Doms CB550F1 project

[DomP]

This morning if made a few discoveries, I had set my float heights to 21mm not the 22mm that they should be.  At least one carb had a twisted float, pushing one side up before the other by around 1.5-2mm.  That must mean I'm getting too much fuel through which may be part of my rich running may be?

I then set the bench sync as suggested by Ken, a really simple and effective method I found. I've posted a few photos to confirm its all good to proceed to refitting.  Mr Honda was having a laugh when he agreed on the carb set up on these, I need a first aid kit just to get them out! 
 

[DomP]

Carb gaps all look OK?

[DomP]

This is the position of my idle screw when just making contact with the adjuster, is this about right?

The cammed stop I'm pointing to with a screwdriver,  is that to set max throttle travel or minimum?

[Oddjob]

The screwdriver pointed one is called the Overtravel Stopper and it should have a gap between it and the butterfly of between 8-12 thou or 2-3mm.

There is another screw (with spring) on the back of the same bracket, this is to prevent the slides locking in place if the throttle is opened too wide, you should adjust this so that when the slide is fully up and the edge has just gone above the carb body you use that screw to set the travel to that amount. It is possible to jam the slides right at the top of the carb and this would mean WOT with no way of stopping the engine except the kill switch.

The idle screw should be making contact, it's what sets the idle speed, if it doesn't make contact and the engine idles it means the throttle slides are set too high.

[DomP]

Yeah that's just how I've left the idle control until I install the carbs, they are right down as far as they will go with just a glimmer of light entering through them. 

Thanks for your help Ken, fingers crossed it will run better once I get them back on.

[DomP]

While the carbs were off ive investigated the carb manifold o rings as it has been suggested to me they can be under sized.  Using a piece of clear 4mm acrylic it is clear that they barely contact the acrylic when pressed against it so I have replaced what were new items with some Vesrah spares I had from the engine rebuild oring kit, far better contact!

[Oddjob]

Where did you get them?

[DomP]

Well I'm absolutely chuffed!  Either the intake orings were seeping in air or my float heights were causing the issue but it now starts and runs pretty perfectly, no hanging idle no stuttering.  Well happy

[Laverdaroo]

Get in, nice one Dom!

A successful fiddle and top skills, well done mate


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[McCabe-Thiele (Ted)]

A great feeling when you fix these issues.👍👍👍

[DomP]

It is indeed, a lot of credit goes to members on here, much of what I have achieved has only been appying their knowledge.

[Oddjob]

What tickover speed did you get with the throttle slides set to that position Dom, did you need to up it with the idle screw?

[DomP]

What tickover speed did you get with the throttle slides set to that position Dom, did you need to up it with the idle screw?

Only a small amount to get a smooth idle, I'm running a Koso gauge so need to adjust the rpm setting on it by connecting up the original gauges.  There's not a significant amount of miles on the rebuilt and rebored engine so until I can actually get it out on the road again I'm not going to run it for fear of glazing the bores, I welcome any advice on running it in safely.

[Oddjob]

We used to say to new owners, 5k revs for the first 500 miles, then first service and after that add another 1000rpm on for every additional 100 miles. Fully run it at 1000 miles or so. Most important of all though was vary the revs, don't let the engine labour, change down on hills even if that means more revs than you should be doing.

[DomP]

Thanks Ken that's exactly what Bryan told me, don't labour it nor baby it.