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CB550 Rebuild running rough.

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Oldbuthopeful:
Hi All  -  Some weeks/months since I posted but rebuild now within spitting distance of booking an MOT.  Only trouble is, when I fired her up for the first time 2 days ago, she wouldn't rev below about 4k. (This old girl hasn't run since 1992 !)  Looked on the Forum for stuff I'd seen previuously on Carbs and decided the slow running jets needed cleaning.  Boy, did they need cleaning !!  They were absolutely solid for over half their length so I acted on Forum advice and used my modelling drills to clear them.  (I build etched brass loco kits as a hobby  -  or used to until the 550 came along !)  Anyway, re-assembled, fiddled the carbs back on and fired up again to-day.  Result  -  will run at tickover but only on 2 pots.  Immediate thoughts were  -  coil or condenser,  but the pots not firing are nos.1 and 3, so I assume it's not electrical.  Has anyone any ideas where I might look for a solution please ?   Oh, there's a nice fat spark at the cylinders that have cold exhaust pipes by the way.
I've tried to post a pic of the bike, but it's too big and I don't have the IT skills to compress it, even with the help of Google and the various free sites out there !  I'll get there eventually.
Any help much appreciated as the summer's tickin' away and it's a long time since I was on the road on 2 wheels !
Dave

Bryanj:
Plug Caps?

Oldbuthopeful:

Checked the plug caps  -  gave them a tweak to make sure they're tight on the lead.  The caps are all new by the way and with the plugs in place and held to earth on the exhaust fins, they all give a good spark.
Funny thing is, last night 1 and 3 weren't firing.  This morning, after the fiddle, 3 and 4 weren't firing, except for one glorious moment
when she started on all four then after no more than 2 seconds, reverted to 2.

What do the spring loaded gnurled brass adjusters do that protrude downwards from the rim of each float chamber ?  Looks like some PO has had a go at them with a pair of pliers.  I set them all to 1.5 turns when I stripped and cleaned the carbs but must confess I wasn't sure what I was doing.  The float chambers of the 'dead' cylinders both have fuel.

meerkat:

--- Quote from: Oldbuthopeful on August 05, 2011, 10:44:21 PM ---I've tried to post a pic of the bike, but it's too big and I don't have the IT skills to compress it, even with the help of Google and the various free sites out there !  I'll get there eventually.

--- End quote ---
Hi Dave,
Try opening the picture in Paint then click on Image in the toolbar. There you have an option to resize the image. I generally start at a 50% reduction and see what size file that is. If OK, save as to your desktop where it's ready for using as an attachment.
Hope this helps !  

mick:
Hi Dave i'm not familiar with the 550 but those adjuster sound like your mixture /air screws? , cheers Mick.

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