• Ciao Guest - You’ve landed at the ultimate Guzzi site. NEW FORUM REGISTRATIONS REQUIRE EMAIL ACTIVATION - CHECK YOUR SPAM FOLDER - Use the CONTACT above if you need help. New to the forum? For all new members, we require ONE post in the Introductions section at the bottom, in order to post in most of the other sections. ALWAYS TRY A SEARCH BEFORE STARTING A NEW TOPIC - Most questions you may have, have likely been already answered. DON'T BE A DRIVE-BY POSTER: As a common courtesy, check back in and reply within 24 hours, or your post will be deleted. Note there's decades of heavily experienced Guzzi professionals on this site, all whom happily give endless amounts of their VALUABLE time for free; BE COURTEOUS AND RESPECTFUL!
  • There is ZERO tolerance on personal attacks and ANY HYPERLINKS to PRODUCT(S) or other competing website(s), including personal pages, social media or other Forums. This ALSO INCLUDES ECU DIAGnostic software, questions and mapping. We work very hard to offer commercially supported products and to keep info relevant here. First offense is a note, second is a warning, third time will get you banned from the site. We don't have the time to chase repeat (and ignorant) offenders. This is NOT a social media platform; It's an ad-free, privately funded website, in small help with user donations. Be sure to see the GTM STORE link above; ALL product purchases help support the site, or you can upgrade your Forum profile or DONATE via the link above.
  • Be sure to see the GTM STORE link also above for our 700+ product inventory, including OEM parts and many of our 100% Made-in-SoCal-USA GTM products and engine kits. In SoCal? Click the SERVICE tab above for the best in service, tires, tuning and installation of our products or custom work, and don't miss our GT MotoCycles® (not) art on the BUILDS tab above. WE'RE HERE ONLINE ONLY - NO PHONE CALLS MADE OR RECEIVED - DO NOT EMAIL AND ASK QUESTIONS OR ASK TO CALL YOU.
  • Like the new V100, GuzziTech is full throttle into the future! We're now running on an all-new server and we've updated our Forum software. The visual differences are obvious, but hopefully you'll notice the super-fast speed. If you notice any glitches or have any issues, please post on the Site Support section at the bottom. If you haven't yet, please upgrade your account which is covered in the Site Support section or via the DONATE tab above, which gives you full site access including the DOWNLOADS section. We really appreciate every $ and your support to keep this site ad-free. Create an account, sign in, upgrade your account, and enjoy. See you on the road in 2024.

'04 Breva 750 Airbox Dumping Oil?

T

The LD

Just got it firing!
Joined
Mar 17, 2016
Messages
4
Location
NJ
Hello, long time lurker here who's been infatuated with Moto Guzzis after I first stumbled onto the brand at Bill's Bike Barn in Pennsylvania. I've been on the lookout for one ever since, when just last week the stars finally the stars aligned and I found a 2004 Breva 750 with less than 3300 miles within my price range. The transaction went smoothly, I looked over the bike, the seller even let me take it for a good test ride...everything checked out. The ride home was wonderful, I've never rode a motorcycle that felt so alive before in my life.

However, when I got home I realized by back tire was coated in oil (this didn't happen when I test rode it of course). I looked under the bike to see a small tube not too far from the rear tire leaking oil. I touched it and the end with the crack just snapped right off. I rode over to my friend again (the side of the tire were covered in oil by the time I got there) and if we're reading the manual I got off this website (thanks for that by the way) correctly then that's the airbox overflow tube, right? I'll include a picture at the bottom of the post.

Anyhow, while I went to work my friend replaced the tube and opened up the airbox. Apparently it was full of oil! He drained it and cleaned it out as much as he possibly could, gave it a quick test ride and found no oil on the tires. I thanked my pal and all seemed well and good, but once I came home there was still some oil on my back tire. It was much less than before though, so I thought it was just the residual draining its way out. However, as the week went on (I am a motorcycling commuter) I'd still find oil on my back tire. Not to mention I checked my oil levels and the dip stick went from from 2/3rd's up the marker down to 1/4th in a week, not good. Went back to friend, who fashioned me a cap out of a bolt as a band-aid for the meanwhile (looks odd but works), and we were stumped.

That's when a tiny detail the seller mentioned rose out of the swamps of my brain, he mentioned he did an airbox mod to, "help the bike breathe better." This didn't seem like a big issue to me since my previous bike had a small airbox mod on it that did no harm and did help. Thankfully the seller included the original airbox (picture below) saying, "you can put it back in if you want to go back to stock or plan on moving to a state like California." I think this may be the issue and plan to have it put back in this weekend, but first I wanted to ask the honorable senseis here at GuzziTech for their guidance. Do you gurus know what could possibly be going wrong and how we could fix it? I really need this bike fixed so I can sell my old bike off.

Here are the pics I promised:

Hoses in question -

ueKY8G9.jpg


The airbox the seller gave me -

NtGcUOP.jpg


Thank you kindly for your time and please excuse any typos, I gotta leave for work before I'm late!
 
That's the evap canister he removed. Depending on how that effort was done, it may have an impact on your issue. For what it's worth, those drains usually have plugs in them. They are plastic and have little clamps to hold them in place.

What bothers me the most about the picture of the evap canister is the hoses with a "Y" on the end. I think those are the hoses that attach to the valve covers and provide crankcase venting. Look at the backside of your valve covers (next to the tank) and see if you have hoses coming out of them. If not, we probably found your problem.
 
Thanks for the quick reply! I ran out to check really quick and there are hoses coming out of the back:
5NLr6rN.jpg
 
That's good. At some point, I would confirm the routing (they should go to the airbox and there shouldn't be any check valves or anything). How hard is the air filter to get to? If its been soaked with oil, it will make the matter much worse. Sometimes, this will all start by someone overfilling the crankcase. The filter will get soaked and the engine will start sucking the oil right out of the crankcase.
 
Last I checked the air filter was fine, but I'll check it along with the routing tomorrow.

Question: Should I even bother putting the evap canister back in? Why would the guy even take that out?

Disclaimer: I'm mechanically challenged (raised by an academic, not a mechanic), apologies and thank you for your patience.
 
Evap canisters have been problematic on motorcycles. They were added as an afterthought to meet emissions regulations in this country (mostly California CARB stuff). They've were first installed on carbureted bikes and sometimes plugged up and kept fuel from flowing into the carbs. So they were taken off. Problem solved. On the Moto Guzzi, a check valve is installed in the vent line before the canister. This is the official tip-over valve. It prevents the fuel from leaking all over if you drop the bike. The valves tend to be cheap crap prone to failure. On my bike, the valve kept the tank from venting when its shut off. If the bike is sitting in the sun, quite a bit of pressure builds up in the tank. It basically keeps fumes from getting to the evap canister. The whole design is crap. I originally took off my canister, but if I sloshed the fuel in the tank when it was full, I got gas going out the vent tube on the ground. I put the evap canister back on, but omitted the check valve. Everything works like it's supposed to and I don't get fuel on the ground.

Assuming all your crankcase vent tubes are going where they are supposed to, I don't think the absence (or presence) of the evap canister has any effect on your oil in the airbox problem.
 
Air filter/box is between the cylinders, so likely good. I too suspect that the crankcase or head vent lines have been blocked off.
If you get a fuel smell when the bike is parked and don't like it, re-install the evap-cann parts per what John says above.
 
My friend said he checked that, but I need to learn how to do this myself. Y'know what that would be under in the manual...I'm not seeing it...? :blush:
 
Last edited:
You must log in or register to reply here.
Back
Top