Reed valve breathers

jrjstuff wrote:

Right on, thanks again for all the help. No one really addressed it but I assume that the breather comming from the case can also be plugged?

No. That is a totally unrelated to the reed-valve air injection system.

Crankcase MUST breath or you will start blowing oil out of everywhere.

You can simply run a hose to the ground from the crankcase breather, but you can't plug it.

EDIT: Nevermind. I see Patton already caught that one.

Post edited by: loudhvx, at: 2008/02/19 13:38

piss on making them. there cheap to buy.


kzzone.com/resources/billet/99285big.jpg

Will those APE covers fit on a 750 cover?

I would think that Mother Kaw would make all covers the same but I believe those APE covers are for the 1000's only?

P.S. jrjstuff, if your stock air box (what year?)is like mine then you can do as they say or locate the proper hose. (#9 in pic)



Post edited by: Bluemeanie, at: 2008/02/19 15:22

Its an 83 750H. Here are a few pic of the bike. I just got it running and there seems to be quite a bit of chatter from the clutch basket when the clutch is out, when it is in, the noise seems to go away quite a bit. I should start a new thread but what do you guys have to say about it? Oh and the breather from my airbox goes down but I think I may be able to fit a tube on it just to keep it clean. The bike needes a lot of work but I am happy for the $200 I spent on it!!

My pics are too big I will have to try and resize them and then post

The breather pipe from the crankcase can just be a hose to the ground. Then you plug the hole in the airbox. Or if you keep the airbox, you can connect the crankcase to the airbox per the diagram. I found this tends to spit some gunk up into the airbox, though, so I use the hose to the ground method. Purists might say that not having airbox vacuum to the crankcase may cause a tiny bit of oil seepage on the crankcase and cam-cover seals, but I haven't really had a problem with it.

Also, if you look at Bluemeanie's diagram, what looks like part #10, the little doughnut, is where the air injection had a tube going to the airbox to get fresh air. That hole in the airbox should now be plugged with a rubber stopper of some sort.

Post edited by: loudhvx, at: 2008/02/19 22:26

That sound like a good idea. Thanks

this is where I got the reed valve covers for my 750M.
tinyurl.com/3434qj

hey guys a common mod on the 12r is to get rid of the smog stuff and connect the crank case vent to the valve cover(very basic and easy to do). block the holes in the airbox. i had this done to my bike this season. its supposed to put a slight vaccum on the crank case, and that can actually boost hp a tiny bit. some guys claim 2-3 hp. the thing is, i have now learned that the air being pumped into the exhaust ports(either from the air box or crank case) causes a bit of turbulance(to "shake up" the air. mixing the fresh air with unburned gas vapour to promote further burning and a cleaner exhaust) and that turbulence can rob a bit of hp(head doesnt flow quite as good) so this year i am going to be running block off plates(Muzzys) and ill be venting the crank case to the exhaust pipe. you see this on lots of drag cars where guys vent the valve covers to the exhaust. when done right, this pulls a vaccum on the crank case, and you get a better flowing head from the block offs. the best of both worldsB)

So, are you guys saying that the way Kaw made it so the bike passed emissions way back when was to add air to the exhaust to dilute it?

It doesn't re-burn anything in the exhaust? If that's the case I'm going to consider taking mine off as well since the net effect is the same either way. And the tubes will be out of my way. :woohoo:

77KZ650 wrote:

hey guys a common mod on the 12r is to get rid of the smog stuff and connect the crank case vent to the valve cover(very basic and easy to do). block the holes in the airbox. i had this done to my bike this season. its supposed to put a slight vaccum on the crank case, and that can actually boost hp a tiny bit. some guys claim 2-3 hp. the thing is, i have now learned that the air being pumped into the exhaust ports(either from the air box or crank case) causes a bit of turbulance(to "shake up" the air. mixing the fresh air with unburned gas vapour to promote further burning and a cleaner exhaust) and that turbulence can rob a bit of hp(head doesnt flow quite as good) so this year i am going to be running block off plates(Muzzys) and ill be venting the crank case to the exhaust pipe. you see this on lots of drag cars where guys vent the valve covers to the exhaust. when done right, this pulls a vaccum on the crank case, and you get a better flowing head from the block offs. the best of both worldsB)

Very interesting. I've heard of vacuum pumps for the crankcase, on high-power motors, in order to keep the piston rings from vibrating in the grooves.

When you shut down the throttle, the Kaw system is designed to shut off the airflow into the exhaust. This is to prevent backfires. When the system breaks, most often the symptom you get is big backfires when you close the throttle. Were you getting any backfires while routing the crankcase vent to the reed valves? I guess if the bike is running right, the crankcase is only going to have mostly blow-by exhaust gases so the backfires wouldn't happen.

I just hate the tubing mess on top of the motor.

i didnt notice any backfires, but my reed valves are circa 2001:P
every little bit of power gain is nice when you are racing, plus it makes the ram air more effective on a 12r with the air box(frame) sealed.
im pretty sure a vaccum on the crank case also helps because it makes the air thinner, when a crank is spinning through "thick" air it hurts power. why do you think people get their cranks polished? it makes them more "slippery" through the air and oil.
as an example my uncles drag vette (548ci big block) picked up something like 30 hp when he swapped to a deep sump oil pan. the crank doesnt have to turn thru oil. the less stuff the cank has to turn through the more power you make. even air holds you back when something is turning a few thousand rpm. he vents his motor to the exhaust, and has thought about putting a vac system on it. i think he was quoted on a gain of about 15hp with a really good vac system