Pinging and a white plug

[Murph]

Not the intake seals...didnt have an effect when sprayed...changed them anyways. Resulted in an even idle....rpm remains consistent now.

No vacuume leaks

New plugs

No ground issues ..I replaced one ground and searched for other issues.

Removed battery ...tested...recharged great...starts immediately.

Single fire coil...3 posts...swaped front and rear wires...same result. Coil good.

The only other symptom that showed itself was the backfire... is that indicating lean or rich?....Cant remember.
Whatever caused that backfire is the issue....and Im narrowing it down.

Thanks for hanging in there with me....Im trying.


Update...switched coil wires back to normal....ran worse....runs slightly better swapped?
Runs strong...pulls hard, why would it only be at idle?
Is it safe to run it long term with the coil wires swapped?

[IXL2Relax]

Originally Posted by Murph

(1)The only other symptom that showed itself was the backfire... is that indicating lean or rich?....Cant remember.
Whatever caused that backfire is the issue....and Im narrowing it down.

(2)Update...switched coil wires back to normal....ran worse....runs slightly better swapped?
Runs strong...pulls hard, why would it only be at idle?
Is it safe to run it long term with the coil wires swapped?

(1)Backfires can have fuel or electrical causes. A lean condition can cause backfires. But an intermittent spark trigger can also cause backfires as the spark may be occuring at the wrong time.

(2)It DOES NOT matter which trigger wire is on which coil terminal, so long as the proper (front or back) spark plug wire is in the triggered (selected) tower.

Just a summary - 1995 EVO Engine, Ultima IgMod in Single-Fire Mode with SE Single-Fire Coil.

You might need to try some things unexpected, at this point, with the difference in burn still happening. This has been a stubborn problem.

That's why I suggested the Dual-Fire change in the Ultima module with a dual-fire coil.


At any time, with any changes, did the rear plug burn lighter than the front plug?

BTW, what brand/version plugs are you running?


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[Murph]

At no time did the rear plug burn lighter than the front.

First....front white....back tan....seemed to run ok except for pinging. Which started this whole thing....I noticed the plugs.

After adjustments to timing....front tan....back black....so that would indicate a timing thing...if back/fouling plug....used to run tan...before messing with timing...correct?

Was Harley plugs...now NKG-DCPR7....both plugs ran the same.

This was a fairly new rebuild on top end when I bought it...hasnt been ridden a whole lot...was a trailer queen show bike...so original owner prob never noticed the issue...the pinging led me to look into things.

[IXL2Relax]

Well - You've been checking out all the basic potential sources.

But I would now start checking for the less likely, but possible, sources.

I would do a compression test on both cylinders - Then, depending if you get any low reading or too differential readings, do a leakdown test.

Check on Exhaust Leaks - both cylinders - possible lean condition on front cylinder.

Something is going on - but not an obvious source.


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[Murph]

Whats the usual way to check for exhaust leaks?
Also if this is unusual....couldnt I run hotter or colder plugs...different front to back?...balance the timing.
Plus how do you choose hotter or colder plugs....always used what was commonly posted.

[IXL2Relax]

Originally Posted by Murph

Whats the usual way to check for exhaust leaks?

http://sportsterpedia.com/doku.php/techtalk:ref:carb04

Originally Posted by Murph

Also if this is unusual....couldnt I run hotter or colder plugs...different front to back?...balance the timing.

I would want to know WHY ARE THEY BURNING DIFFERENT? - rather than trying to cover up that fact.

Originally Posted by Murph

Plus how do you choose hotter or colder plugs....always used what was commonly posted.

https://www.ngkntk.in/importance-of-heat-range/


I don't usually recommend products to others, but provide information for them to make a choice. And I don't take all Mfr hype as gospel. I evaluate what I want and why, then try it out before considering it a successful product.

All that to say - I personally run NGK DCPR7EIX Iridium Spark Plugs on my '94 883>1200 conversion.
For me, I found they spark the engine more smoothly.
https://ngksparkplugs.com/wp-content...SparkPlugs.pdf

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[Murph]

Thanks for the info!

Exhaust leak test.....I think I will pass putting oil down the plug holes...I get no backfire on deceleration.

As far as the mechanical issues being discussed...compression and so on..if adjusting the timing a bit corrects or changes the problem..probably not the jugs.

I do need clarification of something....plus I will be digging up info on plugs people are running and why.

My question...If the plug recommended is lets say...NKG DCPR7E

What would the hotter and colder version of this plugs be?..that would work in place of the recommended?

DCPR6E....?
DCPR8E....?

Just concerned with the fitment aspect and such.

Thanks!

[Murph]

I will add...
I thought I added too much oil this year...came out on floor...just a tad...
Removed some oil...still a drip or two from tube.
Possible the rear is being fowled by this?....breather on rear seemed a bit oily when removed.

Just a thought....I did mention the oil thing way back.

Thanks

[brucstoudt]

Originally Posted by Murph

My question...If the plug recommended is lets say...NKG DCPR7E

What would the hotter and colder version of this plugs be?..that would work in place of the recommended?

DCPR6E....?
DCPR8E....?

Just concerned with the fitment aspect and such.

Thanks!

7 is the oem heat range.6 is hotter 8 is colder.i switched to the 8's trying to help with a lean pop on the cv40.this information was included in the link provided by IXL2.i learned by asking a former 2 stroke racer about the NGK heat range.