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post #1 of 4 Old 05-15-2013, 3:08 PM Thread Starter
 
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Crankcase/Head Breather

Gents, I'm rebuilding a 96 RRT and am interested in the small breather hose that comes off the top of the cylinder head and connects into the base of the airbox.
In the American Clymer manual it states that it's there for emissions purposes !!! Now I'm not really bothered by emissions and thought my air filter looked a little "oily".
Surely just clean air is best entering the airbox and not hot oily air !!!

Is it worth disconnecting it or does the crankcase need to "breathe" ?
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post #2 of 4 Old 05-15-2013, 5:57 PM
 
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Re: Crankcase/Head Breather

No - leave it in. As you say it's so the crankcase can breathe.

If the bike isn't braking properly, you don't start by rebuilding the engine.
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post #3 of 4 Old 05-15-2013, 8:15 PM
 
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Re: Crankcase/Head Breather

i've never been a fan of venting the crankcase into the intake, for the stated reason of sucking oil into the combustion chamber. i've seen car set ups where guys have used catch cans and pod filters to vent out from the crankcase, i wonder if there is something comparable for bikes. your crank case needs to vent still, but i don't think it HAS to vent to the intake, other than emissions.
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post #4 of 4 Old 05-15-2013, 10:13 PM
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Re: Crankcase/Head Breather

Quote:
Originally Posted by Flashhart View Post
Gents, I'm rebuilding a 96 RRT and am interested in the small breather hose that comes off the top of the cylinder head and connects into the base of the airbox.
In the American Clymer manual it states that it's there for emissions purposes !!! Now I'm not really bothered by emissions and thought my air filter looked a little "oily".
Surely just clean air is best entering the airbox and not hot oily air !!!

Is it worth disconnecting it or does the crankcase need to "breathe" ?

It is for emissions, crankcase pressure needs to vent. On race bikes we run a catch tank to catch any oil, on a road bike it's better to vent it to the airbox so those oily fumes get burned through the engine.

"I won't forget that ride for a while. Maybe you're right. Living fast might be worth the final crash. Maybe that's the secret you fliers know." - Flight of the Intruder
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