900s2 eating plugs

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DaveDare
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900s2 eating plugs

Post by DaveDare » Sun May 24, 2009 5:41 am

Hi there everyone. My name is Dave. I have a long history of Bevels and Pantahs.

I have a '83 900s2 with a two into one reverse cone pipe fitted. I have just rejuvinated my bike and I am finding the forward cylinder is eating plugs.

The bike has sat for about 4 years and I cracked open the muffler and discovered no muffling at all, so I have rebaffled the exhaust.

As there was no baffling in the muffler I assumed it had been burnt/blown away. So I re baffled.

It is now eating a front plug. I am now thinking the muffle may never had fibreglass baffling and this may be contributing to the problem. Any thoughts???

wdietz186
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Post by wdietz186 » Sun May 24, 2009 6:43 am

Dave, Try to define "eating" plugs.If they are dry,white or burnt looking you are probably running too lean.I would suspect either clogged jets or an air leak at the cyl./manifold gasket.If they are black and sooty and fouling you are too rich.Suspect a float level problem such as a leaking float needle and seat.If they are black and oily you have either a valve guide problem or worn rings.As long as you didn't baffle the exhaust completely shut your packing the muffler shouldn't cause only one cyl. to malfunction.I would start with a good look at the carbs.

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abmartin
SSD900 Darmah
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Post by abmartin » Sun May 24, 2009 10:35 am

I ran my SS for years with an unbaffled Verlicchi two-into-one and had no plug problems with standard carb jetting. I would also recommend that you start by looking at the carbs and manifolds.

Bruce
1979 900SS
Fredericton, NB
Canada

DaveDare
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Post by DaveDare » Sun May 24, 2009 4:09 pm

When I say eating plugs, they are actually being destroted around the ceramic. No longer sparking at the shaft and top of electrode. Just small sparks around the ceramic base.

I guess my issue is I am not sure whether the muffler had baffle in it when I first put them on as I didn't look inside when they aere new. But without the baffle the inside rattles about. Oh and it's earth shatteringly loud.

I will check out the carbs and manifold this weekend. I can't imagine the jets are blocked as it runs exceptionally well, when it's running.

Thanks everyone for your feedback.

Dave::

Vince
750 GT
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Post by Vince » Sun May 24, 2009 6:45 pm

Mate the only time I have seen your plug problem,tiny sparks inside the ceramic and not at the end gap was after the useless dino bloke I tried once recomended a set of Spitfire plugs,they lasted about 100kms before doing what yours do,with the bike running like crap,are you using NGK plugs and if so what ones

DaveDare
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Post by DaveDare » Sun May 24, 2009 7:16 pm

Yes I am using NGK plugs, I was using BP7HS and have changed to BP6HS. I haven't had time to do a plug chop or long ride test yet. I also unwrapped a fair amount of baffle in case this may have been contributing to the problem. As I had not had an issue before I did the re-baffling.

Thanks again guys.

Dave::

wdietz186
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Post by wdietz186 » Mon May 25, 2009 6:32 am

Dave, If the ceramic is cracking you are having some severe detonation problems.This is not a good thing! Are there black specks on the insulator?Is the center electrode eroded?Take a close look at the carb and manifold for leakage and or clogged jets.If they are OK check the timing,You might find the timing is advanced too far.If the plug insulator ceramic is not cracked or eroded but instead glazed and kind of shiny gray you might be having a fuel precipitation problem.Too much lead substitute or oil getting into the combustion chamber can glaze the center electrode and become conductive. Electricity being lazy it will take the shortest path to ground.You didn't say how old the engine is and if it has had a hard life you might be looking at valve guides or tired rings.

DaveDare
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Post by DaveDare » Sat Jun 27, 2009 3:15 am

Hello there, Ok thanks for all of your replies, I checked the inlet manifold gaskets and sure enough they seemed old and badly cracked. I figured this was probably the issue.

I got a new set and popped them on. The bike started and idled without having to warm up straight away...excellent I thought. I let it warm right up and took it for a ride, I got about 1 KLM and it started back firing even worse than before. I thought maybe they manifold nute were not tight enough. I returned and tightened them some more. Went to side off and as soon as I give it some gas it starts backfiring. I tighten the manifold nuts some more and it just keeps doing the same thing, it's now worse than before. Is it possible to over tighten the manifold nuts???

I am totally baffled now. I put my carb guages on and it says manifold leaks??? bloody nora, I must be missing something. Please, any suggestions would be great.

Regards Dave::

DaveDare
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Post by DaveDare » Sat Jun 27, 2009 3:25 am

Any thoughts on whether I need to include any gasket sealant? Would this help?

Dave::

MartinMille BANNED
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Post by MartinMille BANNED » Sat Jun 27, 2009 4:11 am

Dave
I over tightened my manifold nuts last year only to find out when you do so the rubber separates from the metal strip and in turn sucking air.
I got some new manifold gaskets and used good old fashion gasket goo, you know the crap that sticks like ***t and is a dark brownish black in color it does not swell with the fuel vapour and stays tacky and will not go hard, after I did this and as soon as the nylock nut grabbed I stopped

Never had another problem after that

Lumpy
SD900 Darmah
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S2

Post by Lumpy » Sat Jun 27, 2009 5:54 am

Ahhhhh yes, I too thought I`d do the SS a huge favour. New manifold gaskets, just a nip a touch too tight and they sqeezed out, separated and she sounded like One Bung Lung.
It`s an old chessnut on this site but have the pick-up wires been replaced, thats if the Mille`s still ran that system. Mine went bad, stopped advancing on one pot and that pot got hot as rocks. I never rode her far enough to roast plugs, but given the chance I`m sure she would have. Stopping for fuel 2 k`s from home and the pipe of that pot was doing that evil pink pink pink, while I filled her up.

http://www.dansmc.com/spark_plugs/spark ... talog.html
This is a good link with lots of different pictures of plugs to check yours against and give an idea where your heading. In fact Goolge reading spark plugs and there`s a multitude of sites.

DaveDare
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Post by DaveDare » Sat Jun 27, 2009 8:07 pm

Oh dear...What I am hearing is I've tightened the buggers too much. I was suspicious of this. bloody makes sense though. Are they stuffed now? Can I back them off or do you reckon I need to buy some new ones? I guess I could try it and crack some high temp gasket goo around the nut area and outside to of the gasket??? any thoughts. Oh by the way thanks for the help, this bike is driving me bonkers.

Cheers Dave::

MartinMille BANNED
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Post by MartinMille BANNED » Sat Jun 27, 2009 8:38 pm

NOPE ---New ones required

DaveDare
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Post by DaveDare » Sat Jun 27, 2009 9:12 pm

Oh CR_P. Oh well thank god they are relatively inexpensive compared to all the other parts I've had to replace. Thanks heaps for your feedback. I will let you know how I go.

Cheers Dave::

DaveDare
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Post by DaveDare » Sun Jul 05, 2009 4:39 am

OK, Sorry to be a pain guys. Quick question. I am now being overly cautious with the tightening of the manifold gaskets. I am now having much the same problems.

Any ideas on how tight to go? Or am I being too anal now???

What I also want to know is, do you think the mixture screw all the way in and 2 and a half turns out is a good place to start for mixture adjustment?

I am doing a rough adjust with the other cylinder plug out first and then swapping. Problem is I can't seem to get the bloody thing started now.
Your help is awesome, and thanks to Brendon, I may take you up on the offer.

Cheers Dave::

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