Here is the TM parts page.
There is a newer reed petal set, that makes better power with both bottom backups pointing inward
and the single top one pointing away from the petal.
Here is the TM parts page.
There is a newer reed petal set, that makes better power with both bottom backups pointing inward
and the single top one pointing away from the petal.
Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.
theres no rule of thumb for the stiffeners ? I see some are smaller rectangles on top of the main rectangle petals. some were triangle shape. what about the thickness and material in relation to the main petals. has to be some kind of approximation to get started in the right direction![]()
First, what is magmalyte?
I see that the cage itself has a rounded nose. What would be the cage angle and why is the nose rounded and not more v-shaped? Does this have something to do with the shaping on the inside?
Wobbly:
With turning of the backups on the bottom and turning around the backup on top be in line with trying to get the intake charge to favor the top set of reeds. Does this not also change the stiffness of the top set of reeds? Couldn't you just change to a thinner material on the top? Do you have a pic of the reed and cage assembled? Thanks.
My old 50 the NSR one,
It's onto it's 3rd owner now and at the weekend it seized, I was asked to have a quick look as he wanted to get back out on it. I took the top off and there was a ring of melted ally around the outside of the piston and the combustion area of the head had been hammered into the squish area.
I should have taken photo's
when I was checking over the head I found the plug was hand tight, could this have been a case of very lean mixture or has anyone got another idea?
I will ask him to take a couple of photo's if anyone is interested
Yes the whole idea of differing reeds and backups to to bias the flow into the upper ports.
The KZ10 reed block isnt rounded - thats just an artists impression, the angle is 58* and its a normal exit shape.
There are various aero blade inserts made for these, and the biggest/longest horizontal foil section insert works best.
As I said previously you cant simply keep on making the top petal thinner, as you quickly end up with the reeds natural frequency
making it loose control at high rpm and it " flutters " uncontrollably.
I saw this on the flow bench with a set of stock CR125 petals, they have no backups and as soon as the lift/length ratio approaches 1/3
the petals bounce around in a rhythmic pattern - the best petals on the dyno,with backups, went to full lift and sat there.
Notice that the backups only contact the outer sides of the main petals, this seems to be designed to prevent fretting on the outer corners
but obviously they affect the stiffness of the main petals as well.
Maybe it also reduces the turbulent exit flow spilling over the sides of the ports, and forces more flow down the middle.
Re the CHT numbers - yes the range is for water cooled at the bottom end and air cooled up over 200.
Yamaha KT100 engines had a change from sand cast to die cast at some stage, and the different material/ casting technique ( exact same head shape ) caused a drop in CHT
from 230C to 170C.
Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.
Okay, so I can report back that I can now repeatably destroy NGK R7376-10 plugs by running just a tad too lean when pushing to the limits on the dyno in a high bmep application, due to causing "funny" combustion pehenomena. The toolings used to tighten the plug had no influence on the result, unfortunately.
Enough motivation to stop procrastinating on the installation of a deto sensor. With a diameter of about 20mm at the mating side I am asking myself where to put it ideally (and where not to put it). As I run a paper gasket, I suppose somewhere on the water cooled cylinder would be nice, but there is not enough space available, except "on a stick" on one of the bolting areas for the head cover. Where du you guys put yours?
Oh yes it does but here is a lesson I learned the other day.
I have a very heavy dyno drum. 700 KG
In running in a motor, I reved the bike up 10K and then closed the throttle. As it slowly coasted down to an idle, the exhaust pipe began to glow red hot. I opened the throttle and the pipes went from red to black again. I repeated the process to confirm and it replicated the result.
I understand that a lean mixture burns slower and the gasses can still be burning when the exhaust valve opens, hence the exhaust pipes get really hot. So in this case, more air and fuel actually cooled the exhaust.
Cheers Wallace
That's not nice to hear, but good to know. There seem to be two kinds of NGK R7376-10 plugs on the market: one is expensive and reliable; the other is neither.
How much was your version?
And of course you made me curious about your combustion phenomena. Care to elaborate?
As you say: on a stick, like on the RSA-picture below. But with limitations: the sensor should be pulled directly onto the head; no nut in between.Enough motivation to stop procrastinating on the installation of a deto sensor. With a diameter of about 20mm at the mating side I am asking myself where to put it ideally (and where not to put it). As I run a paper gasket, I suppose somewhere on the water cooled cylinder would be nice, but there is not enough space available, except "on a stick" on one of the bolting areas for the head cover. Where du you guys put yours?
I see what you mean Wallace. In an engine running at 10.000 rpm with a closed throttle there should be no combustion at all. In your case the mixture, although very lean, must still have been rich enough to be igniteable. That's not good. And apparently combustion is so slow that the mixture is still burning when the exhaust opens. That's bad. If it makes the exhaust pipe glow red hod, think what it will do to the exhaust valve. Wait a minute: exhaust valve? Carry on; you'll be fine.
Some time ago someone (you?) posted the part number of the expensive kind - and I can confirm that I have recently destroyed the 4th piece of the expensive kind.
(This then led me into conducting a plug test in which the standard NGK BR10ES gapped @ 0,45mm surprisingly matched the 7376. No surprises from Brisk, Bosch and other fancy NGK stuff, but mostly a tad lower or not comparable due to different combustion chamber volume and / or electrode position)
I would love to approach this combustion phenomena with fully indicated engine and a couple of combustion chambers, as I am sure one could learn a lot from it in a short period of time. But for this hobby application I have to do it the oldschool way, I suppose. I will check if I can find a recording of the engine sound. As the engine approaches maximum power or shortly thereafter, there may be a kind of "poof" if it is slightly too lean, and if its a bit leaner there is no "poof" and the engine just dies as if the kill switch would have been activated. If I do not lean the engine off with the e-PJ, nothing happens (except for that lost horse and a bit of powerband). As this is caused by a too lean condition, I suspect it to be pre-ignition and wrongly timed, as it also kills all the resonance in the engine. Fortunately, besides from dead spark plugs, the rest of the engine seems to be fine.
Unfortunately my head cover and the combustion chamber do not share a bolt position as in the RSA. So I could only get the signal from the cylinder, not directly from the head insert. Do you expect this to cause issues or significantly weaken or change the signal?
hi wobbly, i sent you a PM.
WATCHA GONNA DO WHEN THE ULTIMATE WARRIOR AND HULK HOGAN DESTROY YOU!!!!
I can't say without knowing exactly how you are going to mount the sensor. I guess you will just have to find a place in direct solid contact with the combustion chamber, and even then it will be a matter of trial and error.
All parts of an engine vibrate with some frequency, with some amplitude and in one plane or another, and these vibrations may attenuate the detonation-induced vibration to some extent. Conversely, parts resonating in their own root frequency may fool the sensor into reporting detonation when really there isn't any.
I use the Bosch sensor bolted directly to the head frame stay of a CR125 ( so its at right angles to the cylinder axis ) and it works perfectly.
On the TM KZ10 engines I have one longer head cover stud, with a small tophat spacer under the sensor, this also works perfectly.
The frequency/amplitude of a real deto event is very specific, and the little sensor light box I use I can wind up the sensitivity such that all the lower level led's flicker
when running the engine under normal load - and then only the big red warning light comes on when deto is present.
It also has a 0-5V output, showing the level of det on the data logger.
Re the R7376, apart from the Hp gain I found over all the other plugs I tested, the biggest issue it solved was two fold.
When a race engine started to detonate, the Iridium type plugs would crack the porcelain at the tip and fail quickly afterward by dropping pieces onto the piston.
The other plugs with big section earth electrodes have also killed several engines when this piece has dropped off.
The R7376 is expensive due to the tip porcelain construction, and the thin rare earth laser welded ground strap.
I have run hundreds of hours on these plugs and never had a failure ( inside the engine ).
Surely i would imagine a tuning issue that cracks the upper porcelain on a R7376 would do exactly the same to any plug ( or worse, inside a cylinder as I
discovered ).
Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.
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