Spark Plug Colour - Spark Plug Color

[Paul Sutton]

Did the problem transfer from one cylinder to the other?

Entry 10:

Thanks Peanut I think you're right, I did notice the left exhaust was cold yesterday also, it did get warmer but not like the right side.

Entry 14:

Switched plug wires around and left exhaust cold right exhaust hot.

...or, does this mean the plug wires were removed from the coil and swapped to opposite sides?

 

[peanut]

ha ha ha thats exactly what I've been thinking Paul.

I tried to think of a way to write what I intended but it never reads clearly when posted .
What we want to do is to unplug the plug cap from the working cylinder and plug it over onto the non working cylinder and do the same with the other plug cap but I wonder how many owners simply pull the HiTension lead off and swop that over its difficult to describe clearly in text .

Anyway if when the plug lead is swopped over the left cylinder works properly and the right cylinder stops working then it cannot be the spark plug at fault on the left cylinder. It has to be the coil or the hi tension lead or cap that normally supplies the left cylinder that is faulty

 

[peanut]

Thanks for all the replies fellas. My son came over and needed help with his car so I didn't get a chance to check anything on my bike. I'll check the valves in the morning and also try some new plugs, I have a new set in the garage I can throw in. Seems like either of those two things would solve my issue, bikenwas running good before and has no leaks of any sort. The main problem is I don't ride enough and this bike doesn't like to sit for very long lol, every time I get it running right and then sit for a month it's like I have to start over with something or other. Guess I'll just have to ride more!

thats the constant problem with all our classic vehicles isn't it. ! My 30 year old car really doesn't like being left for weeks without a good run. The injectors get sticky with all the petrol additives that get added to our gas these days ...same with the XS650 I have to clean the fuel bowls out if the bike is left for a couple of months.

Anyway how did you get on fixing No1 Son's car ?

 

[Skubik]

Yeah no kidding! I wonder how jay Leno does it to keep all his cars from going down hill! Lol
Yeah son drives up and there's a massive oil leak coming from his valve covers. Took care of that and few other items he's been procrastinating on fixing. Now heading back to my xs650, I think it will be the valves being too tight. Going to adjust them and swap spark plugs also just for giggles. You guys have a great Labor Day weekend!

 

[XSLeo]

I like .003 intake, .006 exhaust. Works well for me.

 

[XSLeo]

I like .003 intake, .006 exhaust. Works well for me.

 

[peanut]

I like .003 intake, .006 exhaust. Works well for me.

heard you the first time Leo
So how does that compare with Yamahas recommendations for Skubics engine in metric ? (can't do imperial measurements anymore )
Yamaha changed there minds about recommended valve lash for the various model years numerous times over the years in their service bulletins

 

[650Skull]

What, your feeler gauges don't have Imperial and metric on them...........
http://www.xs650.com/threads/valve-lash-set-at-004-and-006-still-pretty-loud-normal.45810/

http://www.xs650.com/threads/setting-valve-clearances-confused.19519/

Typed in Valve Settings into advanced search..............http://www.xs650.com/search/4060970/?q=Valve+settings&o=relevance.

 

[gggGary]

Is that a stock tank, petcock? Have you checked for a leaky seal in the petcock vacuum diaphragms? Seen it before, the left side sucks a constant stream of gas through the vacuum port.

 

[Skubik]

No, it's a manual pet cock. Replaced the stock one some time ago. Well the left exhaust valve was very tight and the left intake valve was too lose. I did the recommended .003 intake and .006 exhaust valve adjustment and switched the spark plugs around putting the right spark plug on the left side and vice versa. It started up nicely except that now the the left side valves (exhaust I think) are very loud. I'm gonna open the valves up again and double check my adjustments again. The left exhaust pipe got a little warmer but nowhere near as hot as the right pipe.

 

[peanut]

What, your feeler gauges don't have Imperial and metric on them...........
http://www.xs650.com/threads/valve-lash-set-at-004-and-006-still-pretty-loud-normal.45810/

http://www.xs650.com/threads/setting-valve-clearances-confused.19519/

Typed in Valve Settings into advanced search..............http://www.xs650.com/search/4060970/?q=Valve+settings&o=relevance.

Yes my feeler guages do have both imperial and metric but when I'm sitting in my armchair at 11pm at night watching TV and surfing and my guages are in my garage 75 mts away and its pouring with rain !... plus I was tired and couldn't be arsed to convert

I guess I was just making the point that Yamaha changed their valve lash recommendations many times over the years so even they were undecided .....plus Yamaha XS650 bikes were designed and built with metric dimensions fixings and tolerances not Imperial
Here in Britain we have been Metric for over 50 years now so we are unfamiliar with using Imperial measurement system.

Here is a link to an Engineer who specialises in XS650 engines and has made an exhaustive study of this subject .His explanation, findings and recommendations makes perfect sense to me so I'd sooner follow his advice and my own observations and experience than urban myth http://www.smedspeed.co.uk/tech.html

 

[Skubik]

1980 xs650 special
TCI stock ignition
MikeXS ultimate coil
New ngk plugs and ngk wires
BS34 carbs
Rebuilt adjusted and cleaned carbs all good there.
Manual petcock
Bike starts up.
The issue I was having was a cold left exhaust, wet left plug, loss of power from this.
I've gone down the list of suggestions (thanks all!) and it's not carb related, not the coil, plugs or wires, timing seems to be good. Thought maybe valves not adjusted well and confirmed left side valves out of adjustment.


So..I took my time adjusting my valves on both sides and even put in my new valve adjusters with the Allen head from mikesXS, bike sounded so much quieter and smoother. Still had the issue with cold left exhaust and plug looking sorta wet but spark was present, I used an inline bulb spark tester. Left spark did seem a bit weaker than right side spark. Switched out bpr7eix plugs back bp7es but bike wouldn't stay on, so went back to iridium bpr7eix and started right up and stayed on (cold left exhaust still there), then I tried bpr6eix (hotter) plugs for giggles and messed with fuel screw on left carb to see if I could adjust the wetness out but really didn't get anywhere with that. SO Somewhere online I read that the rectifier/regulator sometimes interferes with your spark signal? Didn't believe it but I disconnected the rectifier anyway and fired the bike up. Started right up and both pipes heated up right away and rather quickly and evenly. Now I just need to re adjust my fuel settings as I think it's running a bit lean with all the messing with the fuel screws I did, but the question on my mind is "how does the rectifier interfere with the spark signal?" And how do I fix that since I'll need to reconnect it. Anyone ever deal with a similar issue? It's nuts but as soon as I disconnected the rectifier plug left side came to life

 

[TwoManyXS1Bs]

You may have found the mysterious weak magnet syndrome.
Do a forum search on "rare earth magnet"...

 

[Skubik]

Will do thanks, it's strange. So I adjusted my idle and fuel screws...3.5 turns out made her sound good and spark plugs looked nice and even on both sides. Stuck with the ngk bpr7eix
I insulated the rectifier's wiring with some wire loom and electrical tape to see if that would make a difference but once I plugged it back in it threw everything off again. Once again cold left exhaust with spark present and wet plug..

 

[peanut]

I don't understand ?

if you have pulled the spark plug cap off the right cylinder and placed it on the left cylinder spark plug and the Left cylinder then starts working properly and getting hot (combustion) then the left coil has to be faulty unless either your high tension lead or the plug cap or the spark plug are faulty on the left cylinder .
I just checked back and yours has TCI ignition I suppose that could be faulty. it would be helpful if you put your bikes model year and full spec in your sig so that posters have a easy go-to reference .

Have a looksee through this http://www.xs650.com/threads/how-to-troubleshoot-the-tci-ignition-system.24161/

 

[DirtyErnie]

Moar Reading!
http://www.dragstuff.com/techarticles/reading-spark-plugs.html
http://www.4secondsflat.com/Spark_plug_reading.html

 

[Skubik]

Thanks Peanut I will add that information to my sig in a bit. The cold left exhaust and wet plug persist regardless of switching plug wires around or switching spark plugs around. This is how I know the coil plugs and wires are good. The right side works well every time with whatever plug or plug wire is connected to it.

When I check for spark on the left side (cold side) using a light spark tester i do show spark but left is always weaker regardless of which plug wire is on there or plug.

Today when I disconnected the rectifier plug I got even spark on both sides and both exhaust pipes heated right up. Wet left plug went away and both sides were burning nicely after I adjusted the fuel screws and idle again.

When I reconnected the rectifier things went back to cold exhaust (left) and wet plug (also left)

Wonder what that's about. I can replace he rectifier if that's the problem but I want to check a few more things. I read on a forum search that a bad ignition switch could be the culprit here.

Thanks DirtyErnie! I'll read up!

 

[Paul Sutton]

Re-Check Entry 33 above: This will tell you about magnetic fields in the alternator area and how they can swamp an old weak TCI pick-up magnet. Easy fix if this is the issue which disconnecting the rectifier/regulator suggests strongly to be the case here.

In the past I used a 0.5mm thick neodymium magnetic with a diameter to match the magnet on the rotor - It was either 5mm or 6mm?? Stuck it on with epoxy glue.

 

[Skubik]

Thanks Paul! Looking into this. It's the first I ever deal with it. Once I have some new info I'll report back.

 

[650Skull]

Being a wasted spark TCI system wouldn't a weak magnet make both sides run bad, not restrict it to one side?????............ I don't know........... it doesn't make sense, ( to me), it would affect one side only.........not to say, don't have a look at it.