spark plugs

[scalded dog]

The yamaha shop was out of bp6es plugs, they gave me bp5es, a hotter plug, my question is, will this harm my valves and pistons, in the long run. Thanks 'Dog

[young nip]

plugs

Dog,
I couldnt get 6's either but Im using 7's. I do have new high out put coils so im going with that for now. As to long term use Im not sure. Perhaps hotter is better for cold weather.Im no expert.
Hey you tech guys which is better to use, hotter or colder when in a pinch for spark????
Steve

[buffalo]

Colder is better if you can't get the right ones, the worst that will happen with cold plugs is fouling and poor performance.... too hot of plug can cause detonation and severe engine damage,
The XS11 engine design is rather forgiving, one step hotter, particularly in cooler weather should not cause any problem unless you are running it really hard... don't think I would run them indefinitely but for the short term they shouldn't hurt any. Take it for a good hard run, listen for pinging, pull the plugs after and look close at the insulators for white flaking or blistering, if the plugs look ok and no nasty noises are heard, you should be ok. Also running premium fuel would be good.
Depending on carb condition and any mods that may have been done it may be running slightly lean, it is not good to run hot plugs in a lean engine. I occasionally run hotter or colder plugs depending on weather conditions, it only takes a minute to change them.
Long and short of it... run premium fuel with 1 step hotter plug and you should be fine for a while, I would change back to standard plug for hot weather, long trips, etc.

[Hobbit]

plug heat range

I used to work as a technical representative for a major sparkplug manufacturer, so perhaps I can add a little information.
The heat range rating of a spark plug refers to the tip temperature of the center electrode. The ideal temp is between 1200 and 1400 degrees F. The length of the insulator and the elctrode material determine how fast it disipates heat.
if the tip temperature is to hot, it can ignite the fuel before the spark occurs; that's why it is better to use higher octane fuel (as mentioned in Buffalo's post) with hotter plugs. To hot and it can cause engine damage. Hope this helps. If you have any specific questions on plugs, maybe I can help.

[scalded dog]

Thanks Guys, I will change them as soon as I can order some more, there are no mods, completely standard, I just wanted to be sure. Later 'Dog

[emayte1]

ngk plugs

Hey Dog, I bought a set of plugs for mine today but they were out of bp6es, but had bp4es. they told me that in the ngk plugs that the lower the number the hotter the plug. apparrently the ngk plugs are opposite from the other manufacturers. Im going to try to check with the ngk boys and find out if thats true or not. if its not i will get back to ya. Matthew

[TopCatGr58]

Heat Ranges for NGK

From the NGK website:

How do I find a colder or hotter plug?

First, consult the NGK numbering system page,(listed on the bottom left of the 411 info page), you should be able to see which digits identify the heat range for your spark plug.
EXAMPLE: The heat range for a BCPR6ES-11 is the "6" (ignore the -11, it is the gap)
After you have identified the numbering system for your plug, merely raise or lower that number to change the heat range.
REMEMBER, NGK PLUGS GET COLDER THE HIGHER THE NUMBER, HOTTER THE LOWER THE NUMBER.

Say you are starting with a BKR6E-11
if you want a colder plug, you would use BKR7E-11
if you want a hotter plug, you would use BKR5E-11
(again, on non-racing plugs, the number after the "-" refers to the gap)

T.C.

[glenn]

Re: plug heat range

Originally posted by Hobbit
I used to work as a technical representative for a major sparkplug manufacturer, so perhaps I can add a little information.
The heat range rating of a spark plug refers to the tip temperature of the center electrode. The ideal temp is between 1200 and 1400 degrees F. The length of the insulator and the elctrode material determine how fast it disipates heat.
if the tip temperature is to hot, it can ignite the fuel before the spark occurs; that's why it is better to use higher octane fuel (as mentioned in Buffalo's post) with hotter plugs. To hot and it can cause engine damage. Hope this helps. If you have any specific questions on plugs, maybe I can help.

Gday
do you have any info on the usage of Iridium plugs. I have used them on my 81 xs650 and used premium unleaded without any drama detected. Your thoughts would be appreciated
Dlenn

[Hobbit]

plugs

Glenn,
Iridium spark plugs are refering to the material used on the center electrode tip. Like a platinum tip plug, the iridium is just a strong material that resist erosion and disapates heat real well.
Should be fine.

[Hobbit]

Iridium plugs

I just did a little web search and found the following link. Keep in mind it is advertising, so the performance claims are questionable.

http://www.autocarparts.com/parts/Denso/

[fusionking]

Those are the guys who make ACCEL plugs

[sixtysix]

I used the standard Denso plugs in my XS last year and they worked fine. I got them at Advance Auto, just gave them the stock plug number BP6ES and they came up with a list of cross references in about 2 seconds.

W20EP-U ...........BP6ES

[wildbill]

Re:spark plugs

The ngk-bp6es can be found at a auto shop{Big A if remember right}.Will find it as NGK BP6ES11,which is the same thing.Cross reference it, bound to find something that will work.Be careful with hotter heat range plugs can cause grief.That is how I found mine.

[scalded dog]

I finally got some sixes intead of fives, my number two cyl was black while the other three were very lite. Iadjusted the idle mix screw a half turn so it will run a little leaner, I just wonder if it would be enough. Thanks 'Dog

[wildbill]

Originally posted by scalded dog
I finally got some sixes intead of fives, my number two cyl was black while the other three were very lite. Iadjusted the idle mix screw a half turn so it will run a little leaner, I just wonder if it would be enough. Thanks 'Dog

I think you better keep a eye on that,you might have to do a little more tinkering.Check your other plugs when you check no.2 or switch the plugs around,might have a plug wire breaking down.That is what happened to my bike,discovered the plug wires were not{did not}have a twisted wire center but a carbon center which are very,very easy to break the core all it takes is a twist or a small kink of the plug wire to do this and then you get a bad reading on your plugs while thinking your plug wires are good when that is your problem .Now I have to replace my plug wires.Keep a eye on this and hope this helps.