OK, I give up....

[Guest Nogbad]

The detonation was truly awful today, couldn't use anything like full throttle even over 5000 rpm. As well as that the idle became erratic, running mostly at 1750 rpm, then occasionally misfiring and resettling at 1250 rpm. Outside temperature was 30°C.

 

I don't want more power, I just want to use the power there is.

I don't want noisier pipes either.

 

At a guess, I would say the ignition was over advanced or the mixture too lean or both. Unfortunately, both these functions are hidden inside the black magic box.

 

So - do I spend money with so called experts? Do I fit a PCIII, or do I give up on all these solutions and get a My15M? I understand engine tuning, but I'm not really good at computer software. I have a colourtune, vacuum gauges and an accurate gas analyser with oxygen, CO and NOx.

[richard100t]

This sounds too simple, but have you pulled the spark plugs & checked them? Those stock plug wires are crap too, make sure they havent broken at the plug end. Thats the best I know to do, I'll leave the more technical stuff to the experts.

[Alex-Corsa]

This sounds too simple, but have you pulled the spark plugs & checked them? Those stock plug wires are crap too, make sure they havent broken at the plug end. Thats the best I know to do, I'll leave the more technical stuff to the experts.

 

As far as spark plugs goes I have in use the iridium ones and yes they're the best to use. At least that's also the opinion of Dynotec.

[Guest Nogbad]

Plugs look fine, as do the leads, although the plugs are just the standard OEM ones

[Anthro]

I would start by the simplest and chepest items related to the problem.

 

Spark plugs are a good start. With the air cooling engine not all spark plugs will take well the high peak temps they may be exposed... even do they may look good they may be gone... certain plugs will work better and longer, but my path is to use regular ones but replace them often. Then spark plugs wiring, then ignition coils...

 

My MG only has detonated 4 times (4000 miles) 2 of them before the first 1000 miles, so to me they do not count ... the other time at 3000 miles and I removed the original sparks (NGK but cheap ones), I installed another other set of inexpensive ones but at least made in Germany (Bosh platimum), and they are doing all right.

 

The last detomation was loud and it happen when I did full throttle while riding at about 2700 rpm... ? (with the new plugs! ) I believe my MG may be running a bit rich?... but I will not mess with the EFI... I'll just wait until the 6000 miles service.

 

I believe that misfiring may be because Timing, failing spark, wrong fuel/air mix proportion and too stiff exhaust valves...

 

But 30 centigrads will be a hard endurance test for both you and the air cooled engine... at least in Texas most of my driving is at the Highway ...

 

Hopefully your MG will get sorted out soon

 

Anthro

[twhitaker]

This happened to me last summer. Fortunately the problem went away when I put in another tank of gas.

[Guest Nogbad]

Well, I am going to delve deeply into Guzzi mysteries and check my TPS tonight, and possibly balance the TB's as well.

 

On the fuel issue, I have been using regular as UK prices are heading for £1 a litre, but tonight I will fill it with BP super high octane before heading home, and we'll see whether it detonates. Current temperature out is about 27°C

[dlaing]

Durring my gearbox reseal and shock spring replacement, I may have fixed my pinging.

There is now pinging only at 5000rpm and WOT.

But I did too many things to know what fixed it.

Here are the things that may have fixed it.

Cleaned BMC air filter. (this should not fix it, unless I over oiled it)

Tightened hose clamps on both sides of throttle bodies. (One going to the left side of airbox was loose enough to leak)

Rebalanced TBs (I don't think this fixed it, because they were balanced before...)

Reset air bypass screws to 0.5 turns out ( Why did I have them set to 1.5 turns? Probably I got mislead by the wrong specs along time ago...or when tuning one day the TBs may have balanced better...or I am just a stupid )

Anyway, the bike has never run better!

FWIW

27,300miles

I am about due for a valve adjustment.

I run the valves .15/.20

TPS is 170mV with engine not running, everything disconnected.

Mistral muffler and FBF airbox kit.

PCIII with mistral map from CD.

I still need to kill the last remnance of pinging.

The PCIII should take care of it...

[Guest Nogbad]

Here is the data:

 

TPS 521mV engine not running 562mV engine running at 1500 rpm idle (Veglia)

 

I used my Morgan Carbtune II and discovered that the throttle bodies were 2cm out of balance on average.

 

They are now spot on on idle, and spot on on 3000 rpm. If you increase the revs gradually to 4000 rpm (the neighbours must now hate me) the imbalance swaps over and you have about 2mm imbalance but opposite to the 1mm at idle. Anyway, the carb sticks are dead level at 3000 rpm and I don't think I can get any better.

 

562mV seems OK as far as other people report on here so I have left well alone. The TPS has never been adjusted as the "Torx" heads are full of yellow paint and the paint across the screws and washers is undamaged.

 

I couldn't road test as I had a few beers.

 

The use of expensive BP ultimate did help the bike a lot though. You could cane it from 5000 rpm at full throttle with only an occasional ping. However, I don't want to pay through the nose for this friggin' desert juice.

[dlaing]

Your settings sound fine.

 

You can test for air leaks by spraying something volatile around the throttle body.

I am not sure what is best.

You don't want to damage the rubber or paint in the area.

Some recommend WD-40

[Guest ratchethack]

Noggy: It sounds like your TBs are about as balanced as anyone could ever expect. There shouldn't be any difference between running & not running on your TPS reading, though. Your idle is too high. It should be 1050 RPM +/- 50. Like many others around here, I go with 1100 RPM as an average just to make sure to keep oil pressure up. Extrapolating roughly, when you drop your idle, your TPS reading could be possibly still a little rich, but OK, sounds like it should be close enough to the right range for running without a PCIII and fighting detonation. I'd back the idle down, keep high octane in the tank (when you come to sell it will you sit & wonder how much better it would have run the whole time you owned it if only you had run it on good gas!? ), and have another beer.

[Guest Nogbad]

Well, on the way to work today the bike was totally different. That half hour spent tweaking the TB balance was the best spent half hour ever.

 

The bike is VERY noticeably smoother, and I can now whack it open on the flat from 3500 rpm in 5th and scream up to the yellow line with hardly a ping, and do the same from just over 4000 rpm in 6th. Hell I was just overtaking everything with a flick of the wrist this morning!

 

The idle is very stable at just on 1400 rpm today. Whether this is due to cooler weather, or the vagaries of the Veglia, who knows. I wasn't going to touch it in the interests of the clutch splines.

 

As for the difference in TPS reading with the engine stopped or running, this difference is reported elsewhere, and I guess it's just regulation. My bike is 4 years old and with the original Guzzi battery. Starting is fine, but it's conceivable the voltage may be starting to droop.

[big J]

Sounds good, Noggers. Is this running better with the high octane fuel?. Maybe you'll have to keep feeding the old girl the good stuff to keep her sweet. Personally, if we could get it here, I'd use it all the time.When I'm back in Scotland, the bike runs noticeably better than on the parrafin available here.

[Guest Nogbad]

Sounds good, Noggers. Is this running better with the high octane fuel?. Maybe you'll have to keep feeding the old girl the good stuff to keep her sweet. Personally, if we could get it here, I'd use it all the time.When I'm back in Scotland, the bike runs noticeably better than on the parrafin available here.

56141[/snapback]

 

Yeah this is on the high octane stuff. Funnily enough, BP Ultimate is actually better than Shell Optimax, even though its only 97 RON not 98. I can get Shell cheaper here than BP though, so that's what it gets. If I commute to work on the bike I can just get two return trips out of the tank, about 168 miles, and it costs me £15 to refill it. Soon racks up the miles at 450 a week though, but I figure its pretty kind to the engine to be started and run for over an hour twice a day. Never see any condensation or whipped cream in the oil.

[mike wilson]

Let me get this right. You have a bike of 1100cc and it takes you (over!!!) an hour to travel ~40 miles?

 

Move.

 

8-)