Ok,

So I have this CBR600 Engine that I need to get running for a dune buggy project. I think it is an 88 or so.

I'm in the process of hooking up the necessary components to start it and see if it runs. I'm not that familiar with 4-stroke motorcycle engines so I need some tips on the vacuum lines. There is a connection for a tube on the top of the valve cover. There is a contraption on the exhaust side that has one metal tube going to the engine at each exhaust port and I figure from the looks of the carburators, there needs to be a vacuum line going to them as well.

I am planning to connect tubes from the valve cover fitting to the carburators and T in the long tube going to the 'contraption'. Can anybody comment if this seems to be right? I looked in some Haynes and Honda manuals but I couldn't find a good diagram of the complete system, just a picture of the engine, then a separate one of the carbs, etc...

The Pictures should give you an idea of what I am talking about.

Thanks for any tips.
Glen



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[IMG]local://upfiles/4102/CBBC8C8BE2674AF9B830BD94948E6D99.jpg[/IMG]

[IMG]local://upfiles/4102/A67B2D16E4194C3BAE3B6660D3E26675.jpg[/IMG]

 

The tube off the valve cover would connect to the airbox on a bike -- you can either plug it or connect to whatever you're using for an air box.

The second picture is the PAIR valve emission crap. Just take it off and mount block off plates above the exhaust outlet (where the black tubes connect).

You got me on the 3rd one though -- looks more like a gas overflow than a vacuum. Most vacuum lines on a bike are very small.

 

Thanks for the info. I was way off.

If everything you say is true, then I'm wondering where the vacuum comes from to run the chokes. Actually, now that I am typing this, I guess it might just come from the engine itself (the engine side of the carbs). That would make sense because there is a very small black tube going from the carbs to the PAIR contraption, and it clearly is running a vacuum actuated valve of some sort.

On the topic of the 3rd one, I found this diagram where the tubes are referred to as Air Vents. Still not sure if they should be connected to something, or just left hanging there.

I've attached the diagram and the tubes/hoses are attached to the part labeled #12 - Air Unions.

Thanks for the tips.
Glen



[IMG]local://upfiles/4102/721672A7018C42EC93CA58F33982B8FE.gif[/IMG]

 

Hmmmmm, air vents ... sounds as good as anything I suppose Still can't figure what they hook up to.