Flash 5 Rises Like a Phoenix from the Ashes of F3

[bakaracer]

If you ever hear an engine ping its already happened and damage is already done or ongoing, unless you have ultrasonic ears. No matter how rich you run an engine with that high of compression it will end in detonation. You need a bigger bang to make up for pressure. If its dieseling its pre ignition.
Not sure what pre detonation is but heres a link to what detonation vs pre "ignition" is.
http://www.streetrodstuff.com/Articles/ ... etonation/

You can hear it if you know what to hear for and what it sounds like. It doesn't always do damage when you hear it.

[sum-azn-kid]

Hey wheelman there are manifolds that go straight back so you can run airboxs. the krs/ stage 6 ones go straight back. Hows that MHR crank running? feel any difference?

[LMH]

Every time you hear a "ping" it has been happening LONG before you hear it,when you hear it it is in a severe state, especially with a 49-130cc engine not using hypereuratic pistons, like I said if you have ultrasonic ears you could hear it from the beginning. Every time it does go under detonation you are changing the metallurgical make up of the cylinder, piston and ring, even if just a little, it is the same concept as forging. It can and will ruin all 3. Not trying to argue with the master engine builders on here but physics is absolute, non negotiable.

[Wheelman-111]

Greetings:


Very helpful and responsible Red Eft correctly pointed out that the literature that comes with the kit - I do read, sometimes - specifies 95 octane or better. Even this "Sport" (not "Racing") kit wants the fuel available to most of Malossi's expected (EURO) users. The brochure also says "N.B. Malossi heads supplied with O-rings must be assembled directly onto the cylinder without the insertion of any other gaskets or sealing grease." Like that, in BOLD.

Now I'm not saying adding a head gasket doesn't solve the compression problem, although in doing so it would be expected to lose the performance advantage that the higher compression confers. I also don't deny that a head gasket under the ring won't seal, but that is my concern. Instead of a dead-flat head meeting a dead-flat cylinder top, we have to consider this O-Ring gap and the effect it has when you try to compress the ridge on a thin Aluminum conventional head gasket. I fear it won't squash properly, or that the groove in the head will vent sooner or later. For these reasons, I'm going with Malossi's instructions and simply putting in the fuel the engineers intended.

We can all agree that Ping, Pre-Ignition, and Detonation are bad. We can also all agree that it won't be posible to hear when it is most likely to occur - riding down a hill at part-throttle with the wind roaring in our ears. For that reason, I plan to continue using a generous mixture of AvGas and Pump Premium. A monthly trip to Deepinnaharta Airstrip and an extra can to mix the twain in the Casa Laboratory isn't all that much more hassle than measuring Motul synthetic.

"These products are reserved solely for races iin locations reserved for those purposes...we decline any and all responsibility for improper use". And so far, I haven't exceeded Malossi's half-throttle and 6K RPM limit for the first 40-60 minutes very much. I won't be able to comment on performance for a while, but my impressions within these limits is that this kit - Piston and Crank paired - has a TON of torque for stop-and-go street riding compared to ANY kit I've had to date - including the 90cc Ministroker.

[bakaracer]

Every time you hear a "ping" it has been happening LONG before you hear it,when you hear it it is in a severe state, especially with a 49-130cc engine not using hypereuratic pistons, like I said if you have ultrasonic ears you could hear it from the beginning. Every time it does go under detonation you are changing the metallurgical make up of the cylinder, piston and ring, even if just a little, it is the same concept as forging. It can and will ruin all 3. Not trying to argue with the master engine builders on here but physics is absolute, non negotiable.

Yeah you are if not you wouldnt be writing this. Pretty much all pistons have silicon in the aluminum. Some more than others.(hypereuratic piston) now days. In automobiles yes its hard to hear ping or knock . Not on these motors. No sound damping to block sound. now if predetonation happens, then of course its to late. Ping and engine knock is different from predetonation.Again if you know what to hear for and know what it sounds like on these engines, you can hear it. Its obvious you don't, that's why your writing this.

[Downsouthdio]

Keep a close eye on your temps

[kingkamehameha]

The lip on the hg gets removed so the squish band works fine wheeldude

[bakaracer]

Every time you hear a "ping" it has been happening LONG before you hear it,when you hear it it is in a severe state, especially with a 49-130cc engine not using hypereuratic pistons, like I said if you have ultrasonic ears you could hear it from the beginning. Every time it does go under detonation you are changing the metallurgical make up of the cylinder, piston and ring, even if just a little, it is the same concept as forging. It can and will ruin all 3. Not trying to argue with the master engine builders on here but physics is absolute, non negotiable.

Instead of pming me and trying to argue s point. First learn the difference between detonation, ping and knock first. Its not rocket science that if a engine pings or knocks to up the octane fuel or rebuild to rid of carbon. As for me coming at you sidewards, you posting this after my comment is not you coming at me first? And if I was ok with building engines that ping, knock or detonate, i wouldnt win races and keep up with supermoto bikes that have twice to 3 times the motor size. That right there is proof that at least i know what I'm doing is right

[fastplastic]

Sorry dude but baka is a boss rephrase statements or get off the subject

[Canadianscoot]

Wheelman,

I too had the same concerns about high compression. Our fuel grades are 87 reg 89 mid and 91 prem. I believe my Malossi kit was rated at 12.8:1......far too high for regular. I ended up cutting my own base gasket that is about 3 times the thickness as the green one included in the kit. I know port timing is changed, but mine runs smooth right through the powerband at 3/4 throttle. Fires up in one kick. My old crusty compression gauge isn't accurate, so I can't give you concrete numbers, but so far so good.

I believe the gasket material is a Fel-pro roll, but not positive. I found it on the shelf at work...lol

[LMH]

I'm just going to stand by the side lines, never did I say you didn't know how to build an engine. Enough drama already, Gnite n I'm glad wheels is doing what malossi recommends and will enjoy the cylinder for a long time.

[Downsouthdio]

Fast, jump off his nuts already lol

[Wheelman-111]

Greetings:

Burbled through the Malossi-recommended hour of *-footing under half throttle. It's impossible to keep it under 6K RPM with my trans setup on the trip to the P.O.without becoming a Camry hood ornament on Deepinnaharta Drive. I was good, keeping it at around 7K and 35-40 MPH. ROUGHLY half and half premium and AVGas.

Temps stayed around 275. Plug looks like this:

F5Plug1HourB9HIX.jpg (137.44 KiB) Viewed 5124 times

This was running that 50 Pilot, somewhat surprisingly. (the Corsa ran a 45-48 in a bigger carb.). Should I be worried? I can tell already the 125 Main is too big.

F5MArnRunning.jpg (141.38 KiB) Viewed 5124 times

Fellow Canadian: 175/14.7 = 11.9:1 as I measured too. I like the thicker base gasket if I come to find Airport trips too irksome. Perhaps Baka will attest that raising the bore a hair increases powerband RPM a few hundred.

[kingkamehameha]

Increasing the cylinder height will narrow your power band and make the bore max out at a lower revv. Is that a chopped plug? The pilot doesnt have to be as spot on as the main because you have the af screw to tune the pilot perfect. The only way that 50 is too big is if you have to turn the af way out past 2 and a half before the rpms peak at iddle. So bow that you have the hg figured out go to honda and buy 3 just incase you mess up on one while dremeling. It basically becomes a spacer like you are looking for. Idk about where you live but 2 stroke race gas cost 14 bucks a gallon here

[bakaracer]

What does the base of that porcelain look like on that plug? The top area is not where the plug read for 2 stroked is at. Sas for raising the cylinder. If your adding a .3mm base gasket, yeah it will raise your rpm power band another 300-500 more. But your also narrowing up the power band and making the matched intake and exhaust port timing unmatched timing wise. That's why its best to lower the compression by using head gaskets or making the combustion chamber larger so those numbers don't change