BritBike Forum logo
BritBike Sponsor BritBike Sponsor BritBike Sponsor
BritBike Sponsor

BritBike Sponsor

BritBike Sponsor
BritBike Sponsor BritBike Sponsor BritBike Sponsor
JWood Auction JRC Engineering dealers JWood Auction
Home | Sponsors, Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons, "OLD" BritBike Forum | DVD- Manuals & Parts books | BritBike Stickers & Decals
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
Photo posting tutorial

Member Spotlight
Chris Newport
Chris Newport
San Jose, CA USA
Posts: 27
Joined: May 2008
Show All Member Profiles 
Shout Box
Search eBay for motorcycle parts in following countries
Australia, Canada, France, Holland, Italy, United Kingdom, USA
Random Gallery photo
Who's Online Now
194 registered members (1xfatboy), 1,758 guests, and 593 spiders.
Key: Admin, Global Mod, Mod
Newest Members
iansouthoz, Lightning Sim, Simon.Holyfield, Bushcreature, Gary Shackleton
10035 Registered Users
Top Posters(30 Days)
Lannis 144
kommando 105
Stuart 64
Popular Topics(Views)
476,918 mail-order LSR
Forum Statistics
Forums33
Topics65,721
Posts635,239
Members10,035
Most Online3,995
Feb 13th, 2017
Like BritBike.com on Facebook

Previous Thread
Next Thread
Print Thread
Rate Thread
Page 1 of 2 1 2
Spark plug reading - to warm ? #139677
04/20/08 6:18 pm
04/20/08 6:18 pm
Joined: Mar 2008
Posts: 341
Lower Rhine Area, Germany
Towner Offline OP
BritBike Forum member
Towner  Offline OP
BritBike Forum member
Joined: Mar 2008
Posts: 341
Lower Rhine Area, Germany
Hi all,

an experienced Triumph mechanic told me my spark plug is a little to hot. But I have adjusted the mixture as rich as possible. I think it's a little warm but acceptable. What do you think ? Should I take a cooler spark plug. It is a T120 RV from 1972 with stock carbs. The photos are taken after riding about 20 miles on a country road with 60-70 mph.

Thanks Ralf

P.S.: It is a Champion N3C plug





Triumph Bonneville 650 T120RV 1972
Norton Commando 850 MKII 1973
Support Your #1 BritBike Forum!
Membership Type! Free
Member
Premium
Member
Premium Life
Member
Vendor
Member
Site
Sponsor
Recognition No Premium Member Premium Life member (5 years) Vendor Member Site Sponsor Membership
Post commercial threads No No No Yes Yes
Custom title No Yes Yes Yes Yes
Upload avatar & photos No Yes Yes Yes Yes
Link avatar & photos Yes Yes Yes Yes Yes
Private Message Storage: 10 100 100 100 100
Length of signatures 255 600 600 600 600
Removes this very advert island between post 1&2 No Yes Yes Yes Yes
Price Free $12.90/year $105.00 No End
$55.00/5 years
$210.00/year
($17.50/month)
Email
Click on button >>
  Premium Member Premium Life member Vendor Member Site Sponsor Membership
Re: Spark plug reading - to warm ? #139678
04/20/08 6:27 pm
04/20/08 6:27 pm
Joined: Aug 2007
Posts: 4,542
Kent UK
Blapper Offline
BritBike Forum member
Blapper  Offline
BritBike Forum member
Joined: Aug 2007
Posts: 4,542
Kent UK
Hi Ralf,

Check this out:
Plug reading

Yours looks at the hot end of good to me.

HTH

Blapper redwine

Re: Spark plug reading - to warm ? #139679
04/20/08 6:31 pm
04/20/08 6:31 pm
Joined: Jun 2006
Posts: 804
Halifax, Butt end of Europe
andrewinpopayan Offline
BritBike Forum member
andrewinpopayan  Offline
BritBike Forum member
Joined: Jun 2006
Posts: 804
Halifax, Butt end of Europe
Plug is too new to get much of a reading, old plugs that have heavy deposits are better for readings.

A spark plug does not alter the combustion state inside the chamber, it just takes a "snapshot".

Equally important are the deposits on the ground strap, which should ideally be about 50% along the length of the straight bit.


99% of carb problems are electrical.

1959 3TA

BMW R1150 Oilhead
Re: Spark plug reading - to warm ? #139680
04/20/08 6:56 pm
04/20/08 6:56 pm
Joined: May 2007
Posts: 104
Cardiff Wales U.K.
D
don1 Offline
BritBike Forum member
don1  Offline
BritBike Forum member
D
Joined: May 2007
Posts: 104
Cardiff Wales U.K.
I agree with Blapper as they are pictured but to take a proper reading you should get the bike warmed up and when it is pulling hard under load, uphill for example pull in the clutch and kill the motor.Do not let it idle.then check the plugs.


don1
Re: Spark plug reading - to warm ? #139681
04/20/08 7:22 pm
04/20/08 7:22 pm
Joined: Oct 2003
Posts: 3,524
Emsworth, sunny south of Engla...
D
dave jones Online content
BritBike Forum member
dave jones  Online Content
BritBike Forum member
D
Joined: Oct 2003
Posts: 3,524
Emsworth, sunny south of Engla...
My plugs look like yours but I have B7ES (N4) plugs. I agree it is at the hotter end of the scale, considering you have N3 plugs.

For absolute maximum power the insulator would be white at the tip with a ring of tan or grey at the base but that would be difficult to maintain, ie, you could easily slip to overheating and I wouldn't recommend this for road use.

You really have to check the plugs at various throttle openings, as mentioned by Don.

If your timing and tappets are spot on with the right plugs and the carb settings are by the book it should be ok. Check them all out.

Dave

Re: Spark plug reading - to warm ? #139682
04/21/08 7:06 am
04/21/08 7:06 am
Joined: Mar 2008
Posts: 341
Lower Rhine Area, Germany
Towner Offline OP
BritBike Forum member
Towner  Offline OP
BritBike Forum member
Joined: Mar 2008
Posts: 341
Lower Rhine Area, Germany
Thanks a lot for all your helpful responses bigt ! The old plugs from the previous owner were NGK B7ES and they had been a little bit darker. I have serviced everything before I took the new Champion plugs. The tappets had been badly adjusted - to less play. I adjusted them to 0.04/0.06. So it is on the safe side. The timing has been strobed. So I wonder why the colder Champion plug burns lighter than the hotter NGK. I think I'll observe it a while until some more deposits placed on it. But I'll definitely ensure that it isn't to hot under hard load.

Thanks Ralf


Triumph Bonneville 650 T120RV 1972
Norton Commando 850 MKII 1973
Re: Spark plug reading - to warm ? #139683
04/21/08 10:52 am
04/21/08 10:52 am
Joined: Oct 2004
Posts: 4,429
Melbourne Australia
Tiger Offline
BritBike Forum member
Tiger  Offline
BritBike Forum member
Joined: Oct 2004
Posts: 4,429
Melbourne Australia
I feel like Panic used to before he was declared Persona Non Grata.
Cannot tell from those photographs Ralf, no idea at all.
Pretty sure it is not detonating though. bigt


1969 TR6R
7.62 x 51 is not a maths puzzle.
Re: Spark plug reading - to warm ? #139684
04/21/08 12:09 pm
04/21/08 12:09 pm
Joined: Dec 2007
Posts: 285
Waldorf, Maryland
Tiger Dale Offline
BritBike Forum member
Tiger Dale  Offline
BritBike Forum member
Joined: Dec 2007
Posts: 285
Waldorf, Maryland
B7ES is not the same heat range as an N-3. But I forget which way it goes. B8ES is the same heat range.

TD

Re: Spark plug reading - to warm ? #139685
04/21/08 1:13 pm
04/21/08 1:13 pm
Joined: Oct 2003
Posts: 3,524
Emsworth, sunny south of Engla...
D
dave jones Online content
BritBike Forum member
dave jones  Online Content
BritBike Forum member
D
Joined: Oct 2003
Posts: 3,524
Emsworth, sunny south of Engla...
That's right. The B8ES is very similar to an N3 but if Towner changed from Champion N3 to NGK B8ES he would find the colour would be slightly darker because they aren't exactly the same. Maybe his original B7ES just had a lot of deposits built up from when the engine wasn't tuned so well because they should have been lightest of all.

Towner- I have never done a plug chop in my life! I do the same as you and ride it around and then look at the colour. Mine stay the same good colour however hard I ride but if I let it idle they darken up a lot. That is either the ignition system or idle mixture but I can't seem to get it any weaker. You can usually feel if there is enough weakness to damage the engine. It would pink, lack power generally, spit back through the carb a lot and get hot.The plug insulator would be sort of a shiny looking bright white, maybe with little metallic specs and the electrode might be eroded. My 1967 manual says N4 but I know that a service bulletin changed them to N3 but I didn't because it was running ok! Your bike would have had N3 recommended from the start.

When you say you adjusted the mixture do you mean the airscrew or did you change all the settings? The airscrew won't help at a steady 60- 70 mph, more likely the cutaway/ needle position. Usually the book timing and carb settings work the best. Have you got air cleaners and original type silencers?

Tiger- Why is Panic not welcome here? Has he been naughty?

Dave

Re: Spark plug reading - to warm ? #139686
04/21/08 2:56 pm
04/21/08 2:56 pm
Joined: Mar 2008
Posts: 341
Lower Rhine Area, Germany
Towner Offline OP
BritBike Forum member
Towner  Offline OP
BritBike Forum member
Joined: Mar 2008
Posts: 341
Lower Rhine Area, Germany
Quote:
Originally posted by dave jones:
When you say you adjusted the mixture do you mean the airscrew or did you change all the settings? The airscrew won't help at a steady 60- 70 mph, more likely the cutaway/ needle position. Usually the book timing and carb settings work the best. Have you got air cleaners and original type silencers?
Dave,

thanks for your friendly response. I only adjusted the airscrew. I didn't change anything at the carbs or air cleaner. But the exhaust isn't original. The pipes are without this connector pipe and the silencers are from the older models. I didn't get panic - I think it isn't such dramatic. This mechanic told me, it were to bright. From my experience with other (not british) bikes I would say the plug color is ok. So I wanted to get another opinion. May be the plug gets brighter because I ride it more than the previous owner. On this picture you can see the exhaust system.

Thanks Ralf



Triumph Bonneville 650 T120RV 1972
Norton Commando 850 MKII 1973
Re: Spark plug reading - to warm ? #139687
04/21/08 6:10 pm
04/21/08 6:10 pm
Joined: Oct 2003
Posts: 3,524
Emsworth, sunny south of Engla...
D
dave jones Online content
BritBike Forum member
dave jones  Online Content
BritBike Forum member
D
Joined: Oct 2003
Posts: 3,524
Emsworth, sunny south of Engla...
That is a nice bike. I like the early oil in frames with the drum brakes.

Those pipes should be ok. The balance pipe makes it a bit quieter, that's all and those silencers are like the ones on my 67 650. You could possibly compare the settings for 72 with those from, say, 68 when those silencers and pipes without a balance were last used. If the settings are richer for 68 then you could try them but otherwise just leave it. Richer settings would mean slides with lower numbers, needle positions with a higher numbers, ie the clip in a position further from the blunt end ( the position closest to the blunt end is number 1), and main jets with higher numbers.

That plug colour seems ok, however, and you can always check once in a while anyway.

I would set the pilot screws in the way it says in the manual but only if you feel that it isn't right, in fact if you do everything by the manual you will be fine!

dave

Re: Spark plug reading - to warm ? #139688
04/22/08 11:13 am
04/22/08 11:13 am
Joined: Mar 2008
Posts: 341
Lower Rhine Area, Germany
Towner Offline OP
BritBike Forum member
Towner  Offline OP
BritBike Forum member
Joined: Mar 2008
Posts: 341
Lower Rhine Area, Germany
Hi Dave,

the carbs are 930 AMAL with 190 main jet, 106 needle, throttle valve No 3. The needle is on position 1. I have also checked for air leaks, but it's ok. Due to the plug reading - in my experience it lasts a while until the color of the plug changes. So it shows the situation of the last 10 miles (circa). What I mean is when you ride slow (e.g. in the city) or let it idle for a long time, it needs at least 10 miles fast ride to burn the plugs free. And when you have ridden a long time on the highway the plugs are bright even if you ride 1 mile in the city afterwards. So I agree with you that it is meaningful to drive around on the country roads (not in the city) and then look at color bigt .

Thanks Ralf


Triumph Bonneville 650 T120RV 1972
Norton Commando 850 MKII 1973
Re: Spark plug reading - to warm ? #139689
04/22/08 4:19 pm
04/22/08 4:19 pm
Joined: Jun 2004
Posts: 411
Columbus, Ohio, 1978 T140E
T
tomterrific Offline
BritBike Forum member
tomterrific  Offline
BritBike Forum member
T
Joined: Jun 2004
Posts: 411
Columbus, Ohio, 1978 T140E
Open the throttle all the way then roll off about half. Does the bike pick up? That means the main is lean, go up a number. Does the bike stutter? That means rich. Just a little trick used to get an idea of the main jetting.

The modern gas doesn't seem to colour the plug as gas did in the past. It does seem to carbon foul plugs just fine.

Tom Grahamn

Re: Spark plug reading - to warm ? #139690
04/22/08 9:27 pm
04/22/08 9:27 pm
Joined: Dec 2001
Posts: 368
PDX
spikethebike Offline
BritBike Forum member
spikethebike  Offline
BritBike Forum member
Joined: Dec 2001
Posts: 368
PDX
Good luck trying to find comparisons between different brands of plugs. I have found several contradictory charts so far.
The plugs at the top of the thread look fine to me, for little run examples.


Spike Cornelius in PDX (Portland, OR)
1965 T100SC
And various others
Re: Spark plug reading - to warm ? #139691
04/23/08 7:33 am
04/23/08 7:33 am
Joined: Mar 2008
Posts: 341
Lower Rhine Area, Germany
Towner Offline OP
BritBike Forum member
Towner  Offline OP
BritBike Forum member
Joined: Mar 2008
Posts: 341
Lower Rhine Area, Germany
Hi Tom,

thanks for the tip bigt . I remember what you mean. It's this behavior when you roll back the throttle from full, that the bike will pick up a little. I didn't noticed this yet, but I will test it !

Thanks Ralf


Triumph Bonneville 650 T120RV 1972
Norton Commando 850 MKII 1973
Re: Spark plug reading - to warm ? #139692
04/23/08 2:50 pm
04/23/08 2:50 pm
Joined: Sep 2007
Posts: 90
Flint Michigan
1
1973 triumph Offline
BritBike Forum
1973 triumph  Offline
BritBike Forum
1
Joined: Sep 2007
Posts: 90
Flint Michigan
Plugs look good to me..
with champs..the lower the number the cooler..its the opisite with NKG`s, the lower the number, the hotter..

Re: Spark plug reading - to warm ? #139693
04/23/08 5:19 pm
04/23/08 5:19 pm
Joined: Oct 2003
Posts: 11,138
North Georgia, USA
RF Whatley Offline
BritBike Forum member
RF Whatley  Offline
BritBike Forum member
Joined: Oct 2003
Posts: 11,138
North Georgia, USA
Downer -
Several thoughts...

A) It's a good bet that the plugs you've shown us can't be used for accurate readings due to some oft over-looked prerequisites...
The ignition timing has to be set first and verified as "spot on"
The fuel has to be first rate "high test". Personally I only trust Amaco/BP and Chevron 93 octane.
As per above, the reading is only a "snap shot", and therefore the "plug chop" method must be employed for an accurate "reading". Anything else is simply an 'average', and since the 'idle' circuit is generally richer than any of the 'run' circuits, a moment of idling can skew the entire effort. If your readings are skewed, how can you trust them? So IMHO your efforts then are wasted, since "anything worth doing is worth doing right" as the old adage teaches us.

B) Additionally, there are common high wear items that decline due to age that come into effect here since your bike is 35 years old. Before I'd start messing with anything mentioned above, I'd make double-darn sure to change these items out: the carb balance hose, the spark plug wires, and some other bits that will cost you a whopping $10.

C) That being said, as an 'average' reading only, the plugs look great to me. Nice and clean burning with no signs of oil burning.

D) Finally, the only thing that really alarms me about the photos (and this really, REALLY sets off alarm bells and flashing red lights) is the lack of ANY lubrication on the spark plug threads. Try adding 2 drops of motor oil from the engine oil tank each time the plugs are inserted into the head. Your cyl head and pocketbook will thank you.


Hope this helps! bigt


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA

"Shop Boy" at Rodi British Bikes
Re: Spark plug reading - to warm ? #139694
04/24/08 10:45 am
04/24/08 10:45 am
Joined: Mar 2008
Posts: 341
Lower Rhine Area, Germany
Towner Offline OP
BritBike Forum member
Towner  Offline OP
BritBike Forum member
Joined: Mar 2008
Posts: 341
Lower Rhine Area, Germany
RF,

thank you very much for your hints. I've got this bike since last September and worked the whole winter on it (my wife is not amused). I renewed all parts which seems to be worn to me. I took the carbs apart, cleaned them and rebuild them with new gaskets. The plug leads are completely new, the balance hose is new and the ignition timing has been strobed. The alternator (rotor + stator Lukas 3 phase) is new as well. After the answers above I run the bike on the country road for about 10 miles with 4000-4500 rpm and than killed the engine. The plug color was the same.

I'll heed your advice to lubricate the plug threads !

@All: Thanks for all your useful responses !

Thanks Ralf


Triumph Bonneville 650 T120RV 1972
Norton Commando 850 MKII 1973
Re: Spark plug reading - to warm ? #139695
04/24/08 11:52 am
04/24/08 11:52 am
Joined: Oct 2003
Posts: 11,138
North Georgia, USA
RF Whatley Offline
BritBike Forum member
RF Whatley  Offline
BritBike Forum member
Joined: Oct 2003
Posts: 11,138
North Georgia, USA
Quote:
Originally posted by Towner:
The plug leads are completely new, the balance hose is new and the ignition timing has been strobed.
Ralf -

And where did you get your new plug leads? If you simply went to a common after-market car parts place and bought 2 automobile plug wires, then you have the wrong type wire.

You'll need metal wire cores, the type cars haven't used since the late 1950's. All else sounds good.

bigt


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA

"Shop Boy" at Rodi British Bikes
Re: Spark plug reading - to warm ? #139696
04/24/08 1:28 pm
04/24/08 1:28 pm
Joined: Mar 2008
Posts: 341
Lower Rhine Area, Germany
Towner Offline OP
BritBike Forum member
Towner  Offline OP
BritBike Forum member
Joined: Mar 2008
Posts: 341
Lower Rhine Area, Germany
RF,

I bought the plug leads at the german parts supplier (http://www.nortonmotors.de). The leads are made by Champion ready with spark plug connector and coil connector. It may have a carbon core. Would that be a problem ? I have a Boyer ignition (Micro MK III).

Thanks Ralf

Edit: May be that I have the wire shown on this site (345-1140 Champion 22"). They write: Note: Resistor plug wires must be used with Boyer Micro-Digital Ignition Kits. http://www.britcycle.com/Products/plugwires3.htm


Triumph Bonneville 650 T120RV 1972
Norton Commando 850 MKII 1973
Re: Spark plug reading - to warm ? #139697
04/24/08 2:55 pm
04/24/08 2:55 pm
Joined: Apr 2005
Posts: 662
Arizona Territory
R
Riff_Raff Offline
BritBike Forum
Riff_Raff  Offline
BritBike Forum
R
Joined: Apr 2005
Posts: 662
Arizona Territory
Plugs look O.K. from here....but I'd keep an eye on 'em every so often.

A couple drops of oil on the spark plug threads will work or you could also buy a tube of Anti Seize & coat the threads with that.


"Factory Stock Is A Suggestion Only"
Re: Spark plug reading - to warm ? #139698
04/24/08 4:52 pm
04/24/08 4:52 pm
Joined: Oct 2003
Posts: 11,138
North Georgia, USA
RF Whatley Offline
BritBike Forum member
RF Whatley  Offline
BritBike Forum member
Joined: Oct 2003
Posts: 11,138
North Georgia, USA
Quote:
Originally posted by Towner:
I have a boyer ignition (Micro MK III)... Resistor plug wires must be used with Boyer Micro-Digital Ignition...
Ah, finally 20-odd posts later we get the details!!

laughing


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA

"Shop Boy" at Rodi British Bikes
Re: Spark plug reading - to warm ? #139699
04/24/08 5:16 pm
04/24/08 5:16 pm
Joined: Nov 2005
Posts: 7,258
Back on the mainland!
JubeePrince Offline

Life member
JubeePrince  Offline

Life member
Joined: Nov 2005
Posts: 7,258
Back on the mainland!
Ralf -

The MKIII is the an@log version of EI (black box)....resistor caps are not necessary...

Boyer-Brandsen Micro-Digital (red box) has the computer chip in it.....for this you need the 5 Kohm resistor caps........


HTH,

Steve


'77 T140J
"Vintage Bike". What's in your garage?

"The paying customer is always right."

Fitting round pegs into square holes since 1961...
Re: Spark plug reading - to warm ? #139700
04/24/08 6:02 pm
04/24/08 6:02 pm
Joined: Mar 2008
Posts: 341
Lower Rhine Area, Germany
Towner Offline OP
BritBike Forum member
Towner  Offline OP
BritBike Forum member
Joined: Mar 2008
Posts: 341
Lower Rhine Area, Germany
Quote:
Originally posted by JubeePrince:
...resistor caps are not necessary...
Hi Steve,

the leads have no resistor caps. It must be in the wire - so I suppose that it has a carbon core. Could that do any harm ?

Thanks Ralf


Triumph Bonneville 650 T120RV 1972
Norton Commando 850 MKII 1973
Re: Spark plug reading - to warm ? #139701
04/24/08 9:38 pm
04/24/08 9:38 pm
Joined: Nov 2005
Posts: 7,258
Back on the mainland!
JubeePrince Offline

Life member
JubeePrince  Offline

Life member
Joined: Nov 2005
Posts: 7,258
Back on the mainland!
Ralf -

Get yourself some good, old-fashioned copper core wire........BCS has them...#345-03/A


Steve


'77 T140J
"Vintage Bike". What's in your garage?

"The paying customer is always right."

Fitting round pegs into square holes since 1961...
Page 1 of 2 1 2

Moderated by  John Healy 


Home | Sponsors | Newsletter | Regalia | Calendar | Bike Project | BritBike Museum | Spiders Cartoons | "OLD" BritBike Forum | DVD- Manuals & Parts books | BritBike Stickers & Decals
Upgrade to: Premium Membership | Premium Life Membership | Vendor Membership | Site Sponsor Membership
Powered by UBB.threads™ PHP Forum Software 7.6.1.1