Carb Issues?

So I was out for a ride yesterday and was headed home when my bike started bogging down like a motha trucka. I was able to nurse it home by using high revs. Got home and thought maybe it was an oil issue because the oil light flicked. Checked the oil, was low, so I got some and headed out to test it. Bike starts fine after sitting, but then quickly becomes bogged down.

I noticed that there is some fuel sitting on the bottom of the outside of the carb, see attached pic. I've read some about the petcocks going bad, could this be the issue? Also, there has been some fuel in the airbox.

Carb rebuild and petcock rebuild? What is the best course of action??

81 550XJ for specs.

Any and all help is appreciated. I'm new to bikes, so be easy on me. haha. I do have the Clymer's, if that helps.

Thanks!

 

Sounds like you may have a float that got stuck open coupled with either a bad petcock or the petcock left in the prime position.
Low oil? Don't think it's related.
Have you or are you planning on busting into the carbs? If not, highly recommended. Many a problem can be solved and prevented from rebuild and periodic carb. maintenance.

 

Mine does the same thing. Also spits fuel from the air box. Not all the time, only sometimes. Today when I fired it up, it did, last week when I rode it didn't. It runs fine, doesn't bog down that I've noticed. Strange.

We'll get it figured out somehow.

When checking your petcock. RES and ON: no fuel PRI: fuel should come out.

 

I'm going to head out and check the petcock to see if that is a portion of the issue.

We will see!

Thanks for the replies, guys.

 

Yup - yours and WarDog12's problem sure sounds like an occasional sticking float or float valve - the fuel into the airbox is the give-away there.

Sounds like time for a carb rebuild, or at least a strong application of Seafoam

 

I figured out that the petcock is just fine, otherwise my garage floor would be flooded with 3 gal of gas! haha.

I'm guessing the carb issue as well. What is the best approach? Get new guts and put em in? Give them a good cleaning and hope that cures it? I put in Seafoam last night, but of course when the bike doesn't stay running, it hard to run any petro through the system. Of course I can hold the throttle pretty far open and that works, but honestly I would rather get it fixed the right way off the bat. I'm thinking there is 20000 mi on these carbs never cleaned, so that might be a place to start.

all the ideas so far are great. Any more?

 

Since carb removal is such a p-i-t-a you may as well do a complete tear-down cleaning and re-build with new float valves and o-rings...
have fun and be patient with it though, after you get your bike put back together you'll enjoy the satisfaction. :lol:

 

Did all that last October, and the bike runs fine. I think it only happens when I prime the carbs a bit first. MiCarl is helping me replace the tires next week, maybe we'll have time to figure that one out too.

Maybe veering a bit off topic, I notice a bit of exhaust leaking from where the muffler joins the header (can post pic if needbe). Is this normal for the XJ's? I've really only worked on cars before and exhaust coming out of anywhere other than the end of the pipe meant something was loose, but here it's bilateral and uniform.

 

What is the best place to get the new parts? Local dealer or someplace online?

 

www.bikebandit.com or www.oldbikebarn.com.

I like Bike Bandits parts search better, and usually they're cheaper than Old Bike Barn. Local dealers can often get old Yamaha parts.

 

This might sound completely idiotic, but I need four of them correct?

 

Yep.

Alos check:

http://www.z1enterprises.com/

 

Thanks, saved a few centavos on that order.

I'm sure I'll be back to ask for more help when I put it all together!