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loss of power. Fuel issue suspected ? Gs550e

Not enough info to diagnose online, but this summer the petcock on my 1100G became a problem. Fuel starved below just half a tank.
Decided after 30,000 miles the screen was clogged, so I replaced the petcock with one off eBay. Works great now.
 
The information is as I know it !! It increases gradually as I expose this very very difficult fault. I'll update later but I'm nowhere near to a fix and have absolutely no idea why it suddenly runs lumpy and I cannot put it down to a particular cylinder.

- but it isn't the petcock - diaphragm fine. Not as expected fallen to bits
- Plugs , Plug caps , HT leads and coils all bench test ok.
- All plugs spark . I can't seem to pin down which plug is black , wet after cleaning . It seems to change. Seemingly impossible.
- I can't seem to get accurate info if I pull a ht lead off plug to see which has issues. It's as if it changes. Currently if I pull 1,2 off a clear issue . If I pull 3,4 there is barely an issue at low revs. However while going along and I pull four off he does give a dramatic lowering of revs.
- I have started to look at the pickups and follow the wiring all the way to the coils.
It is a newtronic ignition and I have not touched it for years.....
I did note two wires that didn't seem to do anything and I have sealed them up.

To strip and test tomorrow :
- get to temp and check timing
- do a compression test
- tomorrow I'll have to strip and clean the carbs and I may put a fuel filter on it as the second I took it off this happened
(No I have not to checked the valves as this is a very sudden problem and it was running perfectly before for months years. I will leave that till last as I know I will need a new gasket)
- find out how to test pickups - be very helpful if anyone knows what wires to test in picture ? Spec is ,60-80 ohms
- find out what spare wires in elec ignition do and test.
 

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The valves recede into the head with mileage, so the clearance goes down. Running perfectly for months/years is immaterial. I'm not saying the valves are the problem, but they could be, and I know one thing for sure: they must be checked regularly, or your engine may be damaged.
 
Do what??? You say "I can't pin down which plug is black", Heck post pictures and I'll try to pin it down for you... Your first post said "Plug 3 was black!!!!" the others were fine. This plug 3 being black is new and was not like that before. I don't understand what you're trying to say.
 
Status: as of now.
- impossible to pin down a single point of issue as seems to change but always to do with lumpy running probably on 3 cylinders or what I'm.begining to think is two good cylinders and two not firing perfectly . even though all plugs spark at tickover.
- new set of plugs and no different .
- if I pull leads off 1,2 cylinders = significant dip in revs . That's good what is expect.
- if I pull leads off 3,4 cylinders= barely audible dip if any drop in revs.
However if riding and I pull plug 4 = significant drop in revs power as would expect.
(Coils lh one goes to 1,4 and rh one goes to 2,3)

If this status remains ill get specific plug data ...... On colour of plugs. We ! / I go from this moment and status. Await results of today.
I'll cast half an eye on this thread to see if I get more abuse ..... But even that helps steer this erratic issue fault finding.

Today's work:
- gonna try a tighter better vacuum pipe from petcock to carbs (it goes to carb 2). I did change this before the issue.
- do a compression test just to see if it's changed from last time when all ok.
- will check the timing , test pickups but have no idea how to on newtronics but will try and find the manual.
- if status has remained static I'll check plugs colour
Then
- if no other quick fixes it's pull the carbs and clean all jets. I have had this similar issue restoring old bikes and it was the jets blocked. Appeared the same too. Impossible to tie down.
I'm pretty sure it's blocked jets. If not it has to be either coils that fail when hot or pickups / newtronics ignition failure .
 
Work starts - 10am
Plugs after yest work. 1&4 look perfect. 2,3 were wettish. But remember the stats above ? (Remember coils go to 1,4. And 2,3.

Will test now with tighter vacuum pipe petcock to carbs then do compressions tests.

(I think dirty jets or faulty Newtronic pickups)
 
Are the coil wires screwed tight into the coils and caps? Happened to me this summer, after working on the engine they worked loose.
 
Update . May answer some.of.your questions.

- coils - before I started sorting this issue it ran same after sorting the following - plug caps , HT leads , coils tested ok. I am sure screwed in perfectly ! All plugs swapped out too.
It made no difference to issue.
(Coils not tested when heated)

- better vacuum pipe petcock to carbs - no difference (but again was almost worse ) you see how hard it is to pin this down . Barely perceivable difference if any.

- To the chap who suggested valve clearances. Yes possible but I just tested the compression (without checking valves) and it is exactly the same as before both wet and dry testing. Pic attached. Perfectly within spec.

Just back from a test run. It ran terribly but I have stats that again are all over the place.
I'll write down now and post
 
Test ride results and pic of plugs on return.

Rode 6 miles up road. Def running poorly immediately as if on 3.
When stopped at 6m point.

Rode 6m as below setup:
Petcock on prime / vac hose disconnected / when running stationary pulling off HT leads only plug 2 had no drop of revs. So dead ?
Then at same time
Petcock on prime / vac hose disconnected from petcock but blanked off / immediate slight increase in revs - cylinder 1,2 when HT lead pulled drop in revs - cylinder 3,4 barely perceptable dip in revs but running poorly.

On way back barely rideable. Had to max revs and feather clutch to get back 6m.

Then I did the compression test and plugs pic

I will add I had a very similar issue before with a newtronics system , renewed and it worked till this issue. (If it is that)
 

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So plan:

As I can go no further and wasted a day already I may as well pull the carbs and clean. It is possible that it could be that !

I think it is :
- carb jets dirty
- newtronics system faulty. I could have blown it with my hapless electrics ?
I still have no idea how to test this ?
- coils cause an issue when hot

Oh will put a strobe on the timing ... Just to check and give results

Stator / regulator - I can test but iv renewed the regulator recently , the stator was fine. Battery ok and I can see it charging while going alone at 14.5v
 
Had to give up as bike will no longer start . It may just start with full choke on for a bit. Turns over fine but will no longer start and run.
I check timing and I'm sure it's fine but it no longer starts. F mark on line at tickover and increases to advance line on both sides ....

This is just an incident pit where the big things that I think are wrong are now breaking down. Did Shirley has to be these big things.

Carbs blocked
Newtronics ignition system bust

Coils now unlikely as they will be cool.

I might do the carbs as easy but a massive massive pain. Iv cracked at this as so much time to zero success in fact getting worse.

I'm that totally done ! Itnwiukd have to be ignition .
Where do I buy a newtronics ignition ?

I think I have a.dyna s ignition system in a box. I think many years ago I bought it but I thought it was too complex to fit and got another neutronic.

Anyone with expertise in a dyna s ignition kit be useful - is it easy to install ?
 

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Carb cleaning:

Carbs off , carb 1 cleaned (don't think it would have caused any issues) but it's now cleaned.

An issue - carb 2 is in danger of stripped Philips screw heads on diaphragm top end. M5×0.8×10 screws. Getting better impact driver to sort. Ordered hex head ones. And soaking in wd40 overnight. May have to Dremel head if I can get to it into a slot head.

Very miserable as things going wrong ......
But at least the carbs will be built to perfection this time and they can be discounted for sure.

Plan-
- finish carbs
- carbs back in and test and see response if any after checking timing again as can't be sure if that as would not tickover last time.

Failure - then it's either coils or the newtronics system.

- incredibly I have a dyna system which looking at it seems to be complete and brand new. After all the other obvious things this will be the final thing I try.

Be a few days now sorting carbs. By all means hit me with thoughts ......
 

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Update :
Carbs off , 4,3,1 carbs cleaned. Carb 3 currently only one that may have had dirt.

Carb 2 - I need to get a better impact driver and jis bits, screw heads stripped at top end. Also ordered hex head bolts to swap out. Poor mechanics I agree but there was a reason ..... Won't happen again messing up bolt heads.

If that doesn't work I'll make it a flat screw head.

Carb 3 only may have had some dirt in but only in pilot jet. I am convinced one hole only was blocked ......

All I know when the carbs are done at least I can discount them trying to get this sorted
 

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Carb off update :
All carbs now dismantled and cleaned.
1,4 ok and we're ok but cleaned.
3 I think had dirt in the pilot jet.
2 - this is mad - the needle jet nozzle was loose in the carb !!!!!

So all now cleaned out back together.
Await new hex bolts for carb tops.

Now what's think ?
Would that cause the mad situation I had ?

Going forward : status
- IV messed with the timing well it may have changed as I couldn't set it correctly as it would not tick over in the end.
- I've turned the tick over screw goodness knows where so that may be a problem trying to start now
- next dry day will put carbs back on.
- jis screwdriver and impact driver ordered about time I had them.
- may order some drain carb screws m6×7×0.75 and two of the screw heads suspect. Unless anyone knows where to get such bolts .

This carb has been on the bike for 5 years but it is not my original I don't think. Life got in the way to remember the last 5 years !!!!! I would have sorted the screw / bolt issues on original so it's odd to see such a mess. But now sorted
 
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