More "popping" thoughts

[Win_surfur]

If the popping is caused by fuel not being totally burnt in the chamber, would a hotter spark or more spark minimize or eliminate the popping? Or leaning it out so that not so much fuel goes into the chamber to begin with?

Just thinkin....see the smoke?

[Jeffsmountainauto]

Incomplete combustion can be caused by a rich or lean condition, as well as base settings and engine mechanical problems. These bikes stock, at least the fi versions, are lean from the factory. Leaning it out more would not benefit the engine.

[RACNRAY]

You are on the right track.

Popping on decel is due to an inadequate amount of fuel (lean air/fuel ratio) in the c/c to support full combustion in the c/c, so that unburned fuel will combust in the exhaust causing the popping we hear. BUT it is richening the a/f mixture that aids in reducing/minimizing the popping rather than leaning it out.

Increasing spark energy is a direction I went a few weeks ago. I ordered a set of DynaTek mini ignition coils for my Vaq. I have investigated, researched, tried and dynoed many different ways to improve spark output thru the years, and increasing spark energy has shown to improve performance many times.

Unfortunately I have not installed the coils as before I put my skoot up on the dyno to perform a back to back comparison of the stock coils to the Dyna coils, I perfomed a simple spark strength test. I have an adjustable spark tester I have used for years, it has worked very well and proven to be purty darn reliable.

The stock coil produced a strong spark up to 32,000 v. Opening up the gap 1 turn more is where the stock coil misfired.

The Dyna coil had a strong spark ONLY up to 28,000 v and commenced misfiring when the gap was opened one more turn. This was NOT a good sign!!

Years ago Nology came out with what they said were hi volt coils. There were really nice as they were very small and compact so it made installation much easier and simpler than the larger Dyna coils. Up to this point in my carreer there was ALWAYS a performance benefit with hi-volt coils so I had no reason to pre-test the spark output. But the comparison was made on my dyno.

Those coils caused a loss of about 2 H.P.!! I was shocked as I had not seen this before. So I believe that may have been when I bought that spark tester, not sure, but the Nology and stock coils were tested and compared. Lo and behold the Nology coils produced a weaker spark, which explained the power loss. The stock coils were re-installed and the power came back.

With this experience I felt the dyno results of my skoot with the Dyna coils would be the same, and certainly not worth the time, fabrication and testing based on what I am already seeing.

I do have expreince with Dyna's CDI system on 4 cylinder skoots. This sytem used with stock coils REALLY wakes up engine, but it is not available for a 2 cylinder engine. Maybe I'll give them a call on the CDI system availability.

There will NOT be a better plug for the 1700's. It has an EXTREMELY projected tip design which puts that plug gap DEEP into the c/c. With the small center electrode and a tapered ground electrode there is ALOT of a/f molecules exposed to that spark when it jumps the gap. I no doubt feel this plug was designed specifically for the 1700's to counter Kawi's (what I feel is a ) bad decision to use a single plug in such a big bore engine. 2 plugs would no doubt produce more and better power, mpg, lower emmisions.

I think now that the recommended plug gap for the 1700's is a very large and much larger than 99% of the skoots out there .039"-.043" gap, which would indicate a that a coil with stronger than what is the norm output is behind that big gap.

At some time I will get my Vaq back up on my dyno and play with plug gaps. I want to see what the stock coils will handle and if there will be any benefit of going to a larger gap. I kinda think so.

RACNRAY

[Win_surfur]

ok, so I was goin the other way. If it needs richening, that means MORE fuel in the c/c, right? or is it more air in the c/c? Or both....lol
hmm...veddy intedesting...if only we could find a head with twin plug ports that would fit the 1700 jugs. That would be an e-ticket ride! Or a supercharger to force air down her throat. Even more of an e-ticket ride. Wish I had my own shop!

[Old Bear]

More fuel, as in lower ratio. For instance, you may have a 14:1 ratio, you would lower the first number (say to 13:1) to decrease the amount of air (13 parts) to fuel (1 part).

[KURT44]

My popping stopped after we advanced the timing.

[Win_surfur]

Did advancing the timing cause your bike to run hotter? It can do that in a car.

[KURT44]

No it did not. This was done with the Power Commander with ignition. Ran it all summer this way. It was advanced a small amount up to 2700 rpm`s. That`s all I can tell you. My Kawi mechanic did this. We both had checked for intake leaks and did not have any. This made it a whole new bike, kinda hard on rear tires now. The acceleration is very good! He made every adjustment possible with the FI and all that did was change where it would pop on decal but could not eliminate it. This did.

[Win_surfur]

hmm..the plot thickens. I have the Cobra Power Pro. Wonder if that coud be used to advance timiing.

[KURT44]

The way it accelerates now, I would even race a new 1400 Concourse!





They would win though

[ctc6698]

Does the Kaw 1700 have pair valves? I'm completely new to the Kawi line but on the Honda 1300 lineup, we would remove the pair valves and put block off plates over them. This usually helped most guys out alot on the popping during decel.
Just a thought.

[RACNRAY]

Originally Posted by Win_surfur

hmm..the plot thickens. I have the Cobra Power Pro. Wonder if that coud be used to advance timiing.

That Cobra unit does not allow ANY access to altering ignition timing at all.

Originally Posted by ctc6698

Does the Kaw 1700 have pair valves? I'm completely new to the Kawi line but on the Honda 1300 lineup, we would remove the pair valves and put block off plates over them. This usually helped most guys out alot on the popping during decel.
Just a thought.

Kawi came out with what is now commonly called the "pair" system in 1979 and had the patent on it. It was not till the patent ran out that other manufacturors started using the system. Kawi calls it the Kleen air system, Suzuki penned it the "pair" system and that seems to be the more common term used.

The 1700's do in fact have the "pair" system and to cancel it out involves nothing more than blocking off the system's intake hose which blocks the supply of air to the engie's exhaust ports.

RACNRAY

[Win_surfur]

Ray - Have you ever tried that?

[RACNRAY]

Originally Posted by Win_surfur

Ray - Have you ever tried that?

UH...tried what??

[ctc6698]

Originally Posted by RACNRAY

UH...tried what??

think he's referring to blocking off the intake hose you mentioned on the pair system