Gas & maybe oil coming out crankcase breather

[CT_KAT]

Hey all, first post here though I've been reading quite a lot on the forums and gaining some good knowledge. I think I've seen the symptoms from my bike on other posts, but I just want to post the details and see if I'm on the right track.

The bike in question is a 1997 Katana 750 with about 3k miles.

I put the bike up last fall after noticing a fuel leak. Didn't have the time or $ to deal with it then. I assumed it was maybe a cracked line or something similar. Anyway... I pulled the tank and the lines and everything looked fine. Reading some posts lead me to believe it may be something with the carbs.

This past weekend I installed a full V&H exhaust (the SuperSport, not the SS2R). I also installed a pair of K&N oval air filters and rejetted with Dynojet Stage 3 needles and jets (after reading another post on this page I may go to stage 1 or what the poster called 'stage 2'). I also replaced the float bowl gaskets and o-rings on the floats. I didn't touch the pilot needles/jets or mixture screw/spring/ring.

Per the jet kit, I set the mixture at 2.5 turns out and fired it up. It started running after a few tries, though I did notice a plastic burning/acidic smell which I assumed was probably paint or other burn-off from the new pipes. There was also some dark smoke which made me think the bike might have been running too rich.

Before the bike settled into a good idle, there was a dump of gas mixed with maybe a little oil from the crankcase breather hose. I shut the bike down, cleaned it up, turned the mixture screws back a full turn (so now at 1.5 turns), and tried again. The bike ran again for a few minutes, and then dumped the gas/oil again through the crankcase breather hose.

Is this a stuck float problem? How can I tell if the float is stuck? What should I be looking for? Is it a piston ring problem? The engine oil level was fine and the bike sits in my garage during the off season.

Sorry for the long post but I wanted to get as much detail out as possible. Any insight is GREATLY appreciated!

[Maxxrox]

Eek.

K&N filters? Stage 3(!) Dynojet?

Just out of curiosity, what's this bike's main purpose?

On topic, check your petcock for proper operation, check the float heights in your carbs. A little bit of liquid in your breather hose is okay after a good while. A large buildup over such a short period points to other problems.


--B

[kraziedn]

dude, using K&N filters on Kat is a big NO NO! put the stock filter back in, see if the problem still occurs.

[CT_KAT]

Mainly I was trying to get more HP. The Dynojet Stage 1 & 3 kit was make for the bike based on what I read off the dynojet site: http://www.dynojet.com/pdf/3130.pdf.

Here's the link to all their kits w/ the 97 Katana being part # 3130:

http://www.dynojet.com/jetkits/motorcycle/suzuki.aspx#700

The filters were recommended per the jet kit instructions which is why I put them on. This is off the instructions:

"For mildly tuned machines using individual filters or velocity stacks. K&N filters #RU-2922"

I guess now I'm sufficiently freaked out by the two response posts. Should I pull all this stuff back off?

[scottynoface]

You're in fun territory now, Stage one worked pretty well for me with a full exhaust and aftermarket filter, but eh, whatever.

As for the breather, how much gunk is it dumping?

[The CyberPoet]

(A) IMHO, take off the aftermarket stuff until you have the other problem (with the venting from the crankcase) resolved. Then, once you've got it healthy, if you want to retackle the upgrades, go ahead.

(B) Read this: http://katriders.com/vb/showthread.php?t=77710

Good luck!
=-= The CyberPoet

[CT_KAT]

Stage one worked pretty well for me with a full exhaust and aftermarket filter, but eh, whatever.

As for the breather, how much gunk is it dumping?

Yeah, I'm going to Stage I once I get home today. I'm going to do a more thorough cleaning of the carbs too. I did the float bowls, o-rings, needles, and jets but I didn't pull the carb slide guides, emulsion tubes, pilot jets, or mixture screw components. Not sure about the air filters, I may go back to OEM airbox based on recommendations here.

I'd say a good cup dumped, but it took a few minutes before it happened.

[The CyberPoet]

I'd say a good cup dumped, but it took a few minutes before it happened.

If you got a full cup in a matter of a minute or three, then either you're missing the plastic screen under the breather square at the top of the valve covers (item #14 in this Valve Cover Fiche), or your floats have been defective and leaked a ton of fuel into the oil (would imply a need to immediately drain the oil and then retackle the float & petcock issues).

Cheers,
=-= The CyberPoet

__________________________________________________ ________
CyberPoet's Katana Maintence and Upgrade Parts Offerings
The Best Metal Steel Aluminum Motorcycle Tire Valves in the World, plus lots of motorcycle & Katana (GSX600F / GSX750F) specific help files.

[CT_KAT]

If you got a full cup in a matter of a minute or three, then either you're missing the plastic screen under the breather square at the top of the valve covers (item #14 in this Valve Cover Fiche), or your floats have been defective and leaked a ton of fuel into the oil (would imply a need to immediately drain the oil and then retackle the float & petcock issues).

Cheers,
=-= The CyberPoet

Thanks CP. The bike ran fine for the last couple years and I never pulled the plastic screen that you referenced so I expect it should still be there. I'll check when I get home to be sure.

What's a good way to determine the condition of the floats? They looked ok when I pulled the carbs apart, but I'm no pro. Can I take the o-rings off and soak the floats in carb cleaner or should they not go in carb cleaner?

[kevin2502000]

First make sure your floats "float". Then clean you needle/seat assembly making sure no crap is in there. Then set your floats to specs. I always flip them upside and blow through the gas lines making sure no air flows. This way you know they are sealing.

[The CyberPoet]

First make sure your floats "float". Then clean you needle/seat assembly making sure no crap is in there. Then set your floats to specs. I always flip them upside and blow through the gas lines making sure no air flows. This way you know they are sealing.

+1 and saved me a bunch of typing.

Cheers,
=-= The CyberPoet

__________________________________________________ ________
CyberPoet's Katana Maintence and Upgrade Parts Offerings
The Best Metal Steel Aluminum Motorcycle Tire Valves in the World, plus lots of motorcycle & Katana (GSX600F / GSX750F) specific help files.

[CT_KAT]

+1 and saved me a bunch of typing.

Cheers,
=-= The CyberPoet

Cool, will do. You guys are awesome, thanks for all the great info!

[moto]

CT KAT,

Disassemble the float cages, and remove & inspect the float needles. If you can detect where the needles have been contacting the seats, they should be replaced. Under magnification, look for a witness line (shiny ring or indentation) in the rubber tip. These will not be avialable separately from the dealer. If you need help locating some, please PM me. This is also a good time to inspect the float seat o-ring and replace it if there is any sign of deformation, shrinking, hardening or cracking. I would definitely recommend staying away from DynoJet products. I don't think it's a good idea to try to tune without an EGA equipped eddy current brake dyno at your disposal (or with the help of someone with one at their disposal). However if you do (or insist on tuning without one) I would not recommend removing the airbox and would recommend Factory Pro tuning components instead of DynoJet.

Regards,

Derek

[CT_KAT]

Great info, thanks Derek. I'm at Guard drill now, but the carbs are sitting on my kitchen table at home just waiting for me to dive back in and work on them. There's a good chance the float needles will need replacing, I'll check that first thing. Has anyone tried Napa carb cleaner http://www.napaonline.com/MasterPage...+Choke+Cleaner and would you recommend using it? I'm thinking of soaking the carbs instead of taking the time to spray the crap of out of them with a can of carb spray.

I'm dissapointed to hear all the bad news about Dynojet and I wish I'd come to this site first before I bought from them. The thing that sucks is I've aready dumped the $125.00 on the kit and I know I'll get the hairy eyeball from my wife if I drop another $125.00 on a Factory Pro along with all the other nickel and diming I've been doing to tune the bike up.

[pilotdada1]

Not sure about the rest of the folks here, but I don't dip outboard carbs or motorcycle carbs. They go in an ultrasonic cleaner or get done by hand with spray.

James