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mm500
Joined: 18 Feb 2014 Posts: 121 Location: Norway
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Posted: Tue Jul 08, 2014 2:59 pm Post subject: Adjusting the carbs |
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I have adjusted the oil pump to minimum , but the bike is running to rich.
I asked Piero about leaning the mixture, but he says the bike need to run rich.
Any experience with adjusting the mixture? |
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brian
Joined: 22 Aug 2011 Posts: 3769 Location: Australia
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Posted: Sun Jul 13, 2014 1:41 am Post subject: |
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You could try leaning it out until it melts a piston and then ritchen up a little, I wouldn't recommend this method though _________________ '99 DB4 #104, '96 SB6 #1165, '94 DB2 J #652, '99 DB4 #088, '08 VTX1800, '93 ZXR750R M1, '95 ZXR750, '95 ZXR750 Race Bike, '94 CBR400rr NC29 Race Bike, '94 CB250, '49 BSA C10 250, '61 BSA A10 650, '89 ZXR750, '91 Ducati 851 |
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mm500
Joined: 18 Feb 2014 Posts: 121 Location: Norway
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Posted: Sun Jul 13, 2014 7:41 am Post subject: |
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hehe, yes I have tried this method on my RS250...
But seriusly,
the bike runs way to rich on all the trottle positions except max.
so the main jet is ok, but I need to adjust the air screw and needle.
Last edited by mm500 on Sun Jul 13, 2014 10:26 am; edited 1 time in total |
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brian
Joined: 22 Aug 2011 Posts: 3769 Location: Australia
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Posted: Sun Jul 13, 2014 8:26 am Post subject: |
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Hopefully one of the expert V-dudes on here can help you. Sorry, i'm no help, just thought i'd answer your post as nobody else had. _________________ '99 DB4 #104, '96 SB6 #1165, '94 DB2 J #652, '99 DB4 #088, '08 VTX1800, '93 ZXR750R M1, '95 ZXR750, '95 ZXR750 Race Bike, '94 CBR400rr NC29 Race Bike, '94 CB250, '49 BSA C10 250, '61 BSA A10 650, '89 ZXR750, '91 Ducati 851 |
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mm500
Joined: 18 Feb 2014 Posts: 121 Location: Norway
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Posted: Sun Jul 13, 2014 10:25 am Post subject: |
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thanks for the bump |
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JRH
Joined: 21 Jan 2013 Posts: 223 Location: West Mids/North East
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Posted: Sun Jul 13, 2014 10:49 am Post subject: |
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Have you done a plug chop?
If it's been set up by Piero, I would think that the jet sizes are ok.
Try going weaker on the mixture screws half a turn at a time. Then plug chop again.
If they are out, then your idle should go a little higher, so you will need to reset that. |
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mm500
Joined: 18 Feb 2014 Posts: 121 Location: Norway
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Posted: Sun Jul 13, 2014 11:15 am Post subject: |
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I have not done a plug shop yet.
The bike makes the BRRRRR sound ( like driving with the chocke on) at 0-60% trottle setting so I 'am thinking I need to adjusting the mixture screw or needle.
Is the mixture screw going in or out to lean this carb? |
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dingbat
Joined: 17 Sep 2013 Posts: 46 Location: uk
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Posted: Sun Jul 13, 2014 12:37 pm Post subject: |
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Hi MM, I had something similar with mine. Its set up rich for sure and I havent touched it yet. but not to the point of rough from 0 to 60 % throttle. Suggest be careful leaning off the midrange by trial and error. Mine had carbs full of muck as I think have others here and I'm sure you checked that already. Forgive the obvious but you never know - If the bike has run a long time riding slow on the rich pump setting when running in and has been warmed up a long time before riding it could just be blocked up with oily gunge collected in the bottom of the exhausts.. Give it a good run up the rev range on your favourite road ! Otherwise known as a good blast ! I did instal leaner needle jets- not the needle itself - a few years ago on my RS 250 with good results. At the time the needle jet mod was standard for the otherwise untuned Aprilia Challenge bikes with arrow pipes in the UK series. I did this mod on the bike before it was tuned with just the arrow pipes and there was a noticeable improvement so its worth a look at trying. I wouldnt want to guess at it though so suggest try it out on a dyno setup first. Most bikes are set up rich at the rpm needed for noise tests at part throttle opening. Might have to live with that Vdue rough spot even though its in an irritating rev band at about 4800 -5200 rpm. Right where you dont want it ! My bike needs a few more miles on it yet before I get serious about it and I dont have much time to ride at present. But I will be having a look at these things too when time permits - all part of the fun ! |
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