Idle problem resolved now back to the high rpm miss...

[HDKILA]

Ok folks I figured out my high idle and I still am having a high speed miss.

I have ruled out anything in the carbs and my synch is good to go.

The bike runs like a freight train until 6-7k rpms and then misses all over the place until redline.

I have yellow spark plug wires and have checked those with the multi-meter and they seems fine. I think I have checked my coils correctly.

The only thing I saw when I had the carbs off was that my carb boots seemed a little bit tore up on the inside lip where they narrow to connect to the motor. I have sprayed the hell out of them with starter fluid and nothing seems to be leaking. But this is at idle...

I feel like the bike is starving for something once I go wot on her...fuel or air I just dont know...

I do get an occasional pop through my supertrapps on decel sometimes but nothing major...

Where should I start with this?

Thanks,
Abe

 

[naughtyG]

I know you're saying you're ruling out everything in carbs, but still:

- problems around 6k could indicate a V-boost issue. It should start opening at 5,750 and be fully open by 6000. Have you checked / adjusted your V-boost cable?

- while you had the carbs off, did you check your V-boost butterflies?

- also maybe try unplugging the V-boost motor altogether and see what happens

I believe there also is a vacuum ignition advance on the V-max. Not 100% sure how to troubleshoot it, but I'd go to the service manual and look this up next.

 

[HDKILA]

I know you're saying you're ruling out everything in carbs, but still:

- problems around 6k could indicate a V-boost issue. It should start opening at 5,750 and be fully open by 6000. Have you checked / adjusted your V-boost cable?

- while you had the carbs off, did you check your V-boost butterflies?

- also maybe try unplugging the V-boost motor altogether and see what happens

I believe there also is a vacuum ignition advance on the V-max. Not 100% sure how to troubleshoot it, but I'd go to the service manual and look this up next.

Already tried disconnecting the vboost and have checked that out...

I will look into the vacuum ignition advance.

 

[HDKILA]

I was reading throught this igntion advance post

http://www.vmaxforum.net/showthread.php?t=5492&page=2

If I simply unplug the connector would this be an easy way to eliminate if this is the problem?

 

[naughtyG]

from that thread I'd say it would be better to unhook the vacuum tube. I'm no expert on this tho, that's why I recommended going for the Yamaha Service Manual.

If you haven't got one you can d/l it from www.vmaxoutlaw.com

 

[maleko89]

Follow vacuum pickup hose to the pressure sensor. On bottom of that you should see a 3-wire connector. With key on there should be 2 volts DC at black/red wire.

 

[maleko89]

I was reading throught this igntion advance post

http://www.vmaxforum.net/showthread.php?t=5492&page=2

If I simply unplug the connector would this be an easy way to eliminate if this is the problem?

If you unplug the connector or hose then the ignitor wouldn't apply supplemental advance. Not sure how that would run.

 

[HDKILA]

If you unplug the connector or hose then the ignitor wouldn't apply supplemental advance. Not sure how that would run.

This is the hose that comes from where I connect to synch on the left side correct? It says it connects to the vboost sensor?

 

[maleko89]

That's the correct hose. That's the pressure sensor and has nothing to do with vboost. It sends signals to ignition unit on when to apply ignition advance.

 

[naughtyG]

So Mark, waddya reckon on Abe's high revs problem? Ignition advance a possibility? I know you've been thru his carbs - do you think he could have a jetting problem?

 

[maleko89]

His jetting is stock and should work fine with stock headers and Supertrapps. It could be carbs. Abe, one thing I neglected to do was check wet float level after running on my bike. Give that a try and make sure they are within spec. If fuel level was too low the bowls would empty at higher rpms. Boots could also be a problem. Otherwise, would start at plugs to see what they look like and verify correct gap.

 

[HDKILA]

I have had this high rpm cutout since I have owned this bike.

At first I was sure it was the carbs because i had rust in the tank and the float bowl were dirty so I sent my carbs to mark along with my airbox.

He adjusted and fixed a few things and test rode and had no high rpm cutout.

So that tells me that I have either a vacum or electrical problem at this point.

It pulls so strong up until that point and then falls on it's face and recovers fairly quickly. It seems like since it recovers somethint is getting blocked or overdone?

 

[maleko89]

Your floats were rich when I got them so it sounds like it could be your ignition or boots. I'll get my spares cleaned up and in the mail.

 

[HDKILA]

Follow vacuum pickup hose to the pressure sensor. On bottom of that you should see a 3-wire connector. With key on there should be 2 volts DC at black/red wire.

Just checked that and it came up EXACTLY 2.0

I suppose it's time for those boots...u still need my address?

 

[maleko89]

Yes please. I promise I won't spam it. If this doesn't work I can send you my pressure sensor and ignitor to try. I'm winterizing the beastie tomorrow.