Power valve carb question

[paul]

Hey Poggers, this bing carb has frustrated me for a couple weeks (months) and I have a decent carb to use but it has a power valve on it with two wires. My question is what makes this operate, a 12 volt source? When does the power valve turn on? this particular carb is a kehien but see people using lectrons and mikunis with their own power valve and just read here that the lectrons are difficult to tune without a power valve. For something that I had in the garage it may be worth trying as it looks pretty new so I thought to ask about making it operate correctly. Thanks for any help,TTPaul

[hrbay]

Paul, too new for me but I can guess the power valve is used on four strokes, to richen up the midrange and for hot starting ?

GC

[Speedy]

quote:Originally posted by paul

Hey Poggers, this bing carb has frustrated me for a couple weeks (months) and I have a decent carb to use but it has a power valve on it with two wires. My question is what makes this operate, a 12 volt source? When does the power valve turn on? this particular carb is a kehien but see people using lectrons and mikunis with their own power valve and just read here that the lectrons are difficult to tune without a power valve. For something that I had in the garage it may be worth trying as it looks pretty new so I thought to ask about making it operate correctly. Thanks for any help,TTPaul

Your KEIHIN carb is from a modern bike like typically KTM.
The 2 wires have nothing to do with a powervalve.They are connected to the modern bike electronic(BLACK) box and changing the ignition timing on modern ignition.
It is deffenetly to no good for your VINTAGE bike.
To get rit of your carb trouble once and forall,get a LECTRON powervalve carb.
For a VINTAGE 175 cc use a 34 mm for a Vintage 250 a 36 mm Lectron.

Helmut"Speedy"Clasen
 Ontario Canada
http://speedy_c.tripod.com
http://picasaweb.google.com/vindurospeedy
2 x Sachs MC-GS 250-7A
1 x Hercules 350-7A 77
2 x Hercules 250-7A 76
2 x Hercules 250-7A 77
Zuendapp 125 GS 72-73

[paul]

Hey, thanks for the help. From what I have read the power valve engages at max torque and was installed on late model KTM's. Probly one on my 02 520. Dont know as I have never had a problem with that..yet. My preference was to keep the bing on it but short or buying new everything I wouldn't know what else to do after changing floats and pilot. Guess the slide is next. I will save my pennies and hook up a lectron soon. My goal was to get it running well before disassembly for paint and polish. Ride on!!! TTP

[Speedy]

quote:Originally posted by paul

Hey, thanks for the help. From what I have read the power valve engages at max torque and was installed on late model KTM's. Probly one on my 02 520. Dont know as I have never had a problem with that..yet. My preference was to keep the bing on it but short or buying new everything I wouldn't know what else to do after changing floats and pilot. Guess the slide is next. I will save my pennies and hook up a lectron soon. My goal was to get it running well before disassembly for paint and polish. Ride on!!! TTP

Paul,.....KTMs dont have POWERVALVE carbs.NEVER had,Probably never will.


Helmut"Speedy"Clasen
 Ontario Canada
http://speedy_c.tripod.com
http://picasaweb.google.com/vindurospeedy
2 x Sachs MC-GS 250-7A
1 x Hercules 350-7A 77
2 x Hercules 250-7A 76
2 x Hercules 250-7A 77
Zuendapp 125 GS 72-73

[Jim A]

Sounds like you are referring to a 2-stroke powerjet carb used on some modern MX 2-strokes. I don't know much other than the powerjet is controlled by the ignition and they can be used without the powerjet hooked up. A search on "powerjet carbs" will tell you more about them.

Jim A

[Big Mac]

Earliest powerjet carb on a KTM was on 38MM Bing used on '81 KTM 495s. It's a mechanical 2nd jet up on the top front of carb, similar to the main jet. The non-powerjet Bing carbs on '81 420s used something like a 280 main jet, while the 495 powerjet Bing used a 145 main and a 140 powerjet, best I recall. Way different animal than the modern electrically activated valves or jets on modern carbs.

Jon McLean
Lake Grove, OR

[paul]

Hey, there was enough stuff laying around the garage to install this kehien so I did tonight. Wouldn't ya know she started first kick albeit rich. Regardless it brought a smile to my face. So its either jet this or find something else. I can not believe these bings are that fussy. AT LEAST 10 trips on and off to set the floats ect. and it still fussed. Hey yall, I tried to keep it stock but would like to ride it a bit sometime. Thanks for the advise, TTPaul