hey guys its clay, i ride a 86 savage, just been trying to work a few bugs out of it here, and im having an issue. my bike fires up great right away everytime no problem. for the first thirty seconds i have all my throttle, then after a minute or so of it running, i only have about half throttle, as soon as i give er a little, it starts sputtering back firing and dies, but if i let off the throttle it runs fine. i changed the spark plug, cleaned the carb, but a carb cleaner mix in the gas tank, i rode it for about a hundred kms trying to burn off all the old gas, and still no better. i talked to a mechanic this morning, and he says it could be the coil? will you guys help me a bit so i dont have to buy and wait on a part.. really apreciate everything on these posts, ride on!!

That means the idle jets works fine but the main jet is clogged.

Arnold wrote on 07/06/12 at 12:13:02:

This was my first thought too.  I'd clean the carb and replace the main jet.  If you have a carb cleaning tool (or a torch tip cleaner), you may be able to just clean the jet.  One version of the tool is shown below.  I'm okay with doing that as a roadside fix if I don't have spare jets but would replace the jet as soon as possible.

i didnt take the carb apart and clean it thoroghly yet, i took the air filter off and sprayed carb cleaner into the intake for about five minutes straight, and drained the carb bowl. im a little nervous about taking the carb apart because i havnt tooken a carb apart yet.. when i drained the bowl the gas smelt like old stale gas. when it dies after it backfires and stuff, i can start the bike instantly while im still rolling down the road. i took it for another rip today, and it seems like its getting worse.  tomorow i have the day off work so i am going to tackle taking the carb apart and cleaning it out real good. i have the book on it, so hopefully that helps alot.

the thing that is confusing me the most is the fact that i can fire it up right away after it dies? thats why i was thinking it could possibly be the coil. my gas tank vent is working fine. another thing is that i changed the spark plug, i rode it for a solid hour, pulled the new plug out, and it is covered in soot.. on the right hand side of the carb there is a flat head screw. i think it is the fuel/air mix screw? not sure, but i can tighten it right up, and it doesnt stall the bike, same if i loosen it off it doesnt seem to be making a difference at all.

it crappity smacking awsome that you guys reply so quick!! thanks!!

Ive seen cars die running 45 MPH, roll to a stop, & start right up. Catalytic was plugging up, soon as the engine dies, the crap falls & the passages open up.
Id take the bowl down, clean it, Mite as well run something thru the jets while youre in there.
Theres nothing there to indicate the problem is air mix, not that its set perfectly, thats just not why its dying,

Hey Claytron1, sound like your jetting may be off. If you can turn the idle mixture screw all the way in with out any change and your plug is sooted up sounds way too rich. Is the carb stock or has someone possibly changed the main jet? Check out this link: http://suzukisavage.com/cgi-bin/YaBB.pl?num=1309246277
An excellent reference by another forum member with alot of carb info.

I'm getting that the carb was really dirty and has now been cleaned a few times, though I'm not clear as to how thoroughly.  I haven't heard that either jet was removed/cleaned/reinstalled or replaced.  I would seriously replace the main jet.  For a stock Mikuni BS40, you can get the jets online, from Lancer or even from most local HD dealers.  The carb has two circuits.  The pilot jet is used for idling while the main jet is used the rest of the time.  There's a slight overlap but if a main jet is clogged, it will act just as you've described.  It's not the only possible explanation but it's very easy and inexpensive to test.  And, though not a fix for this issue, I'd install an inline fuel filter to help keep the carb cleaner.

Serow's thought of the gas tank vent is another good idea and easy/cheap to test.  Just try starting and running it with the gas cap removed.  If that works but it doesn't work properly after replacing the gas cap, the vent is not working.  There are some mods to the tank breathing setup functionality with Savages built to be sold in California and, if that's your case, it might be good to know.

Routy wrote on 07/10/12 at 07:55:24:


+1