So I bought new spark plugs and it doesnt run as well..

[rstacy]

I haven't had my Gen 1 all that long and I did not know anything about the spark plug condition. I found a tip sheet that said that the best plug for my bike would be the NGK DPR8EX-9. It was not a big deal to find the plugs and replace the current NGK Iridium DPR8EIX-9 plugs. The Iridium plugs looked pretty good when I removed them.

 

Since I have installed the new plugs I have noticed that the bike doesn't run as well.

Cold starting isn't as snappy as it had been and the engine is a little lethargic when rolling off of idle. Outside of that I cant tell much difference.

 

Was the Iridium plug really the better plug?

 

Ray

[capn eddie]

yes they are, i went from the ones you put in to the iridium dpr8eix-9 and my 87 vr runs better so i will use the iridium plugs from now on. just my worth.

[BoomerCPO]

I have been using the NGK Iridium plugs for a long time. This past July 4th I changed mine out after putting nearly 50K on them. The old plugs looked perfect despite the miles on them.

I like the way my bike runs with these plugs and I have no intention of using anything else on my bike.

There may be something else going on with your bike which is affecting performance.

Boomer....who sez ya gotta go with what works best for you.

[rstacy]

I bought another set of Iridium plugs. I may just go ahead and install them now and toss the other "new" plugs that are about 2 weeks old.

[BoomerCPO]

I bought another set of Iridium plugs. I may just go ahead and install them now and toss the other "new" plugs that are about 2 weeks old.

 

Save those plugs and bring them to a Venture MD in your area....somebody will have a use for them.... and better to donate them to a fellow Venture rider rather than toss em away.

Boomer

[V7Goose]

IMHO Iridium or platinum plugs have absolutely NO value over normal plugs except longer plug life. Many tests by many sources have proven this over and over, including my own side-by-side tests with another RSV. Note that I do not consider my basic tests for fuel mileage as "proof", just that my results were consistent with more valid technical tests from other sources.

 

I cannot explain why you think you perceive a difference in your bike - perhaps there is something else wrong? And anyone who insists that the iridium plugs are better in some way are certainly free to believe that. I just do not want someone who hasn't already made up their mind about this to blindly accept a statement that they are better. Do your research and then decide for yourself.

Goose

[rstacy]

I cannot explain why you think you perceive a difference in your bike - perhaps there is something else wrong? And anyone who insists that the iridium plugs are better in some way are certainly free to believe that. I just do not want someone who hasn't already made up their mind about this to blindly accept a statement that they are better. Do your research and then decide for yourself.

Goose

 

Hey Goose,

Thanks for the reply.

Its not a perceived difference. Its a difference. Oddly enough it happened immediately after changing the plugs.

The good thing here is we can actually do a side by side test. I will probably put the Iridium plugs in tomorrow night and see if the problem is corrected.

 

Ray

[RSTDdog]

I would check that you didn't inadvertently loosen or change the connections at the wires and plug caps and that every thing is still tight and properly seated etc. Your pulling twisting and moving the wires when changing plugs. Not hard to disturb that plug cap to wire connection since they just thread onto the end, particularly if the wires are old. Let us know what you find out.

 

RSTDdog

[BuddyRich]

Iridium's come pre-gapped. Did you set the gap on the standard plugs you put in ? Standard plugs are not pre-gapped so maybe that's the difference .

[Black Owl]

Just a shot in the dark here. By any chance are you still running the factory OEM leads and caps? If so, you could have damaged the leads which changing the plugs.

[rstacy]

Just a shot in the dark here. By any chance are you still running the factory OEM leads and caps? If so, you could have damaged the leads which changing the plugs.

 

I don't know. How can you tell? I have been thinking about doing some research here to see what is the best way to change the plug wires.

 

 

I installed the Iridium plugs last night.

I must admit that the cold start this morning was no different.

However...once warmed up, rolling off of idle is cleaner. Acceleration under load is also cleaner. Is it night and day? No. But it is smoother.

 

I found this interesting. I received the most MPG to date with the DPR8EX-9 plug. I was never able to break 40 on the old plugs but I got 41 to 41.5 on the DPR8EX-9 plug. Ill check the mpg for the next few tanks and see if the new Iridium plugs do just as well.