right side rich

[leafman60]

Ok guys, please help me out. My '02 Scura (by the way, my shift spring looked perfect after 7000 miles) is running richer on the right side than the left. I dont have a power commander attached. The right pipe gets much more heat as the rich mixture takes it away from the head. Ive checked my valve clearances etc. and Ive balanced the T-bodies. Looking at the exhaust valve from the exhaust outlet, the right valve is sooty while the left is tan/brown. I had a so-called expert supposedly put the bike on a Guzzi diagnostic machine but the problem persists. Any suggestions?? I understand that the mixture can be altered between cylinders with the proper programmer. Is there a knowledgeable Guzzi guy at any dealer in the southeast ???

[dlaing]

Any suggestions??  I understand that the mixture can be altered between cylinders with the proper programmer.

57087[/snapback]

Sorry, no real suggestions....maybe clean the fuel injectors...especially the lean one.

I don't think the mixture can altered between cylinders with any ECU programmer.

However the PCIII USB offers individual cylinder tuning.

But you need to find the source of the problem.

I hope somebody else can offer more insight.

[Cliff]

Second the injector cleaning.

 

You might find some injection service that can check the injectors flow rates.

Maybe also swap them around.

 

It is possible for the ECU to do small corrections left/right as its used on Dukes to perform front/rear adjustment. You could try Wayne at www.tuneboy.com.au.

 

Is it only at idle that this imbalance appears? Don't forget there are idle jets.

Is there any rough running?

[Guest ratchethack]

Leafman, even if you're certain that the TBs are balanced and that the air bypass screws were properly tuned in the process, it's not uncommon for the right-side plug to read somewhat more sooty than the left. I've heard the right-side sooty plug observation before and it's consistent with my own experience - the lack of logical explanation for it nothwithstanding. I've heard conjecture along the lines of ignition timing and firing order inherent with the 90-degree config. You may want to re-visit the air bypass screw settings if you think it's too far out of whack, but unless you're seeing a dramatic difference, it's probably not worth fretting about. Despite all our affection for the Guzzi motor, it ain't exactly the moto-equivalent of a Stradivarius. As Roper has been known to lament, it's merely a ditch-pump motor for God's sake... BTW - You may have things backwards in one respect. Generally speaking, running rich will make a cylinder run cooler, lean will make it run hotter.

[dlaing]

  BTW - You may have things backwards in one respect.  Generally speaking, running rich will make a cylinder run cooler, lean will make it run hotter.

57134[/snapback]

What would that indicate? that his left is running so weak that it is not generating as much heat???

Could that indicate a leaky valve, rather than a manifold leak or clogged injector????

[Guest ratchethack]

What would that indicate? that his left is running so weak that it is not generating as much heat???

Could that indicate a leaky valve, rather than a manifold leak or clogged injector????

Dave, I'm compelled again to invoke the wit and wisdom of Antonio, who has so clearly, aptly, and succinctly stated before in situations like these:

 

"Eeeeeeeeeeeuuuuuuuuuuuhhhmmmmm?????"

 

Or, in other words:

 

"No savvy."

 

Sorry, but I don't think any of what you posted above is indicated here with much probability.

 

What I'm suggesting is that IMHO there's a higher probability that there isn't much of a problem here at all, but that just maybe it's worth a re-balance of the TBs with a bit more attention at idle to the air bypass screws. I'd say knowing that rich = cooler and lean = hotter is important to understand overall, but it's not relevant to Leafman's concern about a rich-reading RHS plug. If you really want to know how much heat disparity you've got between cylinders, unless you're good at using your fingertips as engine temperature probes , you have to use thermometers or better yet, an infrared heat reader.

 

Now then. Knowing which way to turn the air bypass screws would be very important: Opening them increases air in the mixture at idle, closing them decreases. I've seen guys work them like they're dealing with idle jets on carburetors. It may be a long shot, but if a better TB balance can be achieved at idle, he just might come up with a slightly less sooty RH plug and exhaust valve. That'd be my approach, but then, no 2 guys ever seem to have the same take in this particular neck o' the woods, and of course as always, YMMV.

[txrider]

I'd be interested in knowing more about idle air bypass adjustment. Do you simply adjust for the closest balance between cylinders at idle? And is the starting point like, 1/2 turn out from closed?

[Guest ratchethack]

Txrider, the procedure I come closest to following may be found here in a write-up by Ian Johnston:

 

http://www.obairlann.net/~reaper/bmw-bike/guzzi/balance.html

 

Keep in mind, I haven't found any 2 procedures on this that seem to line up very well. I also have a hard copy of another procedure from Jeff in Ohio from April of last year that I got on this forum (that I can't seem to find here now) that's pretty good. What I've done is to read up on it from many sources to understand the operating principles involved, then try NOT to do what I think many tend to end up falling back on - that would be something between, "I'm just too tired of fiddling with this now, so screw it", and relying on anything more closely related to Voodoo than to tried & true practical logic. By being careful and systematic in my approach, I've now got a bike that's smoother, more responsive, and better running by a stretch than when I got it - (and it was pretty good then!) without yet getting a custom PCIII map to match my config. I've also come to the conclusion that there's no absolute perfection to be had in tuning these birds. I now believe that "pretty damn good" is "damn good enough" for all practical purposes. In any case, I wouldn't consider letting anyone else tune it, if that's any measure of my results?

 

I use a DIY water manometer that I've "optimized" for greater ease of use, made out of vinyl tubing - cost approx. $4 USD. The tubing doesn't like touching my headers much , but otherwise works like a champ.

 

I will emphasize that in summer weather (particularly with the heat such as we have here in So California right now) I would not attempt this without 2 fans operating at full blast, one directly on each cylinder. Overheating the engine is a real danger in hot weather with this procedure, and without good cooling airflow, long before you reach overheated, your ability to get an accurate balance will be compromised, as Ian commented.

 

Also - Ian notes that air bypass screws are to adjust mixture and I believe this is incorrect. I may be wrong. In any case, this doesn't mean this procedure is or isn't valid (the procedure works regardless), but I believe what others have stated in other procedures - that they're for fine-tuning individual TB idle speed adjustment only, and unrelated to mixture.

 

Hope this helps.

[txrider]

Thanks, Ratchet, you're the man. And right on about the cooling fan. I got lucky and bid/got a 30" industrial cooling fan that does double duty for cooling the garage in summer and works well to blow over the engine when tuning. I still set a limit of 10 minutes or so run time during tuning.

[Guest ratchethack]

a 30" industrial cooling fan that does double duty for cooling the garage in summer and works well to blow over the engine when tuning.  I still set a limit of 10 minutes or so run time during tuning.

muy bueno!

[dlaing]

Ok guys,  please help me out.  My '02 Scura (by the way, my shift spring looked perfect after 7000 miles) is running richer on the right side than the left.  I dont have a power commander attached. The right pipe gets much more heat as the rich mixture takes it away from the head.  Ive checked my valve clearances etc. and Ive balanced the T-bodies.  Looking at the exhaust valve from the exhaust outlet, the right valve is sooty while the left is tan/brown.  I had a so-called expert supposedly put the bike on a Guzzi diagnostic machine but the problem persists.  Any suggestions??  I understand that the mixture can be altered between cylinders with the proper programmer. Is there a knowledgeable Guzzi guy at any dealer in the southeast ???

57087[/snapback]

Disagreeing once again with Ratchethack, Leafman states that he has balanced the T-bodies, and that it is hotter on side with carbon build up in the exhaust port.

This strikes as being a potentially severe problem.

I don't know how he knows the right side is hotter, but if it by holding his hand near the head, as I assumed, than that is a pretty drastic temperature difference.

The assumed fact that the side with carbon build up is hotter makes me even more concerned.

As for the bypass screw, it simply lets air in and in fact makes it run leaner the more open the screw is.

I suppose his left screw could be too far out (or right too far in) causing leanness and a need for more pull from the right causing the heat on the right....but then I would not call it balanced.

Of course Ratchet proved that I can't even use a measuring tape correctly so it is quite possible that Leafman needs to review the balancing process.

But assuming that Leafman balanced it correctly, I stand by my contention that he likely has a manifold or valve leak.

I would start by smoking a cigar near the exhaust header and use the smoke to detect a leak. Finish the cigar, than use WD40 to check for intake leaks. (Careful, WD40 is flamable and more so than cigars, should not be inhaled)

[al_roethlisberger]

My left hand cylinder ran waaaay hotter than the right sometime during the first year of ownership, and the bike ceased to run correctly.

 

Replacing the ECU fixed this.

 

Obviously this is not an acceptable diagnosis or answer for your problem, but just a point to show that it could be any number of things.

 

Mine happened all of the sudden... ran fine one day... nearly melted the header on the left the next <_>

 

al

[leafman60]

Guys, guys, guys... lol. 1. I know all about rich/lean heat. The richer mixture carried heat away from the combustion chamber and out the exhaust. Riching up the carbs has long been used to affect a cooling influence in special situations. This thing heats the right header and muffler to the point of discoloration all the way and including the muffler body. I didnt just check the plugs. I pulled the header and looked at the exhaust valve. Right is sooty black. Left is good brown.

2. This occurs at full running. After any run, the heat differential is very noticeable. Interestingly, the bike runs great. Good power. No flat spots. The T bodies are correct. I am not a novice mechanic but a dealer has also checked it.

Any more hints?

[Guest Nogbad]

An IC engine is simply a positive displacement pump, given that the cylinders are mechanically connected by the crank and taking it as read that the throttle bodies are balanced and the valve system is as the designer intended, the air flowing through each side of the engine will be as near as dammit identical.

 

If one side is getting way more fuel than the other, you should see that as a smoky exhaust as well as sooting of the valve and plug.

 

Has anyone stuck a CO/O2 meter on each side to compare? Preferably before the Xover. There are some plugs you can remove on the downpipes.

[dlaing]

Any more hints?

57441[/snapback]

I think we just about covered everything.

But we won't give up

What exactly did you and your mechanic check?

Your response seems to indicate that you tried what we suggested.

You should check for leaky manifolds.(as I mentioned)

You should tune it to perfection.(as ratchethack mentioned) I am suprised the TBs balanced fine. Mine do not balance perfectly at both idle and through the rpms, but my plugs are balanced.

Given that it is tuned and manifold leak free, try a compression test.

That should have been one of first things your mechanic should have tried, since it only takes a couple minutes, assuming the engine is warm.

If that is fine, and you are tuned and leak free, we can exclude it being the air pump, so it must be the fuel or ignition.

I don't know how easy it would be to swap fuel injectors, but that would be a good test.

Start with something easier like swapping spark plugs, testing, and then swap plug wires, test, and then swap coils, and test.

If you can get another ECU, swap it out. The ECUs are very reliable, but as Al posted, only NASA quality. (Not to put words in Al's mouth, just my interpretation of the fax, mam, err the facts, sir.)

Sensors should not be an issue as they should effect both cylinders equally for output.