Changed Mufflers > wont idle

[Guest]

Hey guys,

The fairly stock mufflers on from the PO did not fit my originla 4-2 exhaust (they did not use any reducers or anything to fit it, just a but load of exhaust sealant which has come undone)

Anyways, i decided to change them (they were too quiet for me) so got some shorty 16" slash cut emgo mufflers...

Ive installed the mufflers, they fit fairly well onto the pipes (however i do feel some air coming out from around this seal.... which is also due to the fact that the inlet of the muffler has spaces in it that leave small gaps that let air out(?!) (ill take a photo as im not describing this well.

Anyhow, my main issue at the moment is, i cannot get her to idle!!
even when i had the mufflers off and open pipes i could eventually get her to idle (the choke would still get the rpm above 1-2k)
Now i cant even get above 1krpm with full choke. Im a bit baffled how i could get her to idle with open pipes but now not with the mufflers.

Ive fiddled with the PMS screws... no luck there.
when i did this job i also took the exhausts fully off the bike (had to remove the sump to fix the stripped plug hole) (didnt replace any manifold gaskets...i think they were fairly stuck onto the engine manifold)...

Is this just a simple need to rejet or possibly an air leak at the engine/exhaust?

[gs850cafe]

like most everyone will say...jet it up....my bike just has bigger mains.. i went to a 4-1 with a baffle thats about 12 inches? long by 1.5 or 2 inch pipe...so i have a fair amount of blockage...

if i take my baffle out it runs like poo...sounds wicked...but runs like poo crusing around...

i also have a good sealed airbox too, new vac line and clean carbs.

get the jet kit

[nikosg]

ok yeh i figured as much. Just wasnt too sure a jet change was required for a simple change to a slightly shorter louder muffler.

Has anyone done this ? i figure after reading some basic jetting rules on motorcyclecarbs.com that one size increase in the mains would be all id need to do? maybe two?
its still stock headers...

[hampshirehog]

The size of your main jet does not affect idle at all - it's a different circuit completely.

The issue you have is related to the pilot circuit. Could be blocked jets, leaky airbox, poorly sealing exhaust headers, throttle stop not set properly, mixture screw poorly adjusted etc.

[gs850cafe]

ok yeh i figured as much. Just wasnt too sure a jet change was required for a simple change to a slightly shorter louder muffler.

Has anyone done this ? i figure after reading some basic jetting rules on motorcyclecarbs.com that one size increase in the mains would be all id need to do? maybe two?
its still stock headers...

get the jet kit...i changed the mufflers on my old dented stock exhaust...ran lean an hot...header ran a little lean at a wot or down the highway..put 2 sizes bigger in it an it runs just fine except for really really hot days it acts a little silly after about 45-50 miles down the highway

[gs850cafe]

The size of your main jet does not affect idle at all - it's a different circuit completely.

The issue you have is related to the pilot circuit. Could be blocked jets, leaky airbox, poorly sealing exhaust headers, throttle stop not set properly, mixture screw poorly adjusted etc.

+1 on that too previous to my last post i had a leak on cyl 3 on my headed last summer now that i recall it hasnt acted silly since

[nikosg]

The size of your main jet does not affect idle at all - it's a different circuit completely.

The issue you have is related to the pilot circuit. Could be blocked jets, leaky airbox, poorly sealing exhaust headers, throttle stop not set properly, mixture screw poorly adjusted etc.

thank you sir!

is there a way to check the headers for leaks?
should i replace those gaskets on the headers which i didnt initially to see if that changes anything before i do anything else?
i doubt its the airbox as I havent touched that and it ran fairly well before removing the mufflers and headers.