

 

[gr8ded1]

I actually have swapped coils(several times in fact!) in regards to that I actually have several extra used coils I picked up to make sure they weren't bad(swapped them out two or three times before a friend told me about the spark tester!)

 

[[email protected]]

A friend of mine who is a mechanic thinks my stator may be failing and thinks this may be causing or contributing to the issue.

I'm leaning towards most of you guys' suggestion of tci/ignitor I've replaced damn near everything else!

I'm no electrical guru but I would think if the stator was an issue it would be causing problems with more than just 1 cylinder? I've hear a few guys mention that their stators test fine when the bike is cold but the problem shows up when it gets hot.

I think you're on the right track with the TCI. Hopefully Sean has one to loan out. Let us know if you make any progress. Always good to hear a success story!

 

[gr8ded1]

Sean is setting me up with a loaner, thanks Mike! I'll let you know how I make out...fingers crossed!