Running Rich/rough

Dean J · Post by **Dean J** » Thu Mar 20, 2014 7:54 pm

Hey all,

So, my first question in here...

Have ridden my 92 RU? Exup a couple times now, first few times she ran just fine, however today on a short ride every time i stopped the bike would bog down on pulling away. slipped the clutch to whack the revs up and she picked up like a rocket. Also noticed at lower revs and steady throttle the bike feels "wooly" like its not quite getting the fuelling right. again, full throttle and all is fine.

I have noticed that the exhaust exit is properly sooty, and when revving in neutral she does chuck a whisp of black smoke as the revs get up.

Also, when i collected the bike it did dump some fuel out the left hand side of the bike under the tank ( carb overflows?) but hasnt done this since.

So im fairly sure she is running rich, the question is where do i start looking? Bike has effectively a straight through exhaust and K&N filter fitted (prev owner), so thinking its possible they have overcompensated on jets perhaps? or worn emulsion tubes/jets? sticky floats?

Are the needles adjustable on these carbs? or is it all purely down to jet sizes?

Im a fuel injection kinda guy, so not really clued up on carbs at all!!

cheers in advance!

Post by **Stig** » Thu Mar 20, 2014 8:09 pm

hate to say it but it sounds like the toobs are worn. Whip off the carbs and check for wear. Even a slight ovalling of the hole will make the world of difference and milage is no judge for wear.
Mine had done 16k and there were no VISIBLE signs of wear but I changed the toobs last winter because it was bogging off the line and it cured it instantly. I counldnt belive the difference

BTW, I keep several sets of new mikuni emulsion toobs to sell for the 1000 if you need them. thers apost at the top of lounge

Dean J · Post by **Dean J** » Thu Mar 20, 2014 8:23 pm

Cheers dude, i did have an inkling it could be.

Ill get them checked over and if theres nothing else obviously causing it, ill get a set ordered off you

dangerousdave · Post by **dangerousdave** » Sun Mar 30, 2014 9:10 pm

If that doesn't sort it bang a standard air filter in, mine came with k and n and it was like I had to do a gp start off every time as it wouldn't pull until it hit around 3 grand (exup valve working fine as well) , but after filter change it was bang on, some people think by putting a k and n in it will make it go faster but without changing the jets and some fiddling in my experience you won't tell the difference other than it growling at you.
Also had tubes off Stig at a later date and that made a difference too.