Blaster Sputters in High rpms at W.O.T. in 5th and 6th Gear..Jetting?

[snowrider]

Ok so i have a 1998 Blaster, which i've owned for a little over a year now. It has a Keihin PWK 28mm carb, no T.o.r.s., oil block off and toomey silencer. The motor is .040 over newer rebuild, brand new Boyesen reeds, Spark plug B8es, New crank seals etc.

I've had this problem for a little while now, just never rode enough to bother with it but when i am at wide open throttle in 5th and 6th gear it sputters at high rpms. I currently have a 145 main jet needle on the 3rd clip, and a 45 pilot. I've tried just about every combo of jet sizes and needle positions but always end up with the same result, runs very strong up until 5th and sixth gear. Any suggestions?:-/

 

[Awk08]

if you have tried larger and smaller jets with similar results, it has to be something different

is the carb spotless clean
air filter clean and oiled properly
is the float level correct
have you tried a new plug, NGK b8es
results of a "leakdown test"
what do "plug chops" say
have you checked the reeds for cracks/chips

could also be electrical, but the above all needs confirmed before moving onto elctrical tests, but give inside the plug boot and wire a good look

 

[snowrider]

I was thinking the same, the carb is spotless clean , and the air filter is a brand new UNI oiled properly(forgot to mention the lid was removed), I've tried new NGK B8es (which i have a whole box of from the Banshee i used to have), the plug chops look OK but not perfect, And the reeds are brand new as well. As far as the float i think you might be right on there, it almost feels as though it starves for fuel on the top end and i have never really messed with the float yet. I also had my local shop do a leakdown test for me a few weeks back and he said it was perfect. I ordered a new OEM coil and wire/plug boot. But tomorrow i will adjust the float, any idea what the correct height should be for a PWK 28? Thanks again

 

[mmajay]

19mm float height.

 

[Kgibson]

145 seems lean....148 150 152 sounds more like it

 

[snowrider]

Thanks guys, let u all know how i make out tomorrow and ill bump up the jet size to 148/150 as well.

 

[mmajay]

Thanks guys, let u all know how i make out tomorrow and ill bump up the jet size to 148/150 as well.

With your mods listed you need to bump up most likely.

 

[mmajay]

The only odd thing to me is normally a mis jetted motor does it in all the gears unless your short shifting 1-4? , thats just the experiance i had with my jetting issues.

 

[Larry's Shee]

Check that the tank cap vent is open as well as the vent hose if you run one. Pull the tank, pull petcock off, flush tank, clean pick-up screen on petcock , maybe even disassemble it to ensure clean in side. Check vents on carb& vent hoses.