Date: 29-03-24  Time: 12:33 pm

Author Topic: Bogging down  (Read 915 times)

Mustang

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Bogging down
« on: 21 June 2018, 08:41:54 pm »
well bugger, after removing the carbs and airbox Tuesday I cleaned the outsides of the carbs as well as I could then took off the float bowls one at a time, took off the jets and nozzles only and gave them a blast of carb cleaner. I didn’t take off the floats or the carb tops. Now when I’m riding it bogs down over 6k revs in top or 9k revs in 2nd or 3rd. Is this likely to be carbs blocked or an air leak? It rides ok at low revs.

Hugh Mungus

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Re: Bogging down
« Reply #1 on: 21 June 2018, 09:09:48 pm »
Bogging down at 6k revs is more a symptom of the EXUP valve not opening. Check to make sure it hasn't seized or that you haven't dislodged a cable.

Mustang

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Re: Bogging down
« Reply #2 on: 21 June 2018, 10:26:38 pm »
Bogging down at 6k revs is more a symptom of the EXUP valve not opening. Check to make sure it hasn't seized or that you haven't dislodged a cable.


I greased up the exup valve before I did anything but Ive just fitted new cables, I’ll check it out thanks.
« Last Edit: 21 June 2018, 10:27:41 pm by Mustang »

Gnasher

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Re: Bogging down
« Reply #3 on: 22 June 2018, 09:27:59 am »

I'm assuming all was ok before you took the carbs off and you've rechecked all the couplings etc?


Providing you've not damaged something while stripping and blowing air through the jets etc.

Check the starter plungers or choke as it's commonly known, they must all fully return.  What can and does happen is the linkage seizes or more often the linkages returns but the plunger stays open, either way this leans off the mixture at over 4k ish and gives you what your describing.  They sit at 90* across the top of each carb just in front of the inlet rubber union, to check look closely at the area where the forked lever is over the plunger.  It's possible either the cable is fully returned and the linkage is stuck or a plunger/s are stuck open. 


If you can push any of the plungers in with the choke fully closed you've got a problem, as said above it's often the plunger's that sticks, they are usually just dry, remove lift off the rubber cover and apply a little oil to the shaft.  Work the plunger until free, if you can't free it replace it.


The above is a common reason for what you describe, failing that it's possible you've blocked a main jet while blowing them out.       
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Re: Bogging down
« Reply #4 on: 22 June 2018, 02:44:25 pm »
Thanks gnasher I’ll check that out. I hope you are right.
I’ve tried some redex, did nowt, I’ve adjusted the exup cables as the closing one was too tight. The exup moves freely and is I think fully open, it roatates about 90 degrees from closed. The fault is still there however, the bike will rev right up to and beyond the red line in neutral but about 9k it’s like hitting a limiter, the bike just won’t go.


Can we eliminate an air leak?
« Last Edit: 22 June 2018, 03:24:49 pm by Mustang »

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Re: Bogging down
« Reply #5 on: 22 June 2018, 04:26:49 pm »
Anything blocking the air filter intake or anything been sucked into the snorkel like a cleaning rag or something?

Mustang

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Re: Bogging down
« Reply #6 on: 22 June 2018, 04:39:40 pm »
Fixed it! The airbox to carb 3 rubber clip was slipping off , finally got it back on square n not too tigh5, test ride, and ......right up to the redline! 2nd gear 90 mph, 3rd gear 100, ran out of road, getting too much attention from the farmers so that will do nicely. Thanks everyone, I did check the choke plungers and they all do go back but this made me look closer at the rubbers, so I saw the potential problem. Wasn’t looking forward to taking the carbs ou5 again.

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Re: Bogging down
« Reply #7 on: 22 June 2018, 05:06:05 pm »
Cool and coupling problem  :)   
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