Crankcase vent

I’ve ran a couple of searches through the archives with no luck. I’ve got a 1980 KZ1000 with a 1075 big bore kit. To vent the crank case I had some pretty small diameter hose running up under the seat with a little KN filter on it. When I would take it out on the interstate it would start blowing oil. My first thought was I was getting some capillary action out of the small diameter hose. I put a larger diameter hose on it and mounted a bottle under the seat and have the filter run down in the bottle. As long as I stay off the interstate life is good, no oil. But on the interstate I’m getting about an oz every 50 mile. The oil looks clean. I’ve thought about building a reservoir that would hold the oil while the bike is running but let it run back into the crankcase when the pressure drops. The bike is like driving a stick of dynamite. I can’t complain about the performance. Is this a sign of a bigger problem? Is it a common thing? This is my first hotrod KZ so please forgive my ignorance. Oh, it dose not have too much oil in it. The red bike is the one I'm talking about

Not to get off topic here, But Superbowl party at DS2's house this year anyone?

We can be all comfy sitting on the bikes watching the game in his garage!! DS2, Have any trays made up to sit between the Bikes for beverages and Grub?

sounds like to me you are getting excessive blow by, the crank case pressure gets higher with rpm, you might want to do a compression check, do it dry and then add a bit of oil to the cyl,

Over filled, blow-by and/or blocked return pathways for the oil to return to the pump maybe.

If you have room, replace the current tube with a longer one that you can make a loop in it (use zip ties to maintain the loop). Be sure the loop is vertical and not laying flat. From the loop to the engine try to be sure the loop is higher so that any oil left in the tube will run back down into the engine.

Another old trick to stop oil blowing out the breather tube is to insert a length of coil spring in the breather tube. The oil drops out of suspension, collects on the spring and drains back into the cases.

Instead of a compression check a leak down test would be more informative of actual engine condition. Spring in hose makes good sense of taking oil of off suspension. I'll have to remember that one.
Les

DS2... ya'll prolly don't want to watch football for at least a year as a result of this year's Red River Shoot Out?

Anyway, to your blow-by problem. First, check compression. A leakdown isn't necessary as the reasons for blow-by are in the pistons, bores or rings.

I can't think of more than three things that could cause this problem...

1. bore ovaling caused by piston rocking
2. rings bad or not seated
3. part of piston cracked such as between ring grooves

If your compression is down some, you might want to have a look.

After looking at your picture I would say wiredgorge is probally right in saying a compression check would give you enough info to see if that is your problem. Your pictures say you have a fair grasp on the technical end of things. But, if your ring seal is going and you have to get into it to fix it, it's not a bad idea to know where you stand on the topend seal. I personally don't use a compression test any more, guarantee it has the potential to fool a good mechanic if he doesn't pay attention to the tell tail signs. Many people already have a compression tester and it can be a good tool. Just don't assume that low compression numbers mean you have a bad ring seal.
Not trying to stir anything, promise you, but have had guys come to me with #'s saying this or that is my problem. A compression check is a VERY good way to determin overall condition of the engine, not the specifics. Compression ratio and camshaft profiles can play a big part in compression testing.
WOAH, just read my post, sorry, just came from the shop and my mind is going mach on engine works and theorys. Probally shoud delete it but someone may get some good use out of it. My wife wont, and she's the only other one in the room, for now.
Les Holt

Les - You make a good case for a leak down. Your opinion is based on where you come from. If I were doing engine rebuilds for a living... If I needed to provide a written estimate BEFORE tearing down the engine, I would insist on leakdown testing too. You are very correct in that it would identify additional issues in the valve train that may not be related to the blow-by problem. Good point!

A leak down (if that's what I'm really referring to) test AFTER a compression test will also help narrow down the search for a problem. I had really low compression on one cylinder of my GS1000. I set the piston so that both valves were closed and opened the oil fill and hooked a compressor to the hose from my compression tester. If you listen at the intake, exhaust and oil fill hole for an air leak, you can figure out where your problem is - intake valve, exhaust valve, or piston/rings. It turned out I had a cracked piston and you could hear the air leaking through the oil fill hole.

Hope this helps,
Jay

I’d like to thank you guys for your response. It’s been two years or so since I’ve found KZR. For the most part I’ve been able to run searches and find most of the info I’ve needed. I think this is only the second time I’ve posted a question. Unfortunately you guys have just confirmed some of fears I’ve had about this. I was hoping to hear something like, “yeah, they just do that until the rings are seated well�. Or something along that line anyhow. Anyhow I would like to think you guys for all the good information.

Ran429, some of the worst spills I’ve ever taken have been from falling off them motorcycles watching football in the garage. Last week I was watching the OU/Texas game. Somewhere there in the 4th quarter I may have fallen asleep or maybe it was OU that did but, I went one way and the bike went the other. Bumped my head on the drill press, the bike fell and hit the lathe knocking my whiskey bottle to the floor. If it hadn’t been for a plastic bottles and the fact that I had drank most of it. That could have been my worst spill to date. I’ll save you a seat for the Superbowl.

Before KZR I was just this old nerd, engineer that had a KZ900 I would slip around on. Then I found this place. My wife’s ready to choke my most of the time. Now I want to take my old 900 and fix it up like wg’s 2 tone silver carb test bike with the bags and the windshield. It makes you wonder why a fella would go out and spend the money for a Roadking.

You guys have a good weekend,
Steve

whats hat swingarm off of?and look it even has the right tailpiece(no650 stuff on kzs )do you need someone to come over to wash and wax it?nice looking bike!