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Plug fouling

 
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lwmcd1



Joined: 16 May 2008
Posts: 6
Location: Ocala Florida

PostPosted: Fri Jul 04, 2008 4:18 pm    Post subject: Plug fouling Reply with quote

Hey guys,
Any ideas on where to look for a gas fouling right cylinder?
1974/Rita electronic ign. Sparx 3 phase 220 alt. and regulator. 34 mm mikuni single.
Ive tried many things like checking wiring (all new by the way) switching coils,plugs wires etc. no effect. Keeps fouling the right cyl.
thanks,
Larry
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cash



Joined: 10 Nov 2006
Posts: 359
Location: west cumbria

PostPosted: Fri Jul 04, 2008 8:13 pm    Post subject: Reply with quote

The cause is usually oil, though it can be ignition timing related but usually if it is ignition both plugs foul. Try a hotter plug say a N8Y or even N9Y if the fouling is bad.

Cash
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BrianK



Joined: 14 Jun 2007
Posts: 309
Location: Boston, MA USA

PostPosted: Sat Jul 05, 2008 2:15 pm    Post subject: Reply with quote

I've found "fine-wire" (platinum or iridium) plugs much more fouling-resistant in my 73 850. FWIW/YMMV. - Brian
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iusedtolikehondas



Joined: 22 Jun 2008
Posts: 27
Location: napa ca

PostPosted: Sat Jul 05, 2008 2:30 pm    Post subject: Reply with quote

are you sure it's fuel fouling? having the single carb would foul both, right?
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kommando



Joined: 07 May 2005
Posts: 288
Location: Scotland

PostPosted: Sat Jul 05, 2008 9:39 pm    Post subject: Reply with quote

With a single carb you can get bias to one cylinder due to differences between the cylinders eg compression, valve clearances, wear on the cams etc etc.
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mikegray660



Joined: 05 Nov 2006
Posts: 63
Location: Texas

PostPosted: Sun Jul 06, 2008 3:22 am    Post subject: Reply with quote

kommando wrote:
With a single carb you can get bias to one cylinder due to differences between the cylinders eg compression, valve clearances, wear on the cams etc etc.


yes but thats not so much a function of carb through, but rather condition of cylinders/motor - sounds more like one cylinder is a little off - have you run a compression test on them? maybe guides worn - like someone suggested you can run a hotter plug if worn guides to "mask" the problem until you have the time to fix should that be the problem
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Scheffy.G



Joined: 11 May 2007
Posts: 81
Location: San Antonio, TX

PostPosted: Sun Jul 06, 2008 4:29 pm    Post subject: Reply with quote

One more relatively easy electrical thing to try - swap the wiring itself that's going into the coils, assuming you don't have a single coil setup. Since the coils are wired in series, there's always one that's further upstream electrically than the other one. If this changes the firing cylinder it could indicate a grounding issue. Don't assume that everything's good just because the wiring's new. That's what I did and I ended up chasing my tail for weeks.
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lwmcd1



Joined: 16 May 2008
Posts: 6
Location: Ocala Florida

PostPosted: Sat Jul 19, 2008 5:19 pm    Post subject: Reply with quote

[quote="Scheffy.G"]One more relatively easy electrical thing to try - swap the wiring itself that's going into the coils,"
Yep tried that. I change all Elect. over including plugs, plug wires, coils,wires from ign amp. ect. It made no difference.
I've used a hotter plug, and I've chased down all wiring to their source to confirm all connections were good. I did find a couple that were iffy. Fixed those and though it did improve things over all it did nothing about the fouling. The only thing I can think of that I have not tried and it probably won't make and difference is to increase the gap on that cylinder's intake valve so it does not open as wide and so sends less fuel/air to the right side. It is set at the called for 6 right now.
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tpeever



Joined: 21 Aug 2006
Posts: 199
Location: Pullman, WA

PostPosted: Sat Jul 19, 2008 7:31 pm    Post subject: Re: Plug fouling Reply with quote

What about valve seal? My right side fouls a bit as well and I am pretty sure it's a valve issue, either worn guide or seal.

lwmcd1 wrote:
Hey guys,
Any ideas on where to look for a gas fouling right cylinder?
1974/Rita electronic ign. Sparx 3 phase 220 alt. and regulator. 34 mm mikuni single.
Ive tried many things like checking wiring (all new by the way) switching coils,plugs wires etc. no effect. Keeps fouling the right cyl.
thanks,
Larry
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mikegray660



Joined: 05 Nov 2006
Posts: 63
Location: Texas

PostPosted: Sun Jul 20, 2008 4:09 am    Post subject: Reply with quote

[quote="lwmcd1"]
Scheffy.G wrote:
One more relatively easy electrical thing to try - swap the wiring itself that's going into the coils,"
Yep tried that. I change all Elect. over including plugs, plug wires, coils,wires from ign amp. ect. It made no difference.
I've used a hotter plug, and I've chased down all wiring to their source to confirm all connections were good. I did find a couple that were iffy. Fixed those and though it did improve things over all it did nothing about the fouling. The only thing I can think of that I have not tried and it probably won't make and difference is to increase the gap on that cylinder's intake valve so it does not open as wide and so sends less fuel/air to the right side. It is set at the called for 6 right now.


again - compression test?
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lwmcd1



Joined: 16 May 2008
Posts: 6
Location: Ocala Florida

PostPosted: Sun Jul 20, 2008 10:37 am    Post subject: Re: Plug fouling Reply with quote

[quote="tpeever"]What about valve seal? My right side fouls a bit as well and I am pretty sure it's a valve issue, either worn guide or seal.

The top in is very fresh. But I will be running a compression check as soon as I can find my tester. A compression check is something I should have done already I'm sure. I love tinkering but this problem has gone on entirely too long.
Thanks for the input.
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lwmcd1



Joined: 16 May 2008
Posts: 6
Location: Ocala Florida

PostPosted: Sun Jul 20, 2008 10:41 am    Post subject: Reply with quote

iusedtolikehondas wrote:
are you sure it's fuel fouling? having the single carb would foul both, right?


Not if the problem is electrical/ignition
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lwmcd1



Joined: 16 May 2008
Posts: 6
Location: Ocala Florida

PostPosted: Tue Jul 22, 2008 6:04 pm    Post subject: Reply with quote

[/quote]again - compression test?[/quote]

Compression is the same for both cylinders.
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cash



Joined: 10 Nov 2006
Posts: 359
Location: west cumbria

PostPosted: Tue Jul 22, 2008 9:57 pm    Post subject: Reply with quote

If you look down each plug hole using a torch, turn the motor over until you can see the inlet valve. If it's oily you've a stem seal gone, or hopefully not a lose guide. Now here is the long shot, or, if the oil pump gasket is put on the wrong way round the return can be restricted. Too much oil in the sump will give you oiling problems.

Cash
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The Unapproachable Norton Commando

At the end of 1967 the Norton Commando was announced.

The Norton Commando was greeted with a certain amount of scepticism because on first sight the commando appeared to comprise of the old Norton Dominator twin cylinder engine mounted at an inclined angle in a set of new cylinder parts.

It was not realized that the new Norton Commando Isolastic method of engine suspension damped out all engine vibration and produced a machine which had uncanny smoothness for a vertical twin. In due course the critics were silenced and the Norton Commando had the distinction of being regarded as the first of todays so called superbikes. There can be little doubt that the original design concept of the Norton Commando has proved correct, since comparatively few modifications of any real consequence have been made since production commenced during 1968.

Now nearly 40 years later Norton Commando riders like us are a breed of our own, and as far as we are concerned its still more fun to go for a blat on the old Norton Commando, and fast. As a Norton Commando owner and enthusiast, my goal here is to promote and give credit to those who keep the Norton name going.

It is more deserving to give credit to the Commando itself, for after all these years it continues to be respected. The original Commando designers like John Favill are those who deserve the credit for developing this incredible motorcycle.

The Norton Commando Roadster and Interstate of the late seventies, never died. Although the Norton Villiers factory dispersed the tradition lived on. Today Kenny Dreer in the USA is developing the new 952 CC Norton. What a great looking bike this is, and its engineering is still based on the original layout. It will be interesting to see how the new 952CC Norton does in todays tough motorcycle market. One thing is for sure, I would own one if I could afford it.