[.577 Snider]

Hello all,
Back on July 13th, I started a thread in this forum because I was surprised to find an NGK B5ES plug in my B5 instead of a Bosch.  And I read all the replies with intrest. After reading SinghG5 excellent posting , I immediately purchased, gapped to .28 and installed an NGK BPR6ES.  I have ridden about 200 miles since then. At first all I noticed was a slightly different power curve and a slightly lower idle. And I thought that it was probably ok. But three days ago an engine misfire was occurring after starting up that went away after riding a few blocks. Also had some occurrences of engine idle dying while waiting at a red light, that had never happened before. This morning, it was hard to start and running roughly so I shut it down and removed the BPR6ES plug and it is fouled out(dry black fuzz). Replaced it with the B5ES.  Went ahead and rode to work  and back today. Performance is back to quite good. So whats causing the problem?  Plug gap? A defective plug? Altitude is 5280 ft., and I am using 91 octane gas from the same pump each fill up. 
The NGK website lists BPR8ES as the plug for RE500's. But I'm sure that one is to cool.
 The first pic is the B5ES and the next 2 are the BP6ES.
 In the back of my mind I am wondering if there is any damage occurring.
 I am open for ideas and inviting anyone to comment.
Thanks

[Arizoni]

With the NGK sparkplugs, the smaller the number, the hotter the plug.

Obviously going to the cooler #6 wasn't the right direction with your bike so you might want to stick to the #5 or possibly go the a #4 if the 5 starts carboning up.

It might be your altitude that is making the difference.  I'm at 1200 feet although I've ridden up to over 8000 feet without a problem with my NGK BPR6ES.  I'll admit that when I was at that elevation I was riding at speeds of around 60 mph and I didn't check my sparkplug while I was up there.

If you haven't already done it, you might want to check the condition of your air filter.  If it is slightly plugged up it might be the cause of the rich condition.

[GSS]

All good suggestions from Jim. To that I would add throwing in some Seafoam in the gas tank each time you fill up. It really keeps the plugs from getting fouled up.

[GlennF]

Its also possible you have a separate issue that just co-incidentally came up when you changed plugs.

I would check the air filter.

However it appears that the most common cause of unexplained plug fouling on these bikes is a faulty side-stand switch. Unplug the side-stand switch and see if the problem disappears.

[BRADEY]

I think the plug gap should be between 0.7 to 0.8 mm. If you gapped it to 0.28 mm that is way to low.

Try regapping the BPR6ES, if it is working well on all the bikes, it should work on yours as well. Do check the Air filter as well........

[2bikebill]

+ 1.  That plug gap is way too tight

[gremlin]

perhaps he meant .028 inch

[t120rbullet]

You might want to verify that the sparkplug wire is screwed down fully into the cap since when the spark plugs start getting changed often that's when it's going to get unscrewed if not when it came out of the factory. I've seen the screw inside of the cap burnt right off from it arching inside of the cap.

Like has been said before check your air filter. One overfilling of the oil will soak your air filter with oil and it will be running rich until it's been replaced.

The NGK BPR6ES or NGK BPR6EIX is the correct plug for your bike. The 8 that NGK mentions is for the old iron motors. You have to remember that the UCE and the AVL for that matter are a very small sampling of the bikes that RE has on the road. It's going to take time for these company's to catch up and give you some useable data but unless their showing you the 3 different motors and the 3 different plugs that they use who knows which one their talking about.
CJ

[2bikebill]

"....perhaps he meant .028 inch...."

DOH...  you may be right at that..

[JVS]

yeah i regapped my 6ES to approximately 0.75mm as it was about 0.9mm out of the box idk why.

Anyhow, you also might want to check the enricher/manual bi-starter cable - if it's engaged or not. Also, try checking your idle TPS voltage as shown in one of singhg5's videos.

From previous topics and discussion, I've realised that the UCEs tend to run a tad on the rich side.
Just my opinion :/

[jartist]

If it runs fine with the hotter plug then stick with it! There's a lot of factors that can cause plug fouling two of which are altitude and riding style. Spend a lot of time idling or stop and go traffic? Low rev operation or lack of freeway driving? I don't think you're calculations are causing any harm with the bpr5 if it continues to look good and there's no pinging. If it were me I'd still try what's been suggested with checking the tps setting and disconnecting the sidestand switch to try that.  I wouldn't leave the sidestand switch disconnected indefinitely though, they have saved lives.

[.577 Snider]

Ok, I'll be checking on these ideas this weekend.
My bike has always started with the sidestand up or down, kick or electric. After a quick look underneath, I can see the switch is connected. Is there a good schematic  or youtube video available? I'll have to trace some wiring.  How do sidestand switches save lives? 
Gapped plug to .28 inch's.
Thanks for the tips.

[barenekd]

Your -5 looks like my -6 at sea level. It has run faultlessly for 10000 miles. Go with the -5 and enjoy the ride. Your biek cold be running a bit rich because of the altitude. The EFI should have taken care of that, but maybe it hasn't gone quite lean enough yet. what kind of mileage are you getting? I generally 75-80 MPG when I'm riding that high.
You have obviously never taken off with a bike with the sidestand down. When you make that first left turn, they will launch you big time! Pretty sure way to crash!
With my sidestand down, and the bike leaning on it, my engine will start. As soon as I take the weight off the stand it quits. There is obviously a little slop in the sidestand/switch interface. I haven't looked at it closely as it's no big deal. I can't ride off with it that way.
If yours will start in any position, I'd be checking the switch out and see what's not connecting right. That one can getcha!
   
Bare

[jartist]

On some bikes if you ride away with the sidestand down the sidestand will trip the bike on your next sharp left turn. I had a friend take a bad spill that injured him pretty badly that way. Other bikes the sidestand will just fold up.  Sidestand switches can go bad and leave you stranded on the road though so a lot of people disconnect them. On some bikes you have to use a jumper to deactivate them but on the enfield all you have to do is disconnect it so there's no real risk of it preventing you from riding home because if it malfunctions all you have to do is pull the plug on it. I like the piece of mind it gives because I forget stuff. If your bike starts with the sidestand down and doesn't die if you very slowly put it up it's not doing anything anyway. If you want to make it work just use an ohmmeter to see if it works by disconnecting it and checking the leads for continuity. If the switch works it's likely the plug that is making a bad connection.

[jartist]

I agree about the plug. 5 is close enough. If that works good for you use it.