[bluevolt]

Originally Posted by sharanvenu

I thought the life of Iridium Plugs are around 40,000kms. Thats what I read and the dealer confirmed it. How many kms have you done with your Iriduim Plug?

I have done around 1500 KM with iridium plug. The mileage has improved by good margin, previously it was around 35-37 KMPL and now its 41-43 KMPL (Overall).

[sharanvenu]

Originally Posted by bluevolt

I have done around 1500 KM with iridium plug. The mileage has improved by good margin, previously it was around 35-37 KMPL and now its 41-43 KMPL (Overall).

Wow! that is a very good improvement. But I have not felt any improvement in mileage. It is around 50-54kmpl and it always has been.

[tj123]

Originally Posted by sharanvenu

I replace my spark plugs at around 12,000kms. By this mileage the electrodes would be almost fully blown out. You can push it further by adjusting the gap. But still I prefer to replace.

To my surprise the stock NGK sparkplugs looks relatively good it show minor signs of electrode wear after doing over 20 k Kms.
At this rate I could use it for another 10k km’s anyways I don’t want to take a chance replaced ny KGK with a Bosch, I could not get a replacement NGK plug at Honda workshop, they seems to only stock Bosch cost Rs76 /- including taxes.

[bluevolt]

Originally Posted by sharanvenu

Wow! that is a very good improvement. But I have not felt any improvement in mileage. It is around 50-54kmpl and it always has been.

Make sure you got the right plug and check the gap setting (don't damage the pointed electrode). In my case results were instantaneous though no improvement in performance except crisp throttle.

[prajwalkashyap]

I had got Champion plug as stock. The motorcycle is now 36K kms old and the plugs are still sparking fine. I still get about 55 kmpl within the city.

Prajwal

[nomadabhi]

NGK Iridium it has to be.
Have tried alot of variations on my RD and this is the best to work out (even for long drives its proven a success with RD).

Price ranges between 450-550INR

Rarely fuse. If any chance fouled, then you can burn them in petrol cloth and it will work well again.

[sharanvenu]

Originally Posted by bluevolt

Make sure you got the right plug and check the gap setting (don't damage the pointed electrode). In my case results were instantaneous though no improvement in performance except crisp throttle.

I noticed a change in the way the engine sounded though. The exhaust note is a little deeper and throttle response is better. The top speed has improved marginally.
Any body with a platinum spark plug please post their experience please

[Rehaan]

Reader Yezdiar Wadia has written in with the following helpful info:

Did not know that a simple change of spark plug would lead to a good amount of R&D on it from my side.

Having replaced the original (factory fitted) CPR8EA-9 with NGK CR7EK (dual electrode) which did not match to my expectations, to replacing the same to Honda recommended (bought from HSC) BOSCH which again did not match to the original to now CPR7EA-9 which comes close to the original feel of my Unicorn.

Decoding the NGK Spark Plug Code for the members...
C - Hex size
P - Projected tip
R - Resister
# - Heat range **
E - Reach
# - Gap

** = NGK spark plug's heat range goes from 2 (hottest) to 11 (coldest)

[ArizonaJim]

Just a word of caution to those of you who switch from a standard spark plug to one of the Platinum or Iridium tipped plugs.

The pre-set factory electrode gap on a platinum or iridium spark plug cannot be adjusted without possibly damaging the small tip of the center electrode.

The electrode tip is easily bent so it is best left alone.

The small diameter of the tip will need slightly less voltage to fire but the real difference between the rare metal plugs and the original inexpensive plug is the extended life.

The major spark plug companies feel the platinum or iridium spark plug should last more than 50,000 miles (80650 km) in an automobile**.

By the same token, the spark plug companies feel a standard spark plug will last at least 30,000 (48400 km) in an automobile**.

Assuming the numbers are correct, the rare earth spark plugs should last about twice as long as the standard spark plug.

This sounds good until one realizes that the platinum or iridium plugs can cost up to 4 times more than the standard ones.

Unless starting the engine is a problem, where the expensive spark plugs might give some advantage I find it difficult to justify spending the extra money.


I feel that buying two of the standard type spark plugs and changing them twice as often will result in improved starting and is a greater value when all is said and done.

**distance based on using an unleaded fuel.
IMO, a motorcycle spark plug lives in a rather hostile environment so I would reduce those automotive life values by about half. On the other hand, motorcycle spark plugs are usually easily accessible making them easy to replace. All the more reason for buying a standard spark plug for a motorcycle.

[Sutripta]

Originally Posted by ArizonaJim

the real difference between the rare metal plugs and the original inexpensive plug is the extended life.
....
Assuming the numbers are correct, the rare earth spark plugs should last about twice as long as the standard spark plug.

This sounds good until one realizes that the platinum or iridium plugs can cost up to 4 times more than the standard ones.

The eternal juggling act between cost of parts vs cost of labour.

Extended life plugs got a boost because
In some cars (esp. transverse packaging) the plugs can be very difficult to get at (and billable hours add up).
Wasted spark systems.
Plug changes coming up inbetween two service intervals.
The emissions guarantee required by most regulatory authorities.

Personally, on my bikes, would think normal plugs are not just 'good enough' but perfect for required job.

Regards
Sutripta

[Rehaan]

^ Brilliant points Sutripta!

The platinum & iridium plug craze is something I've always wondered about - but never found any truly scientific comparison between them. The points in this thread surely make the whole thing clearer.

cya
R

[dre@ms]

I have a 2006 Unicorn which has clocked 46+k till now. Its still running with stock spark plugs. My mileage after a engine work is now 42 and before was 30. I face the common throttle problem in winters, but no dip in performance till date.

Does my Uni need a spark plug change?

[Sutripta]

^^^
Am sure plug was changed during 'engine work'.

Regards
Sutripta