Replacing plastic breather gear

[BigPeet]

Originally Posted by S&S Cycle

Some differences between stock and our steel breather gear
We changed the timing of the breather gear slightly to increase flywheel cavity vacuum and crankcase oil scavenging.

The slotted scavenge hole vs the stock hole, increases breather po9cket oil scavenging for less carry over.

Thanks

That's dandy. How about some info on the reed valve!

~Pete

[HighPlainsDrftr]

I'm guessing it is the top-breathers that the reed valve is designed for. Wasn't that changed for '93 from bottom-breathers?

[76_iron]

Originally Posted by S&S Cycle

Our steel breather gear comes with an assortment of steel spacers.

The one I recently bought only came with the breather, no spacers. I haven't installed it yet.

[S&S Cycle]

The Reed Valves are listed as 93 and up and that is what they are designed for. With out getting into a long technical dissertation on why they don't work as well. I can say this, you may experience additional oil in the small cavity of a case breather that will not evacuate and you may have oil push out through the breather line on case breathing engines, when using reed valves.

[tweaked1973]

Originally Posted by HighPlainsDrftr

I think the reed valve might help with my problem (high oil consumption at highway speeds, virtually none around town), but I'm puzzled by the need for oversize valves (either rotating or reed valve). The oversize is listed as +.30" which is a huge difference on that diameter a hole. Do they really wear that much, or are the cases reamed to +.30" O/S as a fix?

I've also seen umbrella valves mentioned; it appears they are a post-91 thing. Where are they used?

Edit: Just saw this: http://www.hdforums.com/forum/oil-an...em-on-evo.html
Which says that the reed valves are only for '93-up, contrary to what is widely advertised...

You are right .30 is big, but the breather is .030 which is only .015 off each side. When the bore gets gouged it can be over .010 so in order to smooth it back out you need to go up to .030. Of course then you hope you never have to do it again.

[HighPlainsDrftr]

Numerous sites list it as .300" O/S, not .030" O/S. I went to the S&S catalog and it's .030", so the others are just misprinting it.

[johnjzjz]

before S&S made the .030 breather and its a very nice piece what was done by the real shops was to bore the breather hole, on a bridge port oversize, i believe its been a while -- .100 than press in with a .002 interference heated fit with a machined alloy sleeve -- than bore it to standard / than drill and cut out by hand all the original holes MANY / Many older engine blocks even today you can see the sleave that had been installed years back - this job was not for a novis machinest -- back in the day we fixed every thing it was not like it is now, as you can today just go buy a new part no such thing than -- just my take - jz