99 250 Rebel, Engine wants to cut out at top throttle

[ThunderEagel]

Hello.

My wife has a '99 Rebel 250 that we purchased early this spring. She has not rode it a ton, but has put a few hundred miles on it. The last few times she has tried to ride it to work the engine has stalled out on her, so I finally took it for a spin to see if I could duplicate the problem.

I did take it for a ride and everything was smooth till I started getting on it hard on my way back home, at full throttle or just below and it started cutting out on me, If I let off of the throttle it would come back a little, but would eventually cut out. It starts right back up no problems at all.

Just to make sure, I replaced the fuel line to the carb, as well as a new fuel filter (one of these clear jobs with what looks like a metal rod inside of it), and also replaced the spark plugs with the recommended NGK's (that was what was in it also).

The bike ran better, but still wanted to cut out on me some, but not as bad, and never did totally stall out.

It has about 7k miles on it, air filter looks pristine, gas should be good/OK. If this is some kind of carb adjustment, it is probably out of my realm of taking care of myself.

Any ideas?

Thanks in advance.

[b4v4]

When you had the fuel line off, did you blow back through it into the tank? Also sounds like it could be a float-level problem, or something as simple as cleaning the needle and seat, which would require removing the carb. If your petcock has the little thread-on sediment bowl on the bottom side of it, shut off the gas, take a (I believe it's a 10 mm) wrench and remove this, and have a look at what is inside it. Let me know what ya come up with!

[GearJammer]

Another possibility might be a partially clogged Main Jet......from about 3/4-WOT (wide open throttle), the Main Jet supplies all of the fuel flow. If the bike had sat long enough without running, fuel sitting in the float bowl could have gotten funky enough to create small pieces of sediment & it doesn't take much to block those jets......

[ThunderEagel]

No, I didn't blow back through it. I did completely replace the fuel line though.

A needle and seat issue would only show up at near max throttle? Could it be sticking?

I'm starting to wonder if running some SeaFoam in the tank would help clear things up.

[GearJammer]

SeaFoam is definitely worth a try & can't hurt, especially since you've got the in-line fuel filter.........

[ThunderEagel]

Another possibility might be a partially clogged Main Jet......from about 3/4-WOT (wide open throttle), the Main Jet supplies all of the fuel flow. If the bike had sat long enough without running, fuel sitting in the float bowl could have gotten funky enough to create small pieces of sediment & it doesn't take much to block those jets......

It may have sat for about a month before this problem presented. However my wife generally turns the petcock off, not that that would get the gas out of the bowls.

Thanks for the replies!

[GearJammer]

A month of sitting could quite possibly do it.........Could be sediment slightly clogging the Main Jet or as b4v4 suggested, maybe the float isn't moving as freely after the dormant period.

You could "try" the Seafoam, but if you've got the manual, you might just bite the bullet & do a carb cleaning. It really isn't bad at all & the Clymer's Manual pretty much walks ya thru it. Biggest thing to watch out for is keeping any Carb Cleaner off of any rubber/neoprene parts inside as the Carb Cleaner would melt 'em..........spoken as a caution only, it's really not a difficult job.

[Duke Bushido]

Yep.

Sounds like crud in the carb.

The needle and seat are only one possibility, of course, but yes; such a problem, if very slight, could show up only when peak demand was being made for fuel flow.