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Losing power at high rpms


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MistahT

Mistah T
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Some of you might have figured out I'M BACK ON THE ROAD!! :D

I did a street fighter, didn't like it, and just converted my bike back to stock Raven body. Now I'm having an issue... I haven't ridden much since doctor cleared my arms for use, but twice I've gone WOT in second gear up through the revs. Both times I've had a sudden loss of power around 9 or 10k. I've tried the top gear clutch test and clutch seems to be fine. New plugs last fall, just got brand new Pilot Road 4 tires, so they aren't slipping.

I'll try to recreate this today on my way home. Maybe I'm not aware and hitting rev limiter? I don't think so. Do revs jump when power cuts? No idea, I'll check this time out. Haven't done a fresh oil change this season cause I haven't been riding. Planning on doing one next week. Could this be my issue?

Thanks in advance for the help everyone!

Matthew
 
Glad to hear your back on the road MistahT, if I remember right I believe your running a power commander or juice box right? Maybe check your fuel maps?


-Uncle Al
 
arocholl said:
Glad to hear your back on the road MistahT, if I remember right I believe your running a power commander or juice box right? Maybe check your fuel maps?


-Uncle Al
Click to expand...
Yeah, never know. Could have gotten corrupted somehow. $hit happens. Hopefully it's that easy.
 
Just wiped and reloaded Adv Rev B. Twice I could hit the limiter, but three times I had it cut power hard between 9 and 10k. After shifting up once I still had a loss of power for a moment. Cruising around at a steady speed the bike bucked once. No time tonight to get down to the spark plugs.
 
Take the power commander out of the picture completely and test?
 
I believe MistahT is running a full exhaust, with a decatted bike, you'd risk leaning the motor out without the power commander.

The fact that you were able to hit the limiter a couple times makes me think it's some type of spark or wiring issue. Just my opinion though.


-Uncle Al
 
arocholl said:
I believe MistahT is running a full exhaust, with a decatted bike, you'd risk leaning the motor out without the power commander.

The fact that you were able to hit the limiter a couple times makes me think it's some type of spark or wiring issue. Just my opinion though.


-Uncle Al
Click to expand...

For a simple test, there is no harm in unhooking it. It would take many, many miles to do any sort of damage.
 
T, if I remember correctly (not really, I'm looking at a map)

http://image.motorcyclistonline.com...++w760+ar1/122_1003_10_o+yamaha_fz6r+dyno.jpg

The torque curve of the 6r peaks at about 8k rpm.

HP peaks just short of 10k rpm.

I don't know about your mods, but that's pretty much what you're describing. Basically, 8k rpm is the sweet spot. After that, you've got to tweak it.

I can't help you with the Juice Box. I had one on my CB900 SS, and it was more trouble to me than it was worth.
 
JSP said:
For a simple test, there is no harm in unhooking it. It would take many, many miles to do any sort of damage.
Click to expand...


You are probably right, personally, I'm just not willing to take the chance. You never know what can happen if you get a bad tank of gas. Had that happen to a buddy with an RX-7 but that's an apples to oranges comparison.


-Uncle Al
 
Couldn't get it to duplicate on this morning's commute. I put gas in it 100 miles ago, but otherwise it's had the gas sitting since winter and broken arm time... made it's just the junk from the bottom of the tank?

Will be unhooking the PC tomorrow when I get some time. Right now It's ride to work, do work, ride home, do more work, sleep, repeat.
 
MistahT said:
Couldn't get it to duplicate on this morning's commute. I put gas in it 100 miles ago, but otherwise it's had the gas sitting since winter and broken arm time... made it's just the junk from the bottom of the tank?

Will be unhooking the PC tomorrow when I get some time. Right now It's ride to work, do work, ride home, do more work, sleep, repeat.
Click to expand...

Was the previous gas treated? Could be the old bad gas... I'd put some seafoam or other treatment of your choice in it.. Techron, etc.. Run it. Put some more fresh gas in, run it more. Hopefully it clears out for ya.
 
Last tank of gas before winter was run down to the warning light, then filled fresh with Stabil. This is my first tank since my winter tank. I'll add some Lucas or something next time I hit a gas station and hopefully clear it out.

Y'all, I'm feeling so much better talking through this with you guys. I thought I was having all sorts of issues. When I put my handlebars back on my brake lever was rubbing and my clutch lever was hitting, thought I had clutch issues and other stuff happening, I've been losing my mind!

THANK YOU FOR HELPING ME PROBLEM SOLVE AND REGAIN MY SANITY!!
 
JSP said:
Was the previous gas treated? Could be the old bad gas... I'd put some seafoam or other treatment of your choice in it.. Techron, etc.. Run it. Put some more fresh gas in, run it more. Hopefully it clears out for ya.
Click to expand...


I didn't even think of that problem JSP, that's a really good call.


-Uncle Al
 
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I only got a chance to ride it straight to and home from a concert last night. Drove in with the wife today. I will get a chance to throw fresh gas and treatment in today. I should get home around 10 minutes before I need to run out to a dress rehearsal - just enough time to drop off the wife and the car and gear up! I should have some time tomorrow evening to pull the PCV and make sure that's not an issue.

I did get the problem to replicate last night. Power cut SEVERELY at 10k and stopped altogether at WOT at 11k. I hope and pray it's just nasty gas residue...
 
I've been busier than I expected. Didn't have time to pull the PCV but I did have time to put in some fuel treatment and a fresh tank of gas.

Two days ago I couldn't get it to miss, went all the way to redline no issues.

Then yesterday it was dropping power at 10 and went dead at 11k even with wide open throttle. Throttle was still unresponsive momentarily after a gear change. Then it stalled out of me at the next red light, but then strangely ran perfectly. Feels like when my old carb bikes were getting gummy.

Hope the fuel system cleaner does the trick. At least now I'm less and less worried that it could be a clutch problem
 

Sounds to me like your throttle bodies are slightly out of sync. Does it rev fine? Does it stumble at all, or die when the throttle is snapped, then quickly released?
 
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