Exhaust leak (or worse?)

[nightmoves]

I feel as if this morning I was officially initiated into the guild of vintage motorcycle maintainers by the spiteful gods that be. After spending the past few available weekends tweaking airbox configurations, cleaning up the look of the bike, freshening up the carb boots, and other minor repairs, I was naive enough to think that after a quick carb overhaul everything would be just perfect and I'd be back in the saddle for a weekend of country back roads. Hahaha yeah.

So my carb kits arrived yesterday and this morning I started assembling my tools and parts for the rebuild. I figured, just for the hell of it, I'd start the bike up and take her for a quick spin, mostly because I hadn't heard a motorcycle engine in a week. She didn't perform all that well, but exactly how I left her last week, supposedly only in need of some carb tuning. Took a short loop down the road and back and when I pulled into the driveway again I noticed a gasoline smell. And, sure enough, I looked down to see that the left exhaust pipe was severely leaking what looked like gasoline and oil (but I'm not really sure), spewing out the bottom from a hole just behind the foot peg (which I soon discovered is under both pipes, so I was less worried about just discovering a puncture). The left pipe was relatively cool to the touch, while the right pipe was quite hot, as it should be. I've included photos to try and relay my problem a little better, as I've had little experience with oil / exhaust leaks.

As I had my head under the bike snapping photos as fast as I could to show you guys, I noticed an additional spot where oil was beading up and dripping. You can kinda see it in the photo.

So that's where I am at the moment. I'm not even quite sure where to start with diagnosing the potential problem. Almost too bummed to continue with the carb rebuild, but, I suppose that's just how it goes. Nothing a beer and determination can't handle. Let me know what you guys think. I appreciate the help!


Sent from my iPhone using Tapatalk

 

[carnivorous chicken]

Your left cylinder isn't firing. I would check spark, compression, fuel and air, and timing in that order. To answer your unstated question: you should not have fuel mixed with oil leaking out of your pipes. In fact, because of that, I'd check compression first -- sounds like rings or valves.

 

[nightmoves]

Ok, will do. Just ordered a compression gauge, feeler gauges, and picked up some new plugs. Thanks for the advice. I'll start at the top and work my way down the troubleshooting check list.


Sent from my iPhone using Tapatalk

 

[brightrider]

Well...just a reassuring word before you get too bummed about potential internal engine worries. If the left carb has an issue with its needle and seat, and the carb overflow tube isn't handling things, it is very possible that fuel is filling up the carb bowl, flowing through the carb, and into the cylinder.

There, gas is going to "mix" with any oil residue, then continue to get pumped out of the exhaust, picking up more black stuff. Then that cylinder essentially becomes a fuel "pump"...sucking raw gas in, and pumping it out.

My first step would be a thorough carb rebuild which you have planned, making certain that fuel gets shut off when the floats reach the correct level. Confirm you have spark, sync and tune carbs, change plugs AND engine oil, then see where you stand.

 

[Redliner]

Sniff your oil.

 

[Cookie]

Also, feel of one one of the leak drips. rub it between your fingers. If you're lucky, it's just carbon being washed from inside the pipe by all the raw fuel.Either way, an oil change is definitely in order.

 

[crazypj]

Could be faulty diaphragm in fuel shut off, they don't like E-10 fuel

 

[hillsy]

Sniff your oil.

+1

There's a good chance you now have fuel in your sump - change your oil ASAP.

 

[runmikeyrun]

brightrider and crazypj are right- if things were ok before the carb rebuild then something is probably amiss in the carbs. Pumping way too much fuel into that cylinder is gonna cause it not to fire. My guess is also a misadjusted or stuck float needle. I'm guessing you're also probably leaking some gas out of the carb if you leave the petcock on with the bike not running.

Measuring float height is a bit tricky, especially if your vision is starting to get a little sketchy. Not a difficult process in the least but takes a fine touch. Be careful not to break the tab on the float if you need to bend it.

I'm sure there is a youtube video on how to do it, scope that out. And yes change your oil. Once it's running right figure out your exhaust leak issue.

 

[nightmoves]

Awesome. Thanks for all the advice, guys. I'm definitely changing the oil first thing. Picked up some spare spark plugs, two carb rebuild kits, and plan on carefully inspecting the floats specifically. Also gonna attempt to adjust the valves for the first time. I've been watching the videos from mrmaxstorey over the past few weeks so I'm getting a pretty good idea of what to check / look for. Also might have just scored a new air box, so that's encouraging.

I should be able to get the majority of the repairs done this weekend. I'll check back in with photos and details once I've accomplished something.

Thanks again, everyone.