chillls Posted December 28, 2006 Report Share Posted December 28, 2006 what do you think of the pwk 28mm carbs? i put them on & i have to say it ran better with the stockers on 97 shee, stage one porting, reed spacers, v-force reeds, 2 degree key, 28mm pwk with k&ns on each, stock ignition, b8es plugs, t-5 pipes, any thoughts on these carbs Quote Link to comment Share on other sites More sharing options...
TeamBigginRacing Posted December 28, 2006 Report Share Posted December 28, 2006 what do you think of the pwk 28mm carbs? i put them on & i have to say it ran better with the stockers on 97 shee, stage one porting, reed spacers, v-force reeds, 2 degree key, 28mm pwk with k&ns on each, stock ignition, b8es plugs, t-5 pipes, any thoughts on these carbs i run them(luv them) sounds good 4 your set up, i was told not to run any bigger then 30 on mine or i would lose hp!! See what to other hq'ers say!!! Quote Link to comment Share on other sites More sharing options...
Bansh-eman Posted December 28, 2006 Report Share Posted December 28, 2006 going from stockers to 28mm is only a 2mm differance... i dont see how it could have ran worse? only thing i can think of is your jetting was off... the differance in the amount if fuel from 26 to 28 is very small im assumming your running stock bore and stroke right? Quote Link to comment Share on other sites More sharing options...
David Keith Posted December 28, 2006 Report Share Posted December 28, 2006 going from stockers to 28mm is only a 2mm differance... i dont see how it could have ran worse? only thing i can think of is your jetting was off... the differance in the amount if fuel from 26 to 28 is very small im assumming your running stock bore and stroke right? Just a question here about the very small difference. If we do the math, A=(pi)(radius squared), we find that 26mm diameter has about 531 sq mm of flow area. 28mm diameter has about 615 sq mm of flow area & thats 84 sq mm more than stock. This added amount divided by 531 equals a 16% increase in flow area... Isn't this a pretty significant increase? Quote Link to comment Share on other sites More sharing options...
Bansh-eman Posted December 28, 2006 Report Share Posted December 28, 2006 thats a 16% increase in the diamiter of the bell... you got to think of how much vacume is pulling the fuel through the jets.. also with a bigger carb your going to lean the main more then likely on the same smaller motor to not richen it up some .... the amount of fuel is very minimal from the 2 sizes... one thing that will diffenatly help going to the pwk style is throttle response. but if you go too big(which this case it isnt) you kill the bottom end bedaue your dumping the crap out of fuel.. Quote Link to comment Share on other sites More sharing options...
ToomeySheeLE Posted December 28, 2006 Report Share Posted December 28, 2006 I have some new pwk28's for sale. With Uni filters and throttle cable.. PM me if interested.. If for some reason you think they are too small(which you wont, unless you do some stroking) you can always have them bored to 30mm. Quote Link to comment Share on other sites More sharing options...
Bansh-eman Posted December 28, 2006 Report Share Posted December 28, 2006 i just relized i put the bell in my last post... i ment to put the motor side of the carbs what ever its called.. Quote Link to comment Share on other sites More sharing options...
odaen Posted December 28, 2006 Report Share Posted December 28, 2006 thats a 16% increase in the diamiter of the bell... you got to think of how much vacume is pulling the fuel through the jets.. also with a bigger carb your going to lean the main more then likely on the same smaller motor to not richen it up some .... the amount of fuel is very minimal from the 2 sizes... one thing that will diffenatly help going to the pwk style is throttle response. but if you go too big(which this case it isnt) you kill the bottom end bedaue your dumping the crap out of fuel.. I've read that 3 times now and have come to the conclusion that you are either getting a blow job as you type, or typing faster than normal because you are holding back a big beefy shit. The 16% increase is in area, not diameter. But, I think you are correct in saying that you should gain some better throttle response. Overall, in terms of peak HP, you may not notice that much, because ultimately, if you are jetting correctly your intake velocities will be similar given the small size difference in the area. Quote Link to comment Share on other sites More sharing options...
dajogejr Posted December 28, 2006 Report Share Posted December 28, 2006 They are fine carbs indeed, way better design, and light years easier to work on. They will offer a pretty decent power gain, and are much easier to tune and work with. Plus...you don't have to worry about the dreaded stock carb slide sticking with those!!! Quote Link to comment Share on other sites More sharing options...
Bansh-eman Posted December 28, 2006 Report Share Posted December 28, 2006 The 16% increase is in area, not diameter. ok i guess the way i typed sounded to make secnce in my haed but not on paper... im saying that 16% is a gain from the size of the carb not the amount of fuel its pulling... just cause you go bigger on the carb doesnt mean your going to pull anymore fuel... your motor can only pull its maximum capability... whether it be 26mm or 28mm...just like the water hose analogy some one put about this topic several motnths ago... Quote Link to comment Share on other sites More sharing options...
chillls Posted December 29, 2006 Author Report Share Posted December 29, 2006 going from stockers to 28mm is only a 2mm differance... i dont see how it could have ran worse? only thing i can think of is your jetting was off... the differance in the amount if fuel from 26 to 28 is very small im assumming your running stock bore and stroke right? stock bore & stroke was freshend up when carbs were changed(new rings). it has a tendency to load up while ridding. i have extended the breather lines to the end of the swing arm so fuel would not spray on the bottom of the engine & swing arm (breather lines from carbs) do you think this might have some thing to do with it????????? :confused: Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted December 29, 2006 Report Share Posted December 29, 2006 I would say your jetting is off. What size is the main jet? What size is the pilot jet? What needle do you have? (should be a 3 lettered code. CEK, CEL, DEK, exct.) What Clip Position is it on? How many turns out on the air screw? Did you sync the carbs. Both the Idle adjustmet and the cable lift needs synced. The easiest way is to use a tool that fast sells. It can be done by hand but it wont be as accurate as this tool will get you. Fast Carb Sync Tool LINK Quote Link to comment Share on other sites More sharing options...
rriggs Posted December 29, 2006 Report Share Posted December 29, 2006 i have keihin 28 mm pwk's on my .20 over shee with mild porting..works terrific and throttle response is 10 times better than the stockers Quote Link to comment Share on other sites More sharing options...
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