Big issue with idle

blaster93

New Member
Dec 7, 2010
39
1
0
Green Bay,WI
Im now about ready to give up. Im not familiar with the two stroke setup especially the carb. I just tried starting the blaster for the first time. The problem is it only starts with full choke then shortly dies. The engine topend has been rebuilt with .080 over piston. It has a fmf fatty pipe and silencer and open air cleaner. I also installed a 280 main jet. I put the a/f mix 1.5 turns out. Whats my problem? Its like its running too lean but still smokes a little out back. and also im running klotz at 40:1. Thanks for any help and I will provide any answers to the best of my knowledge.
 
just my opinion but that klotz aint helpin

sounds like a partially clogged pilot jet
and time to open the carb, pull all jets, clean with carb cleaner and blow out with compressed air, then set your float to 20-21.5mm and give it a try
that main jet don't have sh*t to do with idle and the stock pilot is fine with that setup
 
ok i will definetly try that. Thanks again for the help and fast replies. i havnt rebuilt the carb but when I installed the main jet it all looked nice and clean inside.
 
make sure to pull that pilot jet, it's down in a hole beside the main, very small straight screwdriver needed
float measurement is from where the gasket would sit, to the top of the float, while holding the carb at about a 45 degree angle with the float pivot facing up, just so the float tang contacts the float valve, but not pushing in pon the little pin, just touching it
 
ok the pilot jet was a little plugged, could see light through it but barely. so i blew it out and it was better. The float measurement is 20mm.
 
slap her on the ass and let us know how it goes
 
well it idled pretty nice for about a minute or two then quit. after that now it wont run at all. just spits and backfires. im lost. eben put a new plug in it but no good
 
Silly question but...

Is the arrow on your piston pointing at the exhaust. They will run with the piston backwards. If it ran fine b-4 the topend work. I'd look for the obvious first.
N
 
i wouldnt have a clue as i bought it from a friend who had it built. I trust him 100% that he knew what he was doing. I didnt ask him about this problem yet but will have to tomarow. Could the reed valves be cracked? I dont want to pull it apart unless I really have to. Also on a side note its regular unleaded gas mixed if that matters.I just realized that I was supposed to get premium.I guess Ill just keep trying I dont think my main is to small? maybe I need a 300 or something.
 
that gas is ok, and the reeds are worth a look, you already had the carb out, 4 more bolts to get the reeds out, did you clean that carb very well, like everything
has it ever ran since the rebuild ?????
 
well first the main wont have anyhting to do for idle.. but i can tell you with the cold you should have a 300-320 main jet for winter hear in wi..

how long do you leave your choke on?? i choke my 2 strokes for all of 5-10 seconds, than i turn the choke off... my lt250r will idle all day long, what happens if you rev it just alittle once you start it?? does it bog out or does it rev up and stayt reved up for a bit?
 
@awk08 - I cleaned it very good.and before I rebuillt it I rode once down the drivway before the big snowfall.It idled like a champ.

@4cfed-Well I leave it on because if I push it back in it quits right away.When I first started it i kept it on for about 10 sec then pushed it back in and had to hold the throttle 1/8 of the way to keep it going. Then after about 1 min id just quit.

Thanks guys for all your help. Really appriciate it.
 
well it idled pretty nice for about a minute or two then quit. after that now it wont run at all. just spits and backfires. im lost. eben put a new plug in it but no good
Sounds to me like it clogged up again. I would empty the tank, check the fuel tank filter, and clean the hoses. When I did so the filter was extremely dirty.
 
where is the fuel filter? in the tank? Havent thought out that. Before I bought it sat for about a year so you think the pilot is plugged again?
 
did you get all the old gas out before/during the rebuild ???
and a stock bike only has filters/screens up in the petcock, not a visible in line filter,
i'd pull/drain the tank, pull the petcock and give that a look/cleaning, carefully, those screens are delicate
also seeing as how you said it sat for a long time, check the silencer for clogs, supposedly mice have been known to nest there ????
still say check the reeds, and popping/backfiring could mean woodruff key on the flywheel sheared, did you have the flywheel off, get it back on tight and on the keyway ????
just all things i'd be lookin at, eliminate them one at a time
 
I drained the old gas out but didnt clean the tank so ill try that and clean up the jets again. The silencer I just bought. The thing ran perfect after i cleaned out that pilot jet. Maybe it just got plugged again.If all else fails Ill check those reeds.
 
go get your self a few gallons of regular gas, dont have to be premium, take your tank off, pull the petcock out and clean the filter screens, , flush them with carb cleaner, and flush the valve out, and soak it in some gas, take some fresh gas and rinse the tank out a few times make sure no dirt and crap come out when your done, reinstall, clean carb again and run it