hard to start xj1100

[yamahansolo]

hello, i was wondering if i don't have the airbox on the xj will it start correctly? the airbox is full of crap and i wwill need to clean it very good before installing it. the bike will start with starter spray but it will not run. i think the carbs may still need a little more tlc just wanted to make sure something else didn't need to be hooked up due to the yccs system? i bypassed the octopus and checked to make sure the carbs are hooked up right. i do have the service manual. also the only vaccum line going to the manifold "2 goes up to the sensore under the tank. is that all that needs to be hooked up or is there more. i know the carbs are getting fuel because there is fuel in the bowls but i don't know if the hoses are all connected correctly? any help would be appreciated. i am the 2nd owner and all the parts were in boxes and this is my 4th bike rebuild the other 3 were successful as well so i have a pretty good knowledge for bikes i just am trying to get any hints for this model i might be missing.
chris

[TopCatGr58]

Hey there Chris,

Some folks have commented that the XJ won't start or run correctly without the airbox connected, but I think it's more of a matter of it being a bit lean without the box. I've started and run mine(81SH) without ANY filters at all....for a test of the vacuum slides, recent thread with YouTube videos for documentation.

Okay, you've bypassed the Octy, you say there's fuel in the bowls, and it will start with starter spray, but won't keep running, so you've got fire, but apparently not able to draw in the fuel properly.

Like you said, a trip into the carbs is probably in your future. There is pressed in jet in the float bowl that's hard to see and easily clogged, that will prevent the enrichener circuit from working properly. You'll need to pull the Pilot Jet and PILOT JET SCREW, as well as MAIN JET/Main Jet Needle-emulsion tube to ensure that passages are all clean/clear and not gummed up!

But you'll want to also make sure that the intake manifolds don't have any leaks where they mate with the head/engine, as well as the synch port caps not dry/cracked. Yes, the one vacuum hose goes to the boost sensor, the other lines should just be fuel from petcock to carbs! Keep at it!
T.C.

[trbig]

Just to add... on the XJ, there are two brass nipples on each petcock. The front one is a vent, but will let fuel out if on "prime". The rear nipple is the main fuel one.


Tod

[yamahansolo]

thanks! i have already pulled the carbs apart a few times and they were dry for about 10 years before i cleaned them. i was surprised the bike fired right up with the spay! shows how bullet proof yamaha's are. the last bike i bought had sat for a few years and i just did a mild cleaning of the carbs and it fired right up. it was a yx600 radian. i was fearing it was a carb issue but i was just hoping that something was not hooked up right to avoid going in again.
i also had a little sea foam in the tank to help when i filled the carbs for the first time. maybe it's just not starting good because of that.
the airbox is pretty nasty, looks like lotso bugs and a few mice got in. the engine had rags stuffed in it but the airbox was on the ground in his unit and must have made a nice home for lots of small creatures.