CB550 Rebuild running rough.

[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]

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.

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.

[SteveD CB500K0]

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.

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 !  

Or get the Microsoft Image Resizer widget from their website:
Here's the XP version

[mickwinf]

Hi Dave sorry you are having these problems, i had similar issues with my carbs on my k3, i replaced the slow jets as they were solid with gunge, also check the floats and needles, on my bike the little spring loaded pin on the float needle was stuck, caused all sorts of problems! Carbs on these bikes can be troublesome when they have been unused for years as you can see if you read old posts on the forums. Good luck sorting it out, regards,Mick

[Oldbuthopeful]

Thanks for all the tips and help both with IT stuff and the bike.  I may have managed to compress the pics quite
by accident when I clicked on 'optimize'.  (My wife blames me for most of the things that go wrong with the pc because
she says I don't know what I'm doing  -  maybe for once she's right !)

It looks as though I shall have to strip the carbs again and look at the float heights and needle actuating bits.  As I said
earlier, there was a big improvement in the slow running after I'd got the central holes of the slow jets cleared out but may
go for new ones when the bike comes off the road for Winter.

Hope the pics materialize !
Dave

[mick]

Nice looking example you have there Dave the carbs on these old bikes can be a real pain when they aren't in regular use, garden looks good to Dave,  cheers Mick.

[mickwinf]

nice looking bike! try www.siriusconinc.com for slow jets, they are push in ones on the k3 and unavailable elsewhere i had very good service from them.

[Oldbuthopeful]

Thanks for the nice comments and all the advice re. jets etc.  I've just been re-reading various threads on carb problems,
particularly Mickwinf's and they look to be a nightmare.  Anyway, have picked up lots of things to look out for when I get
the carbs off again. 

Can't tell you guys out there how good it is to get all this encouragement when things look less that rosy !

Incidentally, can anyone assure me that a set of 4-into-2 pipes from a 500 will fitt my 550 ?  I know they're not the
ultimate solution, like 4-into-4's but at least they make the bike look 'finished' on the near side.

Thanks again
Dave