Performance and Wolf exhaust

[peterspoon]

I have a wolf exhaust on a recently acquired XZ
It is really torque-y up to about 5 thousand RPM
But I can't get it above that. I can't go beyond about 40 MPH-ish

I have turned the fuel mixture out to about 6 turns and things improved a lot, but still dies out at about 7500 RPM

I was advised that I should close off some of the intake on both carbs with tape.

Any experience with these Wolf exhausts.

The carbs, reportedly had ben thoroughle dipped and cleaned.
Thanks All
Peter
Bye the way the plugs were dry,and very black before I replaced and started playing with the fuel mixture vis-a vis the set screw

[Walt_M.]

Black plugs indicate a rich mixture. Taping over the carbs would only make that worse. Does your airbox have the vacuum operated flapper and does it work? Sounds to me like it isn't opening. Also, not sure what screw you are adjusting on the carbs but, the airscrew shound not be over 4 turns out.

[Lucky]

I have heard that the Wolf exhausts require re-jetting, but someone once also posted that they have them on their bike & they run fine with stock jetting.  I suspect that you have some carb cleaning to do. there is no reason to tape off any part of the carbs, I would follow Walt's suggestion of checking the operation of the vacumme flapper door in the airbox. . Early '82's were not equiped wit the vacumme flapper, and should have been replaced by the dealer when the bike was new. if yours doesn't have the vacumme door, I have all the parts needed ot retrofit yours.

--Lucky

cc: ROV Forum

[silicon_toad2000]

what does the vacumme flapper do and how does it work.
anyone know where i can get the parts in adelaide australia?

[admin]

probably not an issue with the vacuum flapper.
fuel starvation maybe. you've got something plugged up.
either carb jet(s), fuel filter or pickup screen in the gas tank.
one other possiblility is a plugged air filter, I almost didn't mention that but reread your post and saw where you said the plugs were black which does indicate a rich mixture.


about the flapper thing, it was a low speed drivability fix from Yamaha after the bikes came out.
the bikes ran ok without the fix but had a low speed stumble around 4k rpm.
they took the cheap way out to fix the problem when a 2 stage or slide throttle carb would've worked better. (imho)

-Ron

[peterspoon]

I been told by a "Ultimate Cylcle" here abouts that there is a dry black plug and a wet black plug  ???
My plugs were very dry looking and very black / chalk black if that conveys anything.

The blocking of the carbs intake was second nature to him.

As I wound out the Fuel/air mixture scre things defiantely improved.
Iwonder what the plugs look like now?
Just to  stir the pot and get some more feedback.
Thanks All
Peter

[jasonm.]

Black is RICH. If you had it on choke for a while it takes a few miles to burn this off. Otherwise I think your flapper is not opening. If the flapper does not open the bike is undriveable much past 4500rpm when the flapper should start to open. This lets more air in for the jetting to work properly. But if the only thing that is new is the pipes. I would think the wrong baffle is in it.

[peterspoon]

How do I know if the flapper is working or not?
What would likely be the problem with it?
Thanks all
Peter

[Walt_M.]

Check the vacuum line and the diaphragm for leaks. If the flapper is not opening, it will starve the bike for air above 4-5K rpm.
As for plug readings, general rule-wet and black is too much fuel, dry and black is not enough air.

[peterspoon]

This sound like the same scenario
"general rule-wet and black is too much fuel, dry and black is not enough air."

Confused
Peter

[Walt_M.]

Not really, the engine needs about 14 parts air to 1 part fuel to run. If the air is unrestricted but too much fuel is going in due to a loose fuel jet, carb richener left on, etc, the plugs will be wet and black. On the other hand, if the fuel circuits are ok and something, a rag, tape, excessively dirty air filter or airbox flapper not opening is blocking the air intake, the plugs will likely be dry and black. Both are rich conditions but with different causes. Make sense now?

[silicon_toad2000]

I'm an old car wrench, bit new to bikes but engines are engines. Wet black plugs means oil is getting through the rings, dry black plugs is running too rich at whatever rev range you're spending most of your time at. running lean is generally white/grey plugs.

Now before you all go on and say engines are not engines, i mean the crank, pistons, valves ect. the basics. not any this stator, r/r stuff that I'm rapidly wishing i did not have to learn about.

but its all good. the plugs are a great tester for whats going on inside the engine.