My bike won't stop coughing

[Robert Sylvester]

Owned my CA ll for the last 12 years. About 6 months ago it started coughing. It sounds like it only coughs thru the left carb. There is a vent hole for , I believe, the float. Gas sprays out this hole every time she coughs. I don't think we have e-gas in Eureka, CA but I wonder if there was a most susceptable part in the carb to e-gas, what that would be.
So far I've replaced the coils, carb intake rubber sleeves, plugs. I've got Dyna lll ignition form when I first got the bike. I've checked the timing with a strobe light, I've run the valves and retorqued the heads.  The carbs are stock. The plugs look ok but the left plug is noticably leaner.
She starts right up, coughs when cold at warm up speeds which is normal for US lean carbs. Once moving low end is fine, top end is pretty ok, it's around 3000 rpm where it gets nasty with relatively little engine load. Cough cough, no fun. Thanks everyone. One of the many benefits of owning Guzzi is the support.

[rodekyll]

You need a compression and leakdown test.  I think that if this is not a distributor problem it's a burned intake valve or bad cam lobe/lifter.

Who told you it's 'normal' for these to cough?

[Triple Jim]

My '89 Mille will occasionally sneeze, usually the left carb.  I think this is what you're calling a cough, and it does spray a little out the vent.  It happens more often in cold weather, and seems to be a result of the very lean jetting they had in that era.  In my case, it's so seldom that I haven't made it a project to fix it, but if it were to start doing it regularly, I'd look for something making the mixture lean, like a cracked rubber carb-head adapter (sometimes erroneously called a "manifold") or other air leak, or clogging of the carb's pilot system.

[Sasquatch Jim]

 Drop a Smith brothers lozenge in the gas tank.

[fotoguzzi]

have you looked at the float in the carb?

[Chuck in Indiana]

have you looked at the float in the carb?

If that sucker cracked and sunk, (common problem) I'd think it would be running rich..

[fotoguzzi]

If that sucker cracked and sunk, (common problem) I'd think it would be running rich..

if it got a pin hole it might just get off level?

it's been a long time since I messed around a DelOrto

[chuck peterson]

sneezing...my cal111 did that....rejetted to euro specs per Richardson in Guzziology and everything was fine...another time though I found the float needle hanging up keeping the float too low...it was the spring loaded type of float needle

[Vasco DG]

Has it ever had its timing chain looked at or replaced? How much scatter are you getting at idle? I'd suggest throwing a new chain and proper tensioner in it and timing it up again.

New needles and atomisers would probably help too but do the chain first.

Pete

[fotoguzzi]

Has it ever had its timing chain looked at or replaced? How much scatter are you getting at idle? I'd suggest throwing a new chain and proper tensioner in it and timing it up again.

New needles and atomisers would probably help too but do the chain first.

Pete

your still the Guru Pete!

[Vasco DG]

Nope. Never was, never will be.

[jedijoy13]

Hi,

so i've got a similar problem, but mine is much worse.  just getting to troubleshooting.  the bike has been in project form for about the past year and a half. 
before disassembly, it ran fine mechanically.  electrical issues was why i took it apart and embarked on the project.
I disassembled, cleaned and re-assembled the carbs back then.
got it started two weeks ago
it's a bit of a struggle to start it up when cold.
once warm, no issues with starting.

so i went through the owner's manual for the carb procedure and the many articles online.screwed in the idle screw, and backed out 1 1/2 turn.
started.  i increased the idle rpm to about 2k and pulled the plugs one at a time.  the right side, i believe i have dialed in.  i can get it to 1100 and not kill the bike. 

when i do the left side, i can never get it stay on.  so the problems i've been troubleshooting with the left side are as follows. note that this is all with both plugs in
idle screw - no effect until i blip the idle above 2k, then the idle screw starts working (if it's screwed in all of the way, it'll hover at 3-4k), then i can dial it back to 1100 idle
when i first blip the throttle, it sounds like chugging (research online indicates that it might be the accelerator pump not functioning correctly?), but in the higher rpms, it sounds fine
i took it for a test spin around the block.  accelerating slowly and no problem.  if i get on the gas at all, it just surges and is no fun at all.
I never did the valve adjustment or timing because she ran fine before the project, so i plan to do that next.
but my thoughts are the coughing sound comes from the left carb itself and seems to be cause of my issues.
any additional advice tips would be greatly appreciated.

[rodekyll]

Jedi --  If I can give just one piece of advice that is listed to it would be this:

Confirm your baseline before trying to troubleshoot/fix.  In other words, do the valve adjust, timing, air and fuel filters etc first.  Know your compression numbers.  Then go looking for the trouble.  Likewise, do the broad strokes on the carbs first -- throttle stops/slides set, cables synched, etc before attempting mixture and jetting stuff.  In most cases the problem is directly helped by checking down the list of standard stuff.  In no cases does it hurt.

$0.02

[double.d]

My LeMans 1000 used to do this all the time at idle. It stopped after i rewired the bike, put a new Dyna in, stripped the carbs and cleaned them (floats were fine), removed the chokes and set idle at 1200rpm.

Sorry, can't narrow it down any further than that.