Running on one cylinder

I am trying to get my Commando back on the road and getting quietly frustrated here.
The engine has just been apart to have a PW3 cam fitted, so new rings and hone, and an Alton starter has also been fitted. It was previously running with a full auto head, Keihin FCR carbs, Pazon Altair ignition.
It ran sweetly on the bench when initially put together but hasn't been on the road yet.
Now that i have paid for it to be street legal, when started the left pot runs sweetly but on the right it either doesn't fire, or spits back through the carb, or from time to time will run up and then die and go through the cycle again. If revved up occasionaly there will be a "backfire" in the exhaust.
Have tried new plugs, swapping plug leads, swapping coils - all have no effect. Have also checked the plug for spark - lots of nice blue spark visible while turning over with the Alton.
Have also pulled the carbs down 3 times now, removed and cleaned everything except the slides and still no change. Have used carb cleaner and dunked in an ultrasonic cleaner.
The carbs did sit on an unused bike for a few years and took some cleaning initially, plus i had to use some gasket goo on the float bowl to get it to seal (spare o rings etc aren't stocked locally) so maybe some of that is obstructing the fuel flow somewhere.
Any way if there is something obvious i have missed before i tear the carbs down yet again all suggestions would be appreciated.

ntst8 said:

plus i had to use some gasket goo on the float bowl to get it to seal

Click to expand...

Think I'd focus quite closely on that.

Extracted a small blob of silastic (silicone) out of a car carb that wasn't healthy,
after much puzzling and searching.
Not a good idea ANYWHERE in the fuel system, I'd suggest...

Duff battery causing the EI to play silly buggers?

Blocked petrol taps causing fuel starvation to the carbs?

Or, and where my money is, internal blockages in the carbs. Modern carbs are great things, but, especially when compared to Amals, they are SO intolerant of foreign bodies and dirt etc.

I assume you've got top quality filters in your fuel lines?

old fuel? our petrol does not last long sitting about.
If the plugs foul fit new ones as they don't clean up easily.
Or buy my spare Ducati and fit the FCRs to that :wink:
I'll take the Alton as 20% deposit.
http://www.trademe.co.nz/Browse/Listing ... =828211233

Id be looking for a carb problem, or fuel supply to it.

Rohan said:

ntst8 said:

plus i had to use some gasket goo on the float bowl to get it to seal

Click to expand...

Think I'd focus quite closely on that.

Extracted a small blob of silastic (silicone) out of a car carb that wasn't healthy,
after much puzzling and searching.
Not a good idea ANYWHERE in the fuel system, I'd suggest...

Click to expand...

+1 That "goo" is the worst thing to use on a carb...it breaks down with fuel and gets everywhere. Check all the tiny passages with a small piece of copper wire...I'd bet there is some in there.

Yes , silicone is bad news for any fuel applications. Start cleanings.

Only place I found RTV useful was for thread locking the carb screws as locite about stripped screw heads trying to remove later. Exhaust leaks have caused one side mis firing too.

This probably won't help you Iain but many years ago a mate of mine had a Triton that was only running on one cylinder. To cut a very long story short, we eventually found that a baffle had become detached in one of the silencers and blocked it's output off!

daveparry said:

This probably won't help you Iain but many years ago a mate of mine had a Triton that was only running on one cylinder. To cut a very long story short, we eventually found that a baffle had become detached in one of the silencers and blocked it's output off!

Click to expand...

I can empathise with that... Bet it took Ages to find out right ?

Yes it did Eddie, what made things worse was that by the time I got to it he'd taken the head off so I did a lapping in of the valves and re-assembled everything, checked sparks and fuel system and fired it up but hadn't re-fitted the silencers, it ran perfectly until I put the silencers back on, then all was revealed!

Hi Ian. Have you checked your valve clearances. Don't worry if they are loose.
Looking at the replies here. Looks like one carb is working. swap them over to prove it [ temporally of course ]
Look forward to riding down to Kaikoura with you [ you on the Commando that it and that's if you are travelling with Hon Pres. ]
Always put carbs together without sealers. New gasket should be sufficient [ I have got away many times with reusing gaskets though ] Warped carb bodies etc have to be fixed first or replaced.

Dereck
ps maybe consult uncle Lex

Thanks for the feedback one and all.
Dereck - sadly i will be missing this years rally, i leave on Thurs for a 3 week m/c trip around Patagonia, which is the reason i wasn't patient enough to wait for a seal/o ring kit to arrive from overseas. I would not normally use any sort of goo on a carb.
Lex has just done the starer fitting, rewiring for new switchgear etc and it was running well when it left his garage. :cry: Perhaps it is missing his workshop?
The battery is new, and still turns over the Alton no trouble. The pumpers on the carbs work so fuel is getting somewhere, and there are in line filters between the taps and the carbs. Have changed plugs.
Carb was fully dismantled and recleaned again since the first post - no change. Strangely it doesn't seem to improve as the throttle is opened so it isn't just a blocked pilot jet etc. The main jet is definitely not blocked.
So i am starting to lean back to something in the ignition set up.
I haven't yet rechecked valve clearances, so will do, plus i will pull the points cover and recheck the ignition set up.

John, nice Duc, i had a '95 M900 with 39mm FCR's a year or few ago. A scream to ride.

Poo what would I do after blank staring swearing states.
switch items side to side as as mentioned
check float for hang ups or leaked inside
valves going up dn
feel for finger pop off compression or measure
look close in the dark for flashes
spray ether carb brake cleaner wd40 in intake then into jug to see what happens
narrow spark gap and try new plugs just for comic relief

My '83 pu worked fine dragging logs till parked in yd never started since. Fresh 91 oct no booze ag gas with stabie in main over head storage tank topped up from empty a few months ago. Spark jumps screw driver handle to exit elbow to headers with white blue arc seen in bright daylight, carb accelerators pumps spray, spins over like crazy but nothing happens with gas or carb spray into carb, stumped. Been a few weeks with me an others checking every wire and hose and tube and seal, so friends trailered to a real mechanic. If its got gonads or an engine expect troubles. Found some missing SS fasteners for Peel but lost a SS shock blot and both swing arm bushes last night in living room in most uncluttered state in a decade, ugh.

Hi Ian, I should have mentioned check your compressions. You may have donked a stuck valve, or even swallowed some carb slide. [ though I have swallowed carb slide and main-jet needle and bike still going strong.]
Dereck

Substitution(s). :|

pre-Peel inhaled a thumb nail size of slide that then peckered the snot into chamber and crown chipping the intake valve and curling a lip in exhaust valve then spit out headers yet start, idle, lugged and drag raced perfectly so shocked on opening up merely to reseal leaks here and there aggravated by my heated use. So don't expect something as straight forward as merely stuck valve. I too got sucked into Commando being told simple as a lawnmower just need compression, fuel mixture and right timed spark, ha.ha.ha.

Checked
compression - good on both sides,
valve clearances - good
ignition - LED lights with passing of each rotor gap.
In desperation (if all else fails) i have read the Pazon book cover to cover - it is rather small print considering the average age of us Norton owners. It does state that if the rotor is excessively wobbly then it may run on one cylinder or not at all.
There was a slight wobble but i had to look hard to find it, and thinking back this may have all started when i tightened the rotor retaining bolt - so tonight i will start from scratch with the timing.

Oh a Pazion eh, I and my buddy experienced from points to boyahs could not get the basic Pazion to work but intermittently so just teasing hints of firing so gave-up-failed and put back points on my Trixie. There was one or two others that had Pzaion mystery that turned out to do with the fit-clearances of the trigger plate they stumbled on then had to solve. The electronic ignitions are the "black box" mystery component to focus on and myabe try another in desperate eliminations. I still don't know why my Pazion didn't work in my case and just not enough time/interest to do so yet. EVERYTHING in Pazion check list checked perfect and would fire plugs on testing timing but only a second or so firing at first then nothing.

Is someone able to get Pazon on this forum to help diagnose the faults.

Ian, if your problem started after you diddled that bolt, It may necessarily follow that you might have caused the problem by doing so. Commandos are really simple. The only thing complicated is the electronic modifications.
Look at Japanese vehicles. There is a 10,000 % probability that they don't give problems with their electronics, because they are designed correctly in the first place.

let us know if that was the problem.

Dereck.

ps, better take your woollies with you when you go to Patagonia.