pipe woes

[canyncarvr]

Mr./Mrs/Ms. Ima...

You are correct. I am completely in error. Mr. Gorr is wrong. Rhodester is an idiot. So is Gordon Jennings I'm sure.

We are all wrong. You are right.

I apologize for wasting your time.

Hope that makes everything better for you. ;)

 

[skipro3]

I was wondering when you would realize the mistake you were making CC.

Perhaps engine rotation direction has Imathorp confused when "advancing" or "retarding" timing since he can be quoted saying, "I'm starting to think I'm nuts and bike is running bass-ackwards "
The KDX does run counter clockwise, right? That may explain the confusion.
Imathorp points out, "if you play with the timing you will feel the power band move up (effect of advancing) and down (effect of retarding) with the timing." If someone mistakenly assumed the wrong direction of the flywheel rotation, then that might explain a few things.
Just trying to sort this out.

**EDIT**
In re-reading this thread, I see Imathorp stated,"turn the stator plate counter-clockwise to retard and clockwise to advance." So there you go, he does know the direction of engine rotation. Sorry to have butted in.

 

[canyncarvr]

Yep. I just went looking for that to find that you got to it first.

That leaves only one option. We are all wrong, he is right.

God bless America!

Rhodester: re '100%'
Of course I am....I referenced your post. ;) BTW, you do realize it's an honor to be in the company of Gordon Jennings, right?

 

[Rhodester]

CC, I'm truly honored! Since you referenced my post I KNOW you're a genius! :-)
I hate to show my ignorance, but I'm not quite sure who Gordon Jennings is (boy, that was tough to admit....being perfect and all :-) ). Please enlighten me.

 

[skipro3]

http://www.strappe.com/plugs.html
Good read, especially his input on spark advance

 

[canyncarvr]

I know he's been around for a long time. I've read a number of his writings and continually come across virtually the same words in others' writings. He's not just a motorcycle guy..he's found around all sorts of things hot-rod. You'll see references to him in 2-stroke papers, V-8 stuff...he's all around.

I think the attached is of the correct Gordon, fwiw. I've never met him...and I thought he was older.

His 'Two Stroke Tuner's Handbook' is famous. He wrote that in '73. From a review of that book:

This book really puts some method in to your tuning madness, just wonderful. Get it if you can!

I see $5.95 for the book in some places and Amazon has it for only $239! Well..that IS supposed to be a 'collectible'..whatever that is. I don't know if it's even in print any more.

He also apparently wrote, 'Repairing Your Home Video Game.'

Yanno...maybe he's Jaguar in disguise? ;)

Heck..for all I know, they (Jag and Jennings) could be twins!!

 

[Rhodester]

CC, thanks for the heads up on Gordon Jennings. I was running through my mind....let's see...Flash Gordon; super hero.....Gordon Cooper; astronaut.....G. Gordon Liddy; Watergate and talk radio....Gordon Jennings; ?????. Looks like I have some reading to do.

 

[john_bilbrey]

The desert gnarly is the way to go on the 220...

 

[Imathorp]

Well, after reading the awsome thread about ignition timing I am dumb founded. Seriously!

I really wish someone would step in here and not flame on me and explain this to us. I really get tired of the meatless bantering humor me and point (explain) out my mistakes.

all of my previous rant is based off my experience with timing changes on my bike. I know the difference between advance and retard and know the direction of travel of these engines. I have seen several others (in the timing thread) suggest that advancing timing helps bottom end. How, please explain! do they mean flat ground and it just tears it up or can it still tractor up hills that way too?

I have played with advancing the timing and ran the same test hill and the bottom end goes away. the bike comes off the pipe faster and i have to fan the clutch to keep the RPM's way high to get up. if i advance too much the bike cant make the hill without dying.

retard the timing (CCW rotation of the stator plate) and the bottom end power comes back and I can pull the hill without reving it soo high an no need to fan the clutch.

the only thing i have noticed with advancing the timing is the bike does scream on flat ground, the hit is harder, it'll stand on end and pick the tire back up at each shift and the revs go higher. if i take this rude-ass setup into the woods it cant make the hills it did before.

OK, its a big mystery to me now. what am i missing?

 

[canyncarvr]

I apologize.

I am sorry to have wasted your time and mine.

 

[Imathorp]

dang it CC, quit running off and help me out here. I mean it!

I need some insight to this!

this is so GD frustrating, PLEASE, explain this to me.

 

[canyncarvr]

I have tried to do just that. I have linked to a number of threads/sites with information from tuners that have forgotten more about tuning than I will ever know.

It isn't necessary for me to garner such information on my own when others much more knowledgeable than I have already done it.

Again (I haven't gone back to re-read, but from what I recall was said), part of what you said was correct, but some parts were not. Advancing the timing will improve bottom end response and smooth out the 'hit' at the expense of top end performance. Retarding the timing will detract from the bottom end response, increase the 'hit' and improve top end performance.

Mr. Gorr has said that retarding is often a good thing while advancing is likely not...and will often only get you into trouble. I understand the whys and wherefores of his explanation as to how the changes work..to repeat what he says and offer it as some sort of insight on my part is stupid.


I have done both(advance/retard) on my kdx. I have advanced the timing for single track use and retarded it for sand use. In both cases I found the result to be exactly as described above; exactly as stated by Mr. Gorr.


I don't recall calling anyone in to join on a dis of you (your edit of the above post makes this nonsensical at this point). Others that disagreed with you did so simply for correction and advisement....not for making fun or ribbing. THAT came later after the name calling and puffery.

After posting correcting information with expert backup and being called an a$$ for it, you expect..........what exactly?

That's a rhetorical question. No answer required.

 

[Imathorp]

Sorry, I called you what i did because you came out swinging and offered nothing more than "UH OK" type answers instead of filling in the blanks and exchanging with me. lets put everything else behind us

"Advancing the timing will improve bottom end response and smooth out the 'hit' at the expense of top end performance. Retarding the timing will detract from the bottom end response, increase the 'hit' and improve top end performance"

this is exaclty what I'm arguing though. I have found the total opposite on my bike in regards to tight woods bottom end and hill climbing grunt. I'll start my homework and see if i can answer as to why, but if you know....please tell!

Advance=move stator plate CW correct?

 

[Imathorp]

allright, I found some very good info from Eric Gorr's site on the subject. I'll paste the meat of it and then we can discuss. I hope he doesn't mind me doing this.

AFFECTS OF THE IGNITION TIMING

Here is how changes in the static ignition timing affects the power band of a Japanese dirt bike. Advancing the timing will make the power band hit harder in the mid range but fall flat on top end. Advancing the timing gives the flame front in the combustion chamber, adequate time to travel across the chamber to form a great pressure rise. The rapid pressure rise contributes to a power band's "Hit". In some cases the pressure rise can be so great that it causes an audible pinging noise from the engine. As the engine rpm increases, the pressure in the cylinder becomes so great that pumping losses occur to the piston. That is why engines with too much spark advance or too high of a compression ratio, run flat at high rpm.

Retarding the timing will make the power band smoother in the mid-range and give more top end over rev. When the spark fires closer to TDC, the pressure rise in the cylinder isn't as great. The emphasis is on gaining more degrees of retard at high rpm. This causes a shift of the heat from the cylinder to the pipe. This can prevent the piston from melting at high rpm, but the biggest benefit is how the heat affects the tuning in the pipe. When the temperature rises, the velocity of the waves in the pipe increases. At high rpm this can cause a closer synchronization between the returning compression wave and the piston speed. This effectively extends the rpm peak of the pipe.



HOW TO ADJUST THE TIMING

Rotating the stator plate relative to the crankcases changes the timing. Most manufacturers stamp the stator plate with three marks, near the plate's mounting holes. The center mark is the standard timing. If you loosen the plate mounting bolts and rotate the stator plate clockwise to the flywheel's rotation, that will advance the ignition timing. If you rotate the stator plate counterclockwise to the flywheel's rotation, that will retard the ignition timing. Never rotate the stator plate more than .028in/.7mm past the original standard timing mark. Kawasaki and Yamaha stator plates are marked. Honda stators have a sheet metal plate riveted to one of the mount holes. This plate insures that the stator can only be installed in one position. If you want to adjust the ignition timing on a Honda CR, you'll have to file the sheet metal plate, with a 1/4in rat-tail file.


He states, advancing makes the hit harder, this is opposite of Rodester's and CC's comments and correct with my findings. Agreed?

He then stated advanced smoothes out the top end peak, I agree, I havent concentrated on that but this is opposite of what i would have figured. Agreed?

He states retarding makes it "smoother in midrange" exactly what i found and was arguing. Agreed?

He then states retarded allows the peak RPM to rise. Well my findings were that with the retarded timing, the hit was smoother and my bike would carry the rpms higher. I attributed the extended RPM range to my "rev" pipe. I stand corrected on that point but had argued the smoother hit all along. Agreed?

Now, Bottom end we still didnt cover that. I say the retarded timing helps from what i have tried (test hill). I go find the answer to this..... be right back. LOL

 

[Rhodester]

I haven't gone back and read this whole thread again, but I don't recall mentioning the "hit" differences related to timing changes in my comments.

If memory serves me right it's interesting to note the timing curve that Jaguar discussed in his very detailed and informative thread. The timing advances to the point where the KIPS opens (about 6000 RPMs) and then retards as RPMs climb to accentuate the top end power and run out. It seems that the Kawasaki engineers agree that retarding the timing helps the top end.

 

[canyncarvr]

This has become much more complicated than it needs to have been. Yes, a good bit of that is an error on my part concerning 'hits'.

You said:

..retarded my timing way back to keep the torque i was used to having with my "woods" pipe. I now have a bit more of a peaky hard hitter

EG says:

Retarding the timing will make the power band smoother in the mid-range ..

Those are not the same thing. But then, your statement was maybe more about pipes than timing. But 'retard' and 'peaky hard hitter' don't go together.

You said:

..to advance timing .....allowing it to rev higher.

EG says:

Advancing the timing will ..... fall flat on top end

Those are not the same thing either.

As stated earlier...some of what you said is correct, some is not. It doesn't help that in sorting out the 'is' and 'is not's I put in my own error.

I referenced Mr. Gorr's write-ups because he is a master tuner and likely ('ya think? ;) ) knows what effects timing changes have on 2-stroke engines. For one, I would tend to take him at his word. For two, I've found what he says to be exactly so.

I referred to Rhodester's comments because he is also correct.

So, concerning any differences between what Mr. Gorr said and what I said are errors on my part. Errors in reference and structure (grammar) on my part, not coming from taking exception to what he said.

They are also errors on your part coming exactly from taking exception to what Mr. Gorr said (and my experience matches)....and that was my point from the gitgo. You will find that in post #18 on this thread.