August 15th, 2022, 02:21 AM | #1 |
ninjette.org member
Name: Tev
Location: Ireland
Join Date: Aug 2022 Motorcycle(s): 2004 E250 Posts: 18
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Idle not stable - carb issues?
My 2004 starts easily and runs well at speed and at normal temperature but it does have an idling problem. It starts on choke and if you leave it to warm up will eventually idle at 1200-1300 RPM which seems fine. Take the choke off too early and it dies quickly. I thought it needed a little too much choke to keep running as it was 86F outside but maybe that’s this bikes character?
The issue is you drive off down the road and at the next junction the tick over is now 4000RPM for the rest of the ride. You can bring it down with the idle adjuster but that doesn’t feel intuitive as it was idling fine at initial start-up. Tank is clean and the fuel flow is good on this bike, you can pin the throttle and it doesn’t falter. I suspect blocked or partially blocked pilot circuit in the carbs or loose rubbers leaking air. Before I go down that route, I will check the valve clearances too. My question is: are there any common traits or known issues with these carbs? Is there anything I should pay particular attention too? I’m happy stripping and cleaning carbs, the bank of four on my Daytona 1200 went through a period of driving me nuts until I found two blocked choke circuits that had frustrated me for months. |
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August 15th, 2022, 06:08 AM | #2 |
Rev Limiter
Name: Jay
Location: WI
Join Date: Jul 2013 Motorcycle(s): '06 SV650n, '00 Derbi GPR, '64 CA77 Dream 305, '70 CL450 Scrambler, numerous dirt bikes Posts: A lot.
MOTM - Jun '18, Oct '16
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As you stated - check for a vacuum leak.
Have you made fine adjustments to the idle mixture? Have the carbs been synced recently? I would do those things before pulling the carbs. |
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August 18th, 2022, 07:49 PM | #3 |
ninjette.org member
Name: Peter
Location: Northeast
Join Date: Jul 2022 Motorcycle(s): Ninja 250 Posts: 10
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This may not be it but my bike was doing the same
Thing.. come to find out the throttle cable was not returning back to idle. The way it was routed was putting too much bend in it so after giving the bike throttle it would sit around 3-4K. Had to re route the cable and also oiled it a bit |
2 out of 2 members found this post helpful. |
August 19th, 2022, 04:46 AM | #4 |
ninjette.org member
Name: Tev
Location: Ireland
Join Date: Aug 2022 Motorcycle(s): 2004 E250 Posts: 18
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Cable snagged
You were right Patrizio. After taking all the bodywork off to adjust the valve clearances I got a clearer view of the throttle cabling. One of the cables lock-nuts on the adjuster was loose, sometimes that nut was catching on the bracket, other times not. A reminder to check the easy stuff first.
Bike running well now. Valve clearances done, new oil & filter, new coolant, new spark plugs. I am not mad about the airbox to carb rubbers, they are probably next on my to do list but will do for now. |
1 out of 1 members found this post helpful. |
August 19th, 2022, 06:43 AM | #5 |
ninjette.org member
Name: Peter
Location: Northeast
Join Date: Jul 2022 Motorcycle(s): Ninja 250 Posts: 10
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What’s wrong with the rubbers to the carb? I am asking because it seems as if mine will back off over time. Should there be a hose clamp around those?
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August 19th, 2022, 07:08 AM | #6 |
ninjette.org member
Name: Tev
Location: Ireland
Join Date: Aug 2022 Motorcycle(s): 2004 E250 Posts: 18
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There is no hose clamp, just some elasticated springs on mine but they are not great. I have seen this mentioned a few times on the forum. Some have added a hose clamp by the looks of it.
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