Bosch WR56 spark plugs

[Danie.e]

Will the WR56 be OK on the Suzuki GS1000G engine? - we seem to have a few bad batches B8ES from NGK and some do not even last 50km and I am tired of buying new plugs

[greg78gs750]

OMG NO YOUR ENGINE WILL BLOW UP no just kidding, if they are the same spec give em a try. Though ngk's have a reputation for reliability, if it is happening repeatedly the plugs *might* not be the problem?

[Nessism]

Can't find much info on WR56 plugs. They are resistor type which isn't ideal and I think they are for late model cars. Denso W24ES or W24ES-U are direct replacements for B8ES's. I'd look for some of those instead.

[fastbysuzuki]

• Does not list a NGK replacement
• Bosch WR56 replacement spark plugs
• Beru UX56
• Bosch 0242242505
• Champion CET8
• Champion CET8SB
• Champion EON5
• Champion EON5286
• Champion EON5287
• Denso 5307
• Denso IW22
• Denso VW22
• Eyquem 0911007245
• KLAXCAR 43046Z

[Cipher]

you have checked all things that might contribute to failure?
ive never had a bad plug from any maker

are they fouling or what?

[fastbysuzuki]

Have to aggree with other posters regular failure of spark plugs due to a manufacturing fault is highly unlikely, its more likely the fault lies with the bike.

Have you removed the plugs immediately after a "failure"? If so were they wet/ oily?

[fbody_mike]

http://www.ngk-sparkplugs.jp/english/techinfo/fake/index.html

I am guessing the OP did not mean 50 km for plug life on a regular copper plug. Also, NGKs are counterfeited so you have to be careful. See the link above.

[Cipher]

now we need pics

[Danie.e]

Many thanks for the input.

The plugs are wet when I remove them. Top end was redone with sleeves properly honed at engineering shop, and new rings installed. Shims done at our local Suzuki dealer as I do not have shims to do it myself. Valves properly lapped, new valve stem seals. Carbs completely re-done with new (and correct) jets, o-rings etc. Brand new manifold inlet rubbers (genuine part) from Suzuki Warehouse. I have also put in new coils as the one coil was slightly warm after a run around the block and resistance check slightly different from the other coil. Spark definitely not the problem. I can hear there is a noisy tappet but have not yet opened it up after the overhaul and the bike has now only done 290km so far. At the time of my post, I have replaced three NGK BP8ES since the overhaul. One came out of No1 cyl and two out of No2 Cyl. I originally thought that it could be something with No2 carb but the pilot needle is very close to the other three carbs and after vacuum sync the bike is idling awesome with excellent throttle response.
Four days ago I installed a brand new plug in No2 and took a ride to a local pharmacy for some tablets. Driving there it was running perfect. When I got out of the shop and started the bike, it was running on 3 cylinders again. It was this last instance that prompted me to pose the question here.(that last plug was the second one that came out of No2)
1

[roeme]

Counterfeited you say? That might explain why my internet-sourced (from the US) NGK's got out of tolerance after a mere 5000 km on my Guzzi. The first set, factory-installed, lasted roughly 17000 km, then another 3000 when I bumped the electrode back into spec.

[fastbysuzuki]

On the 850 the petcock vacuume pipe leads to number 2 carb if the petcock is faulty it can leak fuel into the #2 carb and flood it possibly fouling the plug I am unsure if your bike is configured like he gs850 but worth a look.
If it is then take the line of the petcock see if there is fuel in the line.
You say you have BP8ES plugs is that a typo?

[bwringer]

Yep, sounds more like your petcock has a bad diaphragm.

And yes, NGK has a problem with counterfeit parts, so it's at least somewhat possible. Might try ND (AKA Nippon Denso or just Denso) plugs, since they're OEM as well.

FWIW on other vehicles, I've tried Bosch plugs because they were on sale, and always had issues. I would stick to the OEM NGK or ND.


And what plugs are you talking about, anyway?
B8ES are correct.
BR8ES are the resistor version. You only need these if you're replaced the wires and/or caps with ones that don't have resistors. That said, the resistor plugs also won't really make any perceptible difference.

[LAB3]

16k miles on Champions in my bike, I should probably pull em to see what they look like.

[Danie.e]

Bike is a GS1000G and the petcock is brand new because the old one was not serviceable anymore. I will check the petcock suggestion as I did not look into that possibility. Went and bought 4 new B8ES plugs today and will install them tomorrow when I have the time. Will report back here in due course

[2BRacing]

I can confirm that an over-rich mixture can kill brand new plugs in no time at all. When I was getting my brother's 650 Katana back on the road again after a hibernation of about 25 years, I installed a new set of NGK D8EA plugs bought at my local Autozone store. While synching and fine-tuning the carbs after cleaning, I started the bike on the "choke" quite a few times. Some more cold starts on the "choke" in the garage to show friends, etc.

When I took it out onto the road for the first time, I progressed only about 1 km before the engine started to run poorly and cut out, and would not restart. After pushing it home, diagnosis showed plugs 3 and 4 totally dead. I only had the old plugs available, so put 2 of them in, and voila! Still running today with 2 new plugs and the 2 old plugs!