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Crankcase "breather box" hose?

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So I took the carb out and cleaned it and when I put it back in, there is this hose.  I'm almost positive that I didn't remove it from anything when I took the carb out and I can't find anywhere it would go.  It's attached to the "crankcase breather box" as I've seen other people call it on here.  As far as I can tell from looking at the parts fiche, it's supposed to be attached to the intake boot, but mine doesn't have the elbow and fitting to attach it to.  Does it serve a purpose? Is this a problem?  What do I do with it?  

 

Thanks!

IMG_3510.jpg

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That hose probably goes from the crankcase vent separator (right-side of engine, black box with three hoses attached) to the airbox boot (top of boot has a 90 degree plastic fitting).  The purpose of the system is to collect spent crankcase fumes (in the separator).  The fumes will condense into a liquid and flow back into the crankcase and the vapors are feed into the intake and burnt off.

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That hose probably goes from the crankcase vent separator (right-side of engine, black box with three hoses attached) to the airbox boot (top of boot has a 90 degree plastic fitting).  The purpose of the system is to collect spent crankcase fumes (in the separator).  The fumes will condense into a liquid and flow back into the crankcase and the vapors are feed into the intake and burnt off.

 

Thanks! Good to know.  So if my the hose it not hooked up to anything (my boot doesn't have said fitting), it just means I won't be meeting emissions requirements?  Will it affect performance at all?

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E model bikes just have the line vent. S and SM have the intake fitting. No matter either way as long as the box is connected properly.

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Peter - It always helps to identify what motorcycle you have. Clearly you have S or SM and you have the Mikuni carb.  The hose has a witness mark of a spring clip.  It was connected to something at one time.  I do not see how you can have an air cleaner connecting boot without the nipple for the crankcase vent hose.  It is possible the 90 deg plastic fitting is missing from the boot (it is a separate piece) and have only a hole in the top of the boot.  That is even worse than not connecting the vent hose as the open hole allows unfiltered air into the carb.  You need to look closer at the air cleaner connecting boot.  The E boot with no place to connect the hose will not fit the S/SM motorcycle with Mikuni carb.

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Noble, sorry for being unclear.  I have a, S model with a Keihin FCR slant-body (39, I believe.  It has the accelerator pump).  I noticed the spring clip mark too, and thought I was going crazy for a second, but the intake boot doesn't have a hole in it.

 

 

EDIT: So does this mean a previous owner installed the E boot so that the FCR carb would fit?  That boot was a bitch to get back in once the carb was mounted, but it seems to fit well once installed.

Edited by peterhorniii

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Oh I see, Yes that clarifies things.  Yes the FCR39 slant body is probably installed with a E air boot so no place to hook up the breather hose.  An E model externs that hose to terminate just above the chain by the radiator fluid catch bottle.

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