mind boggled with weird idle and hide n go seek powerband

C

croom9

New Member
Oct 2, 2011
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Bangor, PA
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ok i picked up a molested decrepit old blaster dirt cheap, it ran amazing for a couple weeks until i had it out on a 5 hour snow storm ride....... it suddenly just went dead and i towed it home. once i tore into it i found it missing a reed petal so i put new reeds in it and rebuilt the carb when i had it apart. now it fires up first kick with the choke on and idles fine, but barely runs with out the choke on.

once its warmed up it rips through 1st and 2nd, but then the powerband becomes hard to find you have to feather it to get it and then it falls flat on its face for the rest of the gears. backfires like crazy and if you pull the clutch in the idle stays up and bounces for a while before coming back down..... im lost any help would be greatly appreciated


heres a little detail on the machine:

pro circuit head pipe/stock silencer
foam filter w/ lid off
boyesen dual stage reeds in stock cage w/spacer between cage and jug
240 main/stock pilot
oil injection delete, premixed precisely at 32:1 on 93 octane
new BR8ES plug
 
hey, another PA. bro !!!!!!

gotta be sumthin you missed in the carb during the rebuild............

was it leakdown tested to check for intake airleaks ????
did you measure and set the floats ???
did you remove and clean all jets...airscrew/pilot/main/choke/float needle ????
is the brass washer back under the main jet ????

what jets and needle clip position, airscrew at 1.5 turns out ????
 
awk08 said:
hey, another PA. bro !!!!!!

gotta be sumthin you missed in the carb during the rebuild............

was it leakdown tested to check for intake airleaks ????
did you measure and set the floats ???
did you remove and clean all jets...airscrew/pilot/main/choke/float needle ????
is the brass washer back under the main jet ????

what jets and needle clip position, airscrew at 1.5 turns out ????
Click to expand...

hey man im in the NE area near the poconos

and i double checked the carb had it apart 3 times there really isnt much to these ones i even replaced the o ring on the choke pin.

floats seemed about right

took out the main nozzle and cleaned it replaced airscrew and i've tried 1.5, 2 and 2.5 with no changes what so ever in the performance

and i had to go get another brass jet washer the last guy smashed this one all to hell and egged it out, luckily the mechanic at the local dealer chucked one at me he had laying around and said good luck
 
is the brass washer under the main jet ????
what size main jet ???
gotta check for airleaks around that intake, them hanging revs points to that
try some rtv sealant on the intake gasket, but ultimately it needs leakdown tested
a compression check would be nice too ???

leakdown tester...................

http://www.blasterforum.com/do-yourself-20/build-use-leakdown-tester-10663/

slick \/ makes and sales them could have you one by wweks end here in PA..............

http://www.blasterforum.com/do-yourself-20/videos-how-perform-air-leakdown-test-31464/
 
dont know a whole lot about jetting i just cleaned the one that was in there and put it back in........ but come to think of it it ran good with the stock pipe before the reed broke



what would you suggest putting in there
 
croom9 said:
heres a little detail on the machine:

Pro circuit head pipe/stock silencer
foam filter w/ lid off
boyesen dual stage reeds in stock cage w/spacer between cage and jug
240 main/stock pilot
oil injection delete, premixed precisely at 32:1 on 93 octane
new br8es plug
Click to expand...

. #240 main ????? .
 
croom9 said:
dont know a whole lot about jetting

what would you suggest putting in there
Click to expand...

/\/\/\ this, time to stop riding it till we get you educated, or your next post will be............"whats a good piston"
 
I'm thinking mulitple issues here, an air leak, compression test, I'd up the main jet to 260-270, do a plug chop and check it. But before anything I'd do a leakdown test on it as you will never jet it correctly if there is a leak on it you'll be chasing your ass and frying that top end.

Here is a thread on how to make one and some directions. I also make the leaktesters and sell them for $30shipped. This is a very important step for these motors!

http://www.blasterforum.com/do-yourself-20/build-use-leakdown-tester-10663/
 
slickerthanyou said:
I'm thinking mulitple issues here, an air leak, compression test, I'd up the main jet to 260-270, do a plug chop and check it. But before anything I'd do a leakdown test on it as you will never jet it correctly if there is a leak on it you'll be chasing your ass and frying that top end.

Here is a thread on how to make one and some directions. I also make the leaktesters and sell them for $30shipped. This is a very important step for these motors!

http://www.blasterforum.com/do-yourself-20/build-use-leakdown-tester-10663/
Click to expand...
thanks for the insight, i tried to put a leakdown together today but the foot pump i used had a really crappy nozzle that leaked like hell but i did manage to pressurize the jug a little bit just enough to spray soapy water around the intake boot as i pumped and didnt see any bubles at all
 
croom9 said:
lmao i was waiting for that one
Click to expand...

glad you took that correctly, lol, but truth

if it's airtight, leakdown confirmed, and you get a....say 270/280 to start main jet in there, it will not pop and carry on, unless the reeds are still bunk, or you sheared a flywheel key, knocking the timing off
and i'll ask again, is the brass washer under the main jet ????
is the needle clip in the middle ???

and here's some more homework...............
http://www.blasterforum.com/do-yourself-20/jetting-101-everything-explained-1625/

pop quiz tomorrow on all the info posts i made
 
awk08 said:
glad you took that correctly, lol, but truth

if it's airtight, leakdown confirmed, and you get a....say 270/280 to start main jet in there, it will not pop and carry on, unless the reeds are still bunk, or you sheared a flywheel key, knocking the timing off
and i'll ask again, is the brass washer under the main jet ????
is the needle clip in the middle ???

and here's some more homework...............
http://www.blasterforum.com/do-yourself-20/jetting-101-everything-explained-1625/

pop quiz tomorrow on all the info posts i made
Click to expand...

washer is under the jet and needle is in the middle

and i was wondering about the timing i thought maybe vibration knocked it out, this thing vibrates worse than any 2 stoke ive ever been on its so bad it hurts your wrists when the power band comes on i was thinking the counter balancer is beat or someone took it off, but ive been told u can run without it just stock up on nylocks and locktite
 
croom9 said:
thanks for the insight, i tried to put a leakdown together today but the foot pump i used had a really crappy nozzle that leaked like hell but i did manage to pressurize the jug a little bit just enough to spray soapy water around the intake boot as i pumped and didnt see any bubles at all
Click to expand...

Might want to try other areas too! You are the first reciepient of these Instructions!

14mqc1y.jpg
 
sorry about the delay, the holidays kinda put all my projects on hold for a while, but anywho

leakdown test confirmed no issues, i am sold on the idea that this carb is bunk, it has a hairline crack somewhere or the tors heap of crap on the top is allowing a leak.

I picked up a mikuni vm28 roundslide for 50 bucks which deletes the tors cap but i cant seem to find a good starting point on the air screw or the jet. it came with a 310 and it was way to rich even without the lid, so i put my old carbs 280 in and it still seems rich. any thoughts? Id love to find somebody on here who has had success with one of these trinkets
 
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