Loss of Power

[Rizzo]

Yesterday I had an imprompt street race with a friend who just purchased a Kawasaki Voyager his first big bike and he wanted to see how it compared to mine ('89 VR with 54K miles) as he had ridden mine before. The Voyager held its own until close to 100. After we stopped and discussed how well his new bike ran and then headed out again I noticed a dramatic loss in power over 3000 rpm in every gear. As long as I shifted below 3000 it seemed to run ok. I pulled the plugs today and they looked fine. I put in new plugs and I am having the same problem. Any and all suggestions are welcome. Thanks.

[cliffno350]

Diaphrams????

[GeorgeS]

Plugs OK, not dark, so ignition was probably fireing plugs OK.

 

I think I would start bye suspecting low fuel flow, maby blocked fuel filter.

 

Have you ever completly drained the Fuel tank??

 

With fuel near empty, put in some HEET, in case you have water in bottom of tank, or maby some Crud. Pull hose from petcock, and completly drain it, Rinse with another gallon of gas and drain that.

Change Fuel filter.

 

Drain all 4 carb bowls, put in some fresh gas, and some SEA-Foam, or Valvoline Synthectic Fuel Injector Cleaner.

 

Give the Cleaner some running time, might clear up the problem.

 

Also, open Bowl drains, and let the fuel pump, run some gas thru all 4 Bowl Drains.

 

Your high Speed runs might have stirred up some crude from the bottom of the tank, remember, we never burn that last gallon of gas down there.

[Rizzo]

Thanks for the suggestions. I will try them immediately and report back.

[GeorgeS]

Reporting back is required !!!!

 

[Leadwolf56]

  GeorgeS said:

Plugs OK, not dark, so ignition was probably fireing plugs OK.

 

I think I would start bye suspecting low fuel flow, maby blocked fuel filter.

 

Have you ever completly drained the Fuel tank??

 

With fuel near empty, put in some HEET, in case you have water in bottom of tank, or maby some Crud. Pull hose from petcock, and completly drain it, Rinse with another gallon of gas and drain that.

Change Fuel filter.

 

Drain all 4 carb bowls, put in some fresh gas, and some SEA-Foam, or Valvoline Synthectic Fuel Injector Cleaner.

 

Give the Cleaner some running time, might clear up the problem.

 

Also, open Bowl drains, and let the fuel pump, run some gas thru all 4 Bowl Drains.

 

Your high Speed runs might have stirred up some crude from the bottom of the tank, remember, we never burn that last gallon of gas down there.

 

 

Everything he said. Probably the fuel filter, mine did it last summer, ran fine after i changed it out. I always leave my petcock trned to Reserve too so I use from the bottom of the tank instead of all from the upper outlet. Keeps the crud from building up in your tank and rusting it out.

[bongobobny]

Fuel filter is what I suspect too! The god old law of supply and demand. Low fuel dflow fine for low RPM's but not enough for higher RPM's...

 

Always the possibility of your fuel pump crapping out as well.

[BJB]

Is there an some sort of filter or wire mesh on the intakes in the tank? I suppose if there are, the petcock apparatus would have to be removed to get at them? Would the tank have to be removed to do this or can this be done by just loosening the tank mounting bolts? Something I haven't done yet, and just might have to have the knowledge before taking it apart.

[Jrichard]

Diaphrams-------------happened to me in late Oct.07--------pulled dias. and their small pin-holes -----------replaced all 4 $$$$$$$$$$$$$$$$$$$$$$-------resynch---------prob, was solved------------

[Marcarl]

  BJB said:

Is there an some sort of filter or wire mesh on the intakes in the tank? I suppose if there are, the petcock apparatus would have to be removed to get at them? Would the tank have to be removed to do this or can this be done by just loosening the tank mounting bolts? Something I haven't done yet, and just might have to have the knowledge before taking it apart.

Take the seat off and right there on top of the tank is the access to all that is in the tank. Loosen that cover plate and you're in, or rather everything comes out. Maybe a good time suck the crud out of the bottom as well.

[Rizzo]

Everyone thanks for your suggestions/help. This afternoon I finally got a chance to change out the fuel filter and viola! The problem is gone! Thanks again. How often should the fuel filter be replaced? I checked my owners manual and didn't see it even mentioned (could of overlooked it though). Now I need to tackle some cracked plastic issues.....Anyway I am cleared for take-off again!

[hipshot]

  BJB said:

Is there an some sort of filter or wire mesh on the intakes in the tank? I suppose if there are, the petcock apparatus would have to be removed to get at them? Would the tank have to be removed to do this or can this be done by just loosening the tank mounting bolts? Something I haven't done yet, and just might have to have the knowledge before taking it apart.

 

 

Barry , i tried , without much luck, to show the "petcock screens".

i removed the petcock assembly from mine, without loosening ANY tank bolts.

you have to remove the fuel lines first, then sorta wiggle and turn the unit , as you pull gently down.

second time, was a lot easier, because i disassembled the "valve", before removal.

i think i may have to finally replace the whole petcock assembly , on my '86.

can't seem to stop the fuel "weeping" thing that it has developed.

if you need, i will shoot a couple of new pics, and post them for ya.

just jt

[SilvrT]

  hipshot said:

Barry , i tried , without much luck, to show the "petcock screens".

i removed the petcock assembly from mine, without loosening ANY tank bolts.

you have to remove the fuel lines first, then sorta wiggle and turn the unit , as you pull gently down.

second time, was a lot easier, because i disassembled the "valve", before removal.

i think i may have to finally replace the whole petcock assembly , on my '86.

can't seem to stop the fuel "weeping" thing that it has developed.

if you need, i will shoot a couple of new pics, and post them for ya.

just jt

 

I'd be interested in those pics...I've never done anything with my fuel filter on this scoot or my '85 ... guess I never needed to but it would be a good preventative maintenance thing. I got a bunch of that to do soon, especially before I head off to Los Osos in August.

[bobcat]

  Rizzo said:

Everyone thanks for your suggestions/help. This afternoon I finally got a chance to change out the fuel filter and viola! The problem is gone! Thanks again. How often should the fuel filter be replaced? I checked my owners manual and didn't see it even mentioned (could of overlooked it though). Now I need to tackle some cracked plastic issues.....Anyway I am cleared for take-off again!

 

Rizz.....I change my fuel filter everytime I change the rear tire.(with rear tire off the access is easier)...About cracked plastic.. Go to the end of the existing crack and drill a small hole..this will prevent the continuation of the crack (this method is called "stop drilling")..I use ABS cement to patch cracks..The fairing is made out of ABS so the cement works well and its cheap..I use a toothpick to apply the ABS cement in the cracks..

[Rizzo]

Bobcat

 

Thanks for the info. I wish I had read it earlier or simply remembered fixing a bad crack in my old fiberglass boat so I would have completed the stop crack hole drilling which I did on the boat. Oh well if it reopens I will tackle it then. It was the lower support area of the trunk for the back rest. I added some sheet metal for some further support on both sides hopefully that will take care of it.