no go after carb rebuild..

evol777 · Full Member Joined: Jan 28, 2008 Posts: 16

picked up a second xs last week for a project... was running poorly when i got it so decided to rebuild the carbs.. everything is stock its a 78, did notice the o-rings on the original pilot screw was slightly larger than the new ones... i turned it out 2.25 turns (and then later to 2.5) - It fires up for 5-10 seconds and dies.. if I attempt to give it throttle it dies immediately - any suggestions are greatly appreciated - did not replace the nozzle or needle and the diaphrams have small cracks around the edges - thanks

Shannon60 · Posted: March 2, 2008, 10:22 pm Post subject: Re: no go after carb rebuild..

carbs don't usually need to be rebuilt as much as cleaned most "rebuild kits" don't come with the correct size pilot and main jets, use anything else in those kits but I wouldnt use those. clean the ones that came on the carbs the pilot jet sometimes requires a bristle from a wire brush run thru it (i know they make jet cleaners i'm not a hillbilly but I dont like bending them up trying to cram it in a plugged hole and who cares about one wire bristle) well anyway thats where I'd be fishing then the points

evol777 · Full Member Joined: Jan 28, 2008 Posts: 16

thanks for the reply, i did however check the jet sizes before i installed - they matched the originals - if it ran before i pulled the carbs and now it doesnt... shouldnt the problem be in the carb not the points/timing? or am i wrong in assuming this?

Shannon60 · Posted: March 2, 2008, 10:47 pm Post subject: Re: no go after carb rebuild..

how did you check them? did you look at the numbers or actually compare the hole size to what came out? and no your not wrong but it never hurts to eliminate that as a problem since those are usually the only two reasons these things don't run properly

evol777 · Full Member Joined: Jan 28, 2008 Posts: 16

had just checked the numbers, maybe i'll pull it apart and clean it once more... put the old stuff back in and try again - thanks

Shannon60 · Posted: March 2, 2008, 11:05 pm Post subject: Re: no go after carb rebuild..

also check your diaphrams to make sure that one didnt accidently fold over when you were reinstalling them its been known to happen

Cooltouch · Posted: March 2, 2008, 11:30 pm Post subject: Re: no go after carb rebuild..

Shannon,

It seems like, when time comes to clean the carbs, it takes at least three cleanings before they're really clean. Compressed air really helps a lot.

Best,

ichael

jimdi · 650Rider Supporter Joined: Oct 27, 2005 Posts: 512

Ok - I am ashamed to admit this - but when my new gaskets for my bowls came in from Mikes - the "punchouts" for the vent circuit in the gasket - were left in (holes plugged by gasket) when I assembled it - and the bike wouldn't start at all -
Took it apart - noticed my oversight - pushed out the "punchouts" and she started right up and ran great!

Stupid little things...

What Happened to 650rider.com?

Yamaha xs650