First off a catch can can be a plastic bottle fitted out the way put hose thats conected to breathers into it, been doing that for years drag racing harleys. the old Strokers used to wet sump at high revs. but latter i found out could be poor scavenging from oil pump not scavenging fast enough at higher rev's, you could use an elecric pump to help scavenge the oil back to oil tank if you wanted.

then latter found blow by from cylinder flex at rev's, where the cylinder being on thin side can flex under rev's & cause oil out crank breather, also cracked ring cracked piston can do it too. i rev my twin cam 95 inch to 7,200 & no oil out the breather at all. & my buell year 2000 does not blow any oil out breather ( don't use a catch can at all, just a hose out the back. the bad thing about oil out the breather is, it means motor is wet sumping & wet sumping kills power as too much pressure in crank case. so hope you get that issue sorted out.

When it comes to Harley's I have found that a lot of guys tend to say "that's how a harley is ment to be". To me these guys are the ones I don't listen to, they don't know any better and have never looked into why and how it happens and how it can be fixed!

T1

All engines will breathe! the amount will depend on alot of factors some of which we have already talked about. Anything that is used for racing will have an external breathing system fitted...... At the end of the day, if you fit a catch can and it fills with all ever week or 2 its got way too much blow by...but thats also dependent on how oftern you ride...... having it fitted you'll soon work out if its too much...

T1

Sure thing, i'd be keen to come and have a look/chat. Not saying all bikes/cars push out oil, by breath i mean they all have some degree of blow-by some so little it isnt noticable to the eye. But if your in Melbourne Krash let me know im keen to catch up and talk bikes with you! I think with an air cooled motor getting the right piston to bore clearance would be a hard task given the conditions we live in here (melb), down to 2 degrees in winter and 45 in summer. if the temprature of these motors could be kept stable (water cooled) then clearances could be worked out eaiser. Bore flex/distorsion is very likley! i agree there.

Regards Andrew - T1

i'm in Sydney mate

As far as I know 1/2" 13tpi for 91+ sporty & big twin 93-99.

Slap.

Hey 5ltr I ended up gettin my breather sorted.

http://www.ebay.com/itm/BREATHER-OIL-COLLECTOR-RESERVOIR-EBOC-CATCH-TANK-HARLEY-CHOPPER-PAN-SHOVEL-/230990816193?pt=Motorcycles_Parts_Accessories&vxp=mtr&hash=item35c82023c1#ht_2090wt_1161

Catch can mounts up to the sprocket cover, stock bolt size is 1/4" UNC 2-1/4" long, replaced with a 3" bolt & spacers/washers to suit.

Cheers,

Slap.

Looks good slaps, and baffled as well, good design there...

 

i was thinking about this thread the other day, and found the perfect thing to make a catch can out of, google these part numbers :

64120-06 - mini - 7.7x1"
64100-03 - medium - 7x2"
64101-03 - large - 10x2"

T1

 

EDIT : Slaps where are your oxygen sensors????

 That looks good there slapster....will keep that in mind for mine as well Cheers

Cheers T1. Them moco parts are bloody expensive! Panic Cycles also do components, eg- tank only, tank with fittings, tank without breather filter etc, so you can put together your own. Reasonable prices too. I only saw the other stuff after I bought this unit, but I'm happy with it, you can feel the breather venting when the motor is running & it feels like a quality part.

Slap.

Cheers Stretch. Need some pics of your 90" beast soon mate.

Slap.

 yep finally did mine today see how it runs tomorrow

 lol funny that hey

Yeah catch can looks good Rich.

Slap.

 Yeah thx guys all good  it didn't fall off the bike so sweet as