Carbs running bad

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Marauder
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Carbs running bad

#1 Post by Marauder » Sun May 15, 2016 4:58 am

Morning guys and girls. Having great problems trying to resolve fuel starvation she doesn't know what to be at. New tap /fuel lines jets needles fuel jets/and seats etc plugs/caps changed too.washed tank out filters also. I ve ultrasoniced the carbs earlier before I started rebuild possible further ingress. Crank seals don't appear a problem. Have replacements.

Runs all 4 at cold then as you ride couple miles starts to loose the cylinders typically lowers will keep running, with throttle but gut less. Will die bitch to restart
Ideas please will be greatly appreciated :smt017

rd84
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Re: Carbs running bad

#2 Post by rd84 » Sun May 15, 2016 6:07 am

Did you check the float heights and then the fuel levels when the carbs were installs ? - Do the chokes work OK ? - does the engine pick up if partial choke is applied ? - how long does it take for the fuel bowls to fill ? - check with the fuel tap on prime

Cheers
Paul

Marauder
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Re: Carbs running bad

#3 Post by Marauder » Wed May 18, 2016 3:40 am

Hi Paul, I will recheck heights and levels carbs have been on and of more times than I can think of. Choke seemed to help then not as the miles crept by. Time to refill carbs isn't bad I've replaced tap &pipes as they were badly deposited on the inside see how we go.

rd84
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Re: Carbs running bad

#4 Post by rd84 » Wed May 18, 2016 5:56 am

It can be easy to trap the fuel supply pipes - particularly the left hand one where it passes over the heat shield - I just did the float valves on my bike - only one went wrong but I thought I might as well do them all - so I empathise with you on the problems - removing and refitting the carbs is a miserable job.

Cheers
Paul

rd84
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Re: Carbs running bad

#5 Post by rd84 » Wed May 18, 2016 6:03 am

Just one more thought - have you checked the fuel tank is breathing OK and the vacuum pipe is working ? - have you checked with the fuel tap in the prime position at the end of the run when the engine is running lean - can you hear the fuel bowls filling up in the prime position ? - you shouldn't hear anything if the fuel bowls are full - release the fuel filler cap to see if you have a partial vacuum as well.

Is the fuel tank trapping the fuel lines ?

I don't think there is much left to check on your fuel system !

Cheers
Paul

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solo 2
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Re: Carbs running bad

#6 Post by solo 2 » Wed May 18, 2016 9:28 am

Have you checked the plugs to make sure you're not actually wetting out, had the exact same symptoms on mine first couple of rides. Changed the plugs out and everything went fine. In hind sight could have had bad plugs but I would think that's pretty rare.

podman
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Re: Carbs running bad

#7 Post by podman » Thu May 19, 2016 4:55 am

rd84 wrote:It can be easy to trap the fuel supply pipes - particularly the left hand one where it passes over the heat shield - I just did the float valves on my bike - only one went wrong but I thought I might as well do them all - so I empathise with you on the problems - removing and refitting the carbs is a miserable job.

Cheers
Paul

Thats a very good point, my mate broke down last week due to fuel starvation on the first run out with his KR1-R, he had simply made the fuel line too long and it folded on itself as he fitted the tank..

Bunzona
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Re: Carbs running bad

#8 Post by Bunzona » Sun May 29, 2016 1:51 am

Just had exactly the same problem on my first ride out yesterday after full rebuild. Looks like I'll be following the same diagnostic path as you. Did you solve it in the end?

silverstrom
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Re: Carbs running bad

#9 Post by silverstrom » Sun May 29, 2016 2:58 am

http://www.rzrd500.com/500phpBB3/viewto ... 432#p71432" onclick="window.open(this.href);return false;

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phildu31
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Re: Carbs running bad

#10 Post by phildu31 » Sun May 29, 2016 9:18 am

Hi.

Do the carbs still have their heat shield ?

Bunzona
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Re: Carbs running bad

#11 Post by Bunzona » Mon May 30, 2016 6:21 am

Thanks guys. Interesting link. I am running stock fuel lines and petcock and the carbs do have their heat shield. I will carefully go over all the fuel lines again to make sure I don't have a crimp/blockage and will check the filler cap is venting OK (this may be the culprit). Will keep you posted.

silverstrom
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Re: Carbs running bad

#12 Post by silverstrom » Mon May 30, 2016 5:34 pm

A blocked tank vent will certainly cause headaches. Go for a ride and it if happens again remove the cap and see if things change.

Typically that is very early in the troubleshooting process. Blocked bowl vents are another area that is often overlooked.

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2smoke
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Re: Carbs running bad

#13 Post by 2smoke » Mon May 30, 2016 8:55 pm

I just went thru the blocked fuel cap vent thing with my rd350. Idled fine and putted around fine but once on the highway it quickly ran out of fuel in the lines and I had to stop. Opening the cap didn't help me, air was trapped in the clear fuel lines and it wouldn't pull fuel thru.
Anyway I tore the cap all the way apart. Keep going till you find the little ball bearing check valve and hole with felt in it. Test if the felt is clogged up and remove it if necessary. This cured the 350.
Colin

silverstrom
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Re: Carbs running bad

#14 Post by silverstrom » Mon May 30, 2016 10:27 pm

2smoke wrote:I just went thru the blocked fuel cap vent thing with my rd350.

The RD is done and on the road?

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2smoke
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Re: Carbs running bad

#15 Post by 2smoke » Mon May 30, 2016 11:43 pm

silverstrom wrote:
2smoke wrote:I just went thru the blocked fuel cap vent thing with my rd350.

The RD is done and on the road?
Yes sir :grin:

http://www.rzrd500.com/phpBB3/viewtopic ... 7&start=30

About 500 kms on the rebuilt bike now. I`m pretty pleased with it. Took it to the Icehouse on Sunday and had some gawkers. Lol.
Colin

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