Timing and powerbamd

650ed wrote:

kzz1p wrote:

Advancing the timing gives you more bottom end/mid range.
Retarding the timing gives you more mid range/top end, increasing your MPH.

In that case, couldn't the spring rates on the advancer be modified so the timing advance takes place at a slower rate? If this could be done, the advance could be set a little higher at low RPM (giving best bottom end/mid range) and would still not advance so far or as fast as the RPMs increased (giving more mid range/top end).

Yes it can be!...The trick is finding the right springs, it will take some time & testing.

Once again I will say every motor is different. The real work of engine building or tuning, is the trial & error stuff.

Here's a page out of the old Denco catalog....Take it for what, it's worth.

That's it in a nut shell!
Looks like the range in my head was about the recommended in your article, go figure. :laugh:

Oh and if you look at the stock KZ advancer, you will see that both weights come out and hit a tap/ stop. This is the Total Movement of the assy. If one so Desired to change the amount of movement/ Advance, one could adjust these stops/ tabs to take away say 4 degrees, quite easily. Oh I just gave away my little adjustment, oh well.

trianglelaguna wrote:

i wanna "powerbamd"...if they are that goomd...whamt ism itm anmd whemre canm im ormder omne

:laugh: OHHH holy #$%@ I just pissed! :woohoo: :laugh: :blush:

Otakar,

Thanks, I found the info on your sprockets and chain in your build diary, some good reading.

One more question.

I looked in your build thread but couldn't find anywhere that talked about the size of the rear tire. The picture of the gearing chart has the info on the rear tire but it's a bit hard to read. I think it says your running a 130-90-16 rear tire?????

Thanks,

Buzz

otakar wrote:

:ohmy: ????????? That's the first time I have ever heard that? I was always taught that low rpm requires low advance and hi RPM requires large advance. Than, I wonder why the timing advancer on the engine is not made to work the other way around from the way it is? I've learned something new here after 34 years of working on these bikes. Thanks for that info.

:laugh: You can always learn something new... :laugh:

If you get a chance to get some time on a dyno, you'll see that (after full advance is achieved), changing the timing just moves the torque curve forward and back. Advancing the timing lets the engine generate torque sooner, but it teeters off well before redline for average guy street ridin. Careful retarding of the full advance timing can place the absolute peak torque production curve (for best shifting/racing), right at, or just past redline, thus making it better for maintaining high speeds/revs on a track, dragging, or just plain power nuts - as this increases max HP due to the basic formula for correct HP = RPM x TORQUE / 5250

As a trick - you can just bend in the tabs on your advancer to retard full advance slightly for higher output/power at higher rpms, and keep stock inital advance where it is, or advance it slightly, and bend the tabs in further, for a potent combo of both worlds. Using new stock springs actually works best.


Do it, just DO IT!

:laugh:

KruZer wrote:

Otakar,

Thanks, I found the info on your sprockets and chain in your build diary, some good reading.

One more question.

I looked in your build thread but couldn't find anywhere that talked about the size of the rear tire. The picture of the gearing chart has the info on the rear tire but it's a bit hard to read. I think it says your running a 130-90-16 rear tire?????

Thanks,

Buzz

That is correct, that is the right size tire.

Otakar,

Thanks for the reply....

Nice bike. Lot's of hard work and and an eye for what make a nice looking ride......

Congratulations!!!

Buzz

looks like somebody broke their power band! :woohoo:

Is this April?

otakar wrote:

OK- I just found by readout for my bike. GPz1150 .420 cams.
I have a final ratio of 2.22:1 (18/40 sprockets). I can attest that i have to slip the clutch like crazy and rev the engine from a dead stop to role. I believe I have more than normal HP in the bike. In first gear at 9K I am doing 66mph. In second gear at 9k I am doing 96mph. third gear I can do 101mph at 7.4k and 123mph at 9k. These are measured with a GPS. I find that my speedo is only a little off, and my tach is electronic, taken off the coils. I would have to be turning 13.55k to be going 100mph in first and 9.4k in second to be going 100mph. I think that he might be going 100KPH in first turning over 10k. And, since when dose "retarding" your ignition give you more power at top end????

I knew I was seeing 9+ and 90's in second. Thanks for clarifying that I'm running 35 15. And your bike would be a good race for mine ! I would never leave the timing backed off if the engine didn't pull hard up top. Beware my GPZ killer head. You can say high to the fat lady on her way by. But not much will be left of her. What is the intake close number on your bike? 80? 85?. Ignition retard, extended powerband? As the pressure rises in the cyl. theorectical) the flame speed increases. The more retard the more the engine breathes at high rpm. It may be caplable of pumping more air into the cylinders but the rpm is limited by the combustion force against it.. the power gained or lost dependent on the amount of bang in the cylinder, this goes for any rpm. The combustion out runs the piston since the piston is fixed. Pressures develop faster as the gas flashes faster, releasing pressure into the chamber straight down onto the piston top. I have to back the timing down so it runs right at high rpm. I need bigger carbs so I can tell how much the head is TRYING to flow. I need more clinder pressure and some scavenging through exhaust timing, to get more torque up top. The torque needs to be high in the band for me. The stroke will help keep the bike moving into the upper rpm band and walk mph. I need more torque up top. All I really need to do is assemble what I have and tune it. And i know it will rock my socks off. I'm gonna get that engine to suck in alot of air and gas one way or another. It's just a matter of if I end up knowing what I'm doing or not. :woohoo:

Motor Head wrote:

That's it in a nut shell!
Looks like the range in my head was about the recommended in your article, go figure. :laugh:

Oh and if you look at the stock KZ advancer, you will see that both weights come out and hit a tap/ stop. This is the Total Movement of the assy. If one so Desired to change the amount of movement/ Advance, one could adjust these stops/ tabs to take away say 4 degrees, quite easily. Oh I just gave away my little adjustment, oh well.

Motor head
Yes your idea on the spark advance is correct. People have been bending the tabs for years. People have tried many different spring rates.

For myself (only) The spark advance is used for starting the bike and Idling around.....The rest of the time that prick is wide open, so I only worry about total timing. That is why I had suggested indexing your own "timing marks" in the cam degreeing thread.....Once again that's only me.....I am not suggesting it, to no one else.

Look at all the info in this Denco one page article, it's been around for many years. Notice where they use the coldest plugs then jet to them. That may save some heat, in the jetting and timing. Could be good for guys in hot climates.

What about the side gapped plugs or plug indexing. The list of small tricks goes on and on.

Anybody can build these motors but only a few can truely tune them. Maybe it's a Zen thing, being as one with the motor..........I don't know, maybe I'm just full of shit?