05 rx1 hanging idle

[Deptron]

Just had the carbs off again and cleaned the fuel screen/filter under the float needle, ran the sled, and...............no change

 

[Purplecoffin]

Not a for sure solution, rather a thought. ... what springs are in the carbs? I have read that sometimes the springs can cause that?

Just a thought, someone with more experience with these set ups will hopefully critique this idea.

 

[Koenig]

I'm going to throw out a guess here.... There's air leaking through 1 or many of your intake boots, possibly a cracked boot. With 2 strokes, you will lean out fast and a plug(white) will hint at that, but 4 strokes will just idle higher. If 1 boot is leaking the idle will be high until the other cylinders tend to slow it down.
my .02

 

[tproteau]

make sure the vacuum lines from the carb boots are attached to the fuel pump and that the caps from the boots with out lines are still on the boot.

 

[Deptron]

I have my buddies rx warrior in my shop too, last night I put his carbs on my sled, it ran perfect, so it's definitely something in the carbs. Just have no clue what to check next. Thanks everybody for your help up to this point, really appreciate everyone's help.

 

[Koenig]

ok, then my next guess is something is holding one of the slides up a bit. If your carbs are off, verify that all are 'basically' the same height off the base of the carbs. (preset idle are all the same height) If one slide is higher up (allowing more air) engine will idle up. Needs to be re-sync'd

 

[Deptron]

I checked the slides with some feeler gauges, and all seem to be the same.

 

[GUKROKIT]

I do recall a lot of people saying over the years that they had to replace the pilot jets since they were hard to clean. Spraying with carb cleaner and blowing out was sometimes not enough so many resorted to using single strands of copper wire to "scrape" them clean. Stock pilots have a very small orifice. If they aren't perfect the pilot circuit will be lean causing it to hang at idle. Just a thought.

 

[superfan75]

I do recall a lot of people saying over the years that they had to replace the pilot jets since they were hard to clean. Spraying with carb cleaner and blowing out was sometimes not enough so many resorted to using single strands of copper wire to "scrape" them clean. Stock pilots have a very small orifice. If they aren't perfect the pilot circuit will be lean causing it to hang at idle. Just a thought.

Yeah when I clean a carb I always run a thin wire through the jets to make sure the holes are open. Then I run carb cleaner through it and finally blast compressed air through. You have to make sure every port is open fully.

 

[Indy]

did you notice the little o-ring was under each cap on the carbs? I still say the carbs are dirty, one little, tiny, need a magnifying glass to see, piece of #*$&@ is in the jet or jets.

 

[Deptron]

The little orings are there. I ended up buying a used set of carbs off the bay. Threw them on and everything is working perfect. Too bad I was never able to figure out what was wrong with the other set, but at least everything is working properly again. Thanks to everyone for the help. Maybe when I get bored I'll go through the old carbs again and see if I can find anything else.

 

[victorn]

interesting, also having same problem with rpm's not going down right away, especially when after a ride, plus it would also backfire. i turned fuel screws 2 turns out, and by two turns i mean 2 x 180 degrees turns, not 2 x 360. then i was taking them out I checked and they were all approximately 270 degrees out ... I also noticed that throttle cable had play where just by turning lock to lock rpms would jump up pretty high, so i had another used cable laying around so i replaced original with it - it got better.
cleaned jets, including air jet, by soaking them, including screens etc. added in-line fuel filters and shutoffs.
when carb was off did bench sync and after was installed re-synced with electronic sync tool.
is there a way to check for leaking boot?
has anyone ever used ultrasonic cleaners and has anything to suggest? i've seen some neat videos on them and thinking about building one. seems like all gunk comes off pretty clean.

 

[superfan75]

For checking the boots for leaks you can twist them slightly to see if there is a crack. If there is a crack it will open up so you can see it. Also you can spray carb cleaner around the boots with the engine running and if the idle changes then you know that there's a leak somewhere.

 

[BETHEVIPER]

customers sled with the same issue. was running crappy down low, idle hunting, hard starting, classic dirty carbs. You could also hear a misfire in the exhaust once in a while. Cleaned everything, runs like a champ, starts good but the Idle hangs, sometimes above engagement. Fun to ride that way. Tore the carbs and boots off last night. Didn't see anything obvious. Slight corrosion on head where boots bolt.
I am going to pull the slides and check them out. I had a 4 wheeler once that had erratic idle, it was the slide where it attached through the bellows. It was not tight there. Had to remelt a plastic rivet that held it together to get it to tighten up.

 

[Redbeard]

Guys, I just went through the same issue with my 973 carb Vector. Carbs were spotless, plugs were good, etc, but idle was erratic and wouldn't settle down right away. I could even hear a slight pop in the exhaust like Betheviper mentioned. Finally, a sync tool proved my carbs were out of sync! Once I figured out the sync tool, the idle settled to a purr and the exhaust pop went away.

It's my understanding that feeler gauges are not good enough to set the throttle slides. A vacuum gauge is needed while running because compression will be different in each cylinder as valve seats and piston rings wear over time.

Now, I'll admit I didn't really know what I was doing at first, so maybe I just got lucky the carb sync alleviated the problem.

Hope this helps?